Effect of the templates on the synthesis of hollow carbon materials as electrocatalyst supports for direct alcohol fuel cells

Hollow carbon hemispheres (HCHSs) have been synthesized by the aid of polystyrene spheres (PSs) or solid core mesoporous shell silica (SCMSS) as templates. A possible formation mechanism is presented. Scanning and transmission electron microscopic measurements show that the HCHSs have uniform morphologies and high Brunauer–Emmett–Teller surface areas. The high surface areas are beneficial for the dispersion of precious metal nanoparticles. Pd nanoparticles deposited on HCHSs show uniform particle distribution and exhibit excellent performance for alcohol electrooxidation. The ratios of the peak current densities of the ethanol oxidation on Pd/HCHS-PS or Pd/HCHS-SCMSS to Pd/C are 2.74 and 3.35, respectively. The hemispherical structure results in an improvement in the mass transfer and higher alcohol concentrations can be used to increase the energy density of direct alcohol fuel cells.