Preparation And Electrocatalytic Properties Of Black Phosphorus Composites

As a technology that directly converts chemical energy into electric energy to realize efficient and clean utilization of energy,fuel cell alleviates the environmental pollution caused by fossil energy consumption.Direct ethanol fuel cell?DEFC?has a good application prospect due to its advantages of wide fuel sources,high energy conversion efficiency,convenient transportation and safe storage.The activity and stability of the catalyst restrict the development of DEFC.The types and surface properties of catalyst support materials directly affect the morphology,dispersion and particle size of noble metal catalysts,and are closely related to the electrocatalytic performance of fuel cells.Black phosphorus,as a new two-dimensional material discovered after graphene,has attracted extensive attention and research because of its large specific surface area and high electron mobility.However,the poor stability of black phosphorus hinders its application in fuel cell.In order to improve the electrocatalytic performance of catalysts,reduce the amount of fuel cell noble metal catalyst,and thus reduce the catalyst cost,the electrocatalytic performance of catalysts from the preparation of a better stability of black phosphorus composite carrier,and studied the morphology,structure,electrochemical properties of catalysts.The effects of the composition and structure of the composite catalyst on the activity and stability of EOR were evaluated,and the correlation between black phosphorus and other materials in EOR was discussed.The main research content has the following aspects:1.Black phosphorus was prepared by chemical vaper transport method,black phosphorus and graphene were separated to obtain black phosphorus-graphene?BP-G?composites under solvent-thermal conditions,and Pd-based catalysts of different carriers were prepared by dipping reduction method.Through characterization,it was found that P-C bond and P-O-C bond formed between BP and G,which improved the structural stability of BP-G.The electrocatalytic test results showed that the catalyst had the highest catalytic activity when the BP/G ratio was 1:1,and the ECAS of Pd/ BP-G was 210.4 m2 g Pd-1,which was 9.5 times of the commercial Pd/C catalyst?22.05 m2 g Pd-1?.The mass activity of Pd/ BP-G was 3960 m A mgpd-1,which was 5.86 times of the commercial Pd/C catalyst?675.5 m A mgpd-1?.The prepared Pd/ bp-g composite catalyst has high activity and stability.2.The Pd/BP@TiO₂ catalyst was prepared by immersion reduction method by synthesizing BP@TiO₂ composite material in hydrothermal in situ.The microstructure of the catalyst was characterized by SEM and TEM,and the two formed composite materials with heterogeneous structure,which was conducive to the stability of the structure and the charge transmission as an electric catalyst carrier.Electrochemical test results showed that the electrochemical active area of Pd/BP@TiO₂ catalyst was 92.53 m2 g Pd-1,3.2 times that of commercial Pd/C catalyst?30.6 m2 g Pd-1?.The ethanol electrooxidation test in 1M Na OH +1M C2H5 OH solution showed that the mass activity of BP@TiO₂ catalyst was 2067.67 m A mgpd-1,which was 2.6 times higher than that of commercial Pd/C?802.45 m A mgpd-1?,and Pd/BP@TiO₂ catalyst had a lower starting potential compared with Pd/C.The durability of Pd/BP@TiO₂ catalyst was tested.After 5000 cycles,the mass activity of Pd/BP@TiO₂ catalyst only lost 16.2%.In summary,the work of this paper is based on the preparation of a suitable catalyst carrier material on black phosphorus,which improves the stability of black phosphorus.Combined with the synergistic effect of catalyst components and excellent characteristics of carrier material,the catalytic activity and catalytic stability of direct ethanol fuel cell anode catalyst can be significantly improved.