Highly efficient, low cost, durable electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are essential for the sustainable production of hydrogen and oxygen gases through complete water splitting. Owing to their high surface area, electrochemical activity, and stability, layered metal hydroxides have been identified as an efficient catalyst for various electrochemical reactions. This study demonstrates the HER and OER from the vertically aligned cobalt hydroxide nanosheets. The catalyst was coated on glassy carbon substrate by galvanostatic electrodeposition in the presence of 1,4-Butynediol additive. The transient potential oscillations during the deposition results in vertically aligned network of β-Co(OH)₂ nanosheets. The duration of deposition was optimized based on the OER and HER activity. This electrode (CH-500) shows overpotentials of 370 mV and 300 mV to attain 10 mA cm⁻² and a Tafel slope of 52 mV dec⁻¹ and 68 mV for OER and HER, respectively, in alkaline medium. The open-pore structure of the electrode, with 60% higher electrochemically active surface area compared to bulk, facilitates efficient oxyhydroxide formation. Moreover, this binder-free electrodeposited electrode has 80% lower charge transfer resistance than its bulk counterpart. Therefore, the developed vertically aligned β-Co(OH)₂ nanosheet could be a cost-effective efficient catalyst for water splitting.

Graphical abstract

中文翻译：

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瞬态电位振荡驱动的垂直排列氢氧化钴纳米片作为非贵重双功能水分解电催化剂

用于析氢反应（HER）和析氧反应（OER）的高效、低成本、耐用的电催化剂对于通过完全水分解可持续生产氢气和氧气至关重要。由于其高表面积、电化学活性和稳定性，层状金属氢氧化物已被认为是各种电化学反应的有效催化剂。这项研究展示了垂直排列的氢氧化钴纳米片的 HER 和 OER。在1,4-丁炔二醇添加剂存在下，通过恒电流电沉积将催化剂涂覆在玻碳基底上。沉积期间的瞬态电位振荡导致β -Co(OH) ₂纳米片垂直排列的网络。根据 OER 和 HER 活性优化沉积持续时间。该电极(CH-500)在碱性介质中对于OER和HER显示出分别达到10 mA cm ^{-2的370 mV和300 mV的过电势以及52 mV dec -1}和68 mV的塔菲尔斜率。该电极的开孔结构的电化学活性表面积比本体高 60%，有利于羟基氧化物的有效形成。此外，这种无粘合剂电沉积电极的电荷转移电阻比其本体电极低 80%。因此，所开发的垂直排列的β -Co(OH) ₂纳米片可能是一种具有成本效益的高效水分解催化剂。

图形概要