Constructing High Efficiency CoZn x Mn 2-x O 4 Electrocatalyst by Regulating the Electronic Structure and Surface Reconstruction.

It is an effective strategy to develop novel electrocatalysts with controllable defects to enhance their electrocatalytic activity and stability. However, how to precisely design these catalysts on the atom scale remains very difficult. Herein, several vacancy-dependent CoZn x Mn 2-x O 4 catalysts are prepared through tailoring the concentration of Zn ions. The in situ activation of the obtained products accelerates the surface reconstruction. The superior electrocatalytic performance can be ascribed to the formations of MOOH (Mn, Co) active species and abundant oxygen vacancies, which are comparable to noble IrO 2 and Pt/C catalysts. Zn-CoMn 2 O 4 -1.5 catalyst delivers a cell voltage of 1.63 V and long durability. Density functional theory calculations demonstrate that the appropriate Zn ion doping can improve the density states of p electron on the surface of catalysts significantly and benefit the d-band center closing to Fermi level, suggesting their high charge carrier density and low adsorption energy.