Efficient and selective photocatalytic CO2 conversion enabled by FePc nanosheets in a dye-sensitized system

Abstract

Solar-driven photocatalytic CO₂ conversion offers a sustainable solution for greenhouse gas mitigation and renewable energy storage. While metal phthalocyanines (MPc) exhibit excellent CO₂ reduction capabilities, their practical application in dispersed photocatalytic systems faces limitations of the stacking of MPc molecules that reduces active site accessibility, and inefficient electron transfer limited by diffusive mass transport. To address these challenges, we developed a bioinspired dye-sensitized RuP-TiO₂-FePc nanosheets (NSs) hybrid system, where ultrathin FePc NSs obtained by liquid-phase ultrasonic exfoliation enhance active site exposure and mass transfer, while TiO₂ serves as a mediator to facilitate electron transfer between the photosensitizer and FePc NSs. Time-resolved spectroscopic studies demonstrate that TiO₂ plays a dual role: it spatially organizes functional components to enable surface electron transfer by shortening intermolecular distances, while also functioning as a semiconductor bridge to facilitate charge transport. This synergistic design achieves a remarkable CO production rate of 27.3 mmol g^–1 h^–1 (> 98% selectivity) and exceptional stability (TON_CO = 1363 over 100 h), outperforming many noble-metal-based systems. Our work demonstrates a robust strategy for optimizing bulk catalysts through 2D exfoliation and controlled heterogenization, offering a versatile platform for efficient and durable artificial photosynthesis.