Gas-phase total oxidation of nitric oxide using hydrogen peroxide vapor over Pt/TiO ₂

Pt/TiO ₂ catalysts with various Pt loadings (0.1–0.7 wt.%) were synthesized by a combined wet impregnation and H ₂ -reduction method. The as-prepared catalysts were firstly reported being applied in thermal catalytic decomposition of hydrogen peroxide (H ₂ O ₂ ) vapor for treating NO _X . Physico-chemical properties of Pt/TiO ₂ catalysts were investigated by comprehensive techniques, including XRD, Raman, N ₂ adsorption–desorption, TEM, UV–vis DRS, XPS and PL spectroscopy. The activity tests showed that the incorporation of platinum into TiO ₂ led to a significant increase in the catalytic oxidation of NO compared with the unmodified TiO ₂ . Toward NO oxidation from H ₂ O ₂ vapor (molar ratio = 12/1), 0.3 wt.% Pt-TiO ₂ exhibited a remarkable activity in NO _X removal (96.7%) and a high selectivity (89.2%) in their conversion to nitrate species under the optimal condition. XRD and TEM results show that ultrafine Pt particles were well dispersed on the surface of anatase-phase TiO ₂ . XPS analysis indicated that Pt dopant existed as mainly metallic Pt ⁽⁰⁾ and a small portion of Pt ²⁺ in as-prepared materials. The results of PL spectra demonstrated that the platinum nanoparticles on the TiO ₂ surface significantly accelerated electron transfer and served as active sites for the adsorption and activation of H ₂ O ₂ molecules, to facilitate the generation of hydroxyl groups.