Pore-Openness Engineering in a 2D P,S,N-Tridoped Carbon Honeycomb for Efficient Oxygen Reduction Reaction

Multiheteroatom-doped metal-free porous carbons are promising candidates for oxygen reduction reaction (ORR) catalysis. However, achieving precise active-site modulation while simultaneously maximizing accessibility remains a significant challenge. Herein, a two-dimensional (2D) P,S,N-tridoped semiopen carbon honeycomb (PSN-SOCH) was synthesized via a facile multicomponent ice-templating coassembly (MIC) approach. Multiheteroatom doping efficiently modulates the electronic structure of active sites. Meanwhile, the unique highly porous 2D semiopen architecture exhibits a nanoconfinement effect for O₂ transport, which improves the mass-transfer efficiency. As a result, the PSN-SOCH catalyst exhibits a high half-wave potential of 0.87 V in 0.1 M KOH, surpassing those of 2D dual-doped counterparts as well as 2D tridoped carbon honeycombs with differing pore openness. Density functional theory calculations reveal that tridoping enhances charge delocalization and optimizes the adsorption energies of ORR intermediates, thereby accelerating reaction kinetics. Furthermore, finite-element simulations combined with the distribution of relaxation time analysis confirm that the unique semiopen framework facilitates more efficient O₂ transport. This work presents a robust two-in-one strategy for the simultaneous engineering of active sites and mass-transfer efficiency.