The anode oxidation reaction in fuel cell: A DFT study

Although fuel cell (FC) has been regarded as promising “green” power generator, the Pt-based catalysts in the FC hampered their further development for its high cost and scarcity. Direct methanol fuel cell (DMFC) as another kind of proton exchange membrane fuel cell (PEMFC) has been manifested that Pd also performs a certain activity for methanol oxidation reaction (MOR). To better know the mechanism of MOR, we present a DFT study on the first step reaction of MOR on the Pd(111). The results show that methanol prefers to physically adsorb on the Pd(111) through oxygen atom, while the dehydrogenated hydrogen atoms can adsorb either on face-cantered cubic (FCC) or hexagonal close packed (HCP) sites. The intermediate products will form a much stronger interaction with the Pd(111) since they contain more unsaturated bonds. The energy barrier of O-H bond scission is most favourable, while the C-O bond is unfavourable in the first step of MOR.