Degradation Rate Of Rhodamine B Research Articles

ZnO Nano-Rod Arrays Synthesized with Exposed {0001} Facets and the Investigation of Photocatalytic Activity

Zinc oxide (ZnO) possesses superior chemical and physical properties so that it can occupy an essential position in the application of nanostructures. In this paper, ZnO nano-rod arrays were synthesized by a simple one-step hydrothermal approach with the assistance of cetyl trimethyl ammonium bromide (CTAB). Exposure of the {0001} facets could be controlled by adjusting the amount of CTAB and the maximum exposure of the {0001} facets of ZnO nanorods is obtained at 1.2 g of CTAB. The photocurrent, EIS, and PL measurements support the facile charge transfer with minimum recombination of the photogenerated excitons of the ZnO nano-rod arrays obtained at 1.2 g of CTAB. Consequently, the obtained ZnO nano-rod arrays at the optimal CTAB of 1.2 g exhibit an excellent photocatalytic degradation rate of 99.7% for rhodamine B (RhB), while the degradation rate of RhB by the ZnO obtained without CTAB is only 35%.

Ag NPs decorated C–TiO2/Cd0.5Zn0.5S Z-scheme heterojunction for simultaneous RhB degradation and Cr(VI) reduction

In this study, heterojunction photocatalysts, XAg@C-TCZ, based on MOF-derived C–TiO2 and Cd0.5Zn0.5S decorated with Ag nanoparticles (Ag NPs) were successfully synthesized through hydrothermal and calcination methods. The catalytic effectiveness of XAg@C-TCZ was evaluated by simultaneous photocatalytic degradation of rhodamine B (RhB) and reduction of Cr(VI) under simulated sunlight irradiation. The presence of the Z-scheme heterojunction was demonstrated through trapping experiments, X-ray photoelectron spectroscopy (XPS), time-resolved photoluminescence (PL) investigations, and electron spin resonance (ESR) spectroscopy. With an initial RhB and Cr(VI) concentration of 7 mg L−1 and 5 mg L−1, the catalyst 10Ag@C-TCZ achieved a simultaneous removal of 95.2% and 95.5% within 120 min, respectively. With the same catalyst, the degradation rate of RhB was 2.75 times higher and the reduction rate of Cr(VI) was 9.3 times higher compared to pure Cd0.5Zn0.5S. Total organic carbon (TOC) analysis confirmed the extent of mineralization of RhB, while the reduction of Cr(VI) was corroborated by XPS. Compared to pure RhB and Cr(VI) solutions, the reaction rates are smaller in the solution containing both contaminants, which is attributed to the competition for ·O2−. 10Ag@C-TCZ also exhibited a stable catalytic performance in tap water and lake water. This work provides a new perspective on the construction of heterojunctions with doped MOF derivatives for the purification of complex pollutant systems.

Transparent g-C3N4 thin film: Enhanced photocatalytic performance and convenient recycling

Efficient heterogeneous photocatalysis requires photocatalysts to possess high photocatalytic activity, good cycle stability and easy recyclability. In this paper, a g-C3N4 thin film has been successfully prepared utilizing a simple in-situ vapor deposition method using melamine and glass slide as the raw material and substrate, respectively. It was found that the g-C3N4 thin film could easily be separated from the glass slide in cold water and that cyano groups exist in its structure. The as-prepared g-C3N4 thin film can be used as a photocatalyst for the degradation of rhodamine B (RhB) dye. Upon visible light irradiation for 80 min, the degradation rate of RhB could reach 85.9%. After five cycles, the degradation rate could still reach 80.2%. The superior photocatalytic performance was ascribed to the existence of cyano groups, which can improve the charge separation efficiency. It is worth noting that g-C3N4 thin film can be easily separated from the solution using a net and still maintain its structural integrity after the degradation experiment.

Improved visible-light driven photocatalysis by loading Au onto C3N4 nanorods for degradation of RhB and reduction of CO2

In this work, a solution-assembly technique was adopted to compose the g-C3N4 (CN) nanorods (CN1, CN2 and CN3) with a desired microstructure. Subsequently, different amounts of Au nanoparticles (NPs) with sizes ~10 nm were loaded on CN2 nanorods by an in-site reduction approach, thereby a series of plasmonic photocatalyst (CN2-A1, CN2-A2 and CN2-A3) were fabricated. The activities were investigated by photodegrading Rhodamine B (RhB) and photoreducing CO2 into CO with the irradiation of visible light, respectively. And the degradation rates of RhB over CN2-A2 photocatalyst were 97.28% in 80 min, which was 1.45 times higher than that of pure CN2 (66.90%). Moreover, without any sacrificial agents, the reduction yields of CO2 into CO by CN2-A2 photocatalyst was 3.11 μmol/g in 4 h, that was 2.46 times higher than that of CN2 (1.26 μmol/g). The improved photocatalytic performance was owning to the stronger localized surface plasmon resonance (LSPR) effect, which not only increased the utilization efficiency of visible light, but also sped up the formation and separation of photo-induced carriers. In addition, a potential charge transfer mechanism was tentatively proposed on account of as-obtained test dates.

