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Lateral-Size-Mediated Efficient Oxygen Evolution Reaction: Insights into the Atomically Thin Quantum Dot Structure of NiFe2O4
ACS Catalysis ( IF 11.3 ) Pub Date : 2017-07-26 00:00:00 , DOI: 10.1021/acscatal.7b00007
Haidong Yang 1 , Yang Liu 1 , Sha Luo 1 , Ziming Zhao 1 , Xiang Wang 1 , Yutong Luo 1 , Zhixiu Wang 2 , Jun Jin 1 , Jiantai Ma 1
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The study of high-performance electrocatalysts for driving the oxygen evolution reaction (OER) is important for energy storage and conversion systems. As a representative of inverse-spinel-structured oxide catalysts, nickel ferrite (NiFe2O4) has recently gained interest because of its earth abundance and environmental friendliness. However, the gained electrocatalytic performance of NiFe2O4 for the OER is still far from the state-of-the-art requirements because of its poor reactivity and finite number of surface active sites. Here, we prepared a series of atomically thin NiFe2O4 catalysts with different lateral sizes through a mild and controllable method. We found that the atomically thin NiFe2O4 quantum dots (AT NiFe2O4 QDs) show the highest OER performance with a current density of 10 mA cm–2 at a low overpotential of 262 mV and a small Tafel slope of 37 mV decade–1. The outstanding OER performance of AT NiFe2O4 QDs is even comparable to that of commercial RuO2 catalyst, which can be attributed to its high reactivity and the high fraction of active edge sites resulting from the synergetic effect between the atomically thin thickness and the small lateral size of the atomically thin quantum dot (AT QD) structural motif. The experimental results reveal a negative correlation between lateral size and OER performance in alkaline media. Specifically speaking, the number of low-coordinated oxygen atoms increases with decreasing lateral size, and this leads to significantly more oxygen vacancies that can lower the adsorption energy of H2O, increasing the catalytic OER efficiency of AT NiFe2O4 QDs.

中文翻译:

横向尺寸介导的高效氧气析出反应:NiFe 2 O 4原子薄量子点结构的见解

用于驱动氧释放反应(OER)的高性能电催化剂的研究对于能量存储和转化系统非常重要。作为反尖晶石结构的氧化物催化剂的代表,镍铁氧体(NiFe 2 O 4)最近因其对地球的丰富性和环境友好性而引起了人们的兴趣。然而,由于NiFe 2 O 4具有较差的反应性和有限数量的表面活性位,因此其对OER的电催化性能仍远未达到最新技术要求。在这里,我们准备了一系列原子上薄的NiFe 2 O 4通过温和且可控的方法制备具有不同横向尺寸的催化剂。我们发现原子薄的NiFe 2 O 4量子点(AT NiFe 2 O 4 QDs)在262 mV的低过电势和37 mV的小Tafel斜率下表现出最高的OER性能,电流密度为10 mA cm –2十年–1。AT NiFe 2 O 4 QD的出色的OER性能甚至可与商业RuO 2媲美催化剂,可以归因于其高反应性和原子薄的量子点(AT QD)结构基序的原子薄的厚度和较小的横向尺寸之间的协同效应所产生的高活性边缘位点。实验结果表明,在碱性介质中,横向尺寸与OER性能之间呈负相关。具体而言,低配位氧原子的数量随着横向尺寸的减小而增加,这导致明显更多的氧空位,从而降低了H 2 O的吸附能,从而提高了AT NiFe 2 O 4 QD的催化OER效率。
更新日期:2017-07-28
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