Authors: Minmin Yan, Hao Yang, Zhichao Gong, Jiarui Zhu, Christopher Allen, Tao Cheng, Huilong Fei
Published: 2024-04-15
Source: Full article
AbstractThe 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 (E1/2 = 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.