Non-precious metal activated MoSi2N4 monolayers for high-performance OER and ORR electrocatalysts: A first-principles study

Abstract

Developing high-performance electrocatalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is crucial for energy conversion and storage. Recently, a new type of two-dimensional material MoSi2N4 was successfully synthesized and received considerable attention because of novel properties and potential applications. Herein, by means of first principles calculation, the OER/ORR activities of 3d transition metal (TM) atoms embedded MoSi2N4 (TM@MSN) were investigated. The calculated results indicate that TM atoms on MoSi2N4 exhibit good electrochemical stability. On TM sites, Ti@MSN shows the highest OER activity with an overpotential of 0.48 V, whereas Cr@MSN is the most active ORR catalyst with an overpotential of 0.48 V. The Si site (Si−N1−Cu) of Cu@MSN follows the dual-site mechanism, exhibiting the same OER/ORR overpotential as that of N site (0.55/0.65 V). Interestingly, the outer N site (Zn−N1) of Zn@MSN achieves the lowest OER overpotential of 0.38 V, better than that of the state-of-the-art RuO2 catalyst. We demonstrate that 3d TM atoms not only serve as active sites themselves but also activate the host atoms to improve OER/ORR performance of MoSi2N4. Our work opens new windows of opportunity for developing novel catalysts beyond the precious metal-based electrocatalysts for efficient energy conversion and storage.