Gas-Phase TiO2 Photosensitized Mineralization of Some VOCs: Mechanistic Suggestions through a Langmuir-Hinshelwood Kinetic Approach

A jointed experimental and theoretical investigation pointing out new insights about the microscopic mechanism of the volatile organic compounds (VOCs) photocatalytic elimination by TiO2 was done. Methane, hexane, isooctane, acetone and methanol were photomineralized in a batch reactor. Values of K (adsorption constant on TiO2) and k (mineralization rate constant) of the five VOCs (treating the kinetic data through a Langmuir-Hinshelwood approach) were determined. Recorded K (in the range of 0.74 x 10(-2)-1.11 x 10(-2) ppm(-1)) and k (in the range of 1.9-9.9 ppm min(-1)) values and performed theoretical calculations allowed us to suggest the involvement of an electron transfer step between the VOC and the hole, TiO2(h(+)), as the rate-determining one.

Automated summary

An experimental and theoretical investigation was conducted on the microscopic mechanism of VOCs photocatalytic elimination by TiO2, revealing the involvement of an electron transfer step as the rate-determining one. K and k values for various VOCs were determined through experiment and calculations, providing new insights into the process.