Study On The Carbon Support Materials Of Anode Catalyst In Direct Formic Acid Fuel Cell

Driven by the demand of clean and high-efficiency energy conversion devices, directformic acid fuel cells (DFAFCs) have received considerable attentions due to the formicacid possessing fast oxidation kinetics, less toxicity, lower crossover rate through Nafionmembrane than methanol. However, the lower catalystic activity, lower stability, easilydeactivated and easily corroded of anode catalysts still limit the commercial developmentof fuel cell.This paper studies the effect of several usually used carbon materials on Pd catalystfor formic acid electrooxidation, and found that multi-walled carbon nanotubes possessthe best catalytic activity and stability when it was used as a supported materials. Newactive sites are formed due to the interaction between Pd and carbon after adding carbonmaterials into Pd catalyst， and carbon materials playing a vital role. The results revealthat the carbon material is not only used as support, but also involves the new active sitesformation during formic acid electrooxidation reaction. The results are helpful inunderstanding the effect of carbon support in the Pd/C catalyst and reaction mechanism offormic acid elextrooxidation on the Pd/C catalyst and finding suitable materials for formicacid electrooxidation reaction.Meanwhile, this paper also systematically studied the effect of nitrogen-dopedacetylene carbon black supported Pd nanocatalyst on formic acid electrooxidation. Thenitrogen-doped acetylene carbon black (N-C) is prepared by annealing acetylene carbonblack and melamine under the protection of N2at different temperatures. The resultantN-C materials are used as the support of Pd catalyst (Pd/N-C) for formic acidelectrooxidation. The catalytic activity of the Pd/N-C catalyst towards formic acidelectrooxidation is evaluated by cyclic voltammetry, COadstripping voltammetry andchronoamperometry. The results show that when the heat-treatment temperature of supportis900°C, the corresponding catalyst, Pd/N-C-900, generate2.84-fold and0.96-foldhigher activity than homemade and commercial Pd/C catalysts in0.5mol L-1H2SO4and0.5mol L-1HCOOH solution. The COadstripping voltammetry results demonstrate that Pd/N-C-900has much better resistance to CO poisoning. Moreover, the effect of formicacid concentration and the temperature on the Pd/N-C catalysts are also explored, whichconfirms the really enhanced performances for formic acid electrooxidation. It is foundedthat the doping of nitrogen results an increase in the performance for formic acidelectrooxidation due to the improved Pd nanoparticles (Pd NPs) dispersion and themodified electronic effect. The results indicate that the Pd/N-C catalyst has greatapplication prospect as a high-performance anode catalyst for direct formic acid fuel cells.