Construction Of Interface Between Metal And Oxide/carbide And Its Enhanced Electrocatalytic Performance For Fuel Cells

Fuel cells can efficiently convert chemical energy into electrical energy and become important part of future energy development as a clean energy conversion device.The large-scale commercial application of PEMFC is still limited by the development of Pt-base electrocatalysts.On the anode side,the cheap hydrogen produced by catalytic reforming of fossils contains trace impurities(CO,H2S),which can cause severe poisoning or even deactivation of the catalyst.Solving the anti-poisoning performance of the catalyst has been troubled by researchers for decades.On the cathode side,the cathode catalyst mainly uses Pt/C catalyst,the carbon support corrodes in the acidic,humid,and high-oxygen operating environment of the fuel cell,which causes the surface Pt to agglomerate or fall off,catalyst layer.water flooding This reduces the activity and mass transfer performance,making it difficult for the catalyst to satisfy the stability requirements of the fuel cell for long-term operation.In this thesis,a new idea of catalyst designs is developed based on interface regulation.The metal-oxide interface is constructed to strength interaction between the precious metal and the support to improve the anti-poisoning performance;The main research this thesis contents are as follows:1.By coating MoO2 layer on the commercial PtRu/C catalyst with hydrothermal method to construct the PtRu-MoO2 interface.This method significantly improve the CO tolerance of the catalyst with hardly affecting the high HOR activity of the PtRu/C catalyst.After 0.1 V(RHE)potentiostatic testing for 2 hours in 1%CO/H2.It still retains about 85%of catalytic activity which is 3.7 times compared to original.After replacing the surface MoO2 layer with SiO2 the excellent anti-poisoning performance still remains.It shows that the anti-poisoning design strategy of the oxide barrier layer has a certain versatility.The oxide barrier layer can simultaneously affect CO diffusion kinetics and adsorption thermodynamics,but the thermodynamic adsorption caused by competitive adsorption takes the dominant position.2.Successfully prepared～5.04 nm Pt particles on commercial WC support by intermittent microwave heating method..This Pt/WC nanosheets have ultra-high ORR stability.After 10,000 cycles of accelerated experiments,the electrochemically active area attenuates only 6.11%,and the mass activity attenuates 30%.This catalyst perform slightly higher activity than that of commercial Pt/C while maintaining high stability.At 0.9 V,the area activity of the Pt/WC catalyst is 0.29 mA cm-2 and the mass activity is 0.18 A mgPt-1,respectively 1.45 times and 1.1 times of commercial Pt/C.