Optimizing electron transfer pathways via in situ growth of non-metal oxide on hydrogen-bonded organic framework for efficient hydrogen evolution.

The incorporation of non-precious metal semiconductors to construct organic-inorganic S-scheme heterojunctions is an effective strategy for enhancing the efficiency of photocatalytic hydrogen production. In this study, we investigated the in-situ growth of HOF/W18O49 binary composite systems using hydrogen-bonded organic frameworks to improve charge transfer mechanisms. These accumulated electrons recombine with holes in the HOF valence band, resulting in the spatial separation of HOF conduction band electrons, which aggregate at the catalytically active surface and drive the reduction reaction. In addressing the issue of high recombination rates of photo-generated electron-hole pairs, the introduction of the noble metal Pt may not be the optimal solution; the ternary system Pt/HOF/W18O49 exhibits significantly lower performance in photocatalytic hydrogen production experiments compared to the binary composite catalyst HOF/W18O49. This suggests that the deposition of platinum (Pt) not only adversely affects oxygen vacancy sites but also reduces the light absorption capacity of the HOF/W18O49 system, leading to a disruption of the heterojunction interface equilibrium. This study highlights the crucial yet often overlooked interaction between cocatalyst loading and defect engineering, providing new insights for the rational design of high-performance heterojunction photocatalysts.