Mo4/3B2O2-supported single-atom catalysts for oxygen reduction reaction

Exploring earth-abundant and inexpensive electrocatalysts to realize efficient oxygen reduction reaction (ORR) is urgently desired. In this work, through first-principles calculations, we have strategically designed a series of single-atom catalysts (SACs) for ORR by immobilizing single atoms on the surface of Mo4/3B2O2, denoted as TM@Mo4/3B2O2 (TM representing 3d, 4d, and 5d transition metal atoms, excluding Tc and Hg). Significantly, for 4e ORR, the best catalyst was Co@Mo4/3B2O2 and Ru@Mo4/3B2O2, with an overpotential of 0.61 V and 0.63 V, close to the commonly used Pt catalyst (0.45 V). In 2e ORR, Zn@Mo4/3B2O2 had the best catalytic activity, with Delta G(*OOH) of -2.47 eV, close to the commonly used Pd catalyst (G* OOH = -3.17 eV). By calculating the electronic properties of SACs, it was found that the number of electrons gained by the intermediate *O-2 and *OOH from the SACs determines the O-2 adsorption structures and ORR reaction pathways. In addition, there are two descriptors: ICOHP and a composition descriptor which provides atomic-level insights, that were found to summarize the ORR activity rules. Our work enriches the applications of the MBenes family in catalysis, and provides feasible guidance for the design of low-cost and high-effect ORR catalysts.