CHEMISTRY AN ASIAN JOURNAL Accepted Article Title: Direct Synthesis of Porous Nanorod-Type Graphitic Carbon Nitride/CuO Composite from Cu-Melamine Supramolecular Framework towards Enhanced Photocatalytic Performance
Authors: Junkuo Gao; Jiangpeng Wang; Hui Xu; Xuefeng Qian; Yingying Dong; Guodong Qian; Juming Yao
This manuscript has been accepted after peer review and the authors have elected to post their Accepted Article online prior to editing, proofing, and formal publication of the final Version of Record (VoR). This work is currently citable by using the Digital Object Identifier (DOI) given below. The VoR will be published online in Early View as soon as possible and may be different to this Accepted Article as a result of editing. Readers should obtain the VoR from the journal website shown below when it is published to ensure accuracy of information. The authors are responsible for the content of this Accepted Article.
To be cited as: Chem. Asian J. 10.1002/asia.201500131 Link to VoR: http://dx.doi.org/10.1002/asia.201500131
A sister journal of Angewandte Chemie and Chemistry – A European Journal
Supported by
Federation of Asian Chemical Societies
Chemistry - An Asian Journal
10.1002/asia.201500131
COMMUNICATIONS Direct Synthesis of Porous Nanorod-Type Graphitic Carbon Nitride/CuO Composite from Cu-Melamine Supramolecular Framework towards Enhanced Photocatalytic Performance Jiangpeng Wang,[a,c]‡ Hui Xu,[b]‡ Xuefeng Qian,[a] Yingying Dong, [a,c] Junkuo Gao,*[a] Guodong Qian*[b] and Juming Yao[a]
Abstract: Facile and direct synthesis of porous nanorod-type graphitic Carbon Nitride/CuO composite (CuO-g-C3N4) was reported by using Cu-melamine supramolecular framework as precursor. The CuO-g-C3N4 nanocomposite demonstrated improved visible-lightdriven photocatalytic activities. The results indicate that metalmelamine supramolecular frameworks can be promising precursors for the preparation of efficient g-C3N4 nanocomposite photocatalysts.
Due to its unique two-dimensional graphene-like structure, nontoxicity, excellent chemical stability and low cost, graphitic carbon nitride (g-C3N4) has been receiving great attention in the past years. [1] In fact, g-C3N4 has already been demonstrated to have a broad range of applications such as fluorescent sensor, super capacitor, photocatalysis and so on.[2] In the past two decades, g-C3N4 was extensively studied and successfully applied in photocatalytic water splitting and organic pollutant photo-degradation, mainly because of its unique structure, good stability and photo-response in the visible-light region.[3] The formation of porous structure and well-controlled morphology are crucial to improve the photocatalytic activities.[4] Although extensive research has been carried out for the modifications of g-C3N4 synthesis, those exhibiting porosity and well-controlled morphology are still of few percentage. This is mainly due to the fact that
[a]
[b]
[b]
‡
J. Wang, X. Qian, Y. Dong, Prof. Dr. J. Gao, Prof. Dr. J. Yao The Key laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, National Engineering Lab for Textile Fiber Materials and Processing Technology (Zhejiang), College of Materials and Textiles Zhejiang Sci-Tech University Hangzhou 310018, P. R. China E-mail: [email protected] Dr. H. Xu, Prof. Dr. G. Qian State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering Zhejiang University Hangzhou 310027, P. R. China E-mail: [email protected] J. Wang, Y. Dong Qixin Honors School Zhejiang Sci-Tech University Hangzhou 310018, P. R. China Both authors have equal contribution to this paper. Supporting information for this article is given via a link at the end of the document.
carbon nitrides can be synthesized via simple heating of nitrogen-rich organic compounds such as cyanamide or melamine, wherein the solid-state chemistry-like conditions only lead to the formation of final nonporous condensed bulk materials. One efficient strategy to obtain well-controlled morphology is hard-template approach via the replication of a rigid template material which already possesses controlled porosity and morphology.[3b, 5] However this method consists of complex steps and needs removal of the template matrix. Another strategy is to make use of molecular self-assembly by using different organic supramolecular as ordered textures to obtain preformed micro- or nanostructures, as recently reported by Wang, Shalom and Thomas groups. [4a, 6] The researchers reported the condensation of organic supramolecular complexes such as cyanuric acid-melamine at thermal heating condition resulted in well-ordered carbon nitrides materials with different morphologies such as nanoparticles, hollow spheres and porous nanosheets. As specific morphologies often imply high photoactivity, it is of significance to develop new strategies controlling the morphologies of g-C3N4. Metal-organic supramolecular frameworks, self-assembled from metallic nodes and organic ligands through metal coordination, hydrogen bonding and π-π interactions, have been emerging as a new type of precursors for porous carbons and metal oxide/carbon composites. [7] Due to the highly ordered crystalline structures, metal-organic supramolecular frameworks would be good candidates for use as both sacrificial templates and precursors to give porous g-C3N4 under proper thermal condensation conditions. The diverse metal ions and a variety of organic linkers as well as the reaction conditions such as temperature, solvent and molar ratio, can lead to high tailorable structures, [8] which could subsequently influence the morphologies of formed g-C3N4. In addition, because of coordination modes of the metal nodes in metal-organic supramolecular frameworks, the g-C3N4 composites containing nanostructured metal or metal oxides species are prone to form and further improve the performance. More importantly, in most cases, the templating of metal-organic supramolecular frameworks is simpler and cheaper as compared to hard template approach which involves silica nanostructures, making them ideal precursors for g-C3N4 materials. To the best of our knowledge, reports on the synthesis of metal oxide/ g-C3N4 nanocomposite materials
Chemistry - An Asian Journal
10.1002/asia.201500131
COMMUNICATIONS with nanoporosity and well-controlled morphology by metalorganic supramolecular frameworks are still scarce. Herein, we reported a new synthetic approach for the preparation of porous nanorod-type g-C3N4/metal oxide composites with enhanced photocatalytic properties by using Cu-melamine supramolecular framework as precursor (Scheme 1). The copper-melamine supramolecular framework [Cu(μ-OAc)(μ-OCH3)(MA)] (Cu-MA1) was obtained by the reaction of Cu(OAc) 2 and melamine in methanol solution as a blue solid. Cu-MA1 framework forms a three dimensional porous structure with hexagonal pores linked by the N-H…N self-complementary hydrogen bonds, as reported in the literature (Figure S1).[9] CuO/g-C3N4 nanocomposite (CuO-gC3N4) was obtained by heating Cu-MA1 framework at 550 oC for 4 h under argon atmosphere. XRD pattern of CuO-g-C3N4 was shown in Figure 1. The strong peak located at 27.6o could be assigned to the (002) peak of g-C3N4, which shift slightly to higher diffraction angle compared with pure g-C3N4 (27.3o). The small peaks at 35.4 o, 37.4o and 38.7o matches well with the characteristic peaks of crystalline CuO, indicating the existence of CuO phase in the nano-composite. The XRD pattern clearly demonstrated that both CuO and g-C3N4 are contained in CuO-g-C3N4. To the best of our knowledge, there was no report on the synthesis of g-C3N4/CuO nanocomposites. Elemental analysis (EA) showed that the total amount of C, N and H elements in CuO-g-C3N4 is about 58.85%, while the amount of CuO is about 41.42%, which is quite consistent with the results from TG curves (Figure S5). The N/C molar ratio in CuO-g-C3N4 is 1.48, which is higher than the value of g-C3N4 (1.33). The high N/C value could be resulted from the inhibition of polymeric condensation by CuO species. When Cu-MA1 framework was heated at 800 o C under argon atmosphere, only metal Cu particles were obtained as confirmed by XRD (Figure S6), due to the decomposition of g-C3N4 component and the resulting reduction atmosphere.
