Shi Wenping, Zhang Yuning, Bo Lili, Guan Xiaolin, Wang Yunxia, Tong Jinhui
Key Laboratory of Polymer Materials of Gansu Province, Key Laboratory of Eco-functional Polymer Materials of the Ministry of Education, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, Gansu 730070, China.
College of Science, Gansu Agricultural University, Lanzhou, Gansu 730070, China.
Inorg Chem. 2021 Dec 20;60(24):19136-19144. doi: 10.1021/acs.inorgchem.1c02931. Epub 2021 Nov 28.
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 CuCoO was greatly enhanced through cation substitution and size reduction. Ce-substituted spinel CuCeCoO (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 and a Tafel slope of 57.5 mV·dec, which outperform commercial RuO 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.
探索用于析氧反应（OER）的有效电催化剂是许多能量存储和转换系统的关键需求，这些系统包括燃料电池、水电解和金属空气电池。过渡金属氧化物（TMOs）因其在地壳中储量丰富、电子性质可调节等特点，在OER催化剂方面备受关注。缺陷工程是调节电子结构、控制尺寸从而提高其本征活性的常用且最重要的策略。在此，通过阳离子取代和尺寸减小，尖晶石CuCoO的OER性能得到了极大提高。采用简单便捷的相转移共沉淀策略合成了量子点尺度（2-8nm）的Ce取代尖晶石CuCeCoO（δ = 0.45、0.5和0.55）纳米颗粒。所制备的样品高度分散，在10 mA·cm时表现出294 mV的低过电位和57.5 mV·dec的塔菲尔斜率，优于商业RuO以及报道的大多数高性能类似催化剂。实验和计算结果均证实，适当含量的Ce取代可产生丰富的氧空位，调节中间体吸附，从而降低决速步骤的能垒，并极大提高催化剂的OER活性。这项工作不仅提供了先进的OER催化剂，还开辟了一条在量子点尺度深入理解原始TMO催化剂结构-活性关系以及合理设计更高效OER催化剂的通用途径。
