MOF Derived Pt Based Catalyst For Alcohols Electrooxidation

The direct alcohols fuel cell was a kind of power sources for automobiles and portable electronics due to their high energy density,low pollutant emission and mild operating temperature.Developing high-performance catalysts for the alcohols oxidation reaction is still highly desired to realize the commercialization of this technology as the alcohols fuels oxidation process is very complex and sluggish.Platinum is the most effective monometallic catalyst for alcohols fuel oxidation but its surface tends to poisoning by the adsorbed intermediate species leading to reduced catalytic activity and stability.Considering its unique catalytic ability but limited resource on earth,it is urgent to increasing Pt catalytic efficiency for application in the fuel cells technique.The purpose of this paper is that combine Pt and MOF(Metal-organic Framework)to prepare stable and effective catalysts for direct alcohol fuel cell,which synergistic effect between the Pt and transition metal or support could promote the catalytic performance.Detailed research contents are listed as follows:(1)PtCo-NC catalyst was synthesized by combining Pt nanoparticles with ZIF-67 after annealing in the tube furnace and the in situ generated N-doped carbon(NC)from ZIF-67 was functionalized to support the PtCo alloy nanoparticle,obtained the PtCo-NC catalyst.The structure and morphology were probed by X-ray diffraction(XRD),scanning electron microscope(SEM)and transmission electron microscope(TEM),and the electrochemical performance was evaluated for alcohols fuels of methanol and ethanol oxidation.Compared with the reference sample of Pt/C,several times performance enhancement for alcohols fuel oxidation was found on PtCo-NC catalyst as well as the good catalytic stability.The high catalytic performance for alcohols fuel oxidation could be due to the largely improved anti-CO poisoning ability and the synergistic effect between the in situ formed PtCo nanoparticle and the N-doped carbon support.(2)PtNi-C catalyst was synthesized by combining Pt nanoparticles with Ni-BTC MOF(Nickel-Benzenetricarboxylic Acid Metal-organic Framework)after annealing in the tube furnace and the unstable Ni species can be easily leached out in nitric acid,obtained PtNi-C catalyst which after acid leaching,and the stable PtNi nanoparticles trapped in the graphite carbon layer were obtained.The greatly improved catalytic ability for alcohol fuels oxidation was verified by comparing the fresh and acid leached catalysts.The current work guides the importance of unstable assistant promoter removal for the MOF derived catalysts.This is meaningful for the similar catalyst preparation and performance study.(3)Pt-Cu-Mo2C catalyst is successfully fabricated by a facile approach based on galvanic replacement and used as an efficient catalyst for alcohol oxidation.By tune the usage of chloroplatinic acid,a series of catalyst were synthesized.The structure of the as-synthesized Pt-Cu-Mo2C catalyst has been analyzed using TEM,XRD,and X-ray photoelectron spectroscopy(XPS).The Pt-Cu-Mo2C-1:3(the atom ratio of Pt:Cu in reactant is 1:3)catalyst show the best performance.The Pt distributed evenly on the Cu-Mo2C support that exposure more active site and enhanced the interaction between Pt and support.The electronic effect exists between Pt and Cu-Mo2C support,Pt gain electron from support that downshift the d-band center,improve the catalyst performance.Meanwhile,Cu and Mo2C provide oxygenated species to enhance alcohol oxidation process.Because of the synergetic effect of Pt and support in the alcohol oxidation,the activity and durability of the prepared Pt-Cu-Mo2C catalyst is significantly enhanced.