Selectivity of direct ethanol fuel cell dictated by a unique partial oxidation channel

Self-consistent periodic slab calculations based on gradient-corrected density functional theory (DFT-GGA) were conducted to investigate the potential energy diagram for ethanol oxidation over Pt(111). Ethanol oxidation on Pt is found to be dominated by an one-step concerted dehydrogenation pathway to produce acetaldehyde, which is about 600 times faster than the traditionally regarded stepwise pathways. The same mechanism is transferable to methanol oxidation but with a minor contribution. The results can help to clarify the long-standing puzzles on the selectivity of direct alcohol fuel cell over Pt.