纳米碳载Pt-TiO_2催化剂制备及对甲醇电催化氧化性能研究
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摘要
炭载TiO_2与PEG混合,超声振荡1 h,80℃搅拌2 h。滴加氯铂酸,调节p H值,分别用Na BH4,甲醛及甲酸还原,制得Pt-TiO_2/C催化剂a,b及c。用循环伏安法研究甲醇及CO分别在25℃和60℃的0.5 mol/L H2SO4溶液中在Pt-TiO_2/C上的氧化情况。结果表明,甲醇在60℃的酸性溶液中氧化时3种催化剂的氧化峰电位增大,峰电流密度升高,起始峰电位负移,说明升高温度有利于甲醇氧化,并且无论在25℃还是在60℃,催化剂c的电氧化能力最好,起始氧化电位最低,峰电流和峰电位最大。60℃时CO的峰电流密度和25℃时相比无太大变化,但起始氧化电位和峰电位明显负移,说明升高温度对CO的电氧化很有利,催化剂c的抗CO能力比a,b强,活性最高。
Carbon supported TiO_2 was mixed with PEG,which were ultrasonicly uvibrated 1 h,stirring 2 h at 80 ℃,dropping platinum chloride acid,adjusting p H value. The Pt-TiO_2/C catalysts a,b and c were prepared with NaBH_4,HCHO and HCOOH as three different reductants respectively. The Pt-TiO_2/C catalysts prepared have been characterized by cyclic voltammetry( CV) techniques and therefore the electrocatalytic oxidation activity of methanol and the adsorption of CO in 0. 5 mol/L H_2SO_4 solution at 25 ℃and 60 ℃ has been studied. The results showed that the oxidation peak potential of the three catalysts increased as well as the peak current density and the initial peak potential shifted negatively when the methanol was oxidized in acidic solution at 60 ℃. Result indicated that the elevated temperature was favorable for the oxidation of methanol whether at 25 ℃ or at 60 ℃,catalystic has the highest electrocatalytic oxidation activity,its initial oxidation potential was the lowest and the peak current and peak potential were the largest. The peak current density of CO didn't change much at 25 ℃ and 60 ℃,but the initial oxidation potential and peak potential had a significant negative shift,indicating that the elevated temperature was beneficial to the electrocatalysis of CO,and the anti CO ability of catalyst c was stronger than that of a and b,and its activity was the highest among the three catalysts.
Carbon supported TiO_2 was mixed with PEG,which were ultrasonicly uvibrated 1 h,stirring 2 h at 80 ℃,dropping platinum chloride acid,adjusting p H value. The Pt-TiO_2/C catalysts a,b and c were prepared with NaBH_4,HCHO and HCOOH as three different reductants respectively. The Pt-TiO_2/C catalysts prepared have been characterized by cyclic voltammetry( CV) techniques and therefore the electrocatalytic oxidation activity of methanol and the adsorption of CO in 0. 5 mol/L H_2SO_4 solution at 25 ℃and 60 ℃ has been studied. The results showed that the oxidation peak potential of the three catalysts increased as well as the peak current density and the initial peak potential shifted negatively when the methanol was oxidized in acidic solution at 60 ℃. Result indicated that the elevated temperature was favorable for the oxidation of methanol whether at 25 ℃ or at 60 ℃,catalystic has the highest electrocatalytic oxidation activity,its initial oxidation potential was the lowest and the peak current and peak potential were the largest. The peak current density of CO didn't change much at 25 ℃ and 60 ℃,but the initial oxidation potential and peak potential had a significant negative shift,indicating that the elevated temperature was beneficial to the electrocatalysis of CO,and the anti CO ability of catalyst c was stronger than that of a and b,and its activity was the highest among the three catalysts.
引文
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[3]Zhdanov V P,Kasemo B.Smulation of CO elerooxidatian on nm-size supported Pt particles stripping vohammetry[J].J Chemical Physics Letters,2003,376:220-225.
[4]Zhou W J,Song S Q,Li W Z,et al.Direct ethanol fuel cells based on Pt Sn anodes:The effect of Sn content on the fuel cell performance[J].J Power Sources,2005,140(1):50-58.
[5]赵卉卉,高颖,邬冰.Pt-Pd纳米催化剂对CO的电催化氧化[J].黑龙江大学自然科学学报,2010,27(2):226-229.
[6]曲微丽,邬冰,孙芳,等.乙二醇在Pt-WO3/C上的电催化氧化[J].物理化学学报,2005,21(7):804-807.
[7]贾羽洁,蒋剑春,孙康,等.Pt/Au原子比对活性炭负载Au-Pt直接甲酸燃料电池阴极催化剂性能的影响[J].燃料化学学报,2012,32(3):32-35.
[8]刘冉,邬冰,高颖,等.高分散Pt Ru/C催化剂的制备及对甲醇及吸附态CO的电催化氧化[J].分子科学学报,2007,23(5):316-321.
[9]刘长鹏,杨辉,邢巍,等.碳载Pt-Ti O2复合催化剂对甲醇氧化的电催化性能[J].高等学校化学学报,2002,23:1367-1370.
[10]Wang Y P,Peng P Y,Ding H Y,et al.Preparation and catalytic activity of active-carbon-supported Ti O2[J].J Acta Scientiae Circumstantiae,2005,25(5):611-617.
[11]Guo J W,Zhao T S,Prabhuram J,et al.Preparation and characterization of a Pt Ru/C nanocatalyst for direct methanol fuel cells[J].J Electrochimica Acta,2005,51(4):754-763.
[12]Honji A,Mori T,Hishinuma Y.Platinum dispersed on carbon catalyst for a fuel cell:A preparation with sorbitan monolaurate[J].J Electrochem Soc,1990,137:2084-2088.