Hierarchically Porous Carbonized Wood Decorated with MoNi<sub>4</sub>‐Embedded MoO<sub>2</sub> Nanosheets: An Efficient Electrocatalyst for Water Splitting
Chengwei Mao, Zhikai Shi, Jiayao Peng, Liqi Ou, Yan Chen, Jianlin Huang
Abstract
Abstract Development of low‐cost electrocatalysts for water splitting is crucial to economical hydrogen production. Here, a highly efficient electrocatalyst composed of MoNi 4 ‐embedded amorphous MoO 2 nanosheets grown on less‐tortuosity hierarchically porous carbonized wood (MoNi 4 /MoO 2 @CW) is reported. The generation of abundant MoNi 4 /MoO 2 heterointerfaces and defects‐rich MoO 2 significantly promote the adsorption and activation of reactant molecules on the MoNi 4 /MoO 2 @CW. The obtained MoNi 4 /MoO 2 @CW catalyst exhibits ultralow overpotentials of 22 and 205 mV for hydrogen evolution reaction and oxygen evolution reaction at a current density of 10 mA cm −2 , respectively. The catalyst can be used for dual‐function electrodes and assembling two‐electrode electrolyzer illustrates 10 mA cm −2 at 1.47 V and superior durability over 24 h for overall water electrolysis. Moreover, it also possesses a high mass activity of 142 Ag −1 MoNi 4 at 200 mV, surpassing the Pt/C catalyst (132 Ag −1 ). The outstanding performance of the MoNi 4 /MoO 2 @CW is attributed to the decrease in energy barrier for water dissociation, optimal adsorption/desorption of H/O‐intermediates, and fast mass transport through the porous structure, as confirmed by experimental results and density functional theory‐based calculations. The MoNi 4 /MoO 2 @CW electrocatalyst has excellent potential for practical water splitting.