Modulating the electronic structure of NiFe hydroxide by Zr doping enables industrial-grade current densities for water oxidation

Abstract

NiFe layered double hydroxide (LDH) is a non-noble benchmark catalyst for oxygen evolution reaction (OER). However, the mechanism of enhancing catalytic activities via incorporating foreign elements is still not resolved. Herein, we modulate the electronic structure of NiFe LDH by introducing high-valence Zr4+ to synergistically improve catalytic activity. NiFeZr LDH requires overpotential of only 182 mV at 10 mA cm−2 with Tafel slope of 38.6 mV dec−1. Impressively, it delivers 2000 mA cm−2 at only 314 mV and has robust durability over 750 h. Operational Raman analysis reveals that the electron transfer after incorporating Zr4+ inhibits oxidation of Ni2+ ions and restrains phase transition from active β-NiOOH to γ-NiOOH during OER process. Guided by density functional theory (DFT) computations, Zr4+ modulator promotes the rate-determining step from OH* to O* via optimizing the oxidation cycle at Fe active sites. This work provides a route for advancing electrocatalysts to meet industrial standards.