Figure 1. The powder XRD patterns for CuO-g-C3N4, g-C3N4 and simulated CuO.
The chemical composition of CuO-g-C3N4 was studied via X-ray photoelectron spectroscopy (XPS), as shown in Figure 2. Sharp photoelectron peaks appeared at binding energies of 932 eV (Cu 2p), 398 eV (N 1s) and 287 eV (C1s), respectively, indicating the existence of Cu, C and N elements in CuO-g-C3N4 sample. The high resolution C1s XPS spectra in g-C3N4 show two sharp peaks at 284.8 eV and 287.8 eV, which could be ascribed to defect-containing sp2-hybridized carbon atoms presented in graphitic domains and a N-C=N coordination, respectively.[10] The high resolution N 1s spectra for CuO-g-C3N4 could be separated into three peaks at 398.3 eV, 398.9 eV and 399.5 eV, respectively. The peak at 398.3 eV could be assigned to the sp2-hybridized nitrogen (C=N-C).[11] The other two peaks are attributed to the tertiary nitrogen N-C3 and amino functional groups carrying hydrogen.[12] The binding energy of Cu 2p1/2 and Cu 2p3/2 in CuO-g-C3N4 are 932.7 eV and 952.4 eV, which are very close to the values in CuO, indicating the +2 state of Cu element.[13]
Figure 2. XPS spectra of the synthesized CuO-g-C3N4. (a) C 1s spectra of CuO-g-C3N4. (b) N 1s spectra of CuO-g-C3N4. (c) Cu 2p spectra of CuO-gC3N4. (d) O 1s spectra of CuO-g-C3N4
Scheme 1. Preparation of porous nanorod-like CuO-g-C3N4 from Cu-melamine 3-D supramolecular framework.
The morphologies of CuO-g-C3N4 and pure g-C3N4 sample synthesized from melamine at the same conditions were
Chemistry - An Asian Journal
10.1002/asia.201500131
COMMUNICATIONS analyzed by SEM and TEM. CuO-g-C3N4 displayed porous nanorod morphology, as shown in Figure 3. The diameters of nanorods are smaller than 300 nm with pores about 20~50 nm along the rods (Figure 3b-c). The length of nanorod could reach to 2 μm as confirmed by TEM (Figure S2). CuO nanoparticles around 50 nm spread on the surface of nanorods (Figure 3d). The high resolution TEM (HRTEM) image of CuO-g-C3N4 revealed lattice fringes with interplanar distance of 0.324 nm in the nanorod part corresponding the (002) plane of g-C3N4 (Figure S3a). The lattice fringes with d-spacing of 0.158 nm in the nanoparticle can be assigned to the (202) crystal plane of CuO (Figure S3b), confirming the crystalline CuO phase of nanoparticles attached on g-C3N4 nanorods and displaying a distinguished and coherent interface between CuO and g-C3N4. The starting Cu-melamine supramolecular framework displayed block-shape crystals, as shown in figure 3a. The pure g-C3N4 displayed a blocky morphology with agglomeration of lamellar structures (Figure S4). The formation of porous nanorod structures of CuO-g-C3N4 from 3-D porous Cu-melamine supramolecular framework may result from the 3-D hydrogen bond directions in CuMA1 precursor which could guide the condensation of melamine molecules. This important role of hydrogen bonds in forming a particular morphology was also confirmed by Shalom et al.[4a] The specific surface areas of CuO-g-C3N4 were studied by nitrogen adsorption isotherm analysis (Figure S7). The specific surface areas of CuO-g-C3N4 and pure g-C3N4 were found to be 15.37 and 5.26 m2 g1 respectively. The surface area of CuO-g-C3N4 was more than 2 times larger than pure g-C3N4 due to the porous nano-structure.
also performed to investigate the electronic properties of CuO-gC3N4. The PL spectra of CuO-g-C3N4 and g-C3N4 under 375 nm excitation were shown in Figure S9. g-C3N4 showed a strong PL emission with a peak at 470 nm, while there was almost no PL emission for CuO-g-C3N4. The obvious PL quenching demonstrated that the recombination of electron-hole pairs in CuO-g-C3N4 nano-composite is decreased, which may result in the improvement of the photocatalytic activity. The visible light photocatalytic activity of CuO-g-C3N4 was evaluated for the photo-degradation of rhodamine B (RhB) under visible light irradiation (λ > 400 nm). As shown in Figure 4, CuOg-C3N4 exhibited much more efficient photocatalytic activity than pure g-C3N4 and commercial CuO. After 20 min visible light irradiation, almost 94% RhB was degraded by CuO-g-C3N4, while only 12% and 5 % RhB was degraded by g-C3N4 and CuO under the same conditions. The excellent photocatalytic activity of CuO-g-C3N4 compared with g-C3N4 may be attributed to the hetero-structures formed between g-C3N4 and CuO, strong absorption in the visible region and larger surface areas. Furthermore, the CuO component was removed from the g-C3N4 nanorod by washing with HNO3 solution, and the photocatalytic activity of the obtained g-C3N4 nanorod (named as g-C3N4-2) was studied. As seen in Figure S10, the photocatalytic activity of g-C3N4-2 was slightly higher than pure g-C3N4 obtained from melamine, which is mainly due to its larger surface areas. Yet, the activity of g-C3N4-2 was obviously reduced when compared with CuO-g-C3N4 nano-composite, indicating that the formation of hetero-structure between CuO and g-C3N4 played the main role for the enhancement of photocatalytic activity. CuO-g-C3N4 also displayed good catalytic stability as confirmed by the threerun photocatalytic tests and XRD pattern after catalysis (Figure S11).
