ScholarWorks@동국대학교

초록

The sluggish kinetics of the oxygen reduction reaction (ORR) and high over potential of oxygen evolution reaction (OER) are big challenges in the development of high-performance zinc-air batteries (ZABs) and fuel cells. In this work, we report a rational design and a simple fabrication strategy of a photo-enhanced Co single-atom catalyst (SAC) comprising g-C3N4 coupled with cobalt-nitrogen-doped hierarchical mesoporous carbon (Co-N/MPC), forming a staggered p-n heterojunction that effectively improves charge separation and enhances electrocatalytic activity. The incorporation of Co SACs and g-C3N4 synergistically optimizes the photogenerated electron-hole pair separation, significantly boosting the intrinsic ORR-OER duplex activity. Under illumination, g-C3N4@Co-N/MPC exhibits an outstanding ORR half-wave potential (E1/2) of 0.841 V (vs. RHE) in 0.1 mol L–1 KOH and a low OER overpotential of 497.4 mV (vs. RHE) at 10 mA cm–2 in 1 mol L–1 KOH. Notably, the catalyst achieves an exceptional peak power density of 850.7 mW cm–2 in ZABs and of 411 mW cm–2 even in H2-air fuel cell. In addition, g-C3N4@Co-N/MPC-based ZABs also show remarkable cycling stability exceeding 250 h. The advanced photo-induced charge separation at the p-n heterojunction facilitates faster electron transfer kinetics, and the mass transport owing to hierarchical mesoporous structure of Co-N-C, thereby reducing the overpotential and enhancing the overall energy conversion efficiency. This work provides a new perspective on designing next-generation of single-atom dispersed oxygen reaction catalysts, paving the way for high-performance photo-enhanced energy storage and conversion systems. © 2025 Dalian Institute of Chemical Physics, the Chinese Academy of Sciences

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