Superior performance of Cu/TiO2 catalyst prepared by ice melting method for low-temperature selective catalytic reduction of NOx by NH3

Abstract

A series of Cu/TiO2 catalysts was successfully synthesized by ice melting method for the first time, and their performance for the selective catalytic reduction of NOx with NH3 was evaluated. The catalyst with Cu/Ti molar ratio of 0.005 exhibited excellent catalytic performance at low temperature. Compared with the traditional co-precipitation method (Cu0.005Ti-Con), the NOx conversion (at 285 °C) and N2 selectivity (at 240 °C) of Cu/TiO2 synthesized by ice melting (named as Cu0.005Ti-Ice) increased by 30 % and 10 %, respectively. Characterization results revealed that Cu0.005Ti-Ice exhibited outstanding physicochemical properties, including smaller grain size of particles, the well dispersion and high surface atomic concentration of Cu species, enrichment of Cu2+ species (34.54 %) and chemical absorbed oxygen species (19.96 %), and excellent redox capacity and acidity. These conditions provided the CuTi-Ice catalysts with enhanced deNOx performance at low temperature. Additionally, the inhibition of the non-selective catalytic reduction and NH3 catalytic oxidation on Cu0.005Ti-Ice catalysts reduced N2O and NO2 concentration, resulting in outstanding SCR activity at low temperature.