Promising CdS quantum dots/FeS2 microsphere Z-scheme heterojunction for boosting C-C coupling and hydrogen production

Abstract

The integration of solar-driven hydrogen production with the selective conversion of biomass-derived alcohols into the value-added chemicals have been found a promising application. Herein, we have successfully developed a series of Z-scheme CdS/FeS₂ photocatalysts via interface engineering, for efficient hydrogen evolution and dehydrogenative C-C coupling. Experimental results illustrate that the optimal CdS/FeS₂-10 composite photocatalysts exhibit a high H₂ production rate of 19.2 mmol g⁻¹h⁻¹, and C-C coupled products generation rate of 11.8 mmol g⁻¹h⁻¹ together with the selectivity of 95.0 %. Moreover, the benzyl alcohol conversion of 36 % and a coupled products yield of 34 % is observed after 2 h of reaction. Mechanistic studies reveal that the exceptional hollow core-shell structure not only enhance the visible light region absorbance, but also effectively induce the spatial charge separation within the Z-scheme heterojunction, resulting in an outstanding photocatalytic performance. Additionally, it observes that a carbon-centered radical (•CH(OH)C₆H₅) generated by the activation of C_α-H bond in benzyl alcohol plays significant roles during the photocatalytic process. This work provides new insights into the synergetic production of H₂ and selective conversion of biomass-derived alcohols to highly value-added chemicals through C-H bond dehydrogenation coupling.