Mechanochemistry as an efficient method in Cu/P25 photocatalysts synthesis for CO2 photoreduction

Abstract

The presented research focuses on the implementation of mechanochemistry in the synthesis of TiO₂-based catalysts with Cu-based species for CO₂ photoreduction. Using a simple and reproducible methodology, 1 wt% of Cu was incorporated on P25 by ball milling using three metal precursor salts. The impregnation of copper was successful using mechanochemistry synthesis, being the percentages of copper impregnated very close to the nominal values. Our results indicate that Cu species are successfully loaded on the surface of P25 titania, which under the milling conditions may develop a detectable amount of brookite phase. When tested in the CO₂ reduction reaction under UV light the highest conversion of CO₂ towards CH₄ and CH₃CHO was obtained for the series of washed samples, which reached CH₄ production rates over 70 μmol/g·h. These samples performed better compared to their unwashed equivalents in the photocatalytic tests. This highlights the washing step as crucial to fully uncover the potential of the prepared catalysts. The accomplished research and acquired results exhibit a significant potential in applying mechanochemistry for an efficient, environmentally friendly, and simple synthesis method for photocatalysts preparation.