Low-Temperature Synthesis and High Visible-Light-Induced Photocatalytic Activity of BiOI/TiO₂ Heterostructures

Abstract

BiOI/TiO 2 heterostructures with different Bi to Ti molar ratios were synthesized through a simple soft-chemical method at a temperature as low as 80°C. The as-prepared powders were characterized by X-ray powder diffraction, electron microscopy, UV-vis diffuse reflectance spectroscopy, nitrogen sorption, and X-ray photoelectron spectroscopy. The photocatalytic activities of these BiOI/TiO 2 heterostructures were evaluated on the degradation of methyl orange under visible-light irradiation (λ > 420 nm). The results revealed that the BiOI/TiO 2 heterostructures exhibited much higher photocatalytic activities than pure BiOI and TiO 2 , respectively, and 50%BiOI/TiO 2 showed the best activity among all these heterostructured photocatalysts. Surface photovoltage spectroscopy and transient photovoltage measurements were used to confirm the formation of heterojunction and probe charge transfer between BiOI and TiO 2 . The visible-light photocatalytic activity enhancement of BiOI/TiO 2 heterostructures could be attributed to its strong absorption in the visible region and low recombination rate of the electron-hole pairs because of the heterojunction formed between BiOI and TiO 2 .

Synthesis and Characterization of 1-D BiSI and 2-D BiOI Nanostructures

“…In the HR-TEM image, the distance of about 0.30 nm between the arrow-heads corresponds to the distance of planes, the growth direction of the rod indicated by a green arrow. The distance of 0.32 nm corresponds to the neighboring distance of [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] planes. The indexed Fourier transform of the image is oriented close to the [113] direction.…”

“…Kumar et al employed a gel technique to obtain 5 mm long BiSI single crystals. 13 On the other hand, BiOI (the same V-VI-VII class compound) has widely been studied in recent years, [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] especially because of a high catalytic activity in the visible region. BiOI has been reported to show a high photocatalytic activity for photodegradation of an organic dye under visible light irradiation.…”

Synthesis, Characterization and Excellent Photocatalytic Performance of Iron-Carbon-Codoped Mesoporous Titania Nanocrystallines

“…It is already accepted that lots of reactive oxygen species (ROSs) including h + , •OH and •O 2 perhaps involved in photocatalytic oxidation process [31,32]. Three factors, namely surface area of the photocatalyst, light absorption capability, and charge separation or transfer are of paramount importance for the efficient degradation reaction.…”

Enhanced Photo-induced Charge Separation and Simulated Solar Photocatalytic Activity of α-Fe2O3/BiOCl Prepared In-situ

“…Among these methods, *Corresponding author; E-mail address: scuzhong@sina.com construction of a heterostructure is an effective and simple strategy to improve the photocatalytic activity of a photocatalyst. In practice, an effective heterojunctions should have the matched band structure, requisite bandgap energy, suitable molar ratio and close contact between the hybrid semiconductors (9,10). The photo-generated electrons will be transferred to semiconductor with more positive conduction band for photocatalysis (11).…”