Selective catalytic reduction of NOx with NH3 over copper-based catalysts: recent advances and future prospects

Selective catalytic reduction of NO with NH3 (NH3-SCR) is a promising technology to reduce the emission of nitrogen oxides (NOx) from diesel engines and industrial flue gases. Due to their advantages of variable valence and high stability, Cu-based catalysts exhibit superior activity and have been widely employed in the NH3-SCR reaction. Herein, we expound the reaction mechanism of NH3-SCR, and summarize the comprehensive advances of Cu-based catalysts (Cu-based small-pore zeolites and Cu-containing metal oxides) developed in the last decade. In this review, the challenges and prospects for Cu-based catalysts are presented to meet the industrial need, and efficient design strategies for promoting the NH3-SCR performance of Cu-based catalysts through support derivation, precursor optimization engineering, secondary metal doping, crystal structure regulation, preparation method modification and interaction and interface engineering are comprehensively proposed and discussed. These proposed strategies are confirmed to be beneficial for enhancing catalysis by accelerating acid and redox cycles. Besides, we sum up the poisoning mechanism of impurities from flue gas on active sites, and provide the corresponding anti-inactivation measures to inhibit the deactivation of catalysts. Finally, we hope to focus on the current opportunities and challenges faced by Cu-based catalysts, further promoting their development and achieving practical applications.