Constructing Hierarchical Fluffy CoO-Co4N@NiFe-LDH Nanorod Arrays for Highly Effective Overall Water Splitting and Urea Electrolysis
Constructing Hierarchical Fluffy CoO-Co4N@NiFe-LDH Nanorod Arrays for Highly Effective Overall Water Splitting and Urea Electrolysis
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DOI：
10.1021/acssuschemeng.1c04674
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发表时间：
2021-10-11
影响因子：
8.4
通讯作者：
Wang, Chundong
中科院分区：
文献类型：
--
作者：
Chen, Baojin;Humayun, Muhammad;Wang, Chundong
探索高效的双功能电催化剂以优化析氢反应和析氧反应已被广泛开展，但仍是一个巨大的挑战。本文采用水热-氮化-电沉积三步法制备了层状CoO-Co4N@NiFe-LDH(层状双氢氧化物)异质结构电极。制备的CoO-Co4N@NiFe-LDH/NF电极需要66 mV和231 mV的低过电位值，以分别为HER和OER在KOH(1M)水溶液中提供10 mA cm(-2)的电流密度。Tafel斜率和电化学阻抗谱结果表明，在整个电解过程中都有良好的反应动力学。随后，用CoO-Co4N@NiFeLDH/Nf作为阳极和阴极，组装了碱性电解槽，在1.529 V的小电压下产生10 mA cm(-2)的电流，并具有28h的稳定性能。令人印象深刻的是，尿介导电解槽也具有高效的催化活性，使得在分水过程中可以安装迟缓的OER。为了驱动含有0.33M尿素的尿介导型电解槽，需要1.393 V的低电压，与无尿素电解槽相比低约136 mV。这项工作为电催化利用低能量分解水生成氢气提供了坚实的步骤。
Exploration of highly efficient bifunctional electro-catalysts for optimal hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) has been widely carried out, though it still remains a big challenge. Herein, a hierarchical CoO-Co4N@NiFe-LDH (layered-double-hydroxides) heterostructure electrode anchored on nickel foam (NF) is prepared via a developed three-step hydrothermal-nitridation-electrodeposition pathway. The fabricated CoO-Co4N@NiFe-LDH/NF electrode needs low overpotential values of 66 and 231 mV to supply a current density value of 10 mA cm(-2) in aqueous solution of KOH (1 M) for HER and OER, respectively. The Tafel slopes and electrochemical impedance spectroscopy results display favorable reaction kinetics throughout the electrolysis process. Subsequently, an alkaline electrolyzer is assembled with CoO-Co4N@NiFeLDH/NF, which serves both as the anode and cathode, yielding 10 mA cm(-2) with a small voltage of 1.529 V and showing a robust stability for 28 h. Impressively, a urine-mediated electrolysis cell shows efficient catalytic activity as well, allowing to mount the sluggish OER during water splitting. To drive the urine-mediated electrolysis cell containing 0.33 M urea, a low voltage of 1.393 V is required, which is about 136 mV lower compared to the urea-free electrolysis cell. This work presents a solid step for the electrocatalytic generation of hydrogen through water splitting by harvesting low energy.