The one-pot synthesis of a ZnSe/ZnS photocatalyst for H2 evolution and microbial bioproduction

Abstract

Low-cost photocatalysts are being developed for the conversion of visible light into H2 and to drive CO2 reduction. Hybrid photosynthesis is a promising approach to convert CO2 and visible light into multicarbon compounds where a photocatalyst energizes the metabolism of an autotrophic microbe. Here, a heterostructure ZnSe/ZnS photocatalyst was synthesized by a simple one-pot method and evaluated for photocatalytic H2 evolution (PHE) as well as for hybrid photosynthesis with the bioplastic-producing bacterium Ralstonia eutropha. ZnSe/ZnS nanoparticles exhibited a PHE 5.5 times higher than pure ZnSe. Photoluminescence and photoelectrochemical characterization of ZnSe/ZnS demonstrated more efficient charge separation probably caused by ZnS defects. Furthermore, ZnSe/ZnS improved 1.3 times bioplastic production from CO2 by R. eutropha, which was not the case for pure ZnSe. These results show ZnSe/ZnS potential for both PHE as well as hybrid photosynthesis and provide insights on the photocatalytic reaction mechanisms involved when the two Zn-based materials are combined.