Novel direct Z-scheme Cu2V2O7/g-C3N4 for visible light photocatalytic conversion of CO2 into valuable fuels

• Published in: Applied surface science 2018-11, Vol.457, p.968-974
• Main Authors: Thanh Truc, Nguyen Thi, Hanh, Nguyen Thi, Nguyen, Minh Viet, Le Chi, Nguyen Thi Phuong, Van Noi, Nguyen, Tran, Dinh Trinh, Ha, Minh Ngoc, Trung, Do Quang, Pham, Thanh-Dong
• Format: Article
• Language: English
• Subjects: CO2 conversion; Cu2V2O7; Direct Z scheme; g-C3N4; Solar fuels
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2018.07.034

[Display omitted] •Successfully established Cu2V2O7/g-C3N4 direct Z-scheme system for CO2 conversion.•Combination of Cu2V2O7 and g-C3N4 prevented recombination of e−/h+ in each material.•The established Cu2V2O7/g-C3N4 converted CO2 into CH4 and CO even under visible light.•The optimal ratio of Cu2V2O7/(Cu2V2O7 + g-C3N4) for selective CO2 conversion was 50% In this study, Cu2V2O7/g-C3N4 direct Z-scheme system was prepared for visible light photocatalytic conversion of CO2 into valuable fuels. As compared to the single Cu2V2O7 and g-C3N4, the established Cu2V2O7/g-C3N4 exhibited great increases in the CO2 conversion efficiency. When Cu2V2O7 was combined with g-C3N4 to establish a direct Z scheme system, both Cu2V2O7 and g-C3N4, which are narrow band-gap material, could absorb visible light for excitation of electrons from the valence band (VB) to the conduction band (CB). Then, the excited electrons existed in the CB of the Cu2V2O7 could return to holes in the VB of the g-C3N4 to prevent recombination of excited holes and electrons in each materials. Thus, the established direct Z scheme Cu2V2O7/g-C3N4 system produced significant amount of available holes and electrons. Finally, the produced holes and electrons reacted with H2O and CO2 to generate CO, CH4 and O2. The 50Cu2V2O7/50g-C3N4, which the Cu2V2O7 mole was equal to the g-C3N4 mole, produced enough electrons and protons for selective CO2 conversion into CH4 rather than CO. The generation rates of CH4, CO and O2 generated from the visible light photocatalytic conversion of CO2 by 50Cu2V2O7/50g-C3N4 were 305, 166 and 706 (µmol g−1 cat. h−1), respectively.