Application Of Graphene Aerogel Support In Liquid Fuel Cell

Graphene aerogel(GA)has been widely used due to its simple preparation process,high porosity,low density,low thermal conductivity,low refractive index and low dielectric constant.Many studies have applied graphene aerogel as support in energy storage devices.In this paper,Pd and Pt alloys were supported by graphene aerogel for anode reaction of direct liquid fuel cells.The three-dimensional structure of graphene aerogel can provide a large surface area,which is conductive to the dispersion of noble metal particles.Furthermore,N-doped graphene aerogel as the support can adjust the electronic structure of graphene and noble metal,promoting the formation of small size noble metal alloy nanoparticles with good dispersion.This paper could be divided into three parts:(1)Graphene aerogel was prepared by freeze-drying method,and PdNi alloy was supported on the graphene aerogel.The physical characterization of PdNi/GA showed that GA has a three-dimensional structure and PdNi nanoparticles dispersed on GA support uniformly.Meanwhile,a strong electronic effect between GA support and alloy particles was also confirmed.When catalyzing formic acid oxidation reaction,the PdNi/GA catalyst exhibited high mass activity of 1699 mA·mg-1.The related CO stripping voltammetry test also showed a strong CO resistance ability,which was one of the reasons for its high catalytic efficiency.(2)Polyvinyl pyrrolidone(PVP)was added as the N source in the freeze-dried precursor solution to prepare N-doped graphene aerogels,which further loaded with PdNi alloy.The physical characterization of PdNi/GA-N showed that the average particle size of PdNi alloy nanoparticles decreased due to the addition of PVP,which suppressed the aggregation of nanoparticles.There was also a strong electronic effect between the N-doped GA and the PdNi alloy.The electrochemical measurement showed that the PdNi/GA-N catalyst could maintain a high catalytic activity(836 mA·mg-1)for formic acid oxidation over a wide voltage range(0.2-0.6 V).The excellent catalytic activity was attributed to the GA-N support,and the synergistic effect between Pd and Ni.(3)PtNi alloy supported by N-doped graphene aerogel(PtNi/GA-N)was synthesized and applied as anodic catalyst for ethanol fuel cells.The physical characterization showed that the PtNi alloy nanoparticles loaded on the three-dimensional GA-N had a small particle size and uniformly dispersed on the surface of graphene.The electrochemical methanol and ethanol oxidation tests of PtNi/GA-N exhibited a high mass activity of 1132.4 mA·mg-1 and 832.7 mA·mg-1,which was still maintained after 6000 s stability test.