Preparation of TiO2‐based catalysts with supercritical fluid technology: characterization and photocatalytic activity in CO2 reduction
2017
Camarillo, Rafael | Tostón, Susana | Martínez, Fabiola | Jimenez, Carlos | Rincón, Jesusa
BACKGROUND: Titanium dioxide is the photocatalyst par excellence in environmental applications. Nevertheless, over the years various methods aiming to improve its efficiency have been presented. Herein, we report that TiO₂ synthesis in supercritical medium can result in a significant enhancement in the rate of CO₂ photocatalytic conversion. RESULTS: Specifically, catalysts obtained from two titanium precursors (titanium tetraisopropoxide and diisopropoxititanium bis(acetylacetonate)) and two alcohols (ethanol and isopropyl alcohol) by hydrothermal synthesis in supercritical CO₂ are shown to exhibit improved properties in comparison with the standard reference catalyst (Degussa P‐25, Evonik). CONCLUSION: In particular, upgraded characteristics are related to reactants adsorption (higher specific surface areas, presence of surface hydroxyl groups), light absorption and excitation (better absorbance in visible range, lower band gap energy), and charge separation (appropriate morphology and crystallinity). Furthermore, when these catalysts are tested in the photocatalytic reduction of CO₂, CO and CH₄ production rates 3‐ and 15.7‐fold higher than those corresponding to the commercial catalyst have been found. © 2016 Society of Chemical Industry
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