Effective Photocatalytic Ethanol Reforming into High‐Value‐Added Multicarbon Compound Coupled with H₂ Production Over Pt‐S₃ Sites at Pt_SA–ZnIn₂S₄ Interface

Abstract Selective photocatalytic production of high‐value acetaldehyde concurrently with H₂ from bioethanol is an appealing approach to meet the urgent environment and energy issues. However, the difficult ethanol dehydrogenation and insufficient active sites for proton reduction within the catalysts, and the long spatial distance between these two sites always restrict their catalytic activity. Here, guided by the strong metal‐substrate interaction effect, an atomic‐level catalyst design strategy to construct Pt‐S₃ single atom on ZnIn₂S₄ nanosheets (Pt_SA‐ZIS) is demonstrated. As active center with optimized H adsorption energy to facilitate H₂ evolution reaction, the unique Pt single atom also donates electrons to its neighboring S atoms with electron‐enriched sites formed to activate the O─H bond in ^*CH₃CHOH and promote the desorption of ^*CH₃CHO. Thus, the synergy between Pt single atom and ZIS together will reduce the energy barrier for the ethanol oxidization to acetaldehyde, and also narrow the spatial distance for proton mass transfer. These features enable Pt_SA‐ZIS photocatalyst to produce acetaldehyde with a selectivity of ≈100%, which will spontaneously transform into 1,1‐diethoxyethane via acetalization to avoid volatilization. Meanwhile, a remarkable H₂ evolution rate (184.4 µmol h⁻¹) is achieved with a high apparent quantum efficiency of 10.50% at 400 nm.