Ceria-based catalysts for low-temperature selective catalytic reduction of NO with NH3

Abstract

Selective catalytic reduction of NO with NH₃ (NH₃-SCR) is a powerful technique for the abatement of NO_x from stationary sources, and the currently used VO_x/TiO₂-based catalysts are widely applicable for medium-temperature conditions but not suitable for NH₃-SCR operated at low temperatures. Recently, low-temperature NH₃-SCR has attracted considerable attention owing to the vast demand in industrial furnaces and its energy-conserving feature. During the past years, a great many studies have demonstrated that ceria-based catalysts are potential candidates as catalysts for low-temperature NH₃-SCR. Herein we summarize the recent advances in the application of ceria-based catalysts for low-temperature NH₃-SCR. The review begins with a brief introduction of the general guideline for low-temperature NH₃-SCR and the interaction between the reactants and CeO₂. The different roles of ceria as a pure support/active species, bulk doping component and surface modifier are discussed. As well, the mechanistic investigations (active sites, intermediates, reaction mechanism) and SO₂/H₂O tolerance are emphasized. Lastly, the perspectives on the opportunities and challenges of ceria-based catalysts for low-temperature NH₃-SCR in future research are presented.