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Electrocatalytic energy conversion technologies, such as electrocatalytic decomposition of water to produce hydrogen, electrocatalytic reduction of carbon dioxide, and electrocatalytic reduction of nitrogen, are important approaches to replace fossil energy, reduce carbon emissions, and obtain renewable fuels. Electrocatalytic oxygen evolution (OER) is an important and versatile anode half-reaction in the conversion of these electrocatalytic energy sources. However, OER is relatively slow in kinetics and requires an efficient oxygen evolution electrocatalyst to reduce the reaction energy barrier, thereby accelerating OER. After decades of efforts, people have developed a large number of highly efficient and stable alkaline OER electrocatalysts, but there has been little success in the development of the acidic OER electrocatalysts. As the electro-catalytic reaction in the acidic PEM electrolysis cell has the advantages of higher mass transfer rate, product purity and efficiency, the development of highly efficient acidic OER electrocatalysts has more important large-scale application significance. At present, the lack of highly active and stable acidic OER electrocatalysts is still a major bottleneck for the development of electrocatalytic energy conversion reactions in acidic media.
Recently, Chen Liang, a researcher at the New Energy Institute under the Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, has developed a highly active and stable OER that can be applied in an acidic electrolyte by designing the surface structure and electronic structure of an electrocatalyst. catalyst. In this study, Su Jianwei fabricated a Cu-doped RuO2 hollow octahedron material assembled from ultra-small nanocrystallites by using Ru metal-exchanged metal-organic framework derivatives as precursors and calcined in air. This method reduces the grain size of the RuO2 nanocrystals by lowering the calcination temperature so that a high Miller index surface with low coordination numbers can be exposed. As an acidic oxygen evolution electrocatalyst, its overpotential at the current density of 10 mA/cm2 was only 188 mV, showing superior electrocatalytic oxygen evolution activity and stability over commercial RuO2 electrocatalysts. Tian Ziqi calculated through density functional theory simulations and found that the three-coordinate Ru atom on the high energy surface is gradually oxidized during the reaction process, which greatly reduces the reaction energy barrier of OER, and Cu doping can greatly improve the electronic structure of RuO2. Its OER catalytic activity. This work was published in Advanced Materials (DOI: 10.1002/adma.201801351) under the title Assembling Ultra-Small Copper-doped Ruthenium Oxide Nanocrystals into Hollow Porous Polyhedra: Highly Robust Electrocatalysts for Oxygen Evolution in Acidic Media.
The above work has received strong support from the National Fund Commission Project, the Zhejiang Provincial Nature Fund Jieqing Project, the Ningbo Innovation Team, and the China Postdoctoral Fund Project.
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