Porous TiO2 thin film-based photocatalytic windows for an enhanced operation of optofluidic microreactors in CO2 conversion

Abstract

[EN] Using a photocatalytic window can simplify the design of an optofluidic microreactor, providing also a more straightforward operation. Therefore, the development of TiO2coatings on glass substrates seems appealing, althougha priorithey would imply a reduced accessible area compared with supported nanoparticle systems. Considering this potential drawback, we have developed an endurable photocatalytic window consisting on an inner protective SiO2layer and anouter mesoporous anatase layer with enhanced surface area and nanoscopic crystallite size (9–16 nm) supported on a glass substrate. The designed photocatalyticwindows are active in the CO2-to-methanol photocatalytic transformation, withmaximum methanol yield (0.52mmol$h 1$cm 2) for greatest porosity valuesand minimum crystallite size. Compared with benchmark supported nanoparticlesystems, the nanoscopic thickness of the coatings allowed to save photoactivematerial using only 11–22mg$cm 2, while its robustness prevented the leachingof active material, thus avoiding the decay of performance at long working periods.