Novel nanorod Ti0·7Ir0·3O2 prepared by facile hydrothermal process: A promising non-carbon support for Pt in PEMFCs

Abstract

Late transition metal doped TiO2 has been exploited for generating efficient catalyst support by enhancing electrical conductivity and modifying properties of TiO2. The Ti0·7Ir0·3O2 nanorod (NRs), a novel catalyst support for Pt nanoparticles, was prepared for the first time via single-step hydrothermal process at low temperature using IrCl3·3H2O and TiCl4 as starting materials. We found that the Ti0·7Ir0·3O2 NRs with 70–80 nm in length and 25–30 nm in width is successful prepared at 210 °C for 12 h without utilizing surfactants or stabilizers. In addition, the Ti0·7Ir0·3O2 NRs was presented principally as a single-phase solid with the TiO2 is in the rutile form with high crystallinity without using further treatment after synthesis. More importantly, we found that the Ti0·7Ir0·3O2 NRs possesses high electrical conductivity (0.028 S cm−1) dealing the intrinsically non-conducted drawback of TiO2. The Pt nanoparticles were then deposited on the support of Ti0·7Ir0·3O2 NRs via chemical reduction method. The properties of 20 wt % Pt/Ti0·7Ir0·3O2 NRs electrocatalyst were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), the cyclic voltammetry (CV). The uniformly distributed small Pt nanoparticles (3–4 nm diameter) were well adhered to the Ti0·7Ir0·3O2 NRs. The electrochemically active surface area (ECSA) of 20 wt % Pt/Ti0·7Ir0·3O2 NRs was higher than that of the commercial 20 wt % Pt/C (E-TEK) due to the small size and good dispersion of Pt nanoparticles on the surface of Ti0·7Ir0·3O2 NRs. Moreover, the ECSA value of the Pt/Ti0·7Ir0·3O2 NRs retained up to 88% after 2000 cycles of cyclic voltammetry, suggesting the high stability of catalyst resulted from strong metal support interaction (SMSI) of Titania-based materials with the noble metals. More importantly, the onset potential of Pt/Ti0·7Ir0·3O2 NRs catalyst towards oxygen reduction reaction is more positive (∼80 mV) compared to commercial Pt/C, indicating the high catalytic activity of the Pt/Ti0·7Ir0·3O2 NRs catalyst. The results of this research suggested that novel Ti0·7Ir0·3O2 NRs could be applied as promising robust non-carbon support for Pt. This research also creates a preliminary step for investigating systematically promising Iridium doped Titania materials.