Regulating the double-site Mn2-N6 electronic structure by manganese clusters for enhanced oxygen reduction

Abstract

Effectively designing the coordination environment of metal atoms in single-atom catalysts to enhance the oxygen reduction reaction (ORR) performance is challenging. Herein, a strategy for regulating the electronic structure of double-site Mn2-N6 by axial traction of Mn cluster is presented. The atomically dispersed homonuclear double-site Mn2-N6 was synthesized. Experimental investigations and theoretical calculations revealed that the oxygen adsorption capacity of double-site Mn2-N6 was stronger than that of Mn-N4, which can improve the weak adsorption of oxygen at isolated Mn active sites. The introduction of Mn clusters broke the planar structure of Mn2-N6 through axial traction, further altering the electron configuration around the active sites and effectively decreasing the adsorption strength of oxygen-containing intermediates and reaction energy barriers, leading to increased intrinsic activity, which greatly improved the ORR performance (E1/2 = 0.91 V). This work presented a novel way of regulating the electronic structure of homonuclear double single-atom sites by clusters.