Electronic and Morphological Dual Modulation of Cobalt Carbonate Hydroxides by Mn Doping toward Highly Efficient and Stable Bifunctional Electrocatalysts for Overall Water Splitting,Journal of the American Chemical Society

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Electronic and Morphological Dual Modulation of Cobalt Carbonate Hydroxides by Mn Doping toward Highly Efficient and Stable Bifunctional Electrocatalysts for Overall Water Splitting
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2017-06-13 00:00:00 , DOI: 10.1021/jacs.7b03507
Tang Tang _{1,

2} , Wen-Jie Jiang _{1,

3} , Shuai Niu ₁ , Ning Liu _{3,

4} , Hao Luo ₁ , Yu-Yun Chen ₁ , Shi-Feng Jin _{3,

4} , Feng Gao ₂ , Li-Jun Wan _{1,

3} , Jin-Song Hu _{1,

3}

Affiliation

Developing bifunctional efficient and durable non-noble electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is highly desirable and challenging for overall water splitting. Herein, Co–Mn carbonate hydroxide (CoMnCH) nanosheet arrays with controllable morphology and composition were developed on nickel foam (NF) as such a bifunctional electrocatalyst. It is discovered that Mn doping in CoCH can simultaneously modulate the nanosheet morphology to significantly increase the electrochemical active surface area for exposing more accessible active sites and tune the electronic structure of Co center to effectively boost its intrinsic activity. As a result, the optimized Co₁Mn₁CH/NF electrode exhibits unprecedented OER activity with an ultralow overpotential of 294 mV at 30 mA cm^–2, compared with all reported metal carbonate hydroxides. Benefited from 3D open nanosheet array topographic structure with tight contact between nanosheets and NF, it is able to deliver a high and stable current density of 1000 mA cm^–2 at only an overpotential of 462 mV with no interference from high-flux oxygen evolution. Despite no reports about effective HER on metal carbonate hydroxides yet, the small overpotential of 180 mV at 10 mA cm^–2 for HER can be also achieved on Co₁Mn₁CH/NF by the dual modulation of Mn doping. This offers a two-electrode electrolyzer using bifunctional Co₁Mn₁CH/NF as both anode and cathode to perform stable overall water splitting with a cell voltage of only 1.68 V at 10 mA cm^–2. These findings may open up opportunities to explore other multimetal carbonate hydroxides as practical bifunctional electrocatalysts for scale-up water electrolysis.

中文翻译：

Mn掺杂对高效稳定的双功能电催化剂进行碳水分解的氢氧化钴的电子和形态学双重调制

开发用于氧释放反应（OER）和氢释放反应（HER）的双功能高效耐用的非贵族电催化剂对于整体水分解非常需要且具有挑战性。在此，在泡沫镍（NF）上开发了具有可控形态和成分的氢氧化Co-Mn碳酸盐氢氧化物（CoMnCH）纳米片阵列，作为这种双功能电催化剂。发现CoCH中的Mn掺杂可同时调节纳米片的形态，从而显着增加电化学活性表面积，以暴露更多可及的活性位点，并调节Co中心的电子结构，以有效提高其固有活性。结果，优化的Co ₁ Mn ₁与所有报道的金属碳酸盐氢氧化物相比，CH / NF电极具有空前的OER活性，在30 mA cm ^–2时具有294 mV的超低超电势。得益于3D开放式纳米片阵列拓扑结构，纳米片与NF之间紧密接触，它能够在462 mV的超电势下提供1000 mA cm ^–2的高且稳定的电流密度，而不受高通量氧气释放的干扰。尽管还没有关于在金属碳酸盐氢氧化物上使用有效HER的报道，但通过Mn掺杂的双重调制，在Co ₁ Mn ₁ CH / NF上也可以在10 mA cm ^–2处获得180 mV的小过电位。这提供了使用双功能Co ₁的两电极电解槽Mn ₁ CH / NF作为阳极和阴极，可在10 mA cm ^–2时以仅1.68 V的电池电压执行稳定的总水分解。这些发现可能为探索其他多金属碳酸盐氢氧化物作为扩大水电解的实用双功能电催化剂提供了机会。

更新日期：2017-06-14

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