Synthesis of Pt/(Co, Zn)Sn(OH)₆ complex catalysts and their catalytic activity towards methanol electrochemical oxidation

The Pt/CoSn(OH)₆ and Pt/ZnSn(OH)₆ complex catalysts were prepared using CoSn(OH)₆ and ZnSn(OH)₆ hollow nanocubes by an ultrasound process with ascorbic acid as the soft reductant, respectively, and demonstrate excellent performance towards the methanol oxidation reaction (MOR). The Pt/CoSn(OH)₆ and Pt/ZnSn(OH)₆ catalysts exhibit higher mass activities (1095.6 mA/mg and 699.5 mA/mg, respectively) compared to Pt/C (594.6 mA/mg) catalyst towards methanol oxidation. XRD, SEM, TEM, XPS and electrochemical measurements were employed to explore the relationships of the crystal structure and the properties of catalysts. CO-stripping experiment results indicate that the hydroxide supports facilitates the removal of CO on Pt surface. The increased activity and resistance of CO poisoning for Pt/CoSn(OH)₆ and Pt/ZnSn(OH)₆ catalysts can be attributed to the strong interaction between the support (Co, Zn)Sn(OH)₆ and Pt in the catalysts and the large amount of hydroxyls on the support surface. The higher relative intensity of Pt in the (Co, Zn)Sn(OH)₆ catalysts also contributes to the higher MOR activity. The (Co, Zn)Sn(OH)₆ towards methanol catalytic electro-oxidation can disclose the influence of the support structure on the catalytic activity and will be helpful for the development and application of complex catalysts in direct methanol fuel cells (DMFCs).