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Preparation of TiO 2 ‐based catalysts with supercritical fluid technology: characterization and photocatalytic activity in CO 2 reduction
Author(s) -
Camarillo Rafael,
Tostón Susana,
Martínez Fabiola,
Jiménez Carlos,
Rincón Jesusa
Publication year - 2017
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.5169
Subject(s) - photocatalysis , isopropyl alcohol , catalysis , supercritical fluid , titanium dioxide , materials science , crystallinity , titanium , chemical engineering , inorganic chemistry , chemistry , organic chemistry , metallurgy , engineering , composite material
Abstract 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 TiO 2 synthesis in supercritical medium can result in a significant enhancement in the rate of CO 2 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 CO 2 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 CO 2 , CO and CH 4 production rates 3‐ and 15.7‐fold higher than those corresponding to the commercial catalyst have been found. © 2016 Society of Chemical Industry