Wang Kang, Fan Chao, Hu Ruihang, Sun Chen, Wang Yan-Qin
Inner Mongolia Key Laboratory of Rare Earth Catalysis, College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, P. R. China.
Dalton Trans. 2025 Jul 22;54(29):11419-11426. doi: 10.1039/d5dt01123j.
During conventional water electrolysis for hydrogen production, the high theoretical potential of the oxygen evolution reaction (OER) leads to excessive energy consumption. In contrast, the urea oxidation reaction (UOR), with its significantly lower theoretical potential, has attracted considerable attention as an energy-efficient alternative for hydrogen production. In this study, we developed a Ni-doped Mn MOF-74 (Ni-Mn MOF-74) catalyst supported on carbon cloth (CC), exhibiting a unique bud-like architecture featuring a petal-surrounded pistil morphology, which exhibits excellent UOR performance in alkaline medium. This catalyst achieves a current density of 100 mA cm at an ultralow potential of 1.40 V ( RHE) in a 1.0 M KOH + 0.5 M urea electrolyte while maintaining remarkable stability. Importantly, in a urea-assisted hydrogen production electrolyzer composed of Ni-Mn MOF-74 (anode) and Pt/C (cathode), the system delivers a current density of 100 mA cm at a cell voltage of only 1.49 V in alkaline freshwater and 1.50 V in alkaline seawater, respectively, while retaining excellent stability. The enhanced UOR activity stems from Ni doping, which effectively modulates the catalyst's morphology and electronic structure; the synergism of Ni and Mn strengthens the adsorption of urea molecules and OH ions, thereby accelerating urea decomposition kinetics.
在传统的水电解制氢过程中，析氧反应（OER）的高理论电位导致了过多的能量消耗。相比之下，尿素氧化反应（UOR）具有显著更低的理论电位，作为一种节能的制氢替代方法受到了广泛关注。在本研究中，我们开发了一种负载在碳布（CC）上的镍掺杂锰MOF-74（Ni-Mn MOF-74）催化剂，其呈现出独特的芽状结构，具有花瓣环绕雌蕊的形态，在碱性介质中表现出优异的UOR性能。该催化剂在1.0 M KOH + 0.5 M尿素电解液中，在1.40 V（RHE）的超低电位下实现了100 mA cm的电流密度，同时保持了显著的稳定性。重要的是，在由Ni-Mn MOF-74（阳极）和Pt/C（阴极）组成的尿素辅助制氢电解槽中，该系统在碱性淡水和碱性海水中分别在仅1.49 V和1.50 V的电池电压下实现了100 mA cm的电流密度，同时保持了优异的稳定性。UOR活性的增强源于镍掺杂，它有效地调节了催化剂的形态和电子结构；镍和锰的协同作用增强了尿素分子和OH离子的吸附，从而加速了尿素分解动力学。
