Urea oxidation reaction (UOR) is an ideal alternative to oxygen evolution reaction (OER) for efficient hydrogen production but is immensely plagued by slow kinetics. Herein, a multilayer hole amorphous boron-nickel catalyst (a-NiB_x) is fabricated through a simple chemical plating method, which displays intriguing catalytic activity toward UOR, demanding a low working potential of 1.4 V to reach 100 mA cm⁻². The high performance is credited to the formation of metaborate (BO₂⁻), which can promote the formation of high-oxidation-state NiOOH active phase and optimize the adsorption of urea molecules. This can be confirmed by the operando spectroscopy characteristics and density functional theory calculations. Consequently, the assembled electrolyzer utilizing NiB_x as bifunctional catalysts exhibited splendid catalytic activity, requiring an evidently lower voltage of 1.66 V to reach a current density of 100 mA cm⁻² and 1.57 V when using Pt/C as a cathode catalyst. Moreover, the assembled electrolyzer secured a robust stability of over 200 h, as well as a four times higher hydrogen production rate than traditional water electrolysis.

中文翻译：

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揭示硼在镍基催化剂上对高效尿素氧化辅助制氢的作用


尿素氧化反应 （UOR） 是高效制氢的析氧反应 （OER） 的理想替代品，但受到缓慢动力学的严重困扰。本文通过简单的化学电镀方法制备了多层空穴非晶硼镍催化剂 （a-NiB _x ），该方法对 UOR 显示出有趣的催化活性，需要 1.4 V 的低工作电位才能达到 100 mA cm ⁻² 。高性能归功于代谢酸盐 （BO ₂ ） 的形成 ⁻ ，它可以促进高氧化态 NiOOH 活性相的形成并优化尿素分子的吸附。这可以通过原位光谱特性和密度泛函理论计算来证实。因此，使用 NiB _x 作为双功能催化剂的组装电解槽表现出出色的催化活性，当使用 Pt/C 作为阴极催化剂时，需要明显较低的 1.66 V 电压才能达到 100 mA cm ⁻² 和 1.57 V 的电流密度。此外，组装好的电解槽确保了超过 200 小时的稳定稳定性，以及比传统水电解高四倍的制氢速率。