Molten salt synthesis is an efficient method for preparation of photocatalyst. Enhancing precursor mixing effect is important. In this study, we found ethanol is important for synthsis of face-to-face type Bi 4 Ti 3 O 12 /Bi 2 Ti 2 O 7 composite photocatalyst. The prepared Bi 4 Ti 3 O 12 /Bi 2 Ti 2 O 7 (B3) composite under molar ratio of Bi:Ti of 4:3.6 displays higher photocatalytic activity compared with Bi 4 Ti 3 O 12 (B1) and Bi 2 Ti 2 O 7 (B4). The photocurrent density of B3 is 2 times higher than B1 and 1.6 times higher than B4, and B3 has smallest charge resistance between sample and solution. Combined with XPS, the study found that the higher photocatalytic activity origins from large charge transfer interface and built-in electric field (BIEF) around such interface, rathor than light absorption and dark adsorption.
Hongfei Shi,Huaqiao Tan,Wan-bin Zhu,Zaicheng Sun,Yuejia Ma,Enbo Wang
A series of Cr-doped Bi4Ti3O12/Bi2Ti2O7 (BTO) heterostructure fibers have been synthesized via a one-step, facile and economical electrospinning/calcination process. SEM and TEM results reveal that the diameters of the as-prepared fibers are 100 ± 30 nm. The light adsorption of Bi4Ti3O12 and Bi2Ti2O7 in the fibers has been remarkably improved by Cr doping. With increased Cr doping, XRD and XPS show that the amount of Bi2Ti2O7 increases in the fibers. As a result, the Bi4Ti3O12/Bi2Ti2O7 heterojunction structure is enhanced, which further promotes the charge separation of photogenerated charge carriers. Photocatalytic tests indicated that the as-prepared Cr-doped Bi4Ti3O12/Bi2Ti2O7 fibers exhibit good photocatalytic activity for photodegradation of methyl orange (MO) under visible-light irradiation.
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