Barati Darband Ghasem, Iravani Danial, Zhang Meiling, Maleki Meysam, Huang Shanrui, Khoshfetrat Seyyed Mehdi, Andaveh Reza, Li Jinyang
Materials and Metallurgical Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad 91775-1111, Iran.
Chemical Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran.
Nanoscale. 2025 Jan 23;17(4):2162-2173. doi: 10.1039/d4nr03486d.
Electrochemical water splitting, with its oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), is undoubtedly the most eco-friendly and sustainable method to produce hydrogen. However, water splitting still requires improvement due to the high energy consumption caused by the slow kinetics and large thermodynamic potential requirements of OER. Urea-water electrolysis has become increasingly appealing compared to water-splitting because of the remarkable decline in the cell potential in the hydrogen production process and less energy consumption; it also offers a favorable opportunity to efficiently treat wastewater containing a significant amount of urea. In this work, Ni-Mn-S/Ni-Cu nano-micro array electrocatalysts were synthesized by a two-step and binder-free electrochemical deposition technique and investigated as an effective electrode for the HER and urea oxidation reaction (UOR). According to the electrochemical results, the optimized electrode (Ni-Mn-S/Ni-Cu/10) showed excellent electrocatalytic activity for the HER (64 mV overpotential to achieve the current density of 10 mA cm and Tafel slope of 81 mV dec) in alkaline solution. When Ni-Mn-S/Ni-Cu/10 is employed as a UOR anode in an alkaline solution containing urea, it achieves a current density of 10 mA cm at 1.247 V RHE. In addition, when the optimized sample was utilized as a bi-functional electrode for overall urea-water electrolysis (HER-UOR), the cell voltage reached 1.302 V at 10 mA cm (which is 141 mV less than that for HER-OER). The electrocatalytic stability results unequivocally revealed small changes in voltage during a 24 h test and showed good durability. This non-noble metal electrocatalyst, prepared by the electrodeposition synthesis method, is a promising solution to implement low-cost hydrogen production and wastewater treatment.
电化学水分解及其析氧反应（OER）和析氢反应（HER），无疑是生产氢气最环保、最可持续的方法。然而，由于OER的缓慢动力学和较大的热力学电位要求导致的高能耗，水分解仍需改进。与水分解相比，尿素水电解在制氢过程中电池电位显著下降且能耗更低，因此越来越有吸引力；它还为高效处理含有大量尿素的废水提供了有利机会。在这项工作中，通过两步无粘结剂电化学沉积技术合成了Ni-Mn-S/Ni-Cu纳米微阵列电催化剂，并将其作为HER和尿素氧化反应（UOR）的有效电极进行了研究。根据电化学结果，优化后的电极（Ni-Mn-S/Ni-Cu/10）在碱性溶液中对HER表现出优异的电催化活性（达到10 mA cm电流密度时的过电位为64 mV，塔菲尔斜率为81 mV dec）。当Ni-Mn-S/Ni-Cu/10在含尿素的碱性溶液中用作UOR阳极时，在1.247 V RHE下可实现10 mA cm的电流密度。此外，当将优化后的样品用作整体尿素水电解（HER-UOR）的双功能电极时，在10 mA cm下电池电压达到1.302 V（比HER-OER低141 mV）。电催化稳定性结果明确显示，在24小时测试期间电压变化很小，具有良好的耐久性。这种通过电沉积合成方法制备的非贵金属电催化剂，是实现低成本制氢和废水处理的一种有前途的解决方案。