Figure 3. (a) SEM image of CuMA1 precursor. (b) SEM image of CuO-g-C3N4. (c and d) TEM image of CuO-g-C3N4.
The optical properties of CuO-g-C3N4 were studied by UV-VisNIR diffuse reflectance spectra and compared with pure g-C3N4, as shown in Figure S8. CuO-g-C3N4 showed strong absorption in the visible region and expanded the absorption to the nearinfrared region, while no absorption at wavelength larger than 600 nm was observed in g-C3N4. CuO is narrow band gap ptype semiconductor (about 1.68 eV) with a conduction band at near 0.46 eV (vs. NHE) as reported in some literatures. [14] The band gap of g-C3N4 is about 2.7 eV, with a conduction band near -1.12 eV (vs. NHE).[15] Photoluminescence (PL) spectra were
Figure 4. (a) The photo-degradation of Rhodamine B (RhB) in solution for CuO-g-C3N4, commercial CuO and bulk g-C3N4. (b) Recycling test on CuO-gC3N4 for photo-degradation of RhB under visible light irradiation (λ > 400 nm).
Chemistry - An Asian Journal
10.1002/asia.201500131
COMMUNICATIONS To investigate the photodegradation mechanism, The active species generated during the photocatalytic process were identified by free radical and hole scavenging experiments, in which isopropanol (IPA), ethylene diamine tetraacetic acid (EDTA) and benzouinone (BQ) were used as the hydroxyl radical (.OH), hole (h+) and superoxide radical (.O2-) scavengers, respectively.[16] As shown in Figure S12, when BQ was added in the photocatalytic system, the photodegradation of RhB was obviously inhibited. The introduction of EDTA slightly reduced the photocatalytic activity. While the addition of IPA showed almost no influence on the photocatalytic activity. Based on the results, we can conclude that the major active species in the system for photodegradation is the .O2-. According to the active species and band gap structure of CuO and g-C3N4, the possible electron and charge transfer process could be expressed in Figure S13, in which the Z-scheme mechanism was established. The excited electrons from CuO were transferred from the CB of CuO to the VB of g-C3N4 part. So the excited electrons in the gC3N4 can reacted with O2 to form .O2- radicals, making .O2- as the major active species in the photodegradation process. In conclusion, a new and facile synthetic approach was developed for the fabrication of porous nanorod gC3N4/metal oxide composites by using metal-melamine supramolecular frameworks as precursor. The morphology and optical properties of synthesized porous nanorod gC3N4/CuO (CuO-g-C3N4) composite were investigated in detail. CuO-g-C3N4 showed strong optical absorption in the whole visible-light region. Photocatalytic studies showed that CuO-g-C3N4 exhibited highly efficient photocatalytic activity and good stability in the degradation of RhB. The results indicate that metal-melamine supramolecular frameworks can be promising precursors for the preparation of efficient g-C3N4 nanocomposite photocatalysts. We expect that the diverse metal-melamine supramolecular frameworks will result in hybrid g-C3N4 materials with controllable morphology and electronic structures, which will have a broader potential for various heterogeneous catalysis.
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9] [10]
Acknowledgements This work is supported by the National Natural Science Foundation of China (No. 51402261) and Science Foundation of Zhejiang Sci-Tech University (ZSTU) under Grant No. 13012138-Y. J. G. acknowledges the financial support from the public technology research plan of Zhejiang Province, China under Grant No. 2014C33041 and support from the Zhejiang Provincial Top Key Academic Discipline of Textile Science and Engineering. Keywords: Carbon Nitride • Photocatalysis • Composites • Nano-Rod • Supramolecular Frameworks
[11] [12] [13]
[14]
[15] [16]
a) Y. Zheng, J. Liu, J. Liang, M. Jaroniec, S. Z. Qiao, Energy Environ. Sci. 2012, 5, 6717-6731; b) X. C. Wang, S. Blechert, M. Antonietti, Acs Catal. 2012, 2, 1596-1606; c) J. X. Low, S. W. Cao, J. G. Yu, S. Wageh, Chem. Commun. 2014, 50, 10768-10777; d) S. W. Cao, J. G. Yu, J. Phys. Chem. Lett. 2014, 5, 2101-2107. a) X. C. Wang, K. Maeda, A. Thomas, K. Takanabe, G. Xin, J. M. Carlsson, K. Domen, M. Antonietti, Nat. Mater. 2009, 8, 76-80; b) K. Schwinghammer, M. B. Mesch, V. Duppel, C. Ziegler, J. Senker, B. V. Lotsch, J. Am. Chem. Soc. 2014, 136, 1730-1733; c) D. J. Martin, K. P. Qiu, S. A. Shevlin, A. D. Handoko, X. W. Chen, Z. X. Guo, J. W. Tang, Angew. Chem. Int. Ed. 2014, 53, 9240-9245; d) T. Y. Ma, S. Dai, M. Jaroniec, S. Z. Qiao, Angew. Chem. Int. Ed. 2014, 53, 7281-7285; e) Z. K. Zhao, Y. T. Dai, J. H. Lin, G. R. Wang, Chem. Mater. 