Pt single atoms/g-C3N4 photocatalysts enabling simultaneous H2 production and CO2 absorption through formic acid photoreforming

Abstract

Single-atom catalysts (SACs) represent a frontier in advanced nanomaterials for sustainable energy conversion, offering maximum metal utilization and unique electronic properties. Here, we report a robust strategy for anchoring platinum (Pt) single atoms onto graphitic carbon nitride (g-C3N4) via strong coordination interactions, forming a stable photocatalyst for green hydrogen production. The isolated Pt single atoms enable full utilization of active sites and the selective dehydrogenation pathway during photoreforming of formic acid. Under visible-light irradiation, the catalysts achieve a hydrogen evolution rate of 55.8 mmol·g-1·h-1 at pH 2.2. The catalyst maintains stable hydrogen evolution over 48 hours, with post-reaction atomic-scale imaging and surface spectroscopy confirming the preservation of atomically dispersed Pt sites. Remarkably, under alkaline conditions (pH 12.2), the system performs CO2-free hydrogen generation, attributed to simultaneous CO2 absorption in the electrolyte while retaining a hydrogen rate of ~ 5 mmol·g-1·h-1. This CO₂-free operation highlights compatibility with formate-based liquid hydrogen carrier systems, supporting low-emission H₂ logistics. This work demonstrates a scalable approach for engineering densely populated single-atom photocatalysts that realize zero-carbon hydrogen generation under mild photocatalytic conditions. The approach provides insights into designing advanced nano-to-atomic materials for sustainable and selective photocatalytic hydrogen production, aligning with global efforts toward carbon-neutral energy technologies.