Rui Li,Qiongke Shi,Luyang Zuo,Yingjun Chen,Wenqiang Li,Huitao Fan,Bo Li,Liya Wang
The shortage of fossil energy has become a growing global concern. It is particularly important to make full use of the infinite solar energy resources, and transform them into sustainable and clean energy. The development of hydrogen energy has become a feasible solution to solve the energy shortage problem. The preparation of photocatalysts featuring efficient charge transfer channels and high hydrogen production activity provides a pathway for the development of hydrogen energy. In this paper, we report for the first time the direct assembly of 2D ZnIn 2 S 4 (ZIS) nanosheets on the surface of CoTiO 3 (CTO). The synthesized CoTiO 3 /ZnIn 2 S 4 (CTO/ZIS) photocatalyst features a direct Z-scheme charge transfer channel, which enhances the separation rate of photogenerated carriers, and accelerates the photocatalytic H 2 evolution (PHE) rate. Without the assistance of any co-catalyst, the PHE rate of prepared CoTiO 3 /ZnIn 2 S 4 was as high as 5.21 mmol g −1 h −1 . Moreover, the H 2 evolution rate of CoTiO 3 /ZnIn 2 S 4 almost did not decrease significantly after four consecutive 4 h cycles. This investigation provides a valuable approach for the exploitation of novel and efficient Z-scheme photocatalysts in the application of solar energy to hydrogen energy conversion.
Novel BiVO 4 @ZnIn 2 S 4 /Ti 3 C 2 MXene quantum dots (QDs) assembly all-solid-state direct Z-scheme photocatalyst is fabricated via in-situ growth combined with two-step solvothermal strategy, which forms a hierarchical core-shell structure. The proper energy band structure of BiVO 4 and ZnIn 2 S 4 and the formation of a good solid-solid contact interface between them promote the construction of Z-scheme system, which achieves effective charge separation. It is surprisingly discovered that Ti 3 C 2 MXene QDs can be applied as cocatalysts for photocatalytic overall water splitting, which could accelerate the surface redox kinetics of the catalyst due to the unique properties of Ti 3 C 2 MXene QDs . In particular, due to its excellent metal conductivity, a Schottky barrier can be formed at the interface in contact with ZnIn 2 S 4 , further promoting charge separation. BiVO 4 @ZnIn 2 S 4 /Ti 3 C 2 MXene QDs achieves effective visible-light-driven pure water splitting into O 2 and H 2 evolution rates up to 50.83 and 102.67 μmol g −1 h −1 (~1:2). In addition, it also shows high photocatalytic degradation Bisphenol A efficiency of ~96.4 %. The high photocatalytic performance can be ascribed to the all-solid-state direct Z-scheme structure favoring spatial charge separation, Ti 3 C 2 MXene QDs as cocatalysts promoting proton reduction, and hierarchical core-shell structure offering more surface active sites. This work provides new insights to fabricate high-performance direct Z-scheme assembly system.
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