2014, 26, 3151-3161; f) H. Xu, J. Yan, X. J. She, L. Xu, J. X. Xia, Y. G. Xu, Y. H. Song, L. Y. Huang, H. M. Li, Nanoscale 2014, 6, 9866-9866. a) D. J. Martin, K. Qiu, S. A. Shevlin, A. D. Handoko, X. Chen, Z. Guo, J. Tang, Angew. Chem. Int. Ed. 2014, 53, 9240-9245; b) Z. Y., L. Lin, X. Ye, F. Guo, X. Wang, Angew. Chem. Int. Ed. 2014, 53, 11936-11930; c) G. G. Zhang, M. W. Zhang, X. X. Ye, X. Q. Qiu, S. Lin, X. C. Wang, Adv. Mater. 2014, 26, 805-809; d) D. Zheng, C. Huang, X. Wang, Nanoscale 2015, 7, 465-470; e) H. Wang, L. Zhang, Z. Chen, J. Hu, S. Li, Z. Wang, J. Liu, X. Wang, Chem. Soc. Rev. 2014, 43, 5234-4244. a) M. Shalom, S. Inal, C. Fettkenhauer, D. Neher, M. Antonietti, J. Am. Chem. Soc. 2013, 135, 7118-7121; b) J. H. Sun, J. S. Zhang, M. W. Zhang, M. Antonietti, X. Z. Fu, X. C. Wang, Nat. Commun. 2012, 3. a) M. Hu, J. Reboul, S. Furukawa, L. Radhakrishnan, Y. J. Zhang, P. Srinivasu, H. Iwai, H. J. Wang, Y. Nemoto, N. Suzuki, S. Kitagawa, Y. Yamauchi, Chem. Commun. 2011, 47, 8124-8126; b) F. Z. Su, S. C. Mathew, G. Lipner, X. Z. Fu, M. Antonietti, S. Blechert, X. C. Wang, J. Am. Chem. Soc. 2010, 132, 1629916301; c) X. F. Chen, Y. S. Jun, K. Takanabe, K. Maeda, K. Domen, X. Z. Fu, M. Antonietti, X. C. Wang, Chem. Mater. 2009, 21, 4093-4095. a) Y. S. Jun, E. Z. Lee, X. C. Wang, W. H. Hong, G. D. Stucky, A. Thomas, Adv. Funct. Mater. 2013, 23, 3661-3667; b) Y. S. Jun, J. Park, S. U. Lee, A. Thomas, W. H. Hong, G. D. Stucky, Angew. Chem. Int. Ed. 2013, 52, 11083-11087; c) Y. Ishida, L. Chabanne, M. Antonietti, M. Shalom, Langmuir 2014, 30, 447-451; d) Y. Cui, Z. Ding, X. Fu, X. Wang, Angew. Chem. Int. Ed. 2012, 51, 1181411818. a) J.-K. Sun, Q. Xu, Energy Environ. Sci. 2014, 7, 2071-2100; b) W. Chaikittisilp, K. Ariga, Y. Yamauchi, J. Mater. Chem. A 2013, 1, 1419; c) M. Hu, J. Reboul, S. Furukawa, L. Radhakrishnan, Y. Zhang, P. Srinivasu, H. Iwai, H. Wang, Y. Nemoto, N. Suzuki, S. Kitagawa, Y. Yamauchi, Chem. Commun. 2011, 47, 8124-8126. a) S. S. Mondal, A. Bhunia, A. Kelling, U. Schilde, C. Janiak, H.-J. Holdt, Chem. Commun. 2014, 50, 5441-5443; b) I. Bassanetti, A. Comotti, P. Sozzani, S. Bracco, G. Calestani, F. Mezzadri, L. Marchiò, J. Am. Chem. Soc. 2014, 136, 14883-14895; c) M. Radha Kishan, J. Tian, P. K. Thallapally, C. A. Fernandez, S. J. Dalgarno, J. E. Warren, B. P. McGrail, J. L. Atwood, Chem. Commun. 2010, 46, 538-540; d) J. Gao, J. Miao, P.-Z. Li, W. Y. Teng, L. Yang, Y. Zhao, B. Liu, Q. Zang, Chem. Commun. 2014, 50, 3786-3788. C. Chen, C.-W. Yeh, J.-D. Chen, Polyhedron 2006, 25, 1307-1312. Y. Cao, Z. Zhang, J. Long, J. Liang, H. Lin, H. Lin, X. Wang, J. Mater. Chem. A 2014, 2, 17797-17807. Q. J. Xiang, J. G. Yu, M. Jaroniec, J. Phys. Chem. C 2011, 115, 7355-7363. J. G. Yu, S. H. Wang, B. Cheng, Z. Lin, F. Huang, Catal. Sci. Technol. 2013, 3, 1782-1789. a) Z. X. Ding, X. F. Chen, M. Antonietti, X. C. Wang, Chemsuschem 2011, 4, 274-281; b) G. Y. Zhang, X. X. Wang, J. L. Long, L. L. Xie, Z. X. Ding, L. Wu, Z. H. Li, X. Z. Fu, Chem. Mater. 2008, 20, 4565-4575; c) A. Gervasini, M. Manzoli, G. Martra, A. Ponti, N. Ravasio, L. Sordelli, F. Zaccheria, J. Phys. Chem. B 2006, 110, 7851-7861. a) Q. B. Zhang, K. L. Zhang, D. G. Xu, G. C. Yang, H. Huang, F. D. Nie, C. M. Liu, S. H. Yang, Prog Mater Sci 2014, 60, 208-337; b) C.-Y. Chiang, K. Aroh, N. Franson, V. R. Satsangi, S. Dass, S. Ehrman, Int. J. Hydrogen Energy 2011, 36, 15519-15526. S. F. Chen, Y. F. Hu, S. G. Meng, X. L. Fu, Appl. Catal. B: Environ. 2014, 150, 564-573. a) S. Zhang, J. Li, X. Wang, Y. Huang, M. Zeng, J. Xu, Acs Appl. Mater. Inter. 2014, 6, 22116-22125; b) J. F. Zhang, Y. F. Hu, X. L. Jiang, S. F. Chen, S. G. Meng, X. L. Fu, J. Hazard. Mater. 2014, 280, 713-722; c) Y. X. Yang, W. Guo, Y. N. Guo, Y. H. Zhao, X. Yuan, Y. H. Guo, J. Hazard. Mater. 2014, 271, 150-159.
Chemistry - An Asian Journal
10.1002/asia.201500131
COMMUNICATIONS Entry for the Table of Contents
COMMUNICATIONS Porous nanorod-type graphitic Carbon Nitride/CuO composite (CuOg-C3N4) was synthesized via a facile approach by using Cu-melamine supramolecular framework as precursor. The CuO-g-C3N4 nanocomposite demonstrated improved visible-light-driven photocatalytic activities for the degradation of rhodamine B. The results indicate that metal-melamine supramolecular frameworks can be promising precursors for the preparation of efficient g-C3N4 nanocomposite photocatalysts.