Synthesis of mesoporous carbon nitride by molten salt-assisted silica aerogel for Rhodamine B adsorption and photocatalytic degradation

As a new nonmetallic photocatalysis material, it is of great attention to develop the carbon nitride (g-C3N4) with good structure and optical properties. Herein, a mesoporous g-C3N4 was prepared by molten salt-assisted silica (SiO2) aerogel template method, the properties of physicochemical and optical were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), specific surface area and pore analysis, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray energy spectrum (XPS), diffuse reflectance spectrum, fluorescence spectrum (PL) and zeta potential, respectively. Rhodamine B (RhB) was used for a series of adsorption and photocatalytic degradation experiments, and the reactive species and the degree of RhB degradation in the reaction process were tested by electron spin resonance (ESR) and UV–Vis absorption spectrum, respectively. The synergistic effect of adsorption and photocatalytic degradation was investigated. The results show that the mesoporous g-C3N4 was synthesized successfully, and presented a hollow tubular porous structure and good optical properties. With the highest specific surface area (164.65 m2·g−1) and narrower band gap (2.47 eV), the sample of M-CN-500 shown the highest degradation rate of RhB (90.9%) after 150 min illumination, and the adsorption capacity and zeta potential were both affected by pH variation. The kinetic model verified that the photocatalytic degradation rate of RhB by mesoporous g-C3N4 was enhanced with the synergistic effect of adsorption. It was also demonstrated that the O2− and h+ were the primary reactive species, and the RhB structure fracture was the main reason in the photocatalytic degradation. A mesoporous g-C3N4 was prepared by molten salt-assisted silica (SiO2) aerogel template method, and the synergistic effect of adsorption and photocatalytic degradation on this catalyst was investigated. Because of its special hollow tubular and porous structure, mesoporous g-C3N4 with high specific surface area can not only improve the adsorption performance, but also enhance the photocatalytic efficiency.

Enhancement of visible light photocatalytic activity of BiVO4 by polypyrrole modification

In this study, the different amounts of polypyrrole modified BiVO4 photocatalyst were synthesized by oxidative polymerization of pyrrole. The photocatalytic activity of polypyrrole and vanadate bismuth (PPy/BiVO4) composite was determined by photocatalytic degradation of Rhodamine B (RhB) under visible light irradiation. The results showed that PPy could not only affect the crystal structure and the morphology of BiVO4 photocatalyst, but also had a great influence on the photocatalytic activity of pure BiVO4. It was also found that PPy/BiVO4 with the highest photocatalytic activity when the doping amount of PPy was 5%, and the RhB degradation rate could reach 95.72%. This paper also discussed the possible mechanism of enhanced activity: the photogenerated holes in the valence band of BiVO4 can be directly transferred to the π orbital of PPy. At the same time, photogenerated electrons can be transferred to the conduction band of BiVO4, resulting in charge separation and stabilization, thereby effectively preventing the recombination of photogenerated electrons and holes.

Bimetal oxalate‐derived synthesis of laponite‐decorated CoFe2O4 porous nanostructures for activation of peroxymonopersulfate towards degradation of rhodamine B

AbstractBACKGROUNDAdvanced oxidation processes based on sulfate radical have been widely employed for oxidation degradation of organic contaminants. Catalytic activation of peroxymonopersulfate (PMS) with transition metal oxides holds great promise for the generation of sulfate radical. In this work, laponite‐decorated CoFe2O4 porous nanostructures have been prepared through the thermal decomposition of laponite/oxalates, and evaluated as a magnetic catalyst to activate PMS for the oxidation of rhodamine B (RhB).RESULTSThe decoration of porous CoFe2O4 microparticles with laponite was evidenced because of the presence of the vibration mode of SiO (at 1359 cm−1) in Fourier transform infrared spectra and the uniform distribution of Si and Mg elements from elemental mapping images. Decorating with laponite also resulted in an increase in amount of surface hydroxyl oxygen species, which facilitated the formation of CoOH complex for PMS activation. Furthermore, the enhanced activation of PMS with laponite‐decorated CoFe2O4 resulted in a faster removal (98.04%) of RhB as compared to undecorated CoFe2O4 (79.62%) within 56 min. Meanwhile, the rate constant increased from 0.0288 (CoFe2O4) to 0.0679 min−1 (laponite‐decorated CoFe2O4). The degradation rate of RhB progressively increased with reaction temperature and catalyst dosage. Scavenging and electron paramagnetic resonance tests manifested that the sulfate and superoxide radicals served as the major active species for the oxidation of RhB molecules.CONCLUSIONThe above results demonstrated positive effects of laponite on the textural property, surface chemical states and catalytic activity of porous CoFe2O4 microparticles. This study provides an insight into the promising role of laponite as an additive in improving PMS activation.

