Bandgap engineering of Zn_1-xCd_xS for glycerol photo(electro)reforming into glyceric acid with hydrogen coproduction

The surplus of glycerol generation from biodiesel fuel production has stimulated the development of efficient technology to realize the sustainability of biomass valorization. Herein, we demonstrate the glycerol valorization by mild photocatalytic and photoelectrocatalytic approaches. Glycerol photo(electro)reforming is realized on the well-designed Zn1-xCdxS solid solution photocatalysts. By continuously changing the ratio of Zn/Cd, Zn1-xCdxS is endowed with a regulatable bandgap structure, which finely controls the redox potential and light absorption. The spontaneous formation of homojunction by hexagonal wurtzite (WZ) and zinc-blende (ZB) facilitates spatial charge separation. As a result, Zn1-xCdxS exhibits the dual ability to simultaneously produce hydrogen and glyceric acid by the electrons and holes, respectively. The theoretical calculation and in-situ spectroscopy analysis reveal the prominent features of hydrogen evolution and glycerol oxidation into glyceric acid on the optimized Zn0.5Cd0.5S. This work provides a good example for glycerol valorization into sustainable fuels and chemicals by rationally designing dually functional photocatalysts.