Unraveling Ni Single-Atom/Nanoparticle Synergy on CdS for Enhanced Lactic Acid Photoreforming to Pyruvic Acid and Hydrogen

Photocatalytic hydrogen production from biomass-derived compounds, such as lactic acid, represents a dual-path strategy toward hydrogen energy and waste valorization. While the synergistic integration of metal single atoms (SAs) and nanoparticles (NPs) holds transformative potential for photocatalysis, the mechanistic origins of their cooperation, particularly their distinct roles in charge dynamics and molecular activation, remain unexplored. Herein, we developed a heterostructure non-noble metal 6.1 wt % Ni/CdS catalyst integrating Ni SAs and NiO NPs to achieve efficient lactic acid conversion with 92.1% pyruvate selectivity and a 74.9% apparent quantum yield (λ = 500 nm). Mechanistic studies reveal a functional division of labor where Ni SAs introduce hole-trapping states near the valence band, while NiO NPs selectively adsorb and dissociate lactic acid molecules. Notably, their synergy facilitates concurrent C–H and O–H bond cleavage, thereby accelerating the reaction pathway. This work not only establishes a benchmark for biomass photoreforming but also deciphers the SA-NP cooperation mechanism, paving the way for the design of multifunctional photocatalysts for chemistry.