Engineering emulsion‐templated polymer monoliths <i>via</i> substituting a single carbon atom with nitrogen to boost photocatalytic hydrogen evolution

Abstract Photocatalytic hydrogen (H 2 ) production holds immense potential as a sustainable energy solution while it is usually hindered by low catalytic efficiency. Engineering the photocatalyst supports is a key strategy for enhancing photocatalytic performance. Here, pyridine‐functionalized porous polymer monoliths are prepared based on emulsion templating, followed by loading platinum (Pt) and cadmium sulfide (CdS) nanoparticles to successfully fabricate a high‐performance photocatalyst Pt/CdS@P4VP. Compared to the counterpart Pt/CdS@PSt, substituting a single carbon atom with nitrogen, that is, replacing styrene with 4‐vinylpyridine, enables achieving a remarkable enhancement in H 2 production rate from 46.3 to 126.6 mmol h −1 m −2 . Combined experimental studies and theoretical simulation unravel that the unique Pt–N coordination not only stabilizes the oxidation state of Pt but also facilitates efficient electron transfer and improves charge separation, thereby enhancing H 2 generation during the photocatalytic process. Additionally, the porous and hydrophilic polymer skeletons provide abundant channels, facilitating the mass transportation of both water and H 2 . This study provides guidance for the rational design of high‐performance photocatalysts for water splitting and offers a way to scale up the photocatalytic reaction system.