Atomically Dispersed Pt on TiO2 Nanosheets for Catalytic Gaseous Acetaldehyde Abatement

Abstract

Increasing volatile organic compounds (VOCs) in the atmosphere have triggered intensive research on photocatalytic oxidation technology to safely photodegrade these volatile organic pollutants. Downsizing metal catalysts up to an atomic level on oxide supports can provide more active sites on the surface for different reactions, i.e., CO oxidation, CO2 reduction, removal of organic pollutants as well as decrease the use of precious metals. Here, we designed atomically dispersed metal catalysts (ADMCs), i.e., Pt on TiO2 nanosheets, which produced a robust and stable photocatalytic degradation of the gas-phase acetaldehyde. The loading of Pt was carried out using different deposition times, such as 2, 4, and 6 h, designated as Pt/T xh at 70 °C. This was followed by vacuum drying (60 °C) and subsequent calcination at 125 °C in an inert atmosphere. The high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) analysis confirmed the presence of atomically dispersed Pt on TiO2 nanosheets. The sample Pt/T 4h displayed a high photodegradation efficiency (100%) than pure TiO2 (38%) for 500 ppm of acetaldehyde with a flow rate of 10 sccm. Also, 700 ppm of CO2 was produced by Pt/T 4h in contrast to 340 ppm by pure TiO2. The experimental data for the sample Pt/T 4h was further characterized using Langmuir–Hinshelwood kinetic models to determine the reaction rates, adsorption equilibrium constants, and water adsorption constant. This study provides a unique opportunity to develop metal-decorated TiO2-based photocatalysts for the robust and efficient removal and mineralization of acetaldehyde from the indoor atmosphere.