Guidelines for the Rational Design of Ni-Based Double Hydroxide Electrocatalysts for the Oxygen Evolution Reaction

The oxygen evolution reaction (OER) is one of the major bottlenecks hindering the implementation of a global economy based on solar fuels. It is known that Ni-based catalysts exhibit remarkable catalytic activities for the OER in alkaline media. In this joint theoretical–experimental study, we provide a thorough characterization of Ni-based double hydroxides with Cr, Mn, Fe, Co, Cu, and Zn at the atomic scale that not only explains the reasons for their high activity but also provides simple design principles for the enhancement of their electrocatalytic properties. Our approach, based on the local symmetry and composition of the active sites, helps rationalize the effect of dopants on the catalytic activity of Ni(OH) 2 . In particular, NiFe, NiCr, and NiMn double hydroxides (DHs) have superior catalytic activity, which reduce the OER potential to reach 0.5 mA cm –2 by 230, 190, and 160 mV, respectively, in comparison to IrO 2 nanoparticles, the state-of-the-art benchmarking catalysts, with 90% Faradaic efficiency for O 2 generation. The active species in NiFe and NiMn DHs are iron and manganese, while in NiCr DH, nickel is the active species.