Improved K-Resistance of a Cu-Modified TiO₂/CeO₂ Catalyst for SCR of NO_x at Low Temperatures

Abstract

The employment of CeTi-based catalysts in the denitration of exhaust from biomass combustion is significantly limited by the poor tolerance to alkali metals. Herein, a CuO modification strategy was proposed to enhance the resistance of CeTi catalysts to K2O. The NO conversion of pristine Ti/Ce decreased from 95% to less than 10% at 250 °C after 1 wt % K loading. As a sharp comparison, CuO-modified Ti/Ce reserved more than 70% in NO conversion under the same test conditions. Combined with diverse characterizations, it was found that the addition of CuO promoted the formation of Cu–O–Ce and Cu–O–Ti species, which showed enhanced redox and acid properties. CuO modification also suppressed the adsorption of inert nitrates resulting from K loading. Moreover, Brønsted acid sites introduced by CuO served as capture sites of alkali metals, thus alleviating the active sites from being poisoned. More retained acidic and redox capacities ensured the excellent catalytic performance of TiCu/Ce under K poisoning.

Effect of Various Acid Anions on Potassium Poisoning and the Mechanism of Commercial V2O5–WO3/TiO2 Catalysts for SCR of NOx

“…Nitrogen oxides (denoted NO x ) emitted from stationary and mobile sources are one of the major air pollutants, which lead to diverse environmental problems such as photochemical smog, haze, and acid rain. , Due to its low cost, simple equipment, and high catalytic denitration efficiency, selective catalytic reduction of NO x with NH 3 (denoted NH 3 -SCR) has become a mainstream process for reducing NO x emission in the flue gas. , V 2 O 5 –WO 3 /TiO 2 (denoted VWTi), which consists of 1–2 wt % V 2 O 5 as an active component and 3–8 wt % WO 3 as a promoter supported on TiO 2 , is the most extensively used catalyst system in the SCR process . This is primarily attributed to its stable high denitrification efficiency and suitable operating temperature range for coal-fired plants.…”