Sulfur‐Tuned Main‐Group Sb−N−C Catalysts for Selective 2‐Electron and 4‐Electron Oxygen Reduction

Abstract The selective oxygen reduction reaction (ORR) is important for various energy conversion processes such as the fuel cells and metal‐air batteries for the 4e⁻ pathway and hydrogen peroxide (H₂O₂) electrosynthesis for the 2e⁻ pathway. However, it remains a challenge to tune the ORR selectivity of a catalyst in a controllable manner. Herein, an efficient strategy for introducing sulfur dopants to regulate the ORR selectivity of main‐group Sb−N−C single‐atom catalysts is reported. Significantly, Sb−N−C with the highest sulfur content follows a 2e⁻ pathway with high H₂O₂ selectivity (96.8%) and remarkable mass activity (96.1 A g⁻¹ at 0.65 V), while the sister catalyst with the lowest sulfur content directs a 4e⁻ pathway with a half‐wave potential (E_1/2 = 0.89 V) that is more positive than commercial Pt/C. In addition, practical applications for these two 2e⁻/4e⁻ ORR catalysts are demonstrated by bulk H₂O₂ electrosynthesis for the degradation of organic pollutants and a high‐power zinc‐air battery, respectively. Combined experimental and theoretical studies reveal that the excellent selectivity for the sulfurized Sb−N−Cs is attributed to the optimal adsorption‐desorption of the ORR intermediates realized through the electronic structure modulation by the sulfur dopants.