Brookite TiO2 as an active photocatalyst for photoconversion of plastic wastes to acetic acid and simultaneous hydrogen production: Comparison with anatase and rutile

TL;DR

This study demonstrates that brookite TiO2 is a highly active and stable photocatalyst for converting plastic waste into acetic acid and hydrogen, outperforming anatase and rutile forms.

Contribution

It introduces brookite TiO2 as a superior photocatalyst for plastic degradation and hydrogen production, with detailed analysis of its charge separation properties.

Findings

Brookite exhibits higher activity than anatase and rutile in photoreforming.

Commercial brookite effectively converts PET to acetic acid under light.

Enhanced charge separation in brookite leads to increased hydrogen and hydroxyl radical generation.

Abstract

Photoreforming is a clean photocatalytic technology for simultaneous plastic waste degradation and hydrogen fuel production, but there are still limited active and stable catalysts for this process. This work introduces the brookite polymorph of TiO2 as an active photocatalyst for photoreforming with an activity higher than anatase and rutile polymorphs for both hydrogen production and plastic degradation. Commercial brookite successfully converts polyethylene terephthalate (PET) plastic to acetic acid under light. The high activity of brookite is attributed to good charge separation, slow decay and moderate electron trap energy, which lead to a higher generation of hydrogen and hydroxyl radicals and accordingly enhanced photo-oxidation of PET plastic. These results introduce brookite as a stable and active catalyst for the photoconversion of water contaminated with microplastics to value-added organic compounds and hydrogen.