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