Selective catalytic reduction of NO with C1–C3 reductants over solvothermally prepared Ga2O3–Al2O3 catalysts: Effects of water vapor and hydrocarbon uptake

The influence of reducing agents (C1–C3 hydrocarbons) upon the selective catalytic reduction (SCR) of nitrogen oxide (NO) on γ-Ga2O3–Al2O3 solid solutions was explored. Under dry conditions, the γ-Ga2O3–Al2O3 solid solutions having large crystallite size had high activity for the SCR of NO with various hydrocarbons. However, under wet conditions, NO conversion on the catalyst decreased drastically for all the hydrocarbons. The decrease of NO conversion caused by the presence of water is due to the preferential adsorption of water which inhibits hydrocarbon adsorption on the catalyst surface. Among reductants of C1–C3 hydrocarbons, the most atom-efficient NO abatement was achieved with C2 hydrocarbons. C3 hydrocarbons were less selective for NO reduction than the other hydrocarbons. It was suggested that only one carbon atom per molecules were used for the SCR reaction, and the other carbon atoms were consumed by the simple combustion reaction.