PtCo复合纳米线的制备及氧还原电催化性能表征
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摘要
采用CoCl_2-EMIC离子液体,在碳纸电极上无模板电沉积得到Co纳米线,然后通过K_2PtCl_4溶液和抗坏血酸进行置换反应制备PtCo复合纳米线,后续热处理得到PtCo-700℃合金纳米线。PtCo复合纳米线中Pt以互相连接的片层结构较好包裹在Co纳米线的表面, Co/Pt摩尔比为12。电化学研究表明:PtCo的电化学活性表面积(ECSA)高达65.1 m~2·g~(-1),比商用JM-Pt/C催化剂高6.9 m~2·g~(-1), PtCo-700℃的ECSA仅为34.7 m~2·g~(-1)。当电位在0.85 V时, PtCo-700℃的质量比和面积比活性均最高,分别是JM-Pt/C催化剂的9.5倍和15倍。500圈加速老化实验后, 0.85 V时, PtCo-700℃的质量比和面积比活性仍最高,分别是JM-Pt/C催化剂的8.7倍和10.3倍。PtCo复合纳米线有效地提高了催化剂的活性,合金化后的PtCo-700℃呈现出更优异的催化性能。此外负载铂钴复合纳米线的碳纸可以直接组装进燃料电池,简化了燃料电池的制备过程。
Co nanowires were electrodeposited from CoCl_2-EMIC ionic liquid on carbon paper without template. Preparing PtCo composite nanowires through the displacement reaction by immersing the carbon paper with Co nanowires into the K_2PtCl_4 solution and ascorbic acid. With the subsequent heat treatment, PtCo-700 ℃ alloy nanowires were prepared. PtCo composite nanowires have shown interconnected sheet structure of Pt layer perfectly coated on the surface of Co nanowires and the Co/Pt molar ratio is 12. Electrochemical results showed that the electrochemical surface area(ECSA) of PtCo composite nanowires was 65.1 m~2·g~(-1), which was 6.9 m~2·g~(-1) higher than that of the commercial JM-Pt/C catalyst, while that of the PtCo-700 ℃ was only 34.7 m~2·g~(-1). At 0.85 V, the mass activities and the specific activities of PtCo-700 ℃ were the highest, 9.5 times and 15.0 times that of JM-Pt/C catalyst respectively. After 500 cycles, at 0.85 V, the mass activities and the specific activities of PtCo-700 ℃ were still the highest. The prepared PtCo composite nanowires effectively improved the activity of the catalyst, and PtCo alloy nanowires showed the higher activity. And the carbon paper supporting the platinum-cobalt composite nanowires could be directly assembled into a fuel cell, thereby simplifying the preparation process of the fuel cell.
Co nanowires were electrodeposited from CoCl_2-EMIC ionic liquid on carbon paper without template. Preparing PtCo composite nanowires through the displacement reaction by immersing the carbon paper with Co nanowires into the K_2PtCl_4 solution and ascorbic acid. With the subsequent heat treatment, PtCo-700 ℃ alloy nanowires were prepared. PtCo composite nanowires have shown interconnected sheet structure of Pt layer perfectly coated on the surface of Co nanowires and the Co/Pt molar ratio is 12. Electrochemical results showed that the electrochemical surface area(ECSA) of PtCo composite nanowires was 65.1 m~2·g~(-1), which was 6.9 m~2·g~(-1) higher than that of the commercial JM-Pt/C catalyst, while that of the PtCo-700 ℃ was only 34.7 m~2·g~(-1). At 0.85 V, the mass activities and the specific activities of PtCo-700 ℃ were the highest, 9.5 times and 15.0 times that of JM-Pt/C catalyst respectively. After 500 cycles, at 0.85 V, the mass activities and the specific activities of PtCo-700 ℃ were still the highest. The prepared PtCo composite nanowires effectively improved the activity of the catalyst, and PtCo alloy nanowires showed the higher activity. And the carbon paper supporting the platinum-cobalt composite nanowires could be directly assembled into a fuel cell, thereby simplifying the preparation process of the fuel cell.
引文
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[17]Yang P X,An M Z,Su C N,Wang F P.Effect of additives on electrodeposition of cobalt in ionic liquids[J].Chinese Journal of Inorganic Chemistry,2009,25(1):112.(杨培霞,安茂忠,苏彩娜,王福平.添加剂对离子液体中电沉积金属钴的影响[J].无机化学学报,2009,25(1):112.)
[18]Chen Y,Wang H,Li B.Electrodeposition of Sm Co alloy nanowires with a large length-diameter ratio from Sm Cl3-Co Cl2-1-ethyl-3-methylimidazolium chloride ionic liquid without template[J].Rsc Advances,2015,5(49):39620.
[19]Garsany Y,Baturina O A,Swiderlyons K E,Kocha S S.Experimental methods for quantifying the activity of platinum electrocatalysts for the oxygen reduction reaction[J].Analytical Chemistry,2010,82(15):6321.
