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Electro-synthesized Co(OH)2@CoSe with Co–OH active sites for overall water splitting electrocatalysis
Nanoscale Advances ( IF 4.6 ) Pub Date : 2020/01/06 , DOI: 10.1039/c9na00725c
Yin Wang 1 , Yutong Yang 1 , Xia Wang 1 , Peihe Li 1 , Hongyang Shao 1 , Tianen Li 1 , Haiyang Liu 1 , Qingfu Zheng 1 , Jing Hu 1 , Limei Duan 1 , Changwen Hu 2 , Jinghai Liu 1
Affiliation  

Constructing noble metal-free electrocatalytically active sites for the simultaneous hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline solution is key to realizing electricity-driven water splitting in practical applications. Here, we rationally designed Co(OH)2@CoSe nanorods (NRs) as an excellent bifunctional electrocatalyst by an in situ electrochemical transformation strategy, where the Co-based nanorod template was converted into Co(OH)2@CoSe at the cathode. The obtained electrode exhibits superior electrocatalytic activity for both the HER (overpotential of 208 mV at 20 mA cm−2) and the OER (268 mV at 20 mA cm−2) at high current density in a 1 M KOH solution. The theoretical calculations and experimental evidence indicate that the chemical coupling Co–OH active site between Co(OH)2 and CoSe regulates the hydrogen adsorption and desorption energy and fast electron transfer capability, which is responsible for the improved HER. Moreover, the Co(OH)2@CoSe NRs can be further converted into CoOOH nanosheets which serve as OER active sites. Toward practical electrolytic cell applications, the Co(OH)2@CoSe nanorods as both the cathode and anode achieved a current density of 100 mA cm−2 at 1.94 V for overall water splitting, better than that of noble metal-based electrocatalysts.

中文翻译:

电合成具有 Co-OH 活性位点的 Co(OH)2@CoSe 用于整体水分解电催化

在碱性溶液中为同时析氢反应(HER)和析氧反应(OER)构建不含贵金属的电催化活性位点是在实际应用中实现电驱动水分解的关键。在这里,我们通过原位电化学转化策略合理地设计了 Co(OH) 2 @CoSe 纳米棒 (NRs) 作为出色的双功能电催化剂,其中 Co 基纳米棒模板在阴极处转化为 Co(OH) 2 @CoSe。所获得的电极对 HER(20 mA cm -2 时为 208 mV 的过电位)和 OER(20 mA cm -2 时为 268 mV)均表现出优异的催化活性) 在 1 M KOH 溶液中的高电流密度下。理论计算和实验证据表明,Co(OH) 2和 CoSe 之间的化学耦合 Co-OH 活性位点调节了氢的吸附和解吸能以及快速电子转移能力,这是提高 HER 的原因。此外,Co(OH) 2 @CoSe NRs 可以进一步转化为作为 OER 活性位点的 CoOOH 纳米片。对于实际的电解池应用,作为阴极和阳极的 Co(OH) 2 @CoSe 纳米棒在 1.94 V 时实现了 100 mA cm -2的电流密度,用于整体水分解,优于基于贵金属的电催化剂。
更新日期:2020-02-19
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