Recently, Wu Zhongshuai, a researcher in the 2D Materials Chemistry and Energy Application Research Group of the State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, and his team developed a ruthenium oxide/graphene 2D heterojunction catalyst with intrinsic defect structure. Realize the oxygen evolution of electrolyzed water with high activity and high stability in the full pH range.
Electrocatalytic water splitting is of great significance in the clean energy system. The oxygen evolution reaction (OER) in the electrolysis water reaction has become a bottleneck that restricts the overall efficiency of the electrolysis water reaction due to its slow kinetic characteristics; electrolyzed water applications include alkaline electrolysis cells and acid electrolysis cells, and the application environment is relatively harsh. Ruthenium oxide is a typical acidic OER catalyst with poor activity under alkaline conditions. Therefore, it is of great research significance to develop effective control strategies to simultaneously increase the electrocatalytic oxygen evolution activity of ruthenium oxide in acidic and alkaline solutions.
The OER activity of ruthenium oxide is closely related to the coordination structure of the Ru site. Studies have found that the RuO5 structure with oxygen deficiencies has better OER activity than the RuO6 in the perfect ruthenium oxide, so the production of Ru sites with oxygen deficiencies is The key to improving the activity of ruthenium oxide OER. In addition, the poor conductivity of ruthenium oxide also limits its catalytic activity. In order to solve these problems, the research team proposed to use the oxygen clusters of graphene oxide to confine the Ru precursor to prepare a highly efficient two-dimensional heterojunction catalyst of ruthenium oxide and graphene with intrinsic oxygen vacancies. Due to the strong coordination between graphene oxide and the Ru precursor, the two-dimensional structure has an ultra-thin thickness of 9 nm, a high specific surface area of ​​125 m2 g-1, and a low resistance of 4 ohms, and synchrotron radiation studies have shown that the catalyst It has an intrinsic RuO5 oxygen-deficient structure. When the current density is 10 mA cm-2, the overpotential of the catalyst in acidic and alkaline electrolytes is only 169 mV and 175 mV, which is the most superior all-pH oxygen evolution electrocatalyst reported so far. The research team combined theoretical calculations and found that the intrinsic oxygen-deficient RuO5 structure can enhance the adsorption of hydroxyl groups and accelerate the decomposition of hydroxyl groups, thereby enhancing the oxygen evolution activity in acidic and alkaline electrolytes. Therefore, this work provides a new solution for the design of two-dimensional catalyst defect structure and electronic control and full pH oxygen evolution electrocatalyst.
Relevant research results were published on "Nano Energy". The research work is funded by the National Natural Science Foundation of China and the National Key Research and Development Program.
Schematic diagram of a two-dimensional catalyst with intrinsic defect structure (a), SEM image (b), TEM image (c) and electrocatalytic oxygen evolution performance diagram in acid and alkaline solutions (d)
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