Electrocatalytic water cracking for hydrogen evolution has drawn attention from researchers owing to its high efficiency. Polymolybdate has excellent redox behaviors and an O-rich surface, becoming attractive electrocatalytic materials. In this work, iso- and hetero-polymolybdate anions were introduced in the crystalline metal–organic coordination system as electrocatalytic electrode material for hydrogen evolution reactions. Semi-rigid bi-pyrazole bi-amide ligand was taken as the organic component, and four complexes were yielded under hydrothermal conditions. The reconstruction and oriented immobilization of polymolybdate occur during the assembly of the architectures, owing to the potential template effect from the metal–organic units. This phenomenon influences the distribution of active sites from polymolybdate. The discrete [AlMo₆(OH)₇O₁₇]²⁻ anions in complex 3 were immobilized among the directionally arranged metal–organic chains and exposed more active sites. The carbon cloth-based electrode modified by complex 3 possesses obvious electrocatalytic activity by achieving a low overpotential of 17.0 mV at a current density of 10 mA cm⁻² in 1 M KOH for the hydrogen evolution reaction. Meanwhile, an overpotential of 33.7 mV can be achieved when the current density is 10 mA cm⁻² in simulated seawater.

中文翻译：

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金属-有机配位单元诱导的多钼酸盐的重建和固定化，以增强电催化制氢


用于析氢的电催化水裂化因其高效率而受到研究人员的关注。多钼酸盐具有出色的氧化还原行为和富含 O 的表面，成为有吸引力的电催化材料。在这项工作中，异异多钼酸盐阴离子被引入晶体金属-有机配位系统中，作为析氢反应的电催化电极材料。以半刚性双吡唑双酰胺配体为有机组分，在水热条件下生成 4 种配合物。多钼酸盐的重建和定向固定发生在结构的组装过程中，这是由于金属-有机单元的潜在模板效应。这种现象会影响多钼酸盐活性位点的分布。复合物 3 中离散的 [AlMo₆（OH）₇O₁₇] ²⁻ 阴离子被固定在定向排列的金属有机链之间，并暴露出更多的活性位点。由络合物 3 改性的碳布基电极具有明显的电催化活性，在 1 M KOH 中，在 10 mA ^cm-2 的电流密度下，析氢反应达到 17.0 mV 的低过电位。同时，当模拟海水中的电流密度为 10 mA ^cm-2 时，可以实现 33.7 mV 的过电位。