Ce Wang,Chao Tan,Weiqiang Lv,Gaolong Zhu,Zhaohuan Wei,Kelvin H.L. Zhang,Weidong He
In this work, we report the synthesis of a Bi 2 O 3 -TiO 2 hetero-junction (HJ) material through a facile colloidal method. The hetero-junction formation follows a growth with a 145°Bi 2 O 3 /TiO 2 crystal angle, owing to the large lattice mismatch between Bi 2 O 3 and TiO 2 crystals. With the Bi 2 O 3 -TiO 2 hetero-junction material as a photocatalyst , methyl orange is degraded completely within two hours under common UV-lamp irradiation. The photo-catalyst remains highly-active for complete photo-degradation of methyl orange even after multiple experiments. The remarkable photo-catalytic properties are attributed to the remarkable mono-dispersivity of the colloidal Bi 2 O 3 -TiO 2 nano-structure as well as the refined band structure with a valence band of 0.85 eV below that of TiO 2 crystal.
Purpose Owing to the limitations of single-mode cancer treatments, combination therapies have attracted much attention. However, constructing a platform for combination therapies in a simple and effective way and improving the overall treatment effect remains a challenge. Our aim was to combine sonodynamic therapy, radiotherapy and chemotherapy together and improve therapeutic outcomes within one nanoplatform.Methods In this work, we sought to exploit the properties of nanoscale heterojunctions to this end. A multifunctional Bi2O3-TiO2@polydopamine-doxorubicin (BTPD) nanoparticle platform was constructed as an anti-cancer theranostic. Under ultrasound irradiation, the Bi2O3-TiO2 core can generate singlet oxygen to damage tumor cells. Meanwhile, the high-Z Bi2O3 can attenuate the energy of X-rays and scatter secondary electrons to enhance radiation damage in the tumor. A thin coating of polydopamine (PDA) increases the biocompatibility but also gives the particles the ability for photoacoustic imaging. Doxorubicin, a DNA repair inhibitor which can hinder tumor recovery from radiation damage, was loaded onto the PDA.Results A comprehensive series of in vitro and in vivo assays demonstrated that the nanoparticles were effectively taken up into cancer cells, where they could induce ROS production and cause cell death. In vivo, this led to a marked reduction in tumor volume in a murine 4T1 cancer model.Conclusion The formulations developed here have significant potential for future investigation and exploration in the treatment of cancer.
Three-dimensional Bi 2 O 3 /TiO 2 hierarchical composites have been successfully prepared by a two-step hydrothermal method and subsequent calcination. The samples were characterized using XRD, SEM, TEM, EDS, BET and DRS. The measurement results signified that heterojunctions of various morphologies β -Bi 2 O 3 growing on the three-dimensional hierarchical anatase TiO 2 nanorods arrays on FTO glass were apparently formed. The morphology of Bi 2 O 3 changed from three-dimension flower-like microstructures to the sphere-like nanoparticles as the Li(OH) dosage increased. The photocatalytic results showed that all samples exhibited much higher photocatalytic activities than that of pure Bi 2 O 3 and TiO 2 (P25) in photocatalytic degradation of methyl blue (MB) under visible-light irradiation. Whereas BTL4 sample exhibited the highest photoactivity with increasing the dosage of Li(OH) to 2 mmol. Furthermore, the absorption edge of the Bi 2 O 3 /TiO 2 series composites displayed a broad-spectrum photoabsorption from UV to visible-light compared with the individual component. The as-synthesized Bi 2 O 3 /TiO 2 composites possessed excellent photocatalytic activity and outstanding recyclability. The enhanced photocatalytic efficiency was mainly attributed to the Bi 2 O 3 /TiO 2 p - n heterojunctions and hierarchical nanostructure. The recombination of photogenerated electron–hole pairs was efficiently suppressed by the Bi 2 O 3 /TiO 2 p - n heterojunctions.
Photoelectrochemical devices have garnered extensive research attention in the field of smart and multifunctional photoelectronics, owing to their lightweight nature, eco-friendliness, and cost-effective manufacturing processes. In this work, Bi2S3/Bi2O3/TiO2heterojunction film was successfully fabricated and functioned as the photoelectrode of photoelectrochemical devices. The designed Bi2S3/Bi2O3/TiO2photoelectrochemical photodetector possesses a broad light detection spectrum ranging from 400 to 900 nm and impressive self-powered characteristics. At 0 V bias, the device exhibits an on/off current ratio of approximately 1.3 × 106. It achieves a commendable detectivity of 5.7 × 1013Jones as subjected to a 0.8 V bias potential, outperforming both bare TiO2and Bi2O3/TiO2photoelectrochemical devices. Moreover, the Bi2S3/Bi2O3/TiO2photoelectrode film shows great promise in pollutant decomposition, achieving nearly 97.7% degradation efficiency within 60 min. The appropriate band energy alignment and the presence of an internal electric field at the interface of the Bi2S3/Bi2O3/TiO2film serve as a potent driving force for the separation and transport of photogenerated carriers. These findings suggest that the Bi2S3/Bi2O3/TiO2heterojunction film could be a viable candidate as a photoelectrode material for the development of high-performance photoelectrochemical optoelectronic devices.
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