双功能2D/3D杂化结构Co_(2)P-CeO_(x)异质结一体化电极的构筑及电催化尿素氧化辅助制氢性能

Construction of Dual-functional 2D/3D Hydrid Co_(2)P-CeO_(x) Heterostructure Integrated Electrode for Electrocatalytic Urea Oxidation Assisted Hydrogen Production

以泡沫镍(NF)为基底,通过多电位阶跃电沉积和低温磷化的方法,制备双功能的多层次二维/三维(2D/3D)杂化结构的Co_(2)P-CeO_(x)一体化电极(Co_(2)P-CeO_(x)/NF),并用于电催化尿素氧化辅助制氢性能研究.结果表明,通过3D CeO_(x)纳米花与2D Co_(2)P纳米片之间的强界面相互作用和良好的电子协同耦合作用,使该一体化电极具有较高的导电性、表面活性和稳定性,强化了电催化析氢反应(HER)和尿素氧化反应(UOR)性能.在两电极电解池体系下进行电催化制氢的同时降解尿素,电流密度达到30 mA/cm^(2)时,所需要电位为1.42 V,比全解水所需电位降低0.17 V,经过10 h电催化尿素的降解效率达76.4%;综合分析表明,2D Co_(2)P与3D CeO_(x)多层次纳米片异质界面处电子的定向转移,引起界面区域的局部电荷重新排布;形成的氧空位提供配位不饱和位点,暴露更多的活性位点,优化反应物分子在催化剂表面的吸附能,进而促进分子活化,使其具有较高的催化反应活性.

A high catalytic activity and stable dual-functional hierarchical 2D/3D hybrid Co_(2)P-CeO_(x)integrated electrode(Co_(2)P-CeO_(x)/NF)for electrocatalytic urea oxidation assisted hydrogen production was prepared by multi-step electrodeposition and low-temperature phosphating on nickel foam(NF).Through the strong interfacial interaction and electron synergistic coupling between 3D CeO_(x) nanoflower and 2D Co_(2)P nanosheet,the as-prepared Co_(2)P-CeO_(x)/NF exhibited high conductivity,catalytic activity and stability,and enhanced the electrocatalytic hydrogen evolution reaction(HER)and urea oxidation reaction(UOR)performance.Assembling an electrolyzer with a straight substitution of UOR for oxygen evolution reaction(OER),it needed only 1.42 V to achieve a current density of 30 mA/cm^(2),which was 0.17 V less than that required for water splitting.After 10 h of electrocatalysis,the degradation efficiency of urea reached 76.4%,realizing the preparation of clean energy hydrogen and synchronous wastewater purification,opening up a new path for green energy development and environmental governance.Based on the comprehensive analysis above,the electron transfer at the heterogeneous interfaces between 2D Co_(2)P nanosheet and 3D CeO_(x) nanoflower would cause the rearrangement of surface/interfacial charges;the formed oxygen vacancies provided coordination unsaturated sites,exposed more active sites,optimized the adsorption energy of reactant molecules on the catalyst surface and promoted molecular activation,making it have higher catalytic activity.In this study,a 2D/3D hybrid Co_(2)P-CeO_(x) heterojunction was constructed to regulate the charge states at the surface/interface of the electrocatalyst and thus improve the catalyst activity,providing a new idea for the construction of other efficient electrocatalysts.