Gao Xiafei, Gao Mengyue, Yu Xueping, Jin Xiaoyong, Ni Gang, Peng Juan
State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China.
Molecules. 2023 Oct 18;28(20):7147. doi: 10.3390/molecules28207147.
The very slow anodic oxygen evolution reaction (OER) greatly limits the development of large-scale hydrogen production via water electrolysis. By replacing OER with an easier urea oxidation reaction (UOR), developing an HER/UOR coupling electrolysis system for hydrogen production could save a significant amount of energy and money. An Al-doped cobalt ferrocyanide (Al-CoFe(CN)) nanocube array was in situ grown on nickel foam (Al-CoFe(CN)/NF). Due to the unique nanocube array structure and regulated electronic structure of Al-CoFe(CN), the as-prepared Al-CoFe(CN)/NF electrode exhibited outstanding catalytic activities and long-term stability to both UOR and HER. The Al-CoFe(CN)/NF electrode needed potentials of 0.169 V and 1.118 V (vs. a reversible hydrogen electrode) to drive 10 mA cm for HER and UOR, respectively, in alkaline conditions. Applying the Al-CoFe(CN)/NF to a whole-urea electrolysis system, 10 mA cm was achieved at a cell voltage of 1.357 V, which saved 11.2% electricity energy compared to that of traditional water splitting. Density functional theory calculations demonstrated that the boosted UOR activity comes from Co sites with Al-doped electronic environments. This promoted and balanced the adsorption/desorption of the main intermediates in the UOR process. This work indicates that Co-based materials as efficient catalysts have great prospects for application in urea electrolysis systems and are expected to achieve low-cost and energy-saving H production.
极缓慢的阳极析氧反应（OER）极大地限制了通过水电解大规模制氢的发展。通过用更易进行的尿素氧化反应（UOR）取代OER，开发用于制氢的HER/UOR耦合电解系统可以节省大量能源和资金。在泡沫镍上原位生长了铝掺杂的钴铁氰化物（Al-CoFe(CN)）纳米立方体阵列（Al-CoFe(CN)/NF）。由于Al-CoFe(CN)独特的纳米立方体阵列结构和调控的电子结构，所制备的Al-CoFe(CN)/NF电极对UOR和HER均表现出优异的催化活性和长期稳定性。在碱性条件下，Al-CoFe(CN)/NF电极驱动HER和UOR达到10 mA cm分别需要0.169 V和1.118 V（相对于可逆氢电极）的电位。将Al-CoFe(CN)/NF应用于全尿素电解系统，在电池电压为1.357 V时实现了10 mA cm，与传统水分解相比节省了11.2%的电能。密度泛函理论计算表明，增强的UOR活性来自具有铝掺杂电子环境的钴位点。这促进并平衡了UOR过程中主要中间体的吸附/解吸。这项工作表明，钴基材料作为高效催化剂在尿素电解系统中具有广阔的应用前景，有望实现低成本和节能的制氢。