JiangPeng Wang, [a,c] Hui Xu,[b] Xuefeng Qian,[a] Ruijing Song,[a,c] Junkuo Gao,*[a] Guodong Qian*[b] and Juming Yao[a] Page No. – Page No. Direct Synthesis of Porous Nanorod-Type Graphitic Carbon Nitride/CuO Composite from CuMelamine Supramolecular Framework towards Enhanced Photocatalytic Performance
Authors: Junkuo Gao; Jiangpeng Wang; Hui Xu; Xuefeng Qian; Yingying Dong; Guodong Qian; Juming Yao
This manuscript has been accepted after peer review and the authors have elected to post their Accepted Article online prior to editing, proofing, and formal publication of the final Version of Record (VoR). This work is currently citable by using the Digital Object Identifier (DOI) given below. The VoR will be published online in Early View as soon as possible and may be different to this Accepted Article as a result of editing. Readers should obtain the VoR from the journal website shown below when it is published to ensure accuracy of information. The authors are responsible for the content of this Accepted Article.
To be cited as: Chem. Asian J. 10.1002/asia.201500131 Link to VoR: http://dx.doi.org/10.1002/asia.201500131
A sister journal of Angewandte Chemie and Chemistry – A European Journal
Supported by
Federation of Asian Chemical Societies
Chemistry - An Asian Journal
10.1002/asia.201500131
COMMUNICATIONS Direct Synthesis of Porous Nanorod-Type Graphitic Carbon Nitride/CuO Composite from Cu-Melamine Supramolecular Framework towards Enhanced Photocatalytic Performance Jiangpeng Wang,[a,c]‡ Hui Xu,[b]‡ Xuefeng Qian,[a] Yingying Dong, [a,c] Junkuo Gao,*[a] Guodong Qian*[b] and Juming Yao[a]
Abstract: Facile and direct synthesis of porous nanorod-type graphitic Carbon Nitride/CuO composite (CuO-g-C3N4) was reported by using Cu-melamine supramolecular framework as precursor. The CuO-g-C3N4 nanocomposite demonstrated improved visible-lightdriven photocatalytic activities. The results indicate that metalmelamine supramolecular frameworks can be promising precursors for the preparation of efficient g-C3N4 nanocomposite photocatalysts.
Due to its unique two-dimensional graphene-like structure, nontoxicity, excellent chemical stability and low cost, graphitic carbon nitride (g-C3N4) has been receiving great attention in the past years. [1] In fact, g-C3N4 has already been demonstrated to have a broad range of applications such as fluorescent sensor, super capacitor, photocatalysis and so on.[2] In the past two decades, g-C3N4 was extensively studied and successfully applied in photocatalytic water splitting and organic pollutant photo-degradation, mainly because of its unique structure, good stability and photo-response in the visible-light region.[3] The formation of porous structure and well-controlled morphology are crucial to improve the photocatalytic activities.[4] Although extensive research has been carried out for the modifications of g-C3N4 synthesis, those exhibiting porosity and well-controlled morphology are still of few percentage. This is mainly due to the fact that
[a]
[b]
[b]
‡
J. Wang, X. Qian, Y. Dong, Prof. Dr. J. Gao, Prof. Dr. J. Yao The Key laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, National Engineering Lab for Textile Fiber Materials and Processing Technology (Zhejiang), College of Materials and Textiles Zhejiang Sci-Tech University Hangzhou 310018, P. R. China E-mail: [email protected] Dr. H. Xu, Prof. Dr. G. Qian State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering Zhejiang University Hangzhou 310027, P. R. China E-mail: [email protected] J. Wang, Y. Dong Qixin Honors School Zhejiang Sci-Tech University Hangzhou 310018, P. R. China Both authors have equal contribution to this paper. Supporting information for this article is given via a link at the end of the document.
carbon nitrides can be synthesized via simple heating of nitrogen-rich organic compounds such as cyanamide or melamine, wherein the solid-state chemistry-like conditions only lead to the formation of final nonporous condensed bulk materials. One efficient strategy to obtain well-controlled morphology is hard-template approach via the replication of a rigid template material which already possesses controlled porosity and morphology.[3b, 5] However this method consists of complex steps and needs removal of the template matrix. Another strategy is to make use of molecular self-assembly by using different organic supramolecular as ordered textures to obtain preformed micro- or nanostructures, as recently reported by Wang, Shalom and Thomas groups. [4a, 6] The researchers reported the condensation of organic supramolecular complexes such as cyanuric acid-melamine at thermal heating condition resulted in well-ordered carbon nitrides materials with different morphologies such as nanoparticles, hollow spheres and porous nanosheets. As specific morphologies often imply high photoactivity, it is of significance to develop new strategies controlling the morphologies of g-C3N4. Metal-organic supramolecular frameworks, self-assembled from metallic nodes and organic ligands through metal coordination, hydrogen bonding and π-π interactions, have been emerging as a new type of precursors for porous carbons and metal oxide/carbon composites. [7] Due to the highly ordered crystalline structures, metal-organic supramolecular frameworks would be good candidates for use as both sacrificial templates and precursors to give porous g-C3N4 under proper thermal condensation conditions. The diverse metal ions and a variety of organic linkers as well as the reaction conditions such as temperature, solvent and molar ratio, can lead to high tailorable structures, [8] which could subsequently influence the morphologies of formed g-C3N4. In addition, because of coordination modes of the metal nodes in metal-organic supramolecular frameworks, the g-C3N4 composites containing nanostructured metal or metal oxides species are prone to form and further improve the performance. More importantly, in most cases, the templating of metal-organic supramolecular frameworks is simpler and cheaper as compared to hard template approach which involves silica nanostructures, making them ideal precursors for g-C3N4 materials. To the best of our knowledge, reports on the synthesis of metal oxide/ g-C3N4 nanocomposite materials
Chemistry - An Asian Journal
10.1002/asia.201500131
COMMUNICATIONS with nanoporosity and well-controlled morphology by metalorganic supramolecular frameworks are still scarce. Herein, we reported a new synthetic approach for the preparation of porous nanorod-type g-C3N4/metal oxide composites with enhanced photocatalytic properties by using Cu-melamine supramolecular framework as precursor (Scheme 1). The copper-melamine supramolecular framework [Cu(μ-OAc)(μ-OCH3)(MA)] (Cu-MA1) was obtained by the reaction of Cu(OAc) 2 and melamine in methanol solution as a blue solid. Cu-MA1 framework forms a three dimensional porous structure with hexagonal pores linked by the N-H…N self-complementary hydrogen bonds, as reported in the literature (Figure S1).[9] CuO/g-C3N4 nanocomposite (CuO-gC3N4) was obtained by heating Cu-MA1 framework at 550 oC for 4 h under argon atmosphere. XRD pattern of CuO-g-C3N4 was shown in Figure 1. The strong peak located at 27.6o could be assigned to the (002) peak of g-C3N4, which shift slightly to higher diffraction angle compared with pure g-C3N4 (27.3o). The small peaks at 35.4 o, 37.4o and 38.7o matches well with the characteristic peaks of crystalline CuO, indicating the existence of CuO phase in the nano-composite. The XRD pattern clearly demonstrated that both CuO and g-C3N4 are contained in CuO-g-C3N4. To the best of our knowledge, there was no report on the synthesis of g-C3N4/CuO nanocomposites. Elemental analysis (EA) showed that the total amount of C, N and H elements in CuO-g-C3N4 is about 58.85%, while the amount of CuO is about 41.42%, which is quite consistent with the results from TG curves (Figure S5). The N/C molar ratio in CuO-g-C3N4 is 1.48, which is higher than the value of g-C3N4 (1.33). The high N/C value could be resulted from the inhibition of polymeric condensation by CuO species. When Cu-MA1 framework was heated at 800 o C under argon atmosphere, only metal Cu particles were obtained as confirmed by XRD (Figure S6), due to the decomposition of g-C3N4 component and the resulting reduction atmosphere.
