A New Strategy for Improving the Efficiency of Low-temperature Selective Catalytic Reduction of NOx with CH4 via the Combination of Non-thermal Plasma and Ag2O/TiO2 Photocatalyst

In the present work, a remarkable combination of non-thermal plasma and photocatalyst was developed to widen the operating temperature window of selective catalytic reduction(SCR) of NO_x with CH₄, especially to improve the low-temperature removal efficiency of NO_x. It was shown that the operating temperature window was significantly widened. Among all the catalysts prepared, 1%Ag₂O/TiO₂ showed the highest catalytic activity for NO_x removal due to the utilization of near ultraviolet light. The conversion of NO_x to N₂ over the in-plasma 1%Ag₂O/TiO₂ photocatalyst at 60 and 300℃ could achieve 31.8% and 53.0%, respectively. The combination mode of plasma and catalyst affected NO_x removal efficiency greatly, the in-plasma catalysis outperformed the post-plasma catalytic mode remarkably, signifying the contribution of photocatalytic processes on the catalysts. Meanwhile, the characterizations of the catalyst demonstrated that the morphology and structure of the Ag₂O/TiO₂ catalyst were unchanged throughout the non-thermal plasma and photocatalytic processes, implying the superior stability of the catalyst.