Catalyst structure and electrocatalytic hydrogen evolution reaction diagram
In recent years, hydrogen production by electrolysis of water has drawn widespread attention in academic circles, looking for cheap and efficient non-platinum catalyst has become a research hot spot nowadays as a star material 'graphene with good conductivity, corrosion resistance, etc., researchers are committed to However, the activity of many carbon-based catalysts is far behind that of noble metals and how to develop graphene-based carbon materials into high-activity electrocatalysts is a hot topic recently.Hefei University of Science and Technology of China Chen Qiaowang, National Institute of Microscale Materials Science and Professor of Materials Science, School of Chemistry and Materials Science, with a metal-organic framework doped with noble metal iridium as a precursor, was calcined to prepare a nitrogen-doped graphene layer wrapped with an iridium-cobalt alloy The core-shell structure material shows high activity and high stability in the hydrogen evolution reaction of acidic electrolytes. Relevant research results have been published in "Advanced Materials".
The iridium-cobalt alloy can transfer electrons to the surface active sites, and the nitrogen-doped graphene layer coated on the surface of the iridium-cobalt alloy is similar to the 'armor', which helps to prevent the alloy core from being corroded by acid. 1.56 wt.%) With a Tafel slope of only 23 mV / dec and an overpotential of only 24 mV at a current density of 10 mA / cm2, showing comparable electrocatalytic hydrogen evolution properties to commercial 20% Pt / C electrocatalysts Density functional theory (DFT) simulation results show that the carbon atoms near the nitrogen doping atoms are the active sites for the electrocatalytic reaction. The introduction of iridium promotes the electron to migrate to the surface of the graphene-like layer and reduces the hydrogen adsorption free energy of the active site , The surface characterization of materials and the imaging analysis of elemental composition reveal that the increase of nitrogen content and the enrichment of iridium on the surface of alloy core are favorable to the improvement of catalyst performance.This work aims to find cheaper and more efficient Electrocatalytic hydrogen evolution catalyst provides a new idea.
Research has been supported by the National Natural Science Foundation of China, the Chinese Academy of Sciences and the Central University of the Ministry of education and other basic scientific research services.
