Synthesis of Pd/TiO2-C composite catalysts and investigation of its performance for the electrooxidation of formic acid

In this work, anatase-TiO2 is investigated as a catalyst support in Pd/TiO2-C composite to improve the electrocatalytic properties of Pd for formic acid oxidation reaction (FAOR). Pd/TiO2 has been synthesized by an impregnation-reduction method and then mixed with Vulcan XC-72R carbon black to obtain Pd/TiO2-C composite. Transmission electron microscopy (TEM) images show Pd nanoparticles (ca.3.5 nm in average diameter) in the Pd/TiO2-C (1:1) composite catalyst were dispersed on the surface of TiO2 with a narrow particle size distribution. Electrochemical tests demonstrate Pd/TiO2-C (1:1) composite has significantly increased catalytic activity and stability compared with Pd/C for FAOR. The proposed reasons for these observations are the excellent acid corrosion and oxidation resistance of TiO2 and the synergistic effect of Pd and TiO2 nanoparticles. The effect of mass ratios of TiO2 to C on the catalytic performance is also discussed. The best catalytic activity and stability for FAOR is found when the mass ratio of TiO2 to C is 1:1. It can be interpreted as the synergistic effects and conductivity reach balance at this point. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.