Figure 1. The powder XRD patterns for CuO-g-C3N4, g-C3N4 and simulated CuO.
The chemical composition of CuO-g-C3N4 was studied via X-ray photoelectron spectroscopy (XPS), as shown in Figure 2. Sharp photoelectron peaks appeared at binding energies of 932 eV (Cu 2p), 398 eV (N 1s) and 287 eV (C1s), respectively, indicating the existence of Cu, C and N elements in CuO-g-C3N4 sample. The high resolution C1s XPS spectra in g-C3N4 show two sharp peaks at 284.8 eV and 287.8 eV, which could be ascribed to defect-containing sp2-hybridized carbon atoms presented in graphitic domains and a N-C=N coordination, respectively.[10] The high resolution N 1s spectra for CuO-g-C3N4 could be separated into three peaks at 398.3 eV, 398.9 eV and 399.5 eV, respectively. The peak at 398.3 eV could be assigned to the sp2-hybridized nitrogen (C=N-C).[11] The other two peaks are attributed to the tertiary nitrogen N-C3 and amino functional groups carrying hydrogen.[12] The binding energy of Cu 2p1/2 and Cu 2p3/2 in CuO-g-C3N4 are 932.7 eV and 952.4 eV, which are very close to the values in CuO, indicating the +2 state of Cu element.[13]
Figure 2. XPS spectra of the synthesized CuO-g-C3N4. (a) C 1s spectra of CuO-g-C3N4. (b) N 1s spectra of CuO-g-C3N4. (c) Cu 2p spectra of CuO-gC3N4. (d) O 1s spectra of CuO-g-C3N4
Scheme 1. Preparation of porous nanorod-like CuO-g-C3N4 from Cu-melamine 3-D supramolecular framework.
The morphologies of CuO-g-C3N4 and pure g-C3N4 sample synthesized from melamine at the same conditions were
Chemistry - An Asian Journal
10.1002/asia.201500131
COMMUNICATIONS analyzed by SEM and TEM. CuO-g-C3N4 displayed porous nanorod morphology, as shown in Figure 3. The diameters of nanorods are smaller than 300 nm with pores about 20~50 nm along the rods (Figure 3b-c). The length of nanorod could reach to 2 μm as confirmed by TEM (Figure S2). CuO nanoparticles around 50 nm spread on the surface of nanorods (Figure 3d). The high resolution TEM (HRTEM) image of CuO-g-C3N4 revealed lattice fringes with interplanar distance of 0.324 nm in the nanorod part corresponding the (002) plane of g-C3N4 (Figure S3a). The lattice fringes with d-spacing of 0.158 nm in the nanoparticle can be assigned to the (202) crystal plane of CuO (Figure S3b), confirming the crystalline CuO phase of nanoparticles attached on g-C3N4 nanorods and displaying a distinguished and coherent interface between CuO and g-C3N4. The starting Cu-melamine supramolecular framework displayed block-shape crystals, as shown in figure 3a. The pure g-C3N4 displayed a blocky morphology with agglomeration of lamellar structures (Figure S4). The formation of porous nanorod structures of CuO-g-C3N4 from 3-D porous Cu-melamine supramolecular framework may result from the 3-D hydrogen bond directions in CuMA1 precursor which could guide the condensation of melamine molecules. This important role of hydrogen bonds in forming a particular morphology was also confirmed by Shalom et al.[4a] The specific surface areas of CuO-g-C3N4 were studied by nitrogen adsorption isotherm analysis (Figure S7). The specific surface areas of CuO-g-C3N4 and pure g-C3N4 were found to be 15.37 and 5.26 m2 g1 respectively. The surface area of CuO-g-C3N4 was more than 2 times larger than pure g-C3N4 due to the porous nano-structure.
also performed to investigate the electronic properties of CuO-gC3N4. The PL spectra of CuO-g-C3N4 and g-C3N4 under 375 nm excitation were shown in Figure S9. g-C3N4 showed a strong PL emission with a peak at 470 nm, while there was almost no PL emission for CuO-g-C3N4. The obvious PL quenching demonstrated that the recombination of electron-hole pairs in CuO-g-C3N4 nano-composite is decreased, which may result in the improvement of the photocatalytic activity. The visible light photocatalytic activity of CuO-g-C3N4 was evaluated for the photo-degradation of rhodamine B (RhB) under visible light irradiation (λ > 400 nm). As shown in Figure 4, CuOg-C3N4 exhibited much more efficient photocatalytic activity than pure g-C3N4 and commercial CuO. After 20 min visible light irradiation, almost 94% RhB was degraded by CuO-g-C3N4, while only 12% and 5 % RhB was degraded by g-C3N4 and CuO under the same conditions. The excellent photocatalytic activity of CuO-g-C3N4 compared with g-C3N4 may be attributed to the hetero-structures formed between g-C3N4 and CuO, strong absorption in the visible region and larger surface areas. Furthermore, the CuO component was removed from the g-C3N4 nanorod by washing with HNO3 solution, and the photocatalytic activity of the obtained g-C3N4 nanorod (named as g-C3N4-2) was studied. As seen in Figure S10, the photocatalytic activity of g-C3N4-2 was slightly higher than pure g-C3N4 obtained from melamine, which is mainly due to its larger surface areas. Yet, the activity of g-C3N4-2 was obviously reduced when compared with CuO-g-C3N4 nano-composite, indicating that the formation of hetero-structure between CuO and g-C3N4 played the main role for the enhancement of photocatalytic activity. CuO-g-C3N4 also displayed good catalytic stability as confirmed by the threerun photocatalytic tests and XRD pattern after catalysis (Figure S11).
