Thermal Decomposition of Diammonium Tetrachloroplatinate to form Platinum Nanoparticles and its Application as Electrode
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Thermal Decomposition of Diammonium Tetrachloroplatinate to form Platinum Nanoparticles and its Application as Electrodes Doralice Meza Caldero´n Æ Ulises Morales Æ Celso Vela´squez Æ Victor H. Lara Æ Leonardo Salgado
Received: 16 June 2009 / Accepted: 16 July 2009 / Published online: 29 July 2009 Ó Springer Science+Business Media, LLC 2009
Abstract Pt nanoparticles were obtained via the thermal decomposition of (NH4)2[PtCl4] (diammonium tetrachloroplatinate) by heating from room temperature to 760 °C. The thermal decomposition process was analyzed using thermogravimetric analysis (TGA) and differential thermal analysis (DTA), X-ray thermodiffraction and infrared spectroscopy. The size and structure of the platinum particles were analyzed using transmission electron microscopy (TEM). The electrochemical activity of Pt particles was assessed by cyclic voltammetry in 0.5 M H2SO4. The TGA and DTA results suggested that the thermal decomposition of the precursor proceeded in two stages: loss of NH4Cl at *300 °C, followed by loss of NH4Cl and Cl2 at *372 °C. Metallic Pt particles were then produced at temperatures of 372 °C and above. At 760 °C, the mean ± SD size of the Pt particles was (4.1 ± 1.6) nm, as determined from TEM measurements. In cyclic voltammetry (CV) measurements, an electrode comprised of glassy carbon and Pt particles in 0.5 M H2SO4 exhibited behavior similar to that observed using a polycrystalline Pt electrode.
D. M. Caldero´n U. Morales V. H. Lara L. Salgado (&) Depto. de Quı´mica, Universidad Auto´noma Metropolitana Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Delegacio´n Iztapalapa, C.P. 09340, Apdo. Postal 55-534 Me´xico, D.F., Me´xico e-mail: [email protected] C. Vela´squez Departamento de Ciencias Naturales y Exactas del Centro Universitario de los Valles, Universidad de Guadalajara, Carretera Guadalajara, Ameca, km. 45.5, C.P. 46600 Ameca, Jalisco, Me´xico
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Keywords Thermal decomposition Diammonium tetrachloroplatinate Pt nanoparticles Electrodes
1 Introduction Pt nanoparticles are of great interest due to their potential technological applications in catalysis and electrocatalysis [1], for example in automotive catalytic converters [2], sensors [3], fuel cells through the electrocatalysis of methanol oxidation [4, 5], and oxygen reduction reactions [6]. Pt nanoparticles are ideal electrocatalysts on account of their high effective surface area, catalytic activity and stability in acidic electrolyte solutions. Much attention has been devoted to developing methods for synthesizing nanoparticles of Pt and other metals. Metal nanoparticles have been prepared by a wide variety of techniques, including laser ablation [7], vapor nucleation [8], thermal decomposition of organometallic compounds [9], sonolysis [10, 11], sol–gel chemistry [12], pulse radiolysis [13], electrochemical reduction [14, 15], and chemical reduction of the corresponding salts [16]. However, the size and surface structure of the synthesized metallic particles are sensitive to the synthesis method and ex
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