Novel surface carbon–oxygen-groups grafted TiO2 for selective catalytic reduction of NOx by NH3 at low temperature

Abstract

Activated coke (AC) with has excellent low-temperature NH3-SCR denitration performance due to its abundant surface-active functional groups including carbon species, while it is easy to burn during industrial application. Herein, a novel surface carbon–oxygen-groups grafted TiO2 was constructed by calcining the solid mixture of polyethylene glycol (PEG) and TiO2. The prepared 0.4PEG/0.6Ti catalyst shows good NH3-SCR denitration activity, and its NOx conversion was up to 80 % above 210 °C, while the pure AC exhibited poor activity. Characterization results suggest that the superior catalytic activity of 0.4PEG/0.6Ti catalyst is mainly attributed to the formation of lactone and carboxyl groups, which can promote the adsorption and activation of NO and NH3 species. Furthermore, NH3 as the reactant can also inhibit the decomposition of carbonyl groups due to over-oxidation, thus 0.4PEG/0.6Ti catalyst has good long-term stability. The reaction mechanism study reveals that the NH3-SCR reactions over catalysts follow the E-R and L-H mechanisms. Finally, the desulfurization-regeneration-denitration test (imitated activated coke simultaneous desulfurization and denitrification process) was carried out, and the results confirm that the prepared PEG/Ti catalyst could be regenerated for denitration after desulfurization. We expect that this work can provide some guidance for the design of low-temperature denitration catalysts.