Research group and collaborators of Professor Wang Xuebin of Nanjing University have made new progress in the field of electrocatalytic water decomposition

Recently, the research group of Professor Wang Xuebin, College of modern engineering and Applied Sciences, Nanjing University, has made new progress in the field of electrocatalytic water decomposition research The research group loaded nifep ultra-thin nano sheet on a new type of three-dimensional reinforced graphene substrate to obtain self-supporting three-dimensional water decomposition electrode The related work is "monolithic electronic integrated of ultra nifep on 3D structured graph for Bifunctionally efficient overall water splitting "was published on nano energy (nano energy, 2019, 58, 870) Energy is an important material basis for the survival and development of human society and an important support for the development and progress of human society The large-scale use of traditional fossil energy with limited reserves has brought problems such as environmental pollution and greenhouse effect, which has seriously hindered the sustainable development of human society Hydrogen, as a clean secondary energy, has a high quality energy ratio, and the combustion products are pollution-free It has been regarded as an ideal energy carrier It is a very promising way to produce hydrogen by electrocatalytic water decomposition However, the reaction kinetics of ER and her is slow and the over potential is high, and most of the catalysts work in acid or alkaline conditions, which increases the energy consumption and production cost Last year, the research group developed coo / co4n heterostructure electrocatalyst to solve the problem of working conditions (acid or alkaline) of water decomposition catalyst, and realized the high-efficiency full decomposition of water in neutral system The related work was published in "coo modified co4n as a heterostructure electrocatalyst for high efficient overall water splitting in neutral media" Journal of Materials Chemistry A (Journal of Materials Chemistry A, 2018, 6, 24767) In order to further reduce the over potential of electrocatalytic oer and her and improve the reaction kinetics performance, Professor Wang Xuebin's research group in the early three-dimensional research work of graphene (nature communications, 2013, 4, 2905; nano energy, 2015, 16, 81; Bulletin of the Chemical Society of Japan, 2018, 92, On the basis of 245), the ultralight three-dimensional self-supporting electrode nifep / SG was designed and synthesized, which was directly used as the reaction electrode for highly efficient electrocatalytic oxygen evolution, hydrogen evolution reaction and total water decomposition Fig 1 preparation process of 3D nifep / SG electrode and 3D SG for electrocatalytic total decomposition of water (source: nano energy) due to its large specific surface area, porous structure, high conductivity and excellent stability, the research team took the lead in using it as the substrate, and obtained 3D nifep / SG self-supporting water decomposition electrode by directly growing ultra-thin nifep nano sheet on SG surface It is found that the introduction of iron can effectively adjust the electronic structure of Ni 2p, make its d-band center float up, reduce the adsorption energy of the adsorption intermediate, reduce the reaction potential barrier, and improve the electrocatalytic activity The catalytic activity of nifep / SG was further enhanced by the ultra-thin nifep nano sheet structure, the porous structure of SG and the direct growth of nifep on SG When directly used as catalytic electrode, the over potential of oer and her is only 218 and 115 MV, respectively, and the voltage of fully decomposed water is only 1.54 V at the current density of 10 Ma cm-2 Using rrde technology, the research team proved that the oer and her processes of 3D nifep / SG have high Faraday efficiency Compared with nifep / NF and nifep / Ti, 3D nifep / SG has smaller impedance and higher mass activity Figure 2 (a) oer polarization curve of nifep / SG, (b) oer Faraday efficiency of nifep / SG sample tested by rrde technology, (c) her polarization curve of nifep / SG, (d-f) rrde technology test her Faraday efficiency of nifep / SG sample (source: nano energy) Li Ruiqing, 2016 doctoral student, School of modern engineering and Applied Sciences, Nanjing University As the first author of the paper, Professor Wang Xuebin is the corresponding author of the paper, and the cooperative units are Hong Kong City University and Japan National Institute of materials The relevant work has been supported by Professor Hu Zheng of Nanjing University, Professor Li Yongle of Shanghai University, and other professors, as well as the great assistance of Professor Gao Libo of Nanjing University and researcher Xu Jie in Raman characterization The research was supported by the general and youth programs of NSFC, the special fund for basic scientific research business expenses of central universities, Jiangsu superior disciplines, Jiangsu natural fund and other projects.