Ce-Substituted Spinel CuCo2O4 Quantum Dots with High Oxygen Vacancies and Greatly Improved Electrocatalytic Activity for Oxygen Evolution Reaction.
Ce-Substituted Spinel CuCo2O4 Quantum Dots with High Oxygen Vacancies and Greatly Improved Electrocatalytic Activity for Oxygen Evolution Reaction.
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DOI：
10.1021/acs.inorgchem.1c02931
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发表时间：
2021-11
影响因子：
4.6
通讯作者：
Wenping Shi;Yuning Zhang;Lili Bo;X. Guan;Yunxia Wang;Jinhui Tong
中科院分区：
文献类型：
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作者：
Wenping Shi;Yuning Zhang;Lili Bo;X. Guan;Yunxia Wang;Jinhui Tong
探索有效的析氧反应（OER）电催化剂是许多能量存储和转换系统的关键要求，包括燃料电池，水电解和金属-空气电池。过渡金属氧化物（TMOs）由于其富含稀土元素、电子性质可调等特点，在OER催化剂中引起了广泛的关注。缺陷工程是调节电子结构和控制尺寸，从而提高其本征活性的一种最普遍和最重要的策略。在此，OER性能的尖晶石型CuCo 2 O 4的大大提高，通过阳离子取代和尺寸减小。采用简单易行的相转移共沉淀法合成了量子点尺度（2-8 nm）的Ce取代尖晶石型CuCeδ Co 2-δOx（δ = 0.45，0.5和0.55）纳米粒子。所制备的样品具有高度分散性，在10 mA·cm-2下的过电位为294 mV，Tafel斜率为57.5 mV·dec-1，优于商业RuO 2和已报道的最高性能的类似催化剂。实验和计算结果都证实，适量的Ce取代可以产生丰富的氧空位，调节中间吸附，从而降低决定步骤的能垒，大大提高催化剂的OER活性。这项工作不仅提供了先进的OER催化剂，而且还打开了一个通用的途径，以了解原始的TMO催化剂的结构-活性关系，在量子点尺度和更有效的OER催化剂的合理设计深入。
Exploring effective electrocatalysts for oxygen evolution reaction (OER) is a crucial requirement of many energy storage and transformation systems, involving fuel cells, water electrolysis, and metal-air batteries. Transition-metal oxides (TMOs) have attracted much attention to OER catalysts because of their earth abundance, tunable electronic properties, and so forth. Defect engineering is a general and the most important strategy to tune the electronic structure and control size, and thus improve their intrinsic activities. Herein, OER performance on spinel CuCo2O4 was greatly enhanced through cation substitution and size reduction. Ce-substituted spinel CuCeδCo2-δOx (δ = 0.45, 0.5 and 0.55) nanoparticles in the quantum dot scale (2-8 nm) were synthesized using a simple and facile phase-transfer coprecipitation strategy. The as-prepared samples were highly dispersed and have displayed a low overpotential of 294 mV at 10 mA·cm-2 and a Tafel slope of 57.5 mV·dec-1, which outperform commercial RuO2 and the most high-performance analogous catalysts reported. The experimental and calculated results all confirm that Ce substitution with an appropriate content can produce rich oxygen vacancies, tune intermediate absorption, consequently lower the energy barrier of the determining step, and greatly enhance the OER activity of the catalysts. This work not only provides advanced OER catalysts but also opens a general avenue to understand the structure-activity relationship of pristine TMO catalysts deeply in the quantum dot scale and the rational design of more efficient OER catalysts.