Electrocatalytic properties of PdCeOx/C anodic catalyst for formic acid electrooxidation

The PdCeOx/C catalyst was prepared and studied as anodic catalyst for formic acid electrooxidation. The morphology, composition and electrocatalytic properties were investigated by transmission electronmicroscopy, energy dispersive X-ray analysis, X-ray diffraction, X-ray photoelectron spectroscopy, the linear sweep voltammetry and chronoamperometry, respectively. The average particle size of Pd nanoparticles for PdCeOx/C catalyst was about 3.4 nm with a narrow size distribution. The electrochemical surface area (ESA) of PdCeOx/C catalyst was larger than the Pd/C catalyst. According to the Tafel plots, the presence of CeOx in the Pd/C catalyst can accelerate the rate of formic acid electrooxidation. The electrochemical measurements showed that the PdCeOx/C catalyst exhibited excellent catalytic activity and stability. For example, the peak current of PdCeOx/C catalyst for formic acid oxidation was about 1.67 times of the Pd/C catalyst and the stable current at 3600 s of PdCeOx/C catalyst was about 7 times of the Pd/C catalyst. The promotion effect should be attributed to the larger ESA, the electronic effect and more oxygen-containing species provided by the CeOx and this catalyst may be used as an effective catalyst for direct formic acid fuel cell.