Coverage Layer Phase Composition-Dependent Photoactivity of One-Dimensional TiO2–Bi2O3 Composites

Abstract

TiO2–Bi2O3 composite rods were synthesized by combining hydrothermal growth of rutile TiO2 rod templates and sputtering deposition of Bi2O3 thin films. The TiO2–Bi2O3 composite rods with β-Bi2O3 phase and α/β-Bi2O3 dual-phase decoration layers were designed, respectively, via in situ radio-frequency magnetron sputtering growth and post-annealing procedures in ambient air. The crystal structure, surface morphology, and photo-absorption performances of the pristine TiO2 rods decorated with various Bi2O3 phases were investigated. The crystal structure analysis reveals that the crystalline TiO2–Bi2O3 rods contained β-Bi2O3 and α/β-Bi2O3 crystallites were separately formed on the TiO2 rod templates with different synthesis approaches. The morphology analysis demonstrates that the β-Bi2O3 coverage layer on the crystalline rutile TiO2 rods showed flat layer morphology; however, the surface morphology of the α/β-Bi2O3 dual-phase coverage layer on the TiO2 rods exhibited a sheet-like feature. The results of photocatalytic decomposition towards methyl orange dyes show that the substantially improved photoactivity of the rutile TiO2 rods was achieved by decorating a thin sheet-like α/β-Bi2O3 coverage layer. The effectively photoinduced charge separation efficiency in the stepped energy band configuration in the composite rods made from the TiO2 and α/β-Bi2O3 explained their markedly improved photoactivity. The TiO2-α/β-Bi2O3 composite rods are promising for use as photocatalysts and photoelectrodes.

Matrix phase induced boosting photoactive performance of ZnO nanowire turf‐coated Bi2O3 plate composites

“…Furthermore, as demonstrated in the aforementioned results, the existence of the ZnO/Bi 2 O 3 heterojunction also improved the charge separation efficiency of the composite. Similar improved photocatalytic abilities owing to the existence of a heterojunction with suitable band alignment between the constituent oxides have been demonstrated in other oxide heterostructures 1,32 …”

Improved photoelectrode performance of chemical solution-derived Bi2O3 crystals via manipulation of crystal characterization

“…The signicant increase in photocurrent density of the Bi 2 O 3 photoelectrode under irradiation indicates the improved separation ability of photogenerated electron (e À )-hole (h + ) pairs in semiconductor oxides. 2,3 The transient photocurrent density vs. time curves results herein demonstrated that the 10S-Bi 2 O 3 photoelectrode exhibited the superior photoinduced electron-hole separation efficiency among various Bi 2 O 3 photoelectrodes. Notably, the photocurrent density of the Bi 2 O 3 photoelectrodes with a dual a/b-Bi 2 O 3 phase is signicantly higher than that of the Bi 2 O 3 photoelectrodes with a pure b-Bi 2 O 3 phase under the similar synthesis solution pH value but with and without seed layer assisted growth, indicating that the a/b homojunction is effective to separate the photoinduced electron-hole pairs.…”

“…Bi 2 O 3 is an environmental friendly material, and it has received much attention due to its unique electrical and optical properties, which leads to its extensive usage in various scientic devices. [1][2][3] Furthermore, it is a promising visible-light-driven photocatalyst with a narrow band gap (2.0-2.9 eV), and the valence band of bismuth oxide is made of a hybrid Bi 6s and O 2p orbit that decreases the symmetry of the band structure and leads to the corresponding dipoles which could enhance its photoactivity. 4 Bi 2 O 3 has different polymorphs; 5 the monoclinic a and tetragonal b phases have been reported to exhibit superior photoactivity among various polymorphs.…”

Enhanced photoactive performance of three-layer structured Ag/Cu2O/TiO2 composites with tunable crystal microstructures

“…1,7 Among these strategies, constructing a TiO 2 -based heterojunction with a visible-light sensitizer is proved to be a promising approach to enhance the photoactive performance of TiO 2 . 1,8,9 Among various visible-light sensitizers, cuprous oxide (Cu 2 O) is an important narrow band gap and p-type semiconductor. 1,10 Diverse synthesis approaches of Cu 2 O also make it widely used as a photosensitive material.…”