Tailored activity of Ce–Ni bimetallic modified V2O5/TiO2 catalyst for NH3-SCR with promising wide temperature window

Abstract

A series of vanadium-based catalysts with different doping amounts of cerium and nickel were prepared by ultrasonic-assisted impregnation. Their catalytic activities were investigated for the selective catalytic reduction of NO with NH3 as the reducing agent (NH3-SCR). XRD, N2 adsorption-desorption, XPS, NH3-TPD, H2-TPR, SEM and HR-TEM were used to probe the physicochemical properties of the catalysts. The characterization results showed that nickel or cerium doping could increase the specific surface area and the concentration of weak acid sites, improve the catalytic activity, and extend the temperature window to some degree. Cerium and nickel co-modification catalyst possesses higher redox ability, and the element is highly dispersed. Besides, the Oα/(Oα+Oβ) ratio and Ce3+/(Ce3++Ce4+) ratio are higher over the co-modification catalyst, and cerium is more active than the redox site of V and plays an essential role in NH3-SCR at low temperatures. In addition, 3.75 V–7Ce-0.1Ni/TiO2 catalyst shows the widest temperature window (200°C–400 °C) and the best catalytic activity (above 90%), and reaches the maximum of 100% at 300 °C.