Figure 3. (a) SEM image of CuMA1 precursor. (b) SEM image of CuO-g-C3N4. (c and d) TEM image of CuO-g-C3N4.
The optical properties of CuO-g-C3N4 were studied by UV-VisNIR diffuse reflectance spectra and compared with pure g-C3N4, as shown in Figure S8. CuO-g-C3N4 showed strong absorption in the visible region and expanded the absorption to the nearinfrared region, while no absorption at wavelength larger than 600 nm was observed in g-C3N4. CuO is narrow band gap ptype semiconductor (about 1.68 eV) with a conduction band at near 0.46 eV (vs. NHE) as reported in some literatures. [14] The band gap of g-C3N4 is about 2.7 eV, with a conduction band near -1.12 eV (vs. NHE).[15] Photoluminescence (PL) spectra were
Figure 4. (a) The photo-degradation of Rhodamine B (RhB) in solution for CuO-g-C3N4, commercial CuO and bulk g-C3N4. (b) Recycling test on CuO-gC3N4 for photo-degradation of RhB under visible light irradiation (λ > 400 nm).
Chemistry - An Asian Journal
10.1002/asia.201500131
COMMUNICATIONS To investigate the photodegradation mechanism, The active species generated during the photocatalytic process were identified by free radical and hole scavenging experiments, in which isopropanol (IPA), ethylene diamine tetraacetic acid (EDTA) and benzouinone (BQ) were used as the hydroxyl radical (.OH), hole (h+) and superoxide radical (.O2-) scavengers, respectively.[16] As shown in Figure S12, when BQ was added in the photocatalytic system, the photodegradation of RhB was obviously inhibited. The introduction of EDTA slightly reduced the photocatalytic activity. While the addition of IPA showed almost no influence on the photocatalytic activity. Based on the results, we can conclude that the major active species in the system for photodegradation is the .O2-. According to the active species and band gap structure of CuO and g-C3N4, the possible electron and charge transfer process could be expressed in Figure S13, in which the Z-scheme mechanism was established. The excited electrons from CuO were transferred from the CB of CuO to the VB of g-C3N4 part. So the excited electrons in the gC3N4 can reacted with O2 to form .O2- radicals, making .O2- as the major active species in the photodegradation process. In conclusion, a new and facile synthetic approach was developed for the fabrication of porous nanorod gC3N4/metal oxide composites by using metal-melamine supramolecular frameworks as precursor. The morphology and optical properties of synthesized porous nanorod gC3N4/CuO (CuO-g-C3N4) composite were investigated in detail. CuO-g-C3N4 showed strong optical absorption in the whole visible-light region. Photocatalytic studies showed that CuO-g-C3N4 exhibited highly efficient photocatalytic activity and good stability in the degradation of RhB. The results indicate that metal-melamine supramolecular frameworks can be promising precursors for the preparation of efficient g-C3N4 nanocomposite photocatalysts. We expect that the diverse metal-melamine supramolecular frameworks will result in hybrid g-C3N4 materials with controllable morphology and electronic structures, which will have a broader potential for various heterogeneous catalysis.
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9] [10]
Acknowledgements This work is supported by the National Natural Science Foundation of China (No. 51402261) and Science Foundation of Zhejiang Sci-Tech University (ZSTU) under Grant No. 13012138-Y. J. G. acknowledges the financial support from the public technology research plan of Zhejiang Province, China under Grant No. 2014C33041 and support from the Zhejiang Provincial Top Key Academic Discipline of Textile Science and Engineering. Keywords: Carbon Nitride • Photocatalysis • Composites • Nano-Rod • Supramolecular Frameworks
[11] [12] [13]
[14]
[15] [16]
a) Y. Zheng, J. Liu, J. Liang, M. Jaroniec, S. Z. Qiao, Energy Environ. Sci. 2012, 5, 6717-6731; b) X. C. Wang, S. Blechert, M. Antonietti, Acs Catal. 2012, 2, 1596-1606; c) J. X. Low, S. W. Cao, J. G. Yu, S. Wageh, Chem. Commun. 2014, 50, 10768-10777; d) S. W. Cao, J. G. Yu, J. Phys. Chem. Lett. 2014, 5, 2101-2107. a) X. C. Wang, K. Maeda, A. Thomas, K. Takanabe, G. Xin, J. M. Carlsson, K. Domen, M. Antonietti, Nat. Mater. 2009, 8, 76-80; b) K. Schwinghammer, M. B. Mesch, V. Duppel, C. Ziegler, J. Senker, B. V. Lotsch, J. Am. Chem. Soc. 2014, 136, 1730-1733; c) D. J. Martin, K. P. Qiu, S. A. Shevlin, A. D. Handoko, X. W. Chen, Z. X. Guo, J. W. Tang, Angew. Chem. Int. Ed. 2014, 53, 9240-9245; d) T. Y. Ma, S. Dai, M. Jaroniec, S. Z. Qiao, Angew. Chem. Int. Ed. 2014, 53, 7281-7285; e) Z. K. Zhao, Y. T. Dai, J. H. Lin, G. R. Wang, Chem. Mater. 