Efficient Alkaline Seawater Oxidation by a Three-dimensional Core-shell Dendritic NiCo@NiFe Layered Double Hydroxide Electrode
Efficient Alkaline Seawater Oxidation by a Three-dimensional Core-shell Dendritic NiCo@NiFe Layered Double Hydroxide Electrode
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DOI：
10.1016/j.mtphys.2022.100841
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发表时间：
2022-09
影响因子：
11.5
通讯作者：
Fanghao Zhang;Yifei Liu;Libo Wu;Minghui Ning;Shaowei Song;X. Xiao;V. Hadjiev;D. Fan;Dezhi Wang;Luo Yu;Shuo Chen;Z. Ren
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作者：
Fanghao Zhang;Yifei Liu;Libo Wu;Minghui Ning;Shaowei Song;X. Xiao;V. Hadjiev;D. Fan;Dezhi Wang;Luo Yu;Shuo Chen;Z. Ren
近年来，由于淡水资源的短缺和海水淡化的前景，电解海水制氢受到越来越多的关注。开发具有高催化活性、长期耐用性和高析氧反应选择性的非贵金属基析氧反应（OER）电催化剂对于大规模海水电解至关重要，但仍然是一个重大挑战。在这里，我们开发了一个三维核壳树枝状催化剂垂直生长NiFe层状双氢氧化物（LDH）纳米片上树枝状的NiCo分支（表示为NiCo@NiFe LDH）。树枝状NiCo@NiFe LDH具有比表面积大、电荷传递快、传质效果好、耐腐蚀等优点，在碱性海水中具有较高的活性和稳定性。在1 M KOH海水中，仅需222 mV的小过电位即可实现100 mA cm− 2的电流密度。为了提供500 mA cm−2的大电流密度，NiCo@NiFe LDH催化剂需要266 mV的创纪录低过电位。接近100%的OER法拉第效率和海水电解后电解质中不存在ClO−表明我们的催化剂具有高OER选择性。NiCo@NiFe LDH在海水中的稳定性通过其在500 mA cm− 2的恒定电流密度下100 h内的小过电位波动来证明。
Seawater electrolysis for hydrogen generation has received increasing attention recently due to the scarcity of freshwater and the additional prospect of seawater desalination. The development of non-noble-metal-based oxygen evolution reaction (OER) electrocatalysts with high catalytic activity, long-term durability, and high OER selectivity is crucial for large-scale seawater electrolysis but remains a significant challenge. Here we develop a three-dimensional core-shell dendritic catalyst by vertically growing NiFe layered double hydroxide (LDH) nanosheets on dendritic NiCo branches (denoted as NiCo@NiFe LDH). The dendritic NiCo@NiFe LDH is highly active and stable in alkaline seawater due to its large surface area, fast charge transfer and effective mass transfer, and excellent corrosion resistance. It requires only a small overpotential of 222 mV to achieve current densities of 100 mA cm−2in 1 M KOH seawater. To deliver a large current density of 500 mA cm−2, the NiCo@NiFe LDH catalyst requires a record-low overpotential of 266 mV. The nearly 100% OER Faradaic efficiency and the absence of ClO−in the electrolyte following seawater electrolysis indicate the high OER selectivity of our catalyst. The stability of NiCo@NiFe LDH in seawater is proven by its small overpotential fluctuation at a constant current density of 500 mA cm−2over 100 h.