Ethanol oxidation on Pd/C promoted with CaSiO3 in alkaline medium

•Thermal-decomposed CaSiO3 was added to XC-72 carbon black as composite support.•Modified electronic structure of Pd facilitates the detachment of CO from Pd surface.•CaSiO3 enhances proton transfer process and improves dehydrogenation process.•CaSiO3 promotes oxidation removal of CO due to easier OH adsorption on electrode.•Pd/50CaSiO3/C catalyst shows highest activity and stability for ethanol oxidation.

In this paper, CaSiO3 was prepared using a thermal decomposition approach and added to Vulcan XC-72 carbon black as support material. The X-ray diffraction and Transmission electron microscopy results show that the addition of CaSiO3 does not significantly change the particle size and distribution of Pd nanoparticles. The X-ray photoelectron spectroscopy reveals the interaction between Pd and CaSiO3. In addition, the electrochemical CO-striping measurement reveals that the Pd/50CaSiO3/C catalyst exhibits the largest electrochemical active surface and best CO tolerance. Moreover, cyclic voltammetry and chronoamperometry tests demonstrate that the Pd supported by CaSiO3 and C (50:50 in wt.%) possesses a much higher current density (1408 mA mg−1) than that of the Pd/C catalyst (743 mA mg−1) towards ethanol oxidation in alkaline media, and better stability as well. These results support the suitability of Pd/50CaSiO3/C catalyst developed in this work as a promising candidate for direct ethanol fuel cells application