Progress in fuel cell research in catalyst materials

Recently, Yue Li, a researcher at the Institute of Micro-Nano Technology and Devices, Institute of Solid State Physics, Institute of Solid Physics, Chinese Academy of Sciences, made new progress in the control of porous gold-silver-platinum (AuAgPt) alloy nanomaterials and their methanol catalysis. The relevant research results are published in Journal of Materials Chemical A (J. Mater.Chem. A, DOI: 10.1039/c8ta04087g).

In recent years, with the rapid development of the economy, China's demand for energy is increasing. As the most important energy source consumed by the world, fossil energy has brought convenience to us and caused serious pollution to the global environment. Therefore, it is becoming more and more important to develop clean energy that can replace fossil energy. A fuel cell is a device that can directly convert chemical energy in fuel and oxidant into electrical energy. It is the “fourth power generation method” after water, firepower, and atomic power generation; because of energy saving, high conversion efficiency, and the proximity advantages of zero emissions have become an important way to solve energy and environmental problems. Among them, methanol fuel cells are widely used in portable equipment because of their high work efficiency and environmental friendliness. Compared with hydrogen energy, methanol is a cheaper liquid fuel, easy to store, easy to transport, and has a higher theoretical energy density. Therefore, methanol fuel cells have very good application potential in the field of new energy.

At present, the catalysts for methanol fuel cells are mainly made of platinum nanomaterials, but the conventional platinum nanomaterials will produce side effects such as poisoning and precipitation during the preparation process, which makes the effective area activity and mass activity of the platinum nanocatalyst gradually decrease, seriously affecting The service life of methanol fuel cells. In addition, the metal platinum required for the preparation of platinum nanomaterials has low storage capacity, high cost, and high cost, which is not conducive to large-scale commercial application of the battery. In order to improve the catalytic activity and stability of methanol fuel cell catalysts, platinum and platinum-based nanocatalysts with different structures have been prepared by various methods, such as platinum nanoparticles with high-index crystal faces, hollow platinum-palladium alloys, and platinum. Nickel alloys, silver-platinum alloys, etc., but the preparation methods of these materials are mostly complicated in process and long in reaction cycle, and the above-mentioned catalytic activity and stability problems are not well solved.

Yue Li's research group successfully prepared a three-dimensional porous AuAgPt ternary alloy nanomaterial catalyst by laser induced method. They firstly reacted the Au@Ag nanocube with potassium chloroplatinate to obtain Au@AgPt nanocubes (Au @ AgPtNCs), and then irradiated the Au@AgPt nanocubes with a laser of 670-700 volts to make Au. @AgPt nanocubes were rapidly melted into solid AuAgPt alloy nanospheres (solid AuAgPt NSs), and then some silver in solid AuAgPt alloy nanospheres was removed by chemical etching to obtain monodisperse three-dimensional porous AuAgPt ternary alloy nanospheres (spongy AuAgPt NSs). The AuAgPt ternary alloy nanospheres not only have higher stability than traditional platinum nanomaterials, but also have large specific surface area and high density active sites, which are easy to adsorb reactants, can effectively improve catalytic activity, and their catalytic properties for methanol. The activity (1.62Amg Pt-1) was 4.6 and 5.1 times that of solid AuAgPt alloy nanospheres (0.35Amg Pt-1) and commercial platinum black (Ptblack) (0.32Amg Pt-1), respectively. These excellent properties benefit from the porous structure of the material itself and the presence of high-index crystal faces, lattice distortions, and twin boundaries on the surface of the material. The results of this study have solved the problems of low catalytic activity, poor stability and short battery life of fuel cells when used.

The above research was supported by the Chinese Academy of Sciences cross-team project and the National Natural Science Foundation project.

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