Controlled synthesis of trimetallic nitrogen-incorporated CoNiFe layered double hydroxide electrocatalysts for boosting the oxygen evolution reaction

The development of non-precious trimetallic electrocatalysts exhibiting high activity and stability is a promising strategy for fabricating efficient electrocatalysts for the oxygen evolution reaction (OER). In this study, trimetallic nitrogen-incorporated CoNiFe (N-CoNiFe) was produced to solve the low OER efficiency using a facile co-precipitation method in the presence of ethanolamine (EA) ligands. A series of CoNiFe catalysts at different EA concentrations were also investigated to determine the effects of the ligand in the co-precipitation of a trimetallic system. The introduction of an optimized EA concentration (20 mM) improved the electrocatalytic performance of N-CoNiFe dramatically, with an overpotential of 318 mV at 10 mA cm^-2 in 1.0 M KOH and a Tafel slope of 72.2 mV dec^-1. In addition, N-CoNiFe shows high durability in the OER process with little change in the overpotential (ca. 16.0 mV) at 10 mA cm^-2 after 2000 cycles, which was smaller than that for commercial Ir/C (38.0 mV).