Tailoring the catalytic sites by regulating photogenerated electron/hole pairs separation spatially for simultaneous selective oxidation of benzyl alcohol and hydrogen evolution.

The ZnIn 2 S 4 @CdS photocatalyst with tuned catalytic sites promotes selective benzyl alcohol oxidation on the ZnIn 2 S 4 surface and H 2 evolution on the CdS surface. [Display omitted] Photocatalytic selective oxidation of alcohols into aldehydes and H 2 is a green strategy for obtaining both value-added chemicals and clean energy. Herein, a dual-purpose ZnIn 2 S 4 @CdS photocatalyst was designed and constructed for efficient catalyzing benzyl alcohol (BA) into benzaldehyde (BAD) with coupled H 2 evolution. To address the deep-rooted problems of pure CdS, such as high recombination of photogenerated carriers and severe photo-corrosion, while also preserving its superiority in H 2 production, ZnIn 2 S 4 with a suitable band structure and adequate oxidizing capability was chosen to match CdS by constructing a coupled reaction. As designed, the photoexcited holes (electrons) in the CdS (ZnIn 2 S 4) were spatially separated and transferred to the ZnIn 2 S 4 (CdS) by electrostatic pull from the built-in electric field, leading to expected BAD production (12.1 mmol g−1 h−1) at the ZnIn 2 S 4 site and H 2 generation (12.2 mmol g−1 h−1) at the CdS site. This composite photocatalyst also exhibited high photostability due to the reasonable hole transfer from CdS to ZnIn 2 S 4. The experimental results suggest that the photocatalytic transform of BA into BAD on ZnIn 2 S 4 @CdS is via a carbon-centered radical mechanism. This work may extend the design of advanced photocatalysts for more chemicals by replacing H 2 evolution with N 2 fixation or CO 2 reduction in the coupled reactions. [ABSTRACT FROM AUTHOR]