Adsorption and oxidation of acetaldehyde on carbon supported Pt, PtSn and PtSn-based trimetallic catalysts by in situ Fourier transform infrared spectroscopy

The adsorption and oxidation of acetaldehyde on carbon supported Pt, Pt₉₀Sn₁₀ and Pt₈₀Sn₁₀M₁₀ (M = Ni, Co, Rh, Pd) catalysts have been investigated by using in situ Fourier transform infrared (FTIR) spectroscopy. The result revealed that Pt ₉₀Sn₁₀/C catalyst is not very efficient for the conversion of acetaldehyde to CO₂ due to the weak adsorption of acetaldehyde in the presence of Sn. However, the addition of a third metal to Pt - Sn facilitates the C-C bond cleavage of acetaldehyde. It seems that acetaldehyde is adsorbed dissociatively on the surface of Pt₈₀Sn₁₀Ni ₁₀/C, Pt₈₀Sn₁₀Co₁₀/C, Pt ₈₀Sn₁₀Rh₁₀/C catalysts, producing CH ₃ and CHO adsorbate species, which can be further oxidized to CO ₂. However, the pathway forming CO₂ for Pt ₈₀Sn₁₀Pd₁₀/C catalyst mainly originates from the oxidation of CH₃CO species. Thus, the presence of third metal in the PtSn catalyst has a strong impact upon the acetaldehyde adsorption behaviour and its reaction products.