Charge‐Polarized Ni─S 4 Single‐Atom Sites Drive Selective Photoreforming of Poly(lactic acid) to Lactate and Hydrogen

ABSTRACT Solar‐driven depolymerization of poly(lactic acid) (PLA) into its lactic acid monomer offers an attractive route to plastic recycling coupled with green hydrogen (H 2 ) production. However, simultaneously achieving high activity and product selectivity remains difficult because of inefficient charge utilization and uncontrolled oxidation pathways. Here, we fabricated cadmium sulfide (CdS) nanorods decorated with atomically dispersed Ni─S 4 sites that drive selective photocatalytic PLA depolymerization coupled with efficient H 2 evolution without any sacrificial reagent. The Ni─S 4 coordination reconstructs the surface electronic structure of CdS, generating interfacial polarization and directing charge separation with markedly prolonged lifetimes for surface redox reactions. Specifically, this redistribution directs photogenerated electrons to proton reduction and localizes holes at the Ni─S 4 sites, which selectively activate the ester carbonyl for hydroxide‐assisted cleavage while suppressing deeper oxidation. As a result, NiSAs/CdS delivers a H 2 production rate of 41.74 mmol g −1 h −1 while selectively converting PLA into lactic acid, with no detectable accumulation of common over‐oxidation byproducts such as pyruvate or acetate. These findings establish a charge‐coupled pathway that couples selective plastic depolymerization with solar‐driven H 2 generation and point to a viable strategy for sustainable plastic upcycling.