Inductive effect between atomically dispersed iridium and transition-metal hydroxide nanosheets enables highly efficient oxygen evolution reaction

Abstract

Oxygen evolution reaction (OER) remains the bottleneck of many energy transformation and storage technologies due to the sluggish kinetics. Transition-metal (TM) hydroxide nanosheets with high-valent TM ions possess high intrinsic catalytic activity toward OER. Herein, by taking advantage of the inductive effect, this work presents a facile and universal strategy to fabricate atomic iridium (Ir) incorporated TM hydroxide nanosheets as highly active OER electrocatalysts. As a representative, the fabricated Ir-Ni(OH)2 (4 wt% Ir) exhibits remarkable OER performance with a low overpotential (235 mV at 10 mA cm−2), a small Tafel slope (58.4 mV dec−1), and excellent durability (60 h) in alkaline solution, significantly outperforming the benchmark IrO2 and Ni(OH)2. Mechanism studies unveil that the inductive effect between Ni and Ir endows Ni(OH)2 with high-valent Ni species, which facilitate the adsorption of nucleophilic intermediates and boost the OER activity and long-term stability of Ir-Ni(OH)2. More importantly, the reported strategy could be extended to synthesize other monometallic/bimetallic TM hydroxide nanosheets (Co, CoMn) as highly efficient OER electrocatalysts. This work should pave a universal and promising avenue to rationally design and controllably synthesize efficient yet robust OER electrocatalysts in energy-related fields.