Li Xiaomin, Zheng Kaitian, Zhang Jiajun, Li Guoning, Xu Chunjian
School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Chemical Engineering Research Center, Tianjin University, Tianjin 300072, China.
Particles and Catalysis Research Group, School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia.
ACS Omega. 2022 Mar 31;7(14):12430-12441. doi: 10.1021/acsomega.2c01423. eCollection 2022 Apr 12.
Restricted by the sluggish kinetics of the oxygen evolution reaction (OER), efficient OER catalysis remains a challenge. Here, a facile strategy was proposed to prepare a hollow dodecahedron constructed by vacancy-rich spinel CoS nanoparticles in a self-generated HS atmosphere of thiourea. The morphology, composition, and electronic structure, especially the sulfur vacancy, of the cobalt sulfides can be regulated by the dose of thiourea. Benefitting from the HS atmosphere, the anion exchange process and vacancy introduction can be accomplished simultaneously. The resulting catalyst exhibits excellent catalytic activity for the OER with a low overpotential of 270 mV to reach a current density of 10 mA cm and a small Tafel slope of 59 mV dec. Combined with various characterizations and electrochemical tests, the as-proposed defect engineering method could delocalize cobalt neighboring electrons and expose more Co sites in spinel CoS, which lowers the charge transfer resistance and facilitates the formation of Co active sites during the preactivation process. This work paves a new way for the rational design of vacancy-enriched transition metal-based catalysts toward an efficient OER.
受析氧反应（OER）缓慢动力学的限制，高效的OER催化仍然是一个挑战。在此，我们提出了一种简便的策略，用于在硫脲自生的HS气氛中制备由富空位尖晶石CoS纳米颗粒构建的空心十二面体。硫化钴的形貌、组成和电子结构，特别是硫空位，可以通过硫脲的用量来调节。受益于HS气氛，阴离子交换过程和空位引入可以同时完成。所得催化剂对OER表现出优异的催化活性，低过电位为270 mV时可达到10 mA cm的电流密度，塔菲尔斜率为59 mV dec。结合各种表征和电化学测试，所提出的缺陷工程方法可以使钴相邻电子离域，并在尖晶石CoS中暴露更多的Co位点，这降低了电荷转移电阻，并促进了预活化过程中Co活性位点的形成。这项工作为合理设计富空位的过渡金属基催化剂以实现高效OER铺平了一条新道路。
