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Earth‐Abundant Silicon for Facilitating Water Oxidation over Iron‐Based Perovskite Electrocatalyst
Advanced Materials Interfaces ( IF 4.3 ) Pub Date : 2018-02-26 , DOI: 10.1002/admi.201701693
Xiaomin Xu 1 , Yubo Chen 1 , Wei Zhou 1 , Yijun Zhong 1 , Daqin Guan 1 , Zongping Shao 1, 2
Affiliation  

Active and affordable electrocatalysts made from Earth‐abundant elements are central to water electrolysis involving the oxygen evolution reaction (OER). While nonprecious transition metal‐based (Co, Ni, Fe) materials are extensively studied as cost‐effective, high‐performance alternatives to noble metal‐based catalysts, iron‐based catalysts with Fe acting as the single active site are rarely investigated due to their intrinsically low reactivity. Here, by taking advantage of the versatility of perovskite structure, metalloid Si, the second most abundant element in Earth's crust, is doped into an Fe‐based perovskite oxide (SrFeO3−δ), to obtain SrFe0.9Si0.1O3−δ as a highly efficient OER catalyst. Remarkably, SrFe0.9Si0.1O3−δ shows an approximately threefold growth in OER activity relative to SrFeO3−δ with a small Tafel slope of 58 mV dec−1, comparing favorably to or even exceeding many Co‐/Ni‐based perovskite catalysts. This enhancement can be ascribed to a structural transition from tetragonal to cubic symmetry upon Si‐doping, which brings about an optimized iron oxidation state, rich oxygen vacancies, and fast charge transfer that are beneficial to the OER catalysis. This work highlights the importance of how incorporating Earth‐abundant, nonprecious elements (e.g., Si) into a perovskite oxide structure can be used to create novel materials for the electrochemical water oxidation.

中文翻译:

富含地球的硅,可促进铁基钙钛矿电催化剂上的水氧化

由富含地球元素制成的活性且价格适中的电催化剂对于涉及氧释放反应(OER)的水电解至关重要。尽管人们广泛研究了非贵金属(钴,镍,铁)过渡材料作为贵金属催化剂的经济有效的高性能替代品,但由于以下原因,很少研究以铁为单一活性中心的铁基催化剂它们固有的低反应性。在这里,通过利用钙钛矿结构的多功能性,将地壳中含量第二高的元素准金属Si掺入铁基钙钛矿氧化物(SrFeO 3− δ)中,以获得SrFe 0.9 Si 0.1 O 3− δ作为高效的OER催化剂。值得注意的是,相对于SrFeO 3− δ,SrFe 0.9 Si 0.1 O 3− δ具有58 mV dec -1的小Tafel斜率,相对于SrFeO 3− δ而言,其OER活性大约增长了三倍。与许多钴/镍基钙钛矿催化剂相比甚至更好。这种增强可以归因于Si掺杂时从四方对称到立方对称的结构转变,这带来了优化的铁氧化态,丰富的氧空位和快速的电荷转移,这对OER催化是有益的。这项工作突显了如何使用富含地球的非贵重元素(例如Si)到钙钛矿氧化物结构中来创建用于电化学水氧化的新型材料的重要性。
更新日期:2018-02-26
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