Hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) are key reactions of the water-cycling associated catalytic process/device. The design of catalysts with a super-hydrophilic/aerophobic structure and optimized electron distribution holds great promise. Here, we have designed a three-dimensional (3D) hollow Ni/NiMoN hierarchical structure with arrayed-sheet surface based on a one-pot hydrothermal route for efficient urea-assisted HER based on a simple hydrothermal process. The Ni/NiMoN catalyst exhibits super-hydrophilic/aerophobic properties with a small droplet contact angle of 6.07° and an underwater bubble contact angle of 155.7°, thus facilitating an escape of bubbles from the electrodes. Density functional theory calculations and X-ray photoelectron spectroscopy results indicate the optimized electronic structure at the interface of Ni and NiMoN, which can promote the adsorption/desorption of reactants and intermediates. The virtues combining with a large specific surface area endow Ni/NiMoN with efficient catalytic activity of low potentials of 25 mV for HER and 1.33 V for UOR at 10 mA cm. The coupled HER and UOR system demonstrates a low cell voltage of 1.42 V at 10 mA cm, which is approximately 209 mV lower than water electrolysis.

中文翻译：

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具有超亲水/疏气表面的空心 NiMo 基氮化物异质结，用于高效尿素辅助制氢


析氢反应（HER）和尿素氧化反应（UOR）是水循环相关催化过程/装置的关键反应。具有超亲水/疏气结构和优化电子分布的催化剂的设计具有广阔的前景。在这里，我们设计了一种基于一锅水热路线的具有阵列片表面的三维（3D）空心Ni/NiMoN分级结构，用于基于简单水热过程的高效尿素辅助HER。 Ni/NiMoN催化剂表现出超亲水/疏气特性，小液滴接触角为6.07°，水下气泡接触角为155.7°，从而有利于气泡从电极中逸出。密度泛函理论计算和X射线光电子能谱结果表明Ni和NiMoN界面处的电子结构优化，可以促进反应物和中间体的吸附/解吸。这些优点与大比表面积相结合，赋予 Ni/NiMoN 高效的催化活性，在 10 mA cm 电流下，HER 电势为 25 mV，UOR 电势为 1.33 V。耦合的 HER 和 UOR 系统在 10 mA cm 时表现出 1.42 V 的低电池电压，比水电解低约 209 mV。