Self‐Supported 3 D Ultrathin Cobalt–Nickel–Boron Nanoflakes as an Efficient Electrocatalyst for the Oxygen Evolution Reaction
Hefeng Yuan, Shiwei Wei, Bin Tang, Zizai Ma, Jinping Li, Manab Kundu, Xiaoguang Wang
Abstract
Abstract The development of highly active and efficient nonprecious‐metal electrocatalysts for the oxygen evolution reaction is important for the design of renewable energy production and storage devices. In this work, highly dense, ultrathin Co–Ni boride nanoflakes supported on a 3 D CoNi skeleton are fabricated in situ by a simple one‐step, high‐temperature, solid‐state boronation process. As a result of the induced high electroactive surface area and low charge transfer resistance, CoNiB‐700 exhibits high catalytic activity at an overpotential of 262 ( η 10 ) and 284 mV ( η 20 ) to deliver current densities of 10 and 20 mA cm −2 , respectively, with a Tafel slope of 58 mV dec −1 in an alkaline medium towards the oxygen evolution reaction. DFT calculations show that the Ni‐regulated Co–B compound has a lower rate‐determining energy barrier for the *OOH intermediate than the mono‐Co–B compound, which facilitates the production of more active catalytic sites for an accelerated surface charge‐transfer process for the oxygen evolution reaction.