Internal and external cultivation: unleashing the potential of photogenerated carrier dynamics behaviors to boost photocatalytic CO2 hydrogenation†

In heterogeneous photocatalysis, the dynamics of charge carriers holds particular significance for comprehending the underlying catalytic mechanism and designing highly efficient photocatalysts. The current technological challenge lies in how to maximize the behavior of carriers and enable them to unleash their potential in photocatalytic reactions. Herein, we present a novel Prussian blue analogue (PBA)-derived InFe-based oxide (denoted as InFe-x), which features internal Fe doping and an external crystalline/amorphous heterojunction, serving as an effective photocatalyst for photocatalytic reverse water gas shift (RWGS) reactions. Experiments and theoretical simulations have confirmed that doping Fe into In₂O₃ can alter the electronic and energy structure and achieve the spin polarization effect, thereby enhancing the intrinsic carrier generation and separation behavior; meanwhile, the formed Fe–In₂O₃/Fe₂O₃ S-scheme heterojunction establishes an internal built-in electric field and creates a new transport pathway for photogenerated carriers, which significantly inhibit the inherent photogenerated electron–hole recombination. Therefore, this “internal and external cultivation” strategy can fundamentally optimize and maximize the behavior of charge carriers, thereby significantly enhancing the photocatalytic CO₂ hydrogenation performance.