Efficient benzaldehyde photosynthesis coupling photocatalytic hydrogen evolution

Photosynthesis of organic compounds in coupling with promoted hydrogen evolution under mild conditions of light irradiation is considered as one of the most efficient and promising approach to obtain high purity hydrogen and value-added chemicals concurrently by utilizing green solar energy. Here, we report the synthesis of NiS nanoparticle-modified CdS nanorod composites (NiS/CdS) as an efficient bifunctional catalyst for the highly selective photocatalytic synthesis of high-value-added product benzaldehyde (BAD) from aqueous solution of benzyl alcohol (BA) under oxygen-free conditions, in accompanying with the efficient hydrogen evolution. The synergetic catalytic effect between NiS and CdS is proposed to play an important role in elevating the photo-redox performance. The composition-optimized 30% NiS/CdS catalyst affords an extraordinarily high H2 generation rate of 207.8 μmol h−1 and a simultaneous BAD generation rate of 163.8 μmol h−1 under visible light irradiation, which are respectively 139 and 950 times higher than those of CdS without NiS modification. To our knowledge, these are the highest photocatalytic production rates of both H2 and aldehyde ever reported on the concurrent photocatalytic of aldehyde synthesis and hydrogen evolution in green aqueous solution. This work provides a highly efficient photosynthesis strategy for the concurrent productions of high-value-added fine chemicals and hydrogen.