应用循环伏安,计时电流,计时电位和XRD等方法研究了碱性介质中甲醇在自制PdNiO/C和Pd/C催化剂上的电化学氧化以及高温热处理对催化剂结构和性能的影响.结果表明,还原温度为70℃,Pd、Ni原子比为8∶2时,PdNiO/C催化剂对甲醇电化学氧化具有较好的催化活性.热处理可增大催化剂粒径,升高结晶度,降低分散度和催化活性,并且可使NiO从Pd的晶格中脱离出来.与Pd/C催化剂相比,优选的PdNiO/C催化剂有更高的催化活性和更好的抗毒化能力.
The electro-oxidation of methanol in alkaline electrolyte at in-house synthesized PdNiO/C and Pd/C catalysts and the effect of heat treatment on the structure and performance of catalysts were studied by cyclic voltammetry,chronoamperometry,chronopotentiometry and X-ray diffraction methods.It is shown that when the reduction temperature is 70℃ and the ratio between Pd and Ni is 8∶2,The PdNiO/C catalyst presents a highest activity for methanol electrooxidation.Calcining can increase the particle size and crystallinity of catalysts,but decrease the dispersion and activity of catalysts, too.Besides,the NiO is disengaged from Pd lattice by heat-treatment.The optimal PdNiO/C catalyst shows higher catalytic activity and much better poisoning resistance than the Pd/C catalyst.
[1]Zeng R,Shen P K.Progress in the research and develop-ment of fuel cells—A Review of the 56th Annual Meet-ing of the International Society of Electrochemistry[J].Battery Bimonthly,2006,136(1):24-26.
[2]TarasevichMR,Karichev Z R,Bogdanovskaya VA.Oxidation of methanol and other low-molecular weight al-cohols on the RuNi catalysts in an alkaline environment[J].Russian Journal of Electrochemistry,2005,41(7):736-745.
[3]Shen P K,Xu C W.Alcohol oxidation on nanocrystallineoxide Pd/C promoted electrocatalysts[J].Electrochem-istry Communications,2006,8:184-188.
[4]Prabhram J,Manoharan R.Effects of incorporation of Cuand Ag in Pd on electrochemical oxidation of methanolin alkaline solution[J].J Applied Electrochemistry,1998,28:935-941.
[5]Beden B,Kadirgan F,Lamy C,et al.Oxidation of meth-anol on platinum electrode in alkaline medium[J].JElectroanal Chem,1982,142:171-190.
[6]Geng D S,Chen L,Lua G X.pH induced size-selectedsynthesis of PtRu nanoparticles,their characterizationand electrocatalytic properties[J].Journal of MolecularCatalysis A:Chemical,2007,265:42-49.
[7]Casella I G,Guascito M R.Electrochemical preparationof a composite gold-cobalt electrode and its electrocata-lytic activity in alkaline medium[J].Electrochimica Ac-ta,1999,45:1113-1120.
[8]Abdel Rahim M A,Abdel Hameed R M,Khalil M W.Nickel as a catalyst for the electro-oxidation of methanolin alkaline medium[J].Journal of Power Sources,2004,134(2):160-169.
[9]El-shafei A A.Electrocatalytic oxidation of methanol ata nickel hydroxide/glassy carbon modified electrode inalkaline medium[J].J Electroanal Chem,1999,471(2):89-95.
[10]Fleischmann M,Korinek K,Pletcher D.The oxidationof organic compounds at a nickel anode in alkaline so-lution[J].J Electroanal Chem,1971,31(1):39-49.