Fe(III)-Pt(II) oxide-co-sensitized brookite TiO2 nanorods for photocatalytic degradation of acetaldehyde under visible light

Abstract

Platinum is widely investigated as co-catalysts for photocatalytic degradation of volatile organic compounds but studies seldom focus on their visible light sensitizing properties. Herein, Pt sensitizers of different oxidation states (0, II, IV) were modified on brookite TiO2 nanorods and investigated for acetaldehyde degradation under visible light. Pt(II) oxide/TiO2 showed the best photocatalytic activity but its stability was compromised by its self-oxidation to Pt(IV) during photo-oxidation reaction. Surface modification of an Fe(III) oxide thin film sensitizer layer around the Pt(II) oxide sensitizer was found to enhance both the stability and activity of Pt(II) oxide/TiO2. In situ double beam photoacoustic spectroscopy (DB-PAS) supported by DFT modeling showed the rapid injection of photoexcited electrons from Fe(III) oxide to Pt(II) oxide promote the stability of Pt(II) oxide, leading to enhanced performance. The findings provide guidance for the rational design of visible light-active metal oxide sensitizers for oxidative removal of indoor air pollutants.