Promoting Bifunctional Water Splitting by Modification of the Electronic Structure at the Interface of NiFe Layered Double Hydroxide and Ag
Promoting Bifunctional Water Splitting by Modification of the Electronic Structure at the Interface of NiFe Layered Double Hydroxide and Ag
复制标题
DOI：
10.1021/acsami.1c05123
复制
发表时间：
2021-05-26
影响因子：
9.5
通讯作者：
Xiao, Chunhui
中科院分区：
文献类型：
--
作者：
Ma, Yaming;Liu, Dongyu;Xiao, Chunhui
电化学水分解是一种通过析氢反应（HER）可再生生产高纯度氢气的有前途的方法。 Ni-Fe层状双氢氧化物（Ni-Fe LDH）是介导析氧反应（OER）的高效材料，OER是阳极水分解的半反应，但LDH通常表现出较差的HER性能。在这里，我们报道了通过电镀蚀刻制备的泡沫镍（Ag@NiFe/NF）上自组织Ag@NiFe层状双氢氧化物核壳电极的制备，用于介导HER和OER（双功能水分解电催化）。这种合成策略允许制备有组织的分层结构，该结构通过调整催化剂的电子结构和增加表面积利用率来改善电化学性能。 X射线光电子能谱（XPS）和理论计算表明，从Ni-Fe LDH到Ag的电子转移影响了反应中间体的吸附，从而增强了催化活性。与基准NiFe氢氧化物材料相比，Ag@NiFe/NF电极在10 mA cm(-2)的电流密度下，析氧和析氢的过电势分别低至180和80 mV，析氧和析氢反应的比活性分别提高了约5倍和约1.5倍。此外，集成的水分解电解槽电极可由 AA 电池驱动。
Electrochemical water splitting is a promising method for the renewable production of high-purity hydrogen via the hydrogen evolution reaction (HER). Ni-Fe layered double hydroxides (Ni-Fe LDHs) are highly efficient materials for mediating the oxygen evolution reaction (OER), a half-reaction for water splitting at the anode, but LDHs typically display poor HER performance. Here, we report the preparation of self-organized Ag@NiFe layered double hydroxide core-shell electrodes on Ni foam (Ag@NiFe/NF) prepared by galvanic etching for mediating both the HER and OER (bifunctional water-splitting electrocatalysis). This synthetic strategy allowed for the preparation of organized hierarchical architectures which displayed improved the electrochemical performance by tuning the electronic structure of the catalyst and increasing the surface area utilization. X-ray photoelectron spectroscopy (XPS) and theoretical calculations revealed that electron transfer from the Ni-Fe LDH to Ag influenced the adsorption of the reaction intermediates leading to enhanced catalytic activity. The Ag@NiFe/NF electrode displayed overpotentials as low as 180 and 80 mV for oxygen and hydrogen evolution, respectively, at a current density of 10 mA cm(-2), and improvements in the specific activity by similar to 5x and similar to 1.5x for the oxygen and hydrogen evolution reaction, respectively, compared to benchmark NiFe hydroxide materials. Additionally, an integrated water-splitting electrolyzer electrode can be driven by an AA battery.