Generation and role of novel catalytic sites for NH3-SCR in bio-derived Chlorella@Mn denitration catalyst driven by calcination temperature

Abstract

More conventional low-temperature denitration catalysts are prepared chemically, and the active sites are mainly metal oxides. In this paper, the catalysts are prepared biologically, and novel denitration active sites of nonmetal-oxygen-metal are formed. The NOx conversion was first increased and then decreased with the increase of calcination temperature, and was below 20 % at 200 ℃ at a reaction temperature of 175 ℃, and was close to 100 % at calcination temperatures of 365 ℃ and 435 ℃, and was below 80 % at 600 ℃. Compared to the Chlorella@Mn catalyst prepared at 435 ℃, which possesses the highest specific surface area (104.7 m2/g), the Chlorella@Mn catalyst prepared at 365 ℃ possesses stronger NOx and NH3 adsorption performance, which is related to the presence of a large number of P-O-Mn and C-O-Mn bonds, the presence of P-O-Mn bond could enhance the electron transfer between P and Mn, C-O-Mn bond can enhance the redox performance. The calcination temperature between 365 ℃ and 435 ℃ is the equilibrium range for denitration performance. L-H and E-R reaction mechanisms presence on Chlorella@Mn catalysts at calcination temperatures from 305 ℃ to 600 ℃, the presence of P-O-Mn and C-O-Mn bonds can also promote the generation of active nitrate species. This study will provide some reference for research on the formation of novel denitration active sites using biological methods.