Catalytic peroxone process for low-temperature denitration with enhanced Ti-OOH formation on P-TiO2: Experimental, DFT, and semi-in-situ UV–vis studies

Abstract

Promoting the formation of Ti-OOH in the TiO2-based-catalyst/H2O2/O3 system is critical to further develop the catalytic peroxone process for low-temperature flue gas denitration. In this study, a series of phosphorus-doped TiO2 with rich Lewis acid sites and high stability was designed and established, achieving 94 % NO oxidation efficiency with less oxidant (373 K, H2O2/NO = 1.2, O3/NO = 0.5) and high GHSV (1.2 × 105 h−1). Combining characterizations and DFT results, a possible mechanism was proposed: phosphorus-doping enhanced the Lewis acidity, which was conducive to the adsorption and activation of H2O2. Moreover, P-TiO2 significantly promoted the H2O dissociation and Ti-OOH formation process by reducing the energy barrier, thereby promoting the synergistic effect between O3 and Ti-OOH. The semi-in-situ UV–vis DRS demonstrated that the catalytic peroxone process occurs at the solid–liquid interface and the Ti-OOH is consumed in the catalytic process. We hope this work provide a new investigation method and insight into the catalyst design.