Impact of dehydrogenation on the methanol oxidation reaction occurring on carbon nanotubes supported Pt catalyst with low Pt loading

Abstract

The electro-catalytic methanol oxidation reaction (MOR) has received considerable research attention due to its importance in the development of direct methanol fuel cells. In this study, the dehydrogenation step in MOR was investigated using low levels of platinum (Pt) which supported on carbon nanotubes as a catalyst. The concentration of H+ had a significant effect on the MOR activity of Pt catalysts supported by carbon nanotubes (Pt/CNTs), indicating that the dehydrogenation process was a critical step in MOR for Pt/CNTs with low Pt loading. Furthermore, the effects of Pt particle size and the distance between the Pt particles were investigated. We suggested a hypothesis: for the Pt catalyst with large particle size, only a few particles were needed for dehydrogenation to proceed; for the Pt catalyst with small particle size, many Pt particles were needed to form a network for the dehydrogenation reaction, but when the Pt particles were close enough, only a few Pt particles were needed. Our study provided insight into the electro-catalytic activity of Pt/CNTs from a mechanistic perspective.