Low-temperature NH3-SCR reaction over 3D Cu/Fe-TiO2-rGO composite catalyst synthesized by photoreduction method

Abstract

Nitrogen oxides is a typical atmospheric pollutant and selective catalytic reduction with NH3 is an efficient and commonly used solution to remove NO from power plants and factories. In this paper, the Cu/Fe-TiO2-rGO catalysts with 3D hierarchical dandelion-like TiO2 microspheres and reduced graphene oxide as carrier were prepared by photocatalytic reduction method. The catalyst possessed the improved NO removal rate due to the following advantages: firstly, graphene oxide improved the specific surface area of Cu/Fe-TiO2-rGO catalyst. In addition, the Fe species promoted NH3 desorption and increased the oxidation of Cu species leading to the improvement of the low temperature activity of the catalyst. In another aspect, the amount of graphene oxide used to prepare MOx/GO by common hydrothermal method is large. The catalyst synthesized by photoreduction method with less amount and higher dispersion degree of reduced graphene oxide possessed the best NO conversion rate over 97 % at 250 °C, and Cu and Fe species were simultaneously distributed on the surface of rGO and 3D TiO2 microspheres. What was more, a large number of Lewis acid sites and a small amount of Brönsted acid sites in the catalysts were detected, and Fe element improved the NO conversion of Cu0.4Fe0.6-TiO2-rGO sample by Langmuir–Hinshelwood mechanism.