[2]Shao M,Chang Q,Dodelet J P,Chenitz R.Recent advances in electrocatalysts for oxygen reduction reaction[J].Chemical Reviews,2016,116(6):3594.
[3]Tang Z Y,Song S D,Liu J H.Research progress of electrocatalysts for proton exchange membrane fuel cells[J].Chinese Journal of Power Sources,2003,27(1):58.(唐致远,宋世栋,刘建华.质子交换膜燃料电池电极催化剂的研究进展[J].电源技术,2003,27(1):58.)
[4]Gan L,Cui C,Rudi S,Strasser P.Core-shell and nanoporous particle architectures and their effect on the activity and stability of Pt ORR electrocatalysts[J].Topics in Catalysis,2014,57(1-4):236.
[5]Shrestha S,Asheghi S,Timbro J,Mustain W E.Temperature controlled surface chemistry of nitrogen-doped mesoporous carbon and its influence on Pt ORR activity[J].Applied Catalysis A General,2013,s464-465(16):233.
[6]Rajalakshmi N,Ryu H,Shaijumon M M,Ramaprabhu S.Performance of polymer electrolyte membrane fuel cells with carbon nanotubes as oxygen reduction catalyst support material[J].Journal of Power Sources,2005,140(2):250.
[7]Stamenkovic'V,Schmidt T J,Ross P N,Markovic'N M.Surface Composition Effects in Electrocatalysis:Kinetics of Oxygen Reduction on Well-Defined Pt3Ni and Pt3Co Alloy Surfaces[M].Perspectives on Irish Nationalism:University Press of Kentucky,2002.149.
[8]Shui J L,Chen C,Li J C M.Evolution of nanoporous Pt-Fe alloy nanowires by dealloying and their catalytic property for oxygen reduction reaction[J].Advanced Functional Materials,2011,21(17):3357.
[9]Antolini E,Salgado J R C,Gonzalez E R.The stability of Pt-M(M=first row transition metal)alloy catalysts and its effect on the activity in low temperature fuel cells:a literature review and tests on a Pt-Co catalyst[J].Journal of Power Sources,2006,160(2):957.
[10]Chen L,Qi Y,Mu S C.Improvement of stability of PtCo alloy catalyst for proton exchange membrane fuel cell by Au modification[J].Surface Technology,2015,(1):29.(陈磊,齐意,木士春.通过Au修饰提高质子交换膜燃料电池Pt Co合金催化剂稳定性[J].表面技术,2015,(1):29.)
[11]Zhang Y H,Li X H,Wu X M,Xu M F,Deng L F.Preparation and properties of Pt-Co/C catalyst for PEM-FC[J].China Precious Metals,2004,25(1):19.(张云河,李新海,吴显明,许名飞,邓凌峰.PEM-FC用Pt-Co/C催化剂的制备及性能[J].贵金属,2004,25(1):19.)
[12]Zhao D J,Yin G P,Wei J.Polymer membrane fuel cell cathode non-Pt catalyst[J].Progress in Chemistry,2009,21(12):2753.(赵东江,尹鸽平,魏杰.聚合物膜燃料电池阴极非Pt催化剂[J].化学进展,2009,21(12):2753.)
[13]Rego R,Oliveira M C,Alcaide F,lvarez G.Development of a carbon paper-supported Pd catalyst for PEM-FC application[J].International Journal of Hydrogen Energy,2012,37(8):7192.
[14]Ohyagi S,Sasaki T.Durability of a PEMFC Pt-Co cathode catalyst layer during voltage cycling tests under supersaturated humidity conditions[J].Electrochimica Acta,2013,102(102):336.
[15]Bertin E,Garbarino S,Ponrouch A,Guay D.Synthesis and characterization of Pt Co nanowires for the electrooxidation of methanol[J].Journal of Power Sources,2012,206(1):20.
[16]Huang H Y,Su C J,Kao C L,Chen P Y.Electrochemical study of Pt and Fe and electrodeposition of Pt Fe alloys from air-and water-stable room temperature ionic liquids[J].Journal of Electroanalytical Chemistry,2010,650(1):1.
[17]Yang P X,An M Z,Su C N,Wang F P.Effect of additives on electrodeposition of cobalt in ionic liquids[J].Chinese Journal of Inorganic Chemistry,2009,25(1):112.(杨培霞,安茂忠,苏彩娜,王福平.添加剂对离子液体中电沉积金属钴的影响[J].无机化学学报,2009,25(1):112.)
[18]Chen Y,Wang H,Li B.Electrodeposition of Sm Co alloy nanowires with a large length-diameter ratio from Sm Cl3-Co Cl2-1-ethyl-3-methylimidazolium chloride ionic liquid without template[J].Rsc Advances,2015,5(49):39620.
[19]Garsany Y,Baturina O A,Swiderlyons K E,Kocha S S.Experimental methods for quantifying the activity of platinum electrocatalysts for the oxygen reduction reaction[J].Analytical Chemistry,2010,82(15):6321.