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

Abstract

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, 2.0wt.% 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 CO2via formate species, leading to the complete oxidation of MeOH to CO2 over Ag/ZrO2 catalyst.