Promotional synergistic effect of Cu and Nb doping on a novel Cu/Ti-Nb ternary oxide catalyst for the selective catalytic reduction of NOx with NH3

•Cu/Ti-Nb oxide catalyst showed an excellent SCR activity and N2 selectivity within 250–425°C at GHSV of 177,000h−1.•Doping of Nb increased the specific surface area, the amount of acid sites and surface oxygen of TiO2.•Copper species could effectively enhance the catalytic performance of Ti2NbOx at 225–400°C.•Both Eley-Rideal (E-R) mechanism and Langmuir-Hinshelwood (H-L) mechanism occurred over 0.8%Cu/Ti2NOx catalyst at 225°C.