Methanol oxidative decomposition over zirconia supported silver catalyst and its reaction mechanism

To develop a new catalyst for catalytic decomposition of volatile organic compounds (VOCs), the activity of various oxide supported silver (Ag) based catalysts for methanol (MeOH) oxidation reaction have been evaluated. Based on the activity evaluation, zirconia (ZrO₂) is considered to be a substitute to ceria (CeO₂) as a support material. The ZrO₂ supported catalyst loading Ag component can oxidize MeOH to CO₂ completely, while the main product is CO for MeOH oxidation over pure ZrO₂. In the present work, 2.0 wt.% Ag/ZrO₂ exhibits excellent activity comparable to Ag/CeO₂. Furthermore, according to in situ FT-IR analysis over Ag/ZrO₂ and pure ZrO₂, it is considered that the methoxy, formate, and bicarbonate species adsorbed on the ZrO₂ surface are intermediate species. We thus deduce that Ag component significantly enhances the oxidation step of methoxy species to CO₂ via formate species, leading to the complete oxidation of MeOH to CO₂ over Ag/ZrO₂ catalyst.