Surface Electrochemistry and Electrocatalysis

Making Ir capable of C-C bond splitting in ethanol oxidation

We previously demonstrated the unique ability of PtRhSnO₂ catalyst to oxidize ethanol to CO₂ at low potentials. More recently, we have shown that the PtIr/SnO₂/C catalyst with high Ir content has outstanding catalytic properties with the most negative EOR onset potential and reasonably good selectivity toward ethanol complete oxidation to CO₂, higher than those of Pt/C and Pt/SnO₂/C.

Structure, synthesis and IR spectra in ETOH oxidation on IrPtSnO₂/C

Among the systems studied, PtIr/SnO₂/C catalyst with highest Ir content, that is, the catalyst with atomic ratio Pt:Ir:Sn = 1:1:1, showed the most negative EOR onset potential and considerably improved capability for C−C bond splitting. PtRh/SnO₂/C electrocatalysts with a suitable Rh content, that is, catalysts with atomic ratio Pt:Rh:Sn = 1:½:1 and 1:⅓:1, exhibit the highest selectivity toward ethanol total oxidation. The highest CO₂ production efficiency of the above catalysts is observed with the PtRh/SnO₂ (with atomic ratio Pt/Rh/Sn of 1:½:1 and 1:⅓:1) > PtIrRh/SnO₂ (with atomic ratio Pt:Ir:Rh:Sn of 1:1:1:1). This finding provides new information on the C−C bond splitting electrocatalysis and can help in designing new catalysts with enhanced activity and selectivity in ethanol electrooxidation.

Journal of the American Chemical Society 135, 132 (Jan, 2013).