Comparison Study toward the Influence of the Second Metals Doping on the Oxygen Evolution Activity of Cobalt Nitrides

We report on the development of secondary metals doped Co5.47N nanosheets [donated as CoM(3:1)-N (M = Fe, Ni, Mn, and Zn; 3:1 is the molar ratio of Co to M)] as nonprecious metal OER catalysts. Electrochemical test results show that the Fe-doped CoFe(3:1)-N possesses superior OER activity (only need an overpotential of 200 mV to drive 10 mA cm(-2)) and long-term durability in 1.0 M KOH which outperform those of RuO2. X-ray photoelectron spectroscopy characterization results reveal that the Fe doping into crystal texture has led to the largest positive shift (similar to 1.2 eV) in binding energy of Co 2p compared to Ni, Mn, and Zn; the Lewis acid effect of Fe3+ can boost the formation of more Co4+ OER active sites. Our finding discloses the enhancing mechanism of OER on second metals-doped bimetallic nitrides and meanwhile affords a new concept toward exploring and designing high-efficiency non-noble metal OER electrocatalysts.