Honeycomb-like MoCo alloy on 3D nitrogen-doped porous graphene for efficient hydrogen evolution reaction

An efficient electrocatalyst is indispensable to significantly reduce energy consumption and accelerate the conversion efficiency of water splitting. In this work, the honeycomb-like porous MoCo alloy on nitrogen-doped three-dimensional (3D) porous graphene substrate (Mo0.3Co0.7@NPG) has been synthesized from the annealing of layered double hydroxide (MoCo-LDH@NPG). Especially, the Mo0.3Co0.7@NPG exhibits low hydrogen evolution overpotential of 75 mV (10 mA·cm–2) and a Tafel slope of 69.9 mV·dec–1, which can be attributed to highly conductive NPG substrate, the unique nanostructure and the synergistic effect of Mo and Co. Moreover, the Mo0.3Co0.7@NPG can maintain the original morphology and high catalytic activity after 50-h stability test. This work proposes a general strategy to synthesize a multi-element alloy on conductive substrates with high porosity for electrocatalytic reaction. 高效的电催化剂可以显著降低电解水的能耗和提高转化效率。本项工作以MoCo双金属氢氧化物作为前驱体, 在三维(3D) 氮掺杂多孔石墨烯衬底上合成了蜂窝状多孔MoCo合金(Mo0.3Co0.7@NPG)。在析氢反应中, Mo0.3Co0.7@NPG的析氢过电位为75 mV (10 mA cm–2), Tafel斜率为69.9 mV dec–1。Mo0.3Co0.7@NPG具有优异的电化学性能主要归功于NPG衬底的高导电性、MoCo合金独特的纳米结构以及Mo和Co的协同作用。此外, 经过50 h的稳定性测试, Mo0.3Co0.7@NPG仍能保持原有的形貌和较高的催化活性。因此, 本项工作对于在高孔隙率导电基板上合成高效的多元素合金电催化剂提供了一种思路。