Catalytic Activity and Durability of Platinum Supported on Titanium Oxide Nanoparticles for Proton Exchange Membrane Fuel Cells

Proton exchange membrane fuel cells (PEMFCs) are believed to have the potential to become a major source of clean energy which make them a promising technology for mobile and stationary power applications. Despite considerably recent advances of PEMFCs, some economical and technical barriers impede their large-scale commercialization. [1, 2]. One of the technical barriers is associated to carbon black, having widely been used as catalyst support for platinum in PEMFCs. Carbon supports have weak interaction with platinum and are susceptible to corrosion in acidic environment of PEMFCs [3]. Therefore, in order to inhibit the corrosion of support and enhance the stability of the catalyst during the operation of PEMFCs, more stable and corrosion resistant catalyst supports are strongly required. Metal oxide-based compounds are good candidates for catalyst support in PEMFCs. The solubility of the metal oxides in acidic and oxidative environments is mostly less than that of the carbon black, indicating that they are more stable compared to the carbon black [4]. Moreover, researchers have found that the metal oxide supports and platinum nanoparticles can form a strong metal-support interaction (SMSI) which can provide electron from support to platinum, affect the unfilled d band vacancies, and increase adsorption, dissociation and desorption of oxygen on the surface of platinum, leading to higher platinum activity for oxygen reduction reaction (ORR) [4]. Metal oxides also have suggested some degree of ORR activity even greater than carbon black with filling their surface vacancies by adsorption and dissociation of oxygen molecules [5]. In the present study, titanium oxide nanoparticles were used as the support for platinum nanoparticles catalysts. The microstructure and phase characterizations of the synthesized catalysts were performed using field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction analysis (XRD). The ORR activity and durability of the catalysts were then studied by cyclic voltammograms (CVs) in N 2 and O 2 saturated 0.1 M HClO 4 electrolyte and accelerated stability test (AST) using rotating disk electrode (RDE) technique. References [1] Brady CDA, Rees EJ, Burstein GT. Electrocatalysis by Nanocrystalline Tungsten Carbides and the Effects of Codeposited Silver. J Power Sources 2008;179:17-26. [2] Schenk A, Grimmer C, Perchthaler M, Winberger S, Pichler B, Heinzl C, Scheu C, Mautner F-A, Bitschnau B, Hacker V. Platinum-cobalt catalysts for the oxygen reduction reaction in high temperature proton exchange membrane fuel cells-long term behavior under ex-situ and in-situ conditions. J Power Sources 2014;266:313-322. [3] Jiang Z-Z, Gu D-M, Wang Z-B, Qu W-L, Yin G-P, Qian K-J. Effect of anatase TiO 2 with different particle sizes and contents on the stability of supported Pt catalysts. J Power Sources 2011;196:8207-8215. [4] Hsieh B-J, Tsai M-C, Pan C-J, Su W-N, Rick J, Chou H-L, Lee J-F, Hwang B-J. Tuning metal support interactions enhances the activity and durability of TiO 2 -supported Pt nanocatalysts. Electrochim Acta 2017;224:452-459. [5]Epling WS, Peden CHF, Henderson MA, Diebold U. Evidence for oxygen adatoms on TiO 2 (110) resulting from O 2 dissociation at vacancy sites. Surf Sci 1998;412/413:333-343.