Charge Dilution of Fe–N ₄ Sites via Te Single-Atom Electron Pumps for Robust Oxygen Reduction

The high desorption energy barrier for OH – hinders the improvement of the oxygen reduction reaction (ORR) and related devices. Here, an Fe-based atom pair catalyst for ORR is discovered through high-throughput density functional theory calculations. The atomic Te around the Fe 1 –N 4 site (Te 1 –N 2 –Fe 1 –N 2 ) served as an electron pump to achieve charge dilution, contributing to an onset potential of 1.03 V and a half-wave potential of 0.94 V. Moreover, a kinetics current density of 32.4 mA cm –2 and remarkable durability up to 20000 continuous electrolysis cycles (1/4 activity decay that of the Fe 1 –N 4 site) were achieved. An ab initio molecular dynamics simulation revealed the formation process of Fe–Te dual atoms. In situ characterization and comparative experiments verify that the charge dilution toward a single Fe site around atomic Te resulted in promoted O 2 conversion and accelerated *OH desorption. The corresponding Al-air batteries showed an open-circuit potential of 1.62 V, a power density of 138.1 mW cm –2, and stable voltages during the long-term discharging process (446 h at 10 mA cm –2 and 270 h at 20 mA cm –2 ). The study demonstrates the single-atom electron pump as an effective strategy for handling the charge density around single-atom sites for electrocatalysis.