ABSTRACT
Poriferous monocrystal-like nanostructures are contributing to fabricate long-distance charge transfer pathways and rapid diffusions of the degraded products, and attracts wide attentions. In this work, layered and poriferous (Al,C)-Ta2O5 mesocrystals were fabricated by topotactic transformation strategy with Ta4AlC3 MAX as starting materials for visible-light photocatalytic antibiotic degradation. The prepared sample exhibited enhanced visible-light absorption and visible-light photocatalytic performance, far superior to those of commercial Ta2O5 and Ta4AlC3 MAX, which was mainly because of the elemental doping in the samples. The experimental results also indicated that continuous attacks of the photo-generated holes and ·O2- species efficiently induced efficient visible-light photodegradation of tetracycline. Current work also indicates a new and potential tantalum-based semiconductors for high-performance environmental photocatalysis.
Subject(s)
Tantalum , Tetracycline , Catalysis , Light , PhotolysisABSTRACT
Mesocrystals are types of fascinating multifunctional materials in fabricating rapid charge transport pathways, and surface engineering could be considered as a significant influencing factor in boosting charge separation for efficient photocatalytic application. In this work, surface engineered Ta2O5-x mesocrystals were synthesized by facile alkali treatment strategy for enhanced visible light photocatalytic tetracycline degradation. The highly enhanced photocatalytic activity could be attributed to the highly increased surface areas and surface hydroxyl groups to compare with those of commercial Ta2O5 and pristine Ta2O5-x mesocrystals, which could provide more surface reactive sites and high electron density center for trapping photo-generated holes. Besides, possible tetracycline transformation pathways over surface engineered Ta2O5-x mesocrystals and visible light photocatalytic mechanism were also proposed in this work. Current work also provides a facile strategy for regulating surface property of ultrawide bandgaps semiconductors for enhanced visible light photocatalytic performance.
Subject(s)
Light , Tetracycline , Anti-Bacterial Agents , Catalysis , Surface PropertiesABSTRACT
Harvesting broad spectral absorption and visible light photocatalysis of ultrawide bandgap semiconductors are one of most significative topics in the solar energy conversion and utilization fields. In this work, amorphous Cl-Ta2O5-x microspheres were prepared by facile solvothermal method for stabilized visible light photocatalytic hydrogen generation. The acetone absorbed on the interfaces of Ta2O5 nanoparticles induced the formation of oxygen vacancies, enhanced visible light absorption, and formation of Ta2O5-x microspheres with preferred orientations as well as Cl doping. The Cl-Ta2O5-x microspheres showed typical amorphous characteristics and obvious visible light absorption in comparison to those of commercial Ta2O5. More importantly, the prepared Cl-Ta2O5-x microspheres also showed stabilized visible light photocatalytic hydrogen generation performance in the spectral regions of 400 nm ≤ λ ≤ 600 nm mainly because of the introduction of oxygen vacancy defects and Cl doping, which might significantly expand the application of tantalum oxide semiconductors in the broad spectral photocatalytic water splitting.
ABSTRACT
Highly ordered mesocrystalline semiconductors often indicate tremendous prospects in the clean energy production and environmental photocatalysis mainly because of their unique superstructure for efficient charge transport pathways and long-lived charges. Here, superstructure Ta3N5 mesocrystals with the high-energy surface {2â¯0â¯0} planes exposed were the first time to be successfully fabricated by topological transformation of Ta2O5 mesocrystals. The prepared Ta3N5 mesocrystals showed enhanced visible-light photocatalytic hydrogen production activity of 98.67⯵molâ¯g-1 for 180â¯min irradiation, which was approximately 5.28 times that of comm-Ta3N5 prepared with commercial Ta2O5 as the starting material, mainly due to the formation of long-distance electron conduction pathways and long-lived charges. The detailed electronic band structures of the prepared Ta3N5 mesocrystals were also investigated by electrochemical method. Finally, possible visible-light photocatalytic mechanisms of Ta3N5 mesocrystals for enhanced hydrogen production was also proposed in detail. Current work also indicates that tantalum-based mesocrystals show great potential to enhance the charge separation for efficient photocatalytic water splitting.
