Study Of Preparations And Performances Of Pd Based Catalysts For Alcohol Electro-oxidation In Alkaline Medium

Direct alcohol fuel cells(DMFCs) has attracted a generally attention due to high-efficiency, low-emission and convenient-storage. Anode catalyst is the key parts to DMFCs. In order to further improve electrocatalytic activity and stability of Pd catalysts in alkaline medium, electrocatalysts were modulated by metal, the support was modified by polymers and composite supports were synthesized. Transmission electron microscopy(TEM) and X-ray photoelectron spectroscopy(XPS) were used to characterize the morphology, composition and structure of catalysts. The electrochemical methods as Cyclic voltammetry(CV), Linear sweep voltammetry(LSV), Electrochemical impedance spectroscopy(EIS) and Chronoamperometry(CA) were applied to study the catalytic activity and stability in the alcohol oxidation reaction. The main research results are as follows:Ni, Fe and Cu metal particles were introduced in Pd/CNTs catalyst. Alloy particles dispersion is improved and particle size is smaller. Ni, Fe and Cu particles can improve the Pd/CNTs catalyst electric catalytic properties towards alcohol. Pd particles showed double functional effect with Ni, Fe and Cu, respectively.The catalyst support was modified by Chitosan and PDDA. Pd particles size on composite support is smaller and not aggregation. Pd(0) content is higher. Compared to the base catalyst, Pd/C-Chit and Pd/CNTs-PDDA catalyst shows excellent electrocatalytic oxidation performance.In the catalyst support preparation, PPy was used. Pd particles size is smaller and its distribution is improved. PPy increased the electrocatalytic performance of Pd/C catalyst. Compared with the Pd/C catalyst, catalytic properties of PANI @ Pd/C catalyst failed to get an overall improvement.The mixed supports, GNPs-CNTs and GNPs-C, improved the distribution of the Pd particles. Compared with single carrier catalyst, mixed supports can improve the electrocatalytic performance towards alcohols.