Selective Photocatalytic Reduction of Nitric Oxide by Carbon Monoxide over Silica-Supported Molybdenum Oxide Catalysts

Abstract

The photocatalytic reduction of NO by CO over a MoO3/SiO2 catalyst (2.5 wt% of Mo), which proceeds under UV irradiation at room temperature, is reported for the first time. N2 and CO2 are found to be the major reaction products, and the selectivity of the photoreduction is close to 100%. After completion of photoconversion of a NO–CO mixture and brief evacuation at room temperature, a new portion of the NO–CO mixture admitted to the catalyst can be converted with the same rate as during the first irradiation. It is shown that MoO3/SiO2 is an inefficient catalyst for the thermal NO reduction by CO, since heating of a NO–CO mixture at 400 and 500°C yields only small amounts of N2 and CO2. A reaction mechanism for the photocatalytic NO reduction by CO over MoO3/SiO2 is proposed and discussed.