The effect of Sn content in Pt-SnO ₂/CNTs for methanol electro-oxidation

The electrocatalyst is one of several impediments for the application of direct methanol fuel cells, which includes the mediocre performance on anode and its endurance against intermediates of methanol oxidation such as carbon monoxide. In this research, a hydrolyze-hydrothermal method has been applied to synthesize the SnO ₂/CNTs nano support, followed by the Pt loading process to prepare the Pt-SnO ₂/CNTs in sequence. CTAB was added into system during hydrothermal process to promote uniform dispersion of the tin oxide on surface of CNTs. The total noble metal loading is 20% in weight. The catalysts were characterized by cyclic voltammetry, and chronoamperometry. For comparison, a series of catalysts with different Sn content were also synthesized. The onset potential of the Pt-SnO ₂/CNTs is much lower than Pt/C, the current density of Pt-SnO ₂/CNTs were nearly double of which on the commercial Pt/C, indicating that SnO ₂ plays a very important role in methanol oxidation and CO oxidation at low potentials. CV curves and chronoamperometry indicated that there was a positive correlation between Sn content and the electrochemical activity.