Solar-driven photocatalytic system for CO₂ fixation and conversion of dopamine into indole derivative

Photocatalytic CO₂ fixation into solar fuels offers a promising route for renewable energy storage by converting CO₂ into chemical bonds. Among various products, formic acid is considered the most reliable candidate for industrial applications due to its high efficiency and sustainable feasibility. Various catalysts, including metals, chalcogenides, transition metals, and carbon-based materials, have been explored for this purpose. Polymeric organic frameworks are a class of crystalline polymers with tunable structures, making them potential candidates for metal-free photocatalysts. However, their low crystallinity often limits light-harvesting efficiency and photocatalytic activity, posing a challenge for industrial applications. The primary obstacles in this field are low activity and poor selectivity of photocatalysts. In this study, we propose a soft-template induction strategy to construct a metal-free heterojunction polymeric framework based on 5,15-di-(4-aminophenyl)-10,20-diphenyl porphyrin (BP) and perylene tetra-anhydride (PT), referred to as PTBP. This polymer exhibits high crystallinity and strong solar light absorption. The PTBP framework demonstrates better performance in solar-powered molecular artificial photosynthesis, achieving significant improvements over PT. Specifically, PTBP exhibits high 1,4-NADH/NADPH regeneration efficiencies (52.51%/58.41%) compared to PT (9.11%/10.1%), a substantial NADH consumption (119.25 μmol) in exclusive solar fuel production from CO₂ within 1 h, and excellent yield (50.37%) in the photocatalytic conversion of dopamine into an indole-derivative, surpassing PT (13.93%). The current finding highlights the benchmark photocatalytic potential of the PTBP polymeric framework's capacity for photocatalysis for CO₂ fixation and conversion of dopamine into indole derivatives.