Revealing Spatially Resolved Exciton Dynamics of Dual Active Centers for Dehydrogenation Oxidation of Benzyl Alcohol Coupled by Hydrogen Evolution

Abstract

ABSTRACT Photooxidation of biomass alcohols coupling H 2 evolution has received increasing attention due to its higher economy. However, the insufficient photoexciton utilization has become a bottleneck restricting its practical application, thereby precisely regulating the microstructure of photocatalysts is crucial for achieving efficient photoactivity. Strategically introducing functional active centers has been proven to be a valid strategy for optimizing the exciton dynamics of photocatalysts. Herein, the cobalt (Co) clusters and single‐atom Co─O sites were co‐decorated on the heterostructured MoS 2 /CdS composite to integrate the merits of heterojunction and non‐precious metal cocatalysis, which was demonstrated by the x‐ray absorption fine structure spectroscopy and spherical aberration‐corrected transmission electron microscope techniques. Remarkable collaborative photoactivity for benzyl alcohol (BA) oxidation (181.8 mmol BAD ·g −1 ·h −1 ) coupling H 2 evolution (64.6 mmol H2 ·g −1 ·h −1 ) was achieved under artificial sunlight. Femtosecond transient absorption spectroscopy and Kelvin probe force microscopy techniques proved the improved spatial separation/transfer kinetics and hindered recombination kinetics of photoexcitons. Based on density functional theory, the Co clusters act as the oxidation sites for BA, and the Co─O sites serve as the H 2 evolution reduction centers, enabling the synergistically enhanced REDOX half‐reactions due to more effective spatial separation of photoexcitons. This study proposes a strategic catalyst construction insight for highly efficient collaborative REDOX photocatalysis.