1. Noble-metal-free CdS/Ni-MOF composites with highly efficient charge separation for photocatalytic H2 evolution.
- Author
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Guo, Junlan, Liang, Yinghua, Liu, Li, Hu, Jinshan, Wang, Huan, An, Weijia, and Cui, Wenquan
- Subjects
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HYDROGEN evolution reactions , *PHOTOCATALYSTS , *VISIBLE spectra , *ELECTROPHILES , *CHARGE exchange , *LACTIC acid , *CATALYTIC activity - Abstract
In this study, the optimized CdS/Ni-MOF photocatalyst with considerable activity and good stability for H 2 evolution was obtained by in-situ growth of CdS nanoparticles on the surface of Ni-MOF. Ni-MOF as an ideal support hinders the aggregation of CdS during the synthesis period. As a noble-metal-free catalyst, the obtained CdS/Ni-MOF composite having an optimal CdS loading of 40 wt% exhibits a remarkable H 2 production rate of 2508 μmol/g/h under visible light, which is about eight times higher than that of single CdS. The CdS/Ni-MOF composites generate electron-hole pairs under visible light. Then, the photo-generated charges in the CB of CdS are directly transferred to Ni-MOF due to the interface contact and the matched positions of the CB of CdS and the LUMO of Ni-MOF, and the holes are consumed by the sacrificial agent (lactic acid). In this case, electron-hole pairs are effectively separated, Moreover, Ni-MOF containing highly dispersed Ni2+ irons could act as the active site for H 2 generation. Ni-MOF acts as a dual role of electron acceptor and co-catalyst in photocatalytic H 2 production from water. This work could pave the way for further development of semiconductor/MOF composites with enhanced-performance. • The CdS/Ni-MOF composites are successfully synthesized. • The CdS/Ni-MOF composites exhibit high charge separation efficiency. • The CdS/Ni-MOF composites offered enhanced performance in photocatalytic H 2 production. Constructing semiconductor-based photocatalysts with high-performance and excellent stability is a promising approach to achieve optimum photocatalytic H 2 production rate from water splitting. In this study, a novel effective visible-light-driven catalyst, namely, CdS/Ni-MOF, has been successfully synthesized by in-situ growth of CdS nanoparticles on the surface of hollow Ni-based metal-organic framework (Ni-MOF) spheres. The heterogeneous interface contact and matched band position promote charge separation. As a noble-metal-free catalyst, the obtained CdS/Ni-MOF composite having an optimal CdS loading of 40 wt.% exhibits a remarkable H 2 production rate of 2508 μmol/g/h under visible light, which is about eight times higher than that of single CdS. Ni-MOF serves as a station for the rapid transfer of photo-induced electrons, leading to the high photocatalytic performance. Meanwhile, Ni-MOF comprising highly dispersed Ni2+ catalytic sites also acts as co-catalyst, which is beneficial for hydrogen evolution. Therefore, Ni-MOF functions as both an electron acceptor and a co-catalyst in the photocatalytic H 2 production from water. This work highlights the advantages of combining semiconductor and MOF functionalities to fabricate a photocatalyst with enhanced catalytic activity. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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