Chen Chunchao, Jin Liujun, Hu Lei, Zhang Tingyu, He Jinghui, Gu Peiyang, Xu Qingfeng, Lu Jianmei
College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, Jiangsu 215123, China.
College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, Jiangsu 215123, China.
J Colloid Interface Sci. 2022 Dec 15;628(Pt B):1008-1018. doi: 10.1016/j.jcis.2022.08.127. Epub 2022 Aug 24.
Electrocatalyzed urea-assisted wastewater splitting is a promising approach for sustainable hydrogen production. However, the lack of cost-efficient electrocatalysts hinders its practical application. Herein, bimetal phosphide (NiCoP) nanowire arrays decorated with ultrathin NiFeCo metal-organic framework (NiFeCo-MOF) nanosheets on porous nickel foam (NF) were designed for urea-assisted wastewater splitting. The core-shell NiCoP@NiFeCo-MOF hybrids were prepared via successive hydrothermal, gas-phase phosphorization and hydrothermal strategies. Encouragingly, the novel NiCoP@NiFeCo-MOF/NF electrode served as an excellent bifunctional electrocatalyst for both the cathodic hydrogen evolution reaction (HER) and the anodic urea oxidation reaction (UOR) in urea-assisted water splitting, which merely required an overpotential of 44 mV to deliver a current density of 10 mA cm for HER and a voltage of 1.37 V to deliver a current density of 100 mA cm for UOR in 1.0 M KOH + 0.5 M urea. Benefiting from the highly exposed electroactive sites in exquisite three-dimensional (3D) hierarchical structure, multicomponent synergistic effect, accelerated electron transfer, easy electrolyte access and diffusion of released gas bubbles, the as-fabricated NiCoP@NiFeCo-MOF/NF exhibited outstanding electrocatalytic performance. The mechanism of water splitting was elucidated by density functional theory calculations. Interestingly, NiFeCo-MOF possessed optimized COO* adsorption ability on Ni sites that were beneficial to UOR intermediates. More significantly, this work paves the way for the design and fabrication of bifunctional electrocatalysts for urea-containing wastewater treatment and sustainable hydrogen production.
电催化尿素辅助废水分解是一种很有前景的可持续制氢方法。然而，缺乏具有成本效益的电催化剂阻碍了其实际应用。在此，设计了在多孔泡沫镍（NF）上装饰有超薄镍铁钴金属有机框架（NiFeCo-MOF）纳米片的双金属磷化物（NiCoP）纳米线阵列用于尿素辅助废水分解。通过连续水热、气相磷化和水热策略制备了核壳结构的NiCoP@NiFeCo-MOF杂化物。令人鼓舞的是，新型的NiCoP@NiFeCo-MOF/NF电极在尿素辅助水分解中对阴极析氢反应（HER）和阳极尿素氧化反应（UOR）均表现出优异的双功能电催化性能，在1.0 M KOH + 0.5 M尿素中，HER仅需44 mV的过电位即可提供10 mA cm的电流密度，UOR仅需1.37 V的电压即可提供100 mA cm的电流密度。得益于其精致的三维（3D）分级结构中高度暴露的电活性位点、多组分协同效应、加速的电子转移、易于电解质进入以及释放气泡的扩散，所制备的NiCoP@NiFeCo-MOF/NF表现出出色的电催化性能。通过密度泛函理论计算阐明了水分解的机理。有趣的是，NiFeCo-MOF在Ni位点上具有优化的COO*吸附能力，这有利于UOR中间体。更重要的是，这项工作为设计和制造用于含尿素废水处理和可持续制氢的双功能电催化剂铺平了道路。
