Tuning the Electronic Structures of Multimetal Oxide Nanoplates to Realize Favorable Adsorption Energies of Oxygenated Intermediates.

Abstract

Highly active oxygen evolution reaction (OER) electrocatalysts are important to effectively transform renewable electricity to fuel and chemicals. In this work, we construct a series of multimetal oxide nanoplate OER electrocatalysts through successive cation exchange followed by electrochemical oxidation, whose electronic structure and diversified metal active sites can be engineered <i>via</i> the mutual synergy among multiple metal species. Among the examined multimetal oxide nanoplates, CoCeNiFeZnCuO_<i>x</i> nanoplates exhibit the optimal adsorption energy of OER intermediates. Together with the high electrochemical active surface area, the CoCeNiFeZnCuO_<i>x</i> nanoplates manage to deliver a small overpotential of 211 mV at an OER current density of 10 mA cm^-2 (η₁₀) with a Tafel slope as low as 21 mV dec^-1 in 1 M KOH solution, superior to commercial IrO₂ (339 mV at η₁₀, Tafel slope of 55 mV dec^-1), which can be stably operated at 10 mA cm^-2 (at an overpotential of 211 mV) and 100 mA cm^-2 (at an overpotential of 307 mV) for 100 h.