Recently, the latest research result of Prof. Wang Qin-led team in hydrogen production by water electrolysis has been published in Nano Letters, an internationally prestigious journal. It is also a top journal in the field whose eff ect factor is 11.189. The article is named Unraveling the Synergistic Effect of Heteroatomic Substitution and Vacancy Engineering in CoFe2O4 for Superior Electrocatalysis Performance and published by the journal as the cover article. Nano Letters is a top journal attached to American Chemical Society and internationally authoritative in the field of nano material chemistry.
The technology for hydrogen production by water electrolysis is one of the important ways to produce highly pure hydrogen in an industrialized manner. However, highly efficient electrocatalyst is needed to promote the reaction kinetics due to the high overpotential and sluggish kinetics of the oxygen evolution reaction (OER) so as to produce a high current density with a low overpotential. Now the precious metal is still the major electrocatalyst for business. But its low deposit and high price greatly limit its large-scale business use. Therefore, it is very important to develop low-cost, efficient and durable non-precious metal electrocatalysts and promote catalytic reaction kinetics. Spinel ferrite has abundant element composition and unique electronic structure. By controlling the reaction conditions, the phase, composition, structure, shape and defects of spinel ferrite can be effectively regulated. This polymetallic oxide whose structure can be regulated has good conductivity and is gradually becoming one candidate for the new-generation electrocatalysts of oxygen evolution reaction. Its electrocatalyst activity can equal that of precious metals. For this reason, Prof. Wang Qin-led team, on the basis of the previous research of regulation of the electrons on vacancy defects（Angew. Chem. Int. Ed, 2021, 60, 19435；Angew. Chem. Int. Ed, 2020, 59, 13778； Adv. Energy Mater, 2018, 8, 1800980）, attempts to introduce some metal ions into octahedral (Oh) Fe sites and tetrahedral (Td) Fe3 to regulate and change their electronic structures and electrocatalytic properties.
X-ray absorption spectra and theoretical calculations reveal that Cr3+ can be precisely doped into octahedral (Oh) Fe sites to replace part of Fe3+ and simultaneously induce Co vacancy. Furthermore, S2– exchange reaction produces new catalytic activity sites like Fe-S, which results in structure distortion of Td-Fe due to compressive strain effect. The change in the local geometry of Td-Fe causes the *OOH intermediate to deviate from the y-axis plane, thus enhancing the adsorption of the *OOH and improving the electrochemical performance. The material shows the excellent oxygen evolution reaction performance and its overpotential is only 250mV. It is the spinel catalytic material with best performance.
The research has been completed in cooperation by Prof. Wang Qin’s team, Zhang Jiangwei, researcher with Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Prof. Kong Yuan with University of Science and Technology of China. Sun Jing, PhD candidate of Prof. Wang Qin’s team, is the first author of the paper. Xue Hui, associate professor, is the co-first author. Prof. Wang Qin is the first correspondence author and IMU is the institution the first authors of the article are with. The research is financially supported by the National Natural Science Foundation of China (NSFC Grants 21666023, 21467019, 21701168), Program of Natural Science Foundation of Inner Mongolia Autonomous Region of China for Supporting Young Talents（2017JQ01）, Natural Science Foundation of Inner Mongolia Autonomous Region of China (Grants 2021ZD11), Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region (Grant NJYT-19-A01).
URL：https://pubs.acs.org/doi/pdf/10.1021/acs.nanolett.1c04425
Website of Wang Qin’s team: https://www.x-mol.com/groups/wangqin/
