Effects of gas phase composition on competitive adsorption properties of formaldehyde on titanium dioxide-supported...

Titanium dioxide-supported platinum (Pt@TiO2) is regarded as a highly efficient photothermal catalyst to degrade various volatile organic compounds (VOCs). To learn more about the hybrid adsorption/catalysis process of VOCs on Pt@TiO2, their dynamic adsorption behavior on the catalyst surface was studied using the single and multicomponent gas phase of FA (i.e., the latter with four aromatic compounds of benzene, toluene, m-xylene, and styrene (BTXS)) through the control of key operating variables (e.g., VOCs concentration, relative humidity (RH) levels, and dosage). According to the performance evaluation, the doping of TiO2 with Pt metal ions significantly enhanced the FA adsorption capacity (e.g., by 50 % higher than the pristine TiO2) with increased OH (OII) surface active sites (reactivity) and surface porosity. However, in the co-presence of BTXS and water vapor, the adsorption affinity for FA vapor declined by 2 to 3 folds of magnitude with a competitive inhibition of the adsorption interaction on the Pt@TiO2 surface. According to the kinetic and isotherms analysis, a complex, multilayered physicochemical process appears to govern the adsorption of FA molecules onto Pt@TiO2 surface. Overall, the outcomes of this work are helpful to verify the enhanced removal potential of Pt@TiO2 against FA through sequential adsorption and catalytic reaction mechanisms.