화학공학소재연구정보센터
Thin Solid Films, Vol.677, 83-89, 2019
Ink-jet Bi2O3 films and powders for CO2 capture and self-cleaning applications
Thin films and powders of bismuth oxide were synthesized by a combined sol-gel and ink-jet printing method. The films were deposited over glass substrates, which were submitted to a heat treatment to promote the formation of the tetragonal polymorph of bismuth oxide (beta-Bi2O3), while the powders crystallized in the monoclinic phase (alpha-Bi2O3). The capacity of the materials to capture CO2 was assessed at room temperature and it was followed by X-ray powder diffraction, scanning electronic microscopy, and gas chromatography. The beta-Bi2O3 film with 3 layers exhibited the highest CO2 capture (1.5 mg(CO2)), while alpha-Bi2O3-powders captured 4.2 mg(CO2). Nevertheless, if the results are normalized per mass of material, the efficiency obtained with the film was twice higher (82 mg(CO2) g(Bi2O3)(-1)) than by powders (42 mg(CO2) g(Bi2O3)(-1)). When exposed to CO2, both Bi2O3 samples (powders and thin films) were converted to Bi2O2CO3; however, some residual Bi2O3 was detected in the samples. The resulting Bi2O3/Bi2O2CO3 mixture was applied as a photocatalyst to remove methylene blue in order to evaluate the sample's self-cleaning performance. The results indicated that a combination of these two materials promoted a synergistic effect related to a more efficient charge transfer due to their favorable band positions. This effect was able to promote up to 45% of removal of the pollutant on the Bi2O3/Bi2O2CO3 surface.