Phase segregation studies on role plays and synergies in supported CuSO_4/TiO_2 catalysts for NO abatement based on experimental and theoretical investigations

摘要

The effect of support and synergies among active components and support in supported catalysts were systematically revealed through various characterizations and theoretical calculations in this paper, using the method of phase segregation. The experimental results illustrated that improvements in catalysts dispersion, surface acidity and redox properties, promotions in surface active oxygen species, and enhancements in electron transfer were found with the introduction of support, eventually lowering the activation energy of NH3-SCR (selective catalysis reduction with ammonia) reactions. Theoretical calculations also clearly demonstrated that support could promote charge transfer, enhance NH3 adsorption and activation, accelerate NO oxidation/activation and efficiently decrease the energy barrier. Combining experimental and theoretical results, NH3-SCR reactions on CuSO4/TiO2 catalysts obeyed Eley-Rideal (ER) mechanism: reactions occurred among adsorbed NH3 species on both Bronsted (B, main) and Lewis acid sites (L) with gaseous NO thorn O-2 to generate nontoxic N-2 and H2O. And this is the first time that comprehensive and mutual evidences have been given via experimental and theoretical studies to interpret the complex synergies in supported catalysts, providing theoretical basis in search of future potential catalysts for industrial denitration. (C) 2020 Elsevier Ltd. All rights reserved.