Photocatalytic Activity under Simulated Sunlight of Bi-Modified TiO₂ Thin Films Obtained by Sol Gel

Abstract

The synthesis of Bi-modified TiO 2 thin films, with different Bi contents, is reported. The obtained materials were characterized by energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy (RS), X-ray diffraction (XRD), photoluminescence (PL), and diffuse reflectance spectroscopy (DRS), in order to obtain information on their chemical composition, vibrational features, and optical properties, respectively. Compositional characterization reveals that the bismuth content can be varied in an easy way from 0.5 to 25.4 at. %. Raman results show that the starting material corresponds to the anatase phase of crystalline TiO 2 , and Bi addition promotes the formation of bismuth titanates, Bi 2 Ti 2 O 7 at Bi contents of 10.4 at. % and the Bi 4 Ti 3 O 12 at Bi contents of 21.5 and 25.4 at. %. Optical measurements reveal that the band gap narrows from 3.3 eV to values as low as 2.7 eV. The photocatalytic activity was tested in the degradation reaction of the Malachite Green carbinol base dye (MG) as a model molecule under simulated sunlight, where the most relevant result is that photocatalytic formulations containing bismuth showed higher catalytic activity than pure TiO 2 . The higher photocatalytic activity of MG degradation of 67% reached by the photocatalytic formulation of 21.5 at. % of bismuth is attributed to the presence of the crystalline phase perovskite-type bismuth titanate, Bi 4 Ti 3 O 12 .

Thin films of titanium dioxide modified with MoO3 nanostructures for photocatalytic applications

“…Subsequently, the MoO3 nanostructures were added continuing the stirring for 5 minutes, afterwards 1 mL of nitric acid was added to promote the transition of the sol to a gel like. This procedure has been reported before to prepare TiO2 thin films modified with different metals [6,7,8].…”

Bismuth as Smart Material and Its Application in the Ninth Principle of Sustainable Chemistry

“…Bismuth's electrocatalytic properties of intermetallic nanocrystallites offer the possibility as fuel cell anode catalysts as confirmed in the high activity platinum/bismuth nanocrystallite as a fuel cell anode catalyst for methanolic acid or methanol oxidation [169]. [172,173]. Either Bi or B separately doped TiO 2 or Bi-B codoped samples displayed improved photocatalytic activities to the acid orange degradation and 2, 4-dichlorophenol under visible light irradiation [174,175].…”

Recent Advances in TiO2 Films Prepared by Sol-Gel Methods for Photocatalytic Degradation of Organic Pollutants and Antibacterial Activities

“…An optimal photocatalytic activity (35% under UV irradiation) was achieved in 5-immersion Ag-doped TiO 2 thin films that were deposited from 7-and 14-day-old solutions. Solís-Casados and coworkers [75] synthesized Bi-doped TiO 2 film with different Bi contents by sol-gel method. The material was characterized with various techniques.…”