Nanostructured semiconductor composites are often considered as types of promising photocatalysts and display great prospects in visible light photocatalytic hydrogen production. In this work, ...nanostructured Pt-on-Au/PCN composites were synthesized by photo-induced synthesis strategy with exfoliated g-C
3
N
4
(PCN) nanosheets as starting materials and served in visible light photocatalytic hydrogen production. The prepared Pt-on-Au/PCN composites showed enhanced visible light absorption and photocatalytic hydrogen production performance. The visible light photocatalytic performance of Pt-on-Au/PCN composites is approximately 54.60 times of pristine g-C
3
N
4
and 3.61 times of Pt/g-C
3
N
4
composites, respectively. These findings could be mainly attributed to the formation of bimetal Pt-on-Au nanostructure for visible light harvesting and charge separation. Besides, possible photocatalytic mechanism of nanostructured Pt-on-Au/PCN composites for hydrogen production is proposed in detail. Current work also offers a new method to design and synthesize other types of metal-on-metal nanostructures for efficient semiconductor photocatalysis.
Acidic and basic sites of catalysts are essential for CO2 capture and activation. In this work, Zr, N-ZnO/ZnAl-LDH-IL composites in ionic liquid and methanol systems were fabricated, and applied to ...catalyze the synthesis of ethylene carbonate (EC) from ethylene glycol (EG) and CO2 with about 4.76 mmolEC gCat.−1 h−1. The composites showed more strong basic sites due to the effective induction of reactive groups on the catalyst surface by Zr doping, resulting in an increase of pyridinic-N groups from 5.48% to 22.25%. More C atoms adjacent to pyridinic-N as strong basic sites was conducive to the activation of CO2 and EG. In addition, the possible catalytic pathway and mechanism of the composites for synthesizing EC as well as the doping of La, Fe, Ce, and Cu were also investigated, which provides an effective strategy for regulating the acid-base centers on the catalyst surface through ionic liquids and methanol solvents.
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•The LDHs were prepared directly in ionic liquid and methanol systems•N, C, and ZnO doping was achieved during the preparation process•Higher pyridinic-N content increased the strong basic sites of the material•The catalytic performance of the samples is up to 4.76 mmolEC gCat.1 h−1
Catalysis; Materials chemistry
•Nanostructured Ag/AgCl@Ti3+-TiO2 mesocrystals were synthesized.•Ag/AgCl@Ti3+-TiO2 mesocrystals showed a superior photocatalytic performance.•The superior performance was attributed to the formation ...of long-lived charges.•Active species and photodegradation pathways of tetracycline were investigated.•Possible visible light photocatalytic mechanism was proposed.
Efficient visible light photocatalytic elimination of pharmaceutical factory wastewater is one of widely concerned and greatly significant attempts in dealing with increasingly serious environmental pollution problems. In this work, hybrid Ag/AgCl nanoparticles were successfully introduced into Ti3+ self-doped TiO2 mesocrystals via precipitation and photo-reduction methods for efficient visible light photocatalytic antibiotic elimination. Some characterization measurements, such as XRD, SEM, TEM, XPS, UV–vis DRS spectra, fluorescence emission spectra, time-resolved fluorescence spectra, FT-IR spectra, and electrochemical measurements, were applied to investigate the physico-chemical properties of nanostructured Ag/AgCl@Ti3+-TiO2 mesocrystals. The experiment results showed that nanostructured Ag/AgCl@Ti3+-TiO2-60 composites presented the best visible light photocatalytic performance for tetracycline degradation, which was approximately 3.52 times of Ti3+-TiO2 mesocrystals and 22.43 times of commercial TiO2. Trapping experiments of active species and DMPO spin-trapping ESR experiments further confirmed that the visible light photocatalytic tetracycline degradation by Ag/AgCl@Ti3+-TiO2 mesocrystals were mainly due to the continuous attacks of photo-generated holes, OH and O2− radicals on tetracycline molecules. Besides, nanostructured Ag/AgCl@Ti3TiO composites were also employed in visible light photocatalytic industrial para-ester wastewater degradation. Finally, possible tetracycline transformation pathways and visible light photocatalytic tetracycline degradation mechanism over plasmonic Ag/AgCl@Ti3+-TiO2 composites were also proposed. Current work indicates that defective semiconductor mesocrystals and their composites have huge prospects in the refractory organic elimination.
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•Ultrathin carbon-coated Zr3+-ZrO2 composites were synthesized;•Zr3+ species and carbon doping induced visible light absorption;•The samples showed efficient photocatalytic ...performance;•Active species and possible intermediates were determined;•Possible visible light photocatalytic mechanism was proposed.
Broadband solar light absorption and visible light photocatalysis of surface modified ultrawide bandgap semiconductors are receiving wide attentions because of their more negative conduction band potential and positive valence band potential for refractory organics degradation. Here, we reported a novel modified solvothermal strategy by the introduction of distilled water into small molecular alcohols to synthesize crystallized carbon-coated Zr3+-ZrO2 composites for enhanced visible light absorption and visible light photocatalytic tetracycline degradation, in which the distilled water favored for the crystallization of Zr3+-ZrO2 and the formed ultrathin carbon layers derived from the polymerization of small molecular alcohols were contributing to the generation of Zr3+ species and well dispersion of Zr3+ self-doped ZrO2 nanoparticles. The experimental results also showed that carbon-coated Zr3+-ZrO2 composites exhibited enhanced visible light absorption, long-lived charges, efficient visible light photocatalytic performance and good recyclable stability. Besides, possible photocatalytic mechanism and antibiotic degradation pathways over carbon-coated Zr3+-ZrO2 composites under visible light irradiation were also proposed in detail.
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•Surface engineered Ta2O5−x mesocrystals were synthesized.•The sample showed enhanced photocatalytic performance.•Alkali modifications induced increased surface areas and surface ...hydroxyl groups.•Possible degraded pathways and mechanism were proposed.
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.
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•Z-scheme Ag/AgCl/Ta2O5−x composites were fabricated.•The sample showed enhanced photodegradation performance.•Efficient photodegradation of other organic contaminants.•Crucial roles ...of oxygen vacancy defects in charge separation.•Possible degraded pathways and mechanism were proposed.
Fabricating rapid and high-efficient charge-transfer pathways is contributing to improving charge separation and receiving extensive concerns in preparation of semiconductors composites photocatalysts. In this work, ternary Ag/AgCl/Ta2O5−x mesocrystals were fabricated for visible-light photodegradation of emerging pollutants by introducing Ag/AgCl nanoparticles into defects engineered Ta2O5−x mesocrystals. The prepared composites showed efficient visible-light absorption and efficient visible-light photodegradation of emerging pollutants, mainly attributed to the fabricating of high-efficient Z-scheme charge-transfer pathways between Ag/AgCl and Ta2O5−x mesocrystals. Note that, the experimental results also demonstrated the significant roles of defects engineered Ta2O5−x mesocrystals in fabricating high-efficient Z-scheme charge-transfer pathways. Besides, the prepared Ag/AgCl and Ta2O5−x composites could be employed for efficient visible-light photodegradation of many other organic contaminants. Current work indicates a promising and high-performance visible-light composite photocatalyst for dealing with emerging contaminants.
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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.
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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 {2 0 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 μmol g−1 for 180 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.
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.
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•Layered and poriferous (Al,C)–Ta2O5 mesocrystals.•Aluminum and carbon doping induced efficient visible-light absorption.•Highly enhanced visible-light photocatalytic performance.•Suggested visible-light photocatalytic mechanism.
