Highly Selective H2 Production From Photoreforming of Formic Acid Triggered by Cu Single‐Atom Sites in a Cocatalyst

ABSTRACT Photoreforming of formic acid (FA) represents a compelling technology for green hydrogen (H 2 ) production, but the application is limited by the relatively low activity and selectivity. Recent advancements have introduced transition‐metal nitrides (TMNs) as a new class of co‐catalysts for photocatalytic FA reforming, showing impressive performance but still having the disadvantage of suboptimal H 2 selectivity. Here, we present a novel Cu–W 2 N 3 cocatalyst with abundant Cu single‐atom sites. On combining with a CdS photocatalyst, the CdS/Cu–W 2 N 3 system demonstrated an elevated H 2 generation rate of 172.69 μmol·h −1 and superior H 2 selectivity in comparison to CdS/W 2 N 3 . Comprehensive experimental and theoretical investigations indicate that the introduction of Cu single‐atom sites in Cu–W 2 N 3 leads to a robust interaction with CdS, which optimizes the charge transfer. More significantly, the Cu single‐atom sites modify the inert surface of the W 2 N 3 cocatalyst, creating conducive electron transfer channels and leading to an abundance of active sites favorable for hydrogen evolution reaction (HER), consequently resulting in higher H 2 selectivity than pristine W 2 N 3 . This study provides a promising approach to achieving an efficient photoreforming reaction with specific selectivity via the design of novel cocatalysts with specialized active sites.