College of Chemistry and Chemical Engineering, Chongqing University , Chongqing 400044, China.
College of Physics, Chongqing University , Chongqing 400044, China.
ACS Appl Mater Interfaces. 2017 Jul 12;9(27):22420-22431. doi: 10.1021/acsami.7b04009. Epub 2017 Jun 26.
First-row (3d) transition-metal catalysts, such as bimetallic Ni-Co, represent an emerging class of electrocatalysts for HER, but they usually suffer from a large overpotential significantly above thermodynamic demands. Here, we doped NiCo catalyst with non3d metals molybdenum (Mo) for improvement in catalyzing the hydrogen evolution reaction. The ternary catalyst was readily obtained by a one-pot process via the sequential electrodeposition of Ni, Co, and Mo precursors on titanium (Ti) support. By tailing the deposition conditions, we fabricated NiCoMo catalysts with three-dimensional dendritic structures, exhibiting large amounts of electrochemically active sites. To attain the benchmark HER current density of -10 mA cm, an overpotential of ∼132 mV is required in 0.1 M KOH for the Mo-doped NiCo (5 atom % Mo in bath), and they produced the decreasing in Tafel slope of ∼108 mV decade exceeding those of binary NiCo alloy catalysts and other contents of Mo doping. In a synergistic effect, dopant incorporation of Mo element may provide near-optimal adsorption energies for HER intermediates promoting the process of water dissociation and hydrogen intermediates production and binding into molecular hydrogen.
第一过渡金属（3d）催化剂，如双金属 Ni-Co，是一种新兴的析氢反应（HER）电催化剂，但它们通常存在较大的过电位，远高于热力学需求。在此，我们通过在钛（Ti）基底上依次电沉积 Ni、Co 和 Mo 前体，采用一锅法掺杂非 3d 金属钼（Mo）以改善 NiCo 催化剂对析氢反应的催化性能。通过调整沉积条件，我们制备了具有三维树枝状结构的 NiCoMo 催化剂，具有大量的电化学活性位点。在 0.1 M KOH 中，Mo 掺杂的 NiCo（浴中 5 原子% Mo）达到基准析氢电流密度-10 mA cm 需要的过电位约为 132 mV，它们的塔菲尔斜率下降到 108 mV decade 以下，优于二元 NiCo 合金催化剂和其他 Mo 掺杂浓度的催化剂。在协同效应中，Mo 元素的掺杂可能会为 HER 中间体提供接近最佳的吸附能，从而促进水分解过程以及氢中间体的生成和结合成氢气。
