Engineering an annular donor–acceptor reaction chamber with spontaneous feedstock collection for boosting CO2 photoreduction

Abstract

The strategic design and meticulous regulation of photocatalysts with customized atomic structures are imperative in the construction of efficient photocatalytic systems that can be finely tuned at both the atomic and molecular levels. Herein, we propose a precise directional doping strategy that is capable of integrating electron donor and acceptor units into microreactive regions. We demonstrate the catalyst structure obtained from this strategy, whereby a porous reaction chamber with an annular electron donor–acceptor structure is constructed within g-C₃N₄ through the interaction between methyl and phosphorus atoms. The obtained photocatalyst (NPEA) exhibits excellent utilization of photogenerated excitons and carriers resulting from the rapid dissociation of excitons within the porous reaction chamber. Meanwhile, the spontaneous collection mechanism formed by the annular electron donor–acceptor structure appears in NPEA. Notably, NPEA relies on the strong adsorption of HCO₃⁻ to enhance the local CO₂ concentration, thereby overcoming the barrier associated with heterogeneous reactions during the CO₂ reduction process. Consequently, NPEA exhibits a CO₂ reduction rate of 23.17 μmol g⁻¹ h⁻¹ (94% selectivity) without requiring a cocatalyst or any sacrificial agent apart from H₂O. This work offers a comprehensive mechanistic understanding of the synergistic integration of doping engineering and molecular modification to tailor photocatalysts for efficient reduction of CO₂ with H₂O.