2014, 26, 3151-3161; f) H. Xu, J. Yan, X. J. She, L. Xu, J. X. Xia, Y. G. Xu, Y. H. Song, L. Y. Huang, H. M. Li, Nanoscale 2014, 6, 9866-9866. a) D. J. Martin, K. Qiu, S. A. Shevlin, A. D. Handoko, X. Chen, Z. Guo, J. Tang, Angew. Chem. Int. Ed. 2014, 53, 9240-9245; b) Z. Y., L. Lin, X. Ye, F. Guo, X. Wang, Angew. Chem. Int. Ed. 2014, 53, 11936-11930; c) G. G. Zhang, M. W. Zhang, X. X. Ye, X. Q. Qiu, S. Lin, X. C. Wang, Adv. Mater. 2014, 26, 805-809; d) D. Zheng, C. Huang, X. Wang, Nanoscale 2015, 7, 465-470; e) H. Wang, L. Zhang, Z. Chen, J. Hu, S. Li, Z. Wang, J. Liu, X. Wang, Chem. Soc. Rev. 2014, 43, 5234-4244. a) M. Shalom, S. Inal, C. Fettkenhauer, D. Neher, M. Antonietti, J. Am. Chem. Soc. 2013, 135, 7118-7121; b) J. H. Sun, J. S. Zhang, M. W. Zhang, M. Antonietti, X. Z. Fu, X. C. Wang, Nat. Commun. 2012, 3. a) M. Hu, J. Reboul, S. Furukawa, L. Radhakrishnan, Y. J. Zhang, P. Srinivasu, H. Iwai, H. J. Wang, Y. Nemoto, N. Suzuki, S. Kitagawa, Y. Yamauchi, Chem. Commun. 2011, 47, 8124-8126; b) F. Z. Su, S. C. Mathew, G. Lipner, X. Z. Fu, M. Antonietti, S. Blechert, X. C. Wang, J. Am. Chem. Soc. 2010, 132, 1629916301; c) X. F. Chen, Y. S. Jun, K. Takanabe, K. Maeda, K. Domen, X. Z. Fu, M. Antonietti, X. C. Wang, Chem. Mater. 2009, 21, 4093-4095. a) Y. S. Jun, E. Z. Lee, X. C. Wang, W. H. Hong, G. D. Stucky, A. Thomas, Adv. Funct. Mater. 2013, 23, 3661-3667; b) Y. S. Jun, J. Park, S. U. Lee, A. Thomas, W. H. Hong, G. D. Stucky, Angew. Chem. Int. Ed. 2013, 52, 11083-11087; c) Y. Ishida, L. Chabanne, M. Antonietti, M. Shalom, Langmuir 2014, 30, 447-451; d) Y. Cui, Z. Ding, X. Fu, X. Wang, Angew. Chem. Int. Ed. 2012, 51, 1181411818. a) J.-K. Sun, Q. Xu, Energy Environ. Sci. 2014, 7, 2071-2100; b) W. Chaikittisilp, K. Ariga, Y. Yamauchi, J. Mater. Chem. A 2013, 1, 1419; c) M. Hu, J. Reboul, S. Furukawa, L. Radhakrishnan, Y. Zhang, P. Srinivasu, H. Iwai, H. Wang, Y. Nemoto, N. Suzuki, S. Kitagawa, Y. Yamauchi, Chem. Commun. 2011, 47, 8124-8126. a) S. S. Mondal, A. Bhunia, A. Kelling, U. Schilde, C. Janiak, H.-J. Holdt, Chem. Commun. 2014, 50, 5441-5443; b) I. Bassanetti, A. Comotti, P. Sozzani, S. Bracco, G. Calestani, F. Mezzadri, L. Marchiò, J. Am. Chem. Soc. 2014, 136, 14883-14895; c) M. Radha Kishan, J. Tian, P. K. Thallapally, C. A. Fernandez, S. J. Dalgarno, J. E. Warren, B. P. McGrail, J. L. Atwood, Chem. Commun. 2010, 46, 538-540; d) J. Gao, J. Miao, P.-Z. Li, W. Y. Teng, L. Yang, Y. Zhao, B. Liu, Q. Zang, Chem. Commun. 2014, 50, 3786-3788. C. Chen, C.-W. Yeh, J.-D. Chen, Polyhedron 2006, 25, 1307-1312. Y. Cao, Z. Zhang, J. Long, J. Liang, H. Lin, H. Lin, X. Wang, J. Mater. Chem. A 2014, 2, 17797-17807. Q. J. Xiang, J. G. Yu, M. Jaroniec, J. Phys. Chem. C 2011, 115, 7355-7363. J. G. Yu, S. H. Wang, B. Cheng, Z. Lin, F. Huang, Catal. Sci. Technol. 2013, 3, 1782-1789. a) Z. X. Ding, X. F. Chen, M. Antonietti, X. C. Wang, Chemsuschem 2011, 4, 274-281; b) G. Y. Zhang, X. X. Wang, J. L. Long, L. L. Xie, Z. X. Ding, L. Wu, Z. H. Li, X. Z. Fu, Chem. Mater. 2008, 20, 4565-4575; c) A. Gervasini, M. Manzoli, G. Martra, A. Ponti, N. Ravasio, L. Sordelli, F. Zaccheria, J. Phys. Chem. B 2006, 110, 7851-7861. a) Q. B. Zhang, K. L. Zhang, D. G. Xu, G. C. Yang, H. Huang, F. D. Nie, C. M. Liu, S. H. Yang, Prog Mater Sci 2014, 60, 208-337; b) C.-Y. Chiang, K. Aroh, N. Franson, V. R. Satsangi, S. Dass, S. Ehrman, Int. J. Hydrogen Energy 2011, 36, 15519-15526. S. F. Chen, Y. F. Hu, S. G. Meng, X. L. Fu, Appl. Catal. B: Environ. 2014, 150, 564-573. a) S. Zhang, J. Li, X. Wang, Y. Huang, M. Zeng, J. Xu, Acs Appl. Mater. Inter. 2014, 6, 22116-22125; b) J. F. Zhang, Y. F. Hu, X. L. Jiang, S. F. Chen, S. G. Meng, X. L. Fu, J. Hazard. Mater. 2014, 280, 713-722; c) Y. X. Yang, W. Guo, Y. N. Guo, Y. H. Zhao, X. Yuan, Y. H. Guo, J. Hazard. Mater. 2014, 271, 150-159.
Chemistry - An Asian Journal
10.1002/asia.201500131
COMMUNICATIONS Entry for the Table of Contents
COMMUNICATIONS Porous nanorod-type graphitic Carbon Nitride/CuO composite (CuOg-C3N4) was synthesized via a facile approach by using Cu-melamine supramolecular framework as precursor. The CuO-g-C3N4 nanocomposite demonstrated improved visible-light-driven photocatalytic activities for the degradation of rhodamine B. The results indicate that metal-melamine supramolecular frameworks can be promising precursors for the preparation of efficient g-C3N4 nanocomposite photocatalysts.
JiangPeng Wang, [a,c] Hui Xu,[b] Xuefeng Qian,[a] Ruijing Song,[a,c] Junkuo Gao,*[a] Guodong Qian*[b] and Juming Yao[a] Page No. – Page No. Direct Synthesis of Porous Nanorod-Type Graphitic Carbon Nitride/CuO Composite from CuMelamine Supramolecular Framework towards Enhanced Photocatalytic Performance
