Laboratory of Functional Micro-nano Materials and Devices, School of Physics and Technology, University of Jinan, Jinan 250022, PR China.
Laboratory of Functional Micro-nano Materials and Devices, School of Physics and Technology, University of Jinan, Jinan 250022, PR China; State Key Laboratory of Powder Metallurgy, Central South University, Changsha, PR China.
J Colloid Interface Sci. 2023 Jul;641:277-288. doi: 10.1016/j.jcis.2023.03.003. Epub 2023 Mar 7.
It is crucial to create a bifunctional catalyst with high efficiency and low cost for electrochemical water splitting under alkaline and neutral pH conditions. This study investigated the in-situ creation of ultrafine Mo-NiS and NiFe LDH nanosheets as an effective and stable electrocatalyst with a three-dimensional (3D) flower-cluster hierarchical structure (Mo-NiS@NiFe LDH). The strong interfacial connection between Mo-NiS and NiFe LDH enhances the formation of metal higher chemical states in the material, optimizes the electronic structure, increases OH adsorption capacity improves electron transfer/mass diffusion, and promotes O/H gas release. As a result, at 10 mA cm, Mo-NiS@NiFe LDH/NF demonstrates the outstanding bifunctional electrocatalytic activity of just 107 mV (HER, hydrogen evolution reaction) and 184 mV (hydrogen evolution reaction) (OER, oxygen evolution reaction). The catalytic performance is remarkably stable after 72 h of continuous operation in 1 M KOH at high current densities (300 mA cm). More interestingly, in the overall water splitting system, the cell voltages for anode and cathode in both alkaline and neutral electrolytes for Mo-NiS@NiFe LDH/NF are only 1.54 V (alkaline) and 2.06 V (neutral) at 10 mA cm. These results demonstrated that the bifunctional electrocatalyst design concept is a viable solution for water splitting in both alkaline and neutral systems.
在碱性和中性 pH 条件下进行电化学水分解，开发高效、低成本的双功能催化剂至关重要。本研究通过原位合成超细 Mo-NiS 和 NiFe LDH 纳米片作为具有三维（3D）花簇分级结构的有效和稳定电催化剂（Mo-NiS@NiFe LDH）进行了研究。Mo-NiS 和 NiFe LDH 之间的强界面连接增强了材料中金属高化学态的形成，优化了电子结构，增加了 OH 吸附能力，提高了电子转移/质量扩散，并促进了 O/H 气体的释放。结果，在 10 mA cm 时，Mo-NiS@NiFe LDH/NF 表现出出色的双功能电催化活性，HER（析氢反应）和 OER（析氧反应）仅需 107 mV 和 184 mV。在高电流密度（300 mA cm）下，在 1 M KOH 中连续运行 72 小时后，催化性能仍具有出色的稳定性。更有趣的是，在整个水分解系统中，Mo-NiS@NiFe LDH/NF 在碱性和中性电解液中用于阳极和阴极的电池电压仅为 1.54 V（碱性）和 2.06 V（中性）在 10 mA cm 时。这些结果表明，双功能电催化剂设计概念是在碱性和中性体系中进行水分解的可行解决方案。
