Low-Temperature Selective Catalytic Reduction of NO with NH₃ over a Biochar-Supported Perovskite Oxide Catalyst

Abstract

Maintaining high denitration efficiency for the selective catalytic reduction with ammonia (NH3-SCR) at low temperatures is challenging. In this work, a modified biochar-supported perovskite oxide catalyst was synthesized and implemented to NO conversion in the low-temperature range of 100–250 °C. Different modification methods were compared, where the combination of nitric acid and air oxidation treatment endowed biochar with abundant acidic surface oxygen-containing groups and a higher specific surface area as a support. The perovskite oxide (LaMnO3) and the LaMnO3/biochar catalysts were prepared to investigate the interactions between the catalyst and the support. The LaMnO3/biochar catalyst exhibited excellent denitration efficiency and good N2 selectivity, achieving over 80% NO conversion within the entire temperature range of 100–250 °C (S N2 > 90%), and the highest NO conversion reached 95.8% at 225 °C (S N2 = 95.4%). This catalyst provided synergistic adsorption capacity for NH3 as a result of the acidic function of perovskite oxide and acidic oxygen-containing functional groups of the modified biochar support. Additionally, LaMnO3 showed an eminent redox capability for NO conversion due to the high content of Mn4+ and chemically adsorbed oxygen species. Finally, NH3-SCR reaction mechanisms were proposed on the basis of transient response experiments and in situ diffuse reflectance infrared Fourier transform spectra (DRIFTS) characterization.

Research progress on biochar-based material adsorption and removal of ibuprofen

“…In addition, loading catalysts on the surface of biochar was a common functionalization method. After loading catalysts on the surface of biochar, reactions such as catalytic degradation, catalytic oxidation, and catalytic reduction, can be achieved to accelerate the removal of IBP (Rangarajan et al, 2022;Fan et al, 2023). Currently, used catalysts included metal oxides, metal nanoparticles, etc., Besides, other surface treatment technologies, such as plasma treatment (Mohammed et al, 2021), electron beam irradiation (Croitoru et al, 2014), etc., can also be used to modify the surface of biochar.…”