Lotus leaves‐derived <scp>MnO_<i>x</i></scp>/biochar as an efficient catalyst for low‐temperature <scp>NH₃‐SCR</scp> removal of <scp>NO_<i>x</i></scp>: effects of modification methods of biochar

Abstract

Abstract In this reported work, lotus leaves‐derived biochar (LBC) was modified using various chemical methods. LBC prepared by different modification methods was used as the carrier for the development of low‐temperature selective catalytic reduction (SCR) catalysts. A comparative study of low‐temperature SCR manganese catalysts based on LBC chemically modified using NaOH, HNO 3 and hexadecylcetyltrimethylammonium bromide (CTAB) was performed, revealing different deNO x performance of these catalysts. For the supported catalysts, the 25%Mn/LBC‐OH catalyst appeared to be optimum since it exhibited over 95% NO x conversion at 225 °C with a space velocity of 37 500 h −1 . The microstructure, phase composition, redox properties and surface acidity were determined using field emission scanning electron microscopy, Brunauer–Emmett–Teller surface area, X‐ray diffraction, H 2 ‐temperature‐programmed reduction, NH 3 ‐temperature‐programmed desorption, and so forth. The results showed that the excellent SCR performance of 25%Mn/LBC‐OH was closely related to its abundant high valence Mn, suitable surface acidity and high redox capability. More importantly, highly dispersed MnO x easily formed on the surface of the LBC‐OH support, which was the key factor in the excellent catalytic activity of 25%Mn/LBC‐OH catalyst. Furthermore, the highly dispersed 25%Mn/LBC‐OH catalyst also exhibited improved tolerance to SO 2 and H 2 O, making this catalyst a good candidate for reducing the NO x emission from coal‐fired power plants. © 2022 Society of Chemical Industry (SCI).