Recently, Professors Jiang Qing and Yang Chuncheng from the College of Materials Science and Engineering, Jilin University collaborated with Professor Chandra Veer Singh from the Department of Materials Science and Engineering, University of Toronto, Canada, and achieved new advances in electrocatalytic oxygen reduction reaction (ORR) and zinc–air batteries. The corresponding research paper, entitled Vacancy-Enhanced Sb-N₄ Sites for the Oxygen Reduction Reaction and Zn-Air Battery, was published online on March 29, 2024 in Nano Letters.

p-block metal single-atom catalysts exhibit excellent resistance to Fenton-like reactions, and their distinctive p-electrons can hybridize with O₂ to lower reaction energy barriers, rendering them promising candidates for ORR catalysis. Nevertheless, p-block metals possess a fully occupied d¹⁰ electronic configuration, which hinders electron transfer during electrochemical processes and thus results in inferior intrinsic catalytic activity.

To address this limitation, this work designs a single-atom catalyst with vacancy-boosted Sb-N₄ moieties for the ORR. Multiple characterization techniques including spherical aberration-corrected transmission electron microscopy, X-ray absorption fine structure spectroscopy and electron paramagnetic resonance spectroscopy verify the existence of abundant Sb-N₄ sites and plentiful carbon vacancies within the single-atom material.

Figure 1. Microstructural characterizations of Sb single-atom catalysts.

Abundant carbon vacancies not only anchor isolated Sb single atoms stably, but also effectively activate the p-orbital electrons of Sb species and tune the adsorption strength toward reaction intermediates, which drastically elevates intrinsic catalytic activity. Benefiting from vacancy-modulated Sb-N₄ active sites, the catalyst delivers outstanding ORR performance with a half-wave potential of 0.905 V and a small Tafel slope of 50.6 mV dec⁻¹. Moreover, the Zn–air battery assembled with this catalyst as the cathode achieves a peak power density of 181 mW cm⁻² and a discharge specific capacity of 794 mAh g⁻¹.

Figure 2. ORR electrocatalytic performance and Zn–air battery performance of Sb single-atom catalysts.