Synthesis of Hierarchical CdS/NiS Photocatalysts Using Ni-MOF-74 as Template for Efficient Ethanol Conversion and Hydrogen Production under Visible Light.

The conversion of ethanol into high-valuable chemicals and H by photocatalytic process provides a sustainable approach to produce carbon-chain-prolonged chemicals and hydrogen energy. In this article, Ni-MOF-74 was added to fabricate the hierarchical CdS/NiS-N composites with an elevated specific surface area during the hydrothermal synthesis of CdS microsphere, and the Ni-MOF-74 facilitate the self-assemble growth of CdS and provide a source of Ni for the formation of NiS. The as-prepared photocatalyst was subjected to photocatalytic ethanol conversion, and the hierarchical composite material CdS/NiS-N (100) formed by adding 100 mg of Ni-MOF-74 exhibits the highest photocatalytic activity and stability in an ethanol aqueous solution with a water content of 10 %. Under visible light irradiation, the conversion rate of ethanol reached 15.2 % at the photocatalytic reaction of 5 h. The selectivity of 2,3-butanediol(2,3-BDO) was 25 %, and the selectivity of acetaldehyde(AA) was 63 %. Through various characterizations, it has been proven that a large specific surface area and the coupling interface between CdS and NiS are key factors in improving photocatalytic performance. This work provides an effective strategy for constructing photocatalysts with coupled cocatalysts/semiconductors and large specific surface areas.