Efficient visible-light-driven alcohol oxidation coupled hydrogen production on 0D/0D “n-NiWO4/p-CdS” S-scheme heterojunction

The theory of S-scheme transfer mechanism have significant implications for exploring the mechanism of photocatalytic carrier migration and its intrinsic dynamics. Modeled NiWO 4 /CdS heterojunction photocatalyst (referred to as NWO/CS) was synthesized using a simple hydrothermal method and applied for alcohol oxidation coupled with H 2 production. Systematically investigates the factors contributing to its enhanced performance and the internal charge transfer mechanisms. The 28% NWO/CS composite exhibited the highest activity, with a H 2 production and the aldehyde generation rates of 16.08 mmol⋅g −1 ⋅h −1 and 16.88 mmol⋅g −1 ⋅h −1 , which are about 320 times higher than those of NiWO 4 (0.05 mmol⋅g −1 ⋅h −1 and 0.06 mmol⋅g −1 ⋅h −1 ) and 16 times higher than that of CdS (1.09 mmol⋅g −1 ⋅h −1 and 1.12 mmol⋅g −1 ⋅h −1 ). Based on the in-situ XPS, transient surface photovoltage, theoretical calculations, and other physicochemical characterization results, we have confirmed that the built-in electric field formed at the interface and the transfer of photogenerated charges follows the S-scheme mechanism between relative “n-NiWO 4 ” and relative “p-CdS” are the key factors that promote efficient charge separation and significantly enhance the subsequent reaction activity. This work provides a theoretical basis for improving photocatalytic performance and understanding photocatalytic mechanisms. • Constructed 0D/0D “n-NiWO 4 /p-CdS” S-scheme heterojunction was used for aromatic alcohol oxidation. • The total hydrogen production of 28 % NiWO 4 /CdS is up to 16.08 mmol⸱h −1 ⸱g −1 . • In-situ XPS, TS-SPV and DFT theoretical calculations were used to study the mechanism. • A possible S-scheme mechanism for enhancing H 2 production was proposed.