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Tuning proton-coupled electron transfer (PCET) is a promising strategy to boost the oxygen reduction reaction (ORR) for hydrogen peroxide (H2O2) synthesis, but the slow transmission rate of protons and electrons to active sites remains a significant bottleneck. To address this, we developed an H-bond-driven PCET process based on carbon quantum dot-anchored C3N5 (CQDs-C3N5) for piezo-catalytic H2O2 synthesis. CQDs-C3N5 exhibited a remarkable piezo-catalytic synthesis rate of 5025 μmol g-1 h-1 under ambient conditions, surpassing that of most reported piezoelectric materials. This efficiency is attributed to the intermolecular H-bonds between CQDs and C3N5, which significantly accelerate PCET in the ORR. The piezoelectric-generated charges, from the dipole field of the C3N5 plane, and protons in water, were rapidly transferred to the C rings of CQDs via H-bond networks. This process facilitated the adsorption of oxygen onto the C2 sites adjacent to the carboxyl groups of CQDs, which in turn led to the formation of H2O2 through a rapidly protonated, indirect 2e- pathway. Additionally, a piezo-self-Fenton reaction system was constructed for oxytetracycline-rich wastewater purification, with effectively effects on chemical oxygen demand, antibiotic-resistant bacteria and antibiotic-resistant genes degradation, etc. This study highlights the critical role of H-bond networks for tuning PCET in the ORR and provides a comprehensive understanding for the precise control of catalytic reaction kinetics through molecular structural engineering.
Li et al. (Tue,) studied this question.