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

In this work, anatase-TiO 2 is investigated as a catalyst support in Pd/TiO 2 –C composite to improve the electrocatalytic properties of Pd for formic acid oxidation reaction (FAOR). Pd/TiO 2 has been synthesized by an impregnation-reduction method and then mixed with Vulcan XC-72R carbon black to obtain Pd/TiO 2 –C composite. Transmission electron microscopy (TEM) images show Pd nanoparticles (ca.3.5 nm in average diameter) in the Pd/TiO 2 –C (1:1) composite catalyst were dispersed on the surface of TiO 2 with a narrow particle size distribution . Electrochemical tests demonstrate Pd/TiO 2 –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 TiO 2 and the synergistic effect of Pd and TiO 2 nanoparticles . The effect of mass ratios of TiO 2 to C on the catalytic performance is also discussed. The best catalytic activity and stability for FAOR is found when the mass ratio of TiO 2 to C is 1:1. It can be interpreted as the synergistic effects and conductivity reach balance at this point.