Facultad Regional Buenos Aires
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Item Photocatalytic CO2 conversion: sol-gel and aerosolization synthesis of CuxO-modified TiO2 over 3D printed supports(2023) Pascual, Julián Ramiro; Altieri, Tamara; Lombardo, María Verónica; Montesinos, Victor Nahuel; Quici, NataliaCuxO-modified TiO2 photocatalysts are powerful materials for conversion of CO2 in methane. However, it is necessary to develop scalable synthesis routes that led to photocatalysts with improved conversion efficiency, elevated photocatalytic activity and low environmental impact. 3D printing facilitates the construction of precise geometrically-controlled reactors in short production times that can speed up the thinking-designing-production cycle of reactors minimizing waste generation. In this work we synthesized CuxO-modified TiO2 photocatalysts following two different routes: (1 ) modification of commercial TiO2 by surface precipitation of Cu2+ (CuxO-TiO2) and (2) one-pot aerosolization of TiO2 and CuxO precursors (CuxO@AerTiO2). The solids were characterized by diffuse reflectance spectroscopy, SEM and XRD. Exploratory experiments for impregnation of photocatalysts in PET monoliths were undertaken. The modification of commercial TiO2 (Aeroxide P25 or Hombikat UV100) was carried out by dropwise addition of 62.9 mL of a 0.05 M Cu2+ solution to 400 mL of a 12.5 g/L of TiO2 suspension in NaOH 0.25 M under continuous stirring. After 4 h, the solid was filtered, washed, dried at 80 °C overnight and, finally, calcinated at 400 °C for 2 h. The effect of copper salt (CuCl2 vs. CuNO3) and Cu loading (0.28, 1 and 5 Cu/Ti At%) was studied. XRD patterns clearly showed the presence of CuO in all cases over the P25 samples, in addition to the anatase and rutile typical signals for the base photocatalyst. When CuCl2 was used as CuxO precursor, well defined nanoparticles of 80 nm where obtained. The synthesis with CuNO3 gave a smooth homogeneous aspect to the solid surface with no distinguishable nanoparticles. The synthesis through aerosolization was based on the one described in the work of Zelcer et al. [1]. Briefly, a solution containing 1.39 g acetylacetone, 1.39 g of glacial acetyc acid, 0.34 g of Ti-iPrOH, 0.0145 g of Cu(NO3)2.3H2O and 0.2 g of Pluronics F127 in 43 mL of MilliQ water was continuously fed to a Büchi B-290 spray drier with a peristaltic pump at a flow rate of 3 mL/min. The liquid was atomized at 220 °C in a two-fluid nozzle with a secondary air-flow of 473 L/h. After collection of the material from the cyclone of the spray drier, the solid was calcined at 440 °C for 4 h. The band-gaps of the synthetized photocatalysts were calculated by the Tauc method being 3.13 eV, 3.17 eV and 3.15 eV for the CuxO-P25, CuxO-UV100 and CuxO@AerTiO2 powders, respectively. Square-based monolith of 3 1.5 3 cm with 15% of PET loading were impregnated by dip-coating in suspensions of 1 – 20 g/L of P25. Once dried at 50°C overnight, all of them were irradiated from one side with a 365 nm UV-LED and the UV-light intensity was measured before and after passing through the impregnated monolith by a 365 nm radiometer. The use of 1 g/L of TiO2 was found as the best option as it absorbs 90% of the UV-light, against the 92.3% absorbed by the monolith impregnated in the 20 g/L suspension. In all cases, the diffuse reflectance spectrum obtained for the Cumodified TiO2 impregnated supports matched the spectrum of the respective powders. The solids synthesized presented promising structural and optical properties and, currently, XRD and SEM analysis are being completed, together with porosimetry for all solids to have broader and comparative information.Item Photocatalytic NOx removal with TiO2-impregnated 3D-printed PET supports(2023-11-20) Binetti Basterrechea, Gian Franco; Montesinos, Victor Nahuel; Quici, NataliaIn this work, we investigated the photocatalytic removal of NOx using 3D-printed supports. Monolithic supports with internal channels were fabricated by Fused Modelling Deposition (FDM) using PET as the filament feedstock. The printing parameters of the supports were optimized to maximize the exposure of the photocatalyst to UV light throughout the monolithic PET printed supports. The removal experiments were carried out in a continuous gas phase flow reactor, which was custom designed in-house incorporating a 3D printed PET support impregnated with TiO2 as photocatalyst. The impregnated and non-impregnated supports were characterized by diffuse reflectance spectrometry, SEM and AFM. The effect of several key-factors on the NOX removal capacity was investigated, including the type of PET filament (native recycled, BPET vs. glycol-modified, PETG), the type of TiO2 (P25 vs Hombikat UV-100), the UV light source (LED vs. tubular lamps), and the number of deposited TiO2 layers. The highest NO and NOx removal were achieved by using PETG supports coated with a single layer of Hombikat UV-100 and irradiating the flat reactor from both sides using two sets of black light lamps. However, the highest selectivity toward nitrate formation was obtained when using P25 under the same experimental conditions. This work demonstrates that 3D printing is a reliable and powerful technique for fabricating photocatalytic reactive supports that can serve as a versatile platform for evaluating photocatalytic performance.Item Photocatalytic NOx removal with TiO2-impregnated 3D-printed PET supports(2023) Binetti Basterrechea, Gian Franco; Montesinos, Victor Nahuel; Quici, NataliaIn this work, the photocatalytic removal of NOx with 3D-printed supports was studied. The technology consisted of a continuous gas flow phase reactor containing a 3D printed PET support impregnated with TiO2 as photocatalyst. The 3D impregnated supports were characterized by diffuse reflectance spectrometry and SEM/EDS. The effect of several key-factors on the removal capacity were studied: type of PET filament (native, BPET vs glycol-modified, PETG), type of TiO2 (P-25 vs Hombikat UV-100), UV-light source (LED vs tubular lamps) and number of deposited TiO2 layers. The highest NO and NOx removal were achieved by only one layer of Hombikat UV-100 over PETG supports, irradiating from both sides of the flat reactor with two sets of black light lamps. This work demonstrate that 3D printing is a reliable and powerful technique for fabrication of photocatalytic reactive supports.