Metal-anchoring, metal oxidation-resistance, and electron transfer behavior of oxygen vacancy-rich TiO2 in supported noble metal catalyst for room temperature HCHO conversion
Waleed Ahmad, Hochan Jeong, Ho‐Hyun Nahm, Yeunhee Lee, Eunseuk Park, Heehyeon Lee, Ghulam Ali, Yong‐Hyun Kim, Jongsoo Jurng, Youngtak Oh
Abstract
Thermal catalytic oxidation at room temperature using a noble metal catalyst is a rapid, stable, and efficient removal strategy for HCHO, a ubiquitous indoor air pollutant. However, the catalytic oxidation optimization through the support defect control has been barely explored. We prepared an oxygen vacancy-rich anatase TiO2 (VO-TiO2) as electron transfer catalyst support for the efficient catalytic conversion of HCHO to CO2 and H2O. VO-TiO2, prepared by chemical vapor condensation with post heat treatment, exhibits void-embedded nanostructures and electron paramagnetic activity, which governs the deposition pattern of Pt nanoparticles upon the impregnation. Pt/VO-TiO2 (0.086 wt% Pt) converted 100% of 10 ppm HCHO at room temperature and 200,000 cm3 h−1 gcat−1 GHSV in >250 min. The X-ray absorption (XAS) studies of used catalysts confirmed the conservation of metallic state of Pt only in oxygen vacancy-rich anatase TiO2 (VO-TiO2). The First-principles density-functional theory calculations revealed that the excess electrons at the oxygen vacancies in VO-TiO2 stabilize the otherwise-vulnerable Pt nanoparticles. This study demonstrates an effective defect control strategy for transforming a TiO2 support into a dynamic electron transfer catalyst platform.