Mn dopant induced high-valence Ni3+ sites and oxygen vacancies for enhanced water oxidation,Materials Chemistry Frontiers

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Mn dopant induced high-valence Ni3+ sites and oxygen vacancies for enhanced water oxidation
Materials Chemistry Frontiers ( IF 6.0 ) Pub Date : 2020-05-28 , DOI: 10.1039/d0qm00300j
Yu Zhang _{1,

2,

3,

4} , Zhiyuan Zeng _{1,

2,

3,

4} , Derek Ho _{1,

2,

3,

4}

Affiliation

Cost effective and durable electrocatalysts are urgently required in the oxygen evolution reaction (OER), a critical process in electrochemical energy storage and conversion devices. Conventional catalysts involve the alloying of rare elements, limiting their wide applications. In this paper, Mn doped ultrathin Ni–Fe–O nanosheets are prepared and demonstrated as an efficient OER catalyst. Mn dopant induces the generation of high valence state Ni³⁺ sites and an increased oxygen vacancy concentration in the Mn–Ni–Fe–O nanosheets, thus achieving enhanced OER kinetics. Experimentation of various dopant concentrations reveals that 2 wt% Mn doping is optimal for OER catalytic performance, achieving low overpotentials of 225 mV at a current density of 10 mA cm⁻² and 297 mV at 100 mA cm⁻², respectively, a small Tafel slope of 38.2 mV dec⁻¹, and excellent stability in an alkaline medium, which is superior to pristine Ni–Fe–O nanosheets and the state-of-the-art RuO₂ catalyst.

中文翻译：

锰掺杂物诱导的高价Ni3 +位和氧空位增强了水的氧化

氧气释放反应（OER）是电化学能量存储和转换设备中的关键过程，因此迫切需要经济高效且耐用的电催化剂。常规催化剂涉及稀有元素的合金化，限制了它们的广泛应用。在本文中，制备了Mn掺杂的超薄Ni–Fe–O纳米片，并证明了其为有效的OER催化剂。Mn掺杂剂可诱导生成高价态Ni ³⁺位点，并在Mn-Ni-Fe-O纳米片中增加氧空位浓度，从而提高OER动力学。各种掺杂剂浓度的实验表明，对于OER催化性能而言，2 wt％的Mn掺杂是最佳的，在10 mA cm ^-2的电流密度下实现225 mV的低过电势，在100 mA cm的情况下达到297 mV的低电势^-2分别具有38.2 mV dec^-1的小Tafel斜率和在碱性介质中的优异稳定性，优于原始的Ni-Fe-O纳米片和最新的RuO₂催化剂。

更新日期：2020-07-02

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