Thermal Decomposition of Diammonium Tetrachloroplatinate to form Platinum Nanoparticles and its Application as Electrodes

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.