Preparation and photocatalytic activity of red light-emitting carbon dots/P25 heterojunction photocatalyst with ultra-wide absorption spectrum

Carbon dots have attracted growing research interest due to its unique properties, and are expected to be used in the field of photocatalysis to solve the visible absorption loss problem of TiO2 (P25). In this paper, red light-emitting carbon dots (RCDs) with high fluorescence quantum yield (40%) and RCDs/P25 heterojunction photocatalysts were synthesized by a simple and green hydrothermal method. Characterization results indicated that RCDs were successfully coupled with P25, and RCDs could effectively broaden the visible absorption region of bare P25 from 410 nm to 800 nm. The photocatalytic activity of the as-synthesized RCDs/P25 on the degradation of rhodamine B (RhB) under visible light irradiation was greatly improved compared with that of bare P25. The degradation rate of RhB by 2%RCDs/P25 reached 98.4% in 150 min, the degradation efficiency was 7.4 times that of bare P25. The RCDs played an important role in improving the photocatalytic activity of RCDs/P25, which not only increased visible light absorption, but also promoted efficient separation of photogenerated electron-hole pairs. Furthermore, the possible degradation mechanism of RCDs/P25 heterojunction photocatalyst was given.

Preparation and photocatalytic activity of TiO2 nanotube arrays prepared on transparent spinel substrate

TiO2 nanotubes (TNTs) were prepared on transparent spinel (MgAl2O4) ceramic material by anodic oxidation of magnetron sputtered Ti layer. The properties of TNTs were compared with nanotubes produced on other three different substrates, Si wafer, polymeric Kapton film, and Ti foil. The photocatalytic activity of TNTs was tested by the removal of two model pollutants rhodamine B (RhB) and bisphenol A (BPA). Depending on the used substrate, the efficiency of TNTs in the degradation of both pollutants increases in the order of Kapton < spinel < Si < Ti. Nanotubes grown on Ti foil exhibited the best photocatalytic activity reaching 88% for the removal of RhB and 36% for the removal of BPA. The degradation rates of RhB could be well described by the pseudo-first order reaction, while the degradation of BPA could be better fitted with fractional first-order kinetic model. The calculations of residual stresses and deformations in the prepared materials with TNT surface layer showed that the composite with spinel substrate is the most stable structure with minimal warping of the laminate.

Combustion synthesis of mesoporous CoAl2O4 for peroxymonosulfate activation to degrade organic pollutants

A mesoporous cobalt aluminate (CoAl2O4) spinel is synthesized through a combustion method and adopted for the activation of peroxymonosulfate (PMS) to degrade organic pollutants. Multiple characterization procedures are conducted to investigate the morphology and physicochemical properties of the CoAl2O4 spinel. Due to its mesoporous structure, large surface area, and high electrical conductivity, the obtained CoAl2O4 exhibits remarkable catalytic activity for Rhodamine B (RhB) degradation. Its RhB degradation rate is 89.0 and 10.5 times greater than those of Co3O4 and CoAl2O4 spinel prepared by a precipitation method, respectively. Moreover, the mesoporous CoAl2O4 spinel demonstrates a broad operating pH range and excellent recyclability. The influence of several parameters (catalyst amount, PMS concentration, initial pH, and coexisting inorganic anions) on the oxidation of RhB is evaluated. Through quenching tests and electron paramagnetic resonance experiments, sulfate radicals are identified as the predominant reactive species in RhB degradation. This paper provides new insights for the development of efficient, stable, and reusable cobalt-based heterogeneous catalysts and promotes the application of persulfate activation technology for the treatment of refractory organic wastewater.

Energy saving intermittent electro-Fenton system combined with commercial MoS2 for effective Rhodamine B degradation

Abstract Without external O2 supply and solution pH adjusting, commercial molybdenum sulfide (MoS2) was firstly applied as co-catalyst in intermittent electro-Fenton process for Rhodamine B (RhB) degradation. In this energy saving system, Fe2+/Fe3+ conversion was facilitated and H2O2 activating was accelerated by MoS2. Granular activated carbon wrapped with stainless steel mesh (GACSS) was used as cathode, from which, H2O2 and iron sources were in-situ generated. With 0.1 g/L MoS2, and 50 mA applied current with 10 min on-10 min off power frequency, RhB degradation rate constant in the MoS2 intermittent electro-Fenton was approximately 2.4 times as that without MoS2 system. Quenching experiments, electron spin resonance (ESR) characterization and free radical fluorescence tests demonstrated hydroxyl radicals (·OH) was the dominant reactive species, and the superiority of intermittent electrolysis mode for RhB degradation. During power on, H2O2 was constantly generated on cathode. In electricity interval, Fe2+/Fe3+ conversion was accelerated on the active sites (Mo4+) to activate residual H2O2 and more ·OH was generated to RhB degradation. Additionally, the characterization analysis (XPS, SEM and FT-IR) demonstrated MoS2 and GACSS cathode exhibited excellent catalytic and chemical stability in recyclability. Low-cost multifunctional cathode with a high efficiency co-catalyst was combined in this energy saving electro-Fenton operating system for RhB degradation.

BiOBr/Ag/AgBr heterojunctions decorated carbon fiber cloth with broad-spectral photoresponse as filter-membrane-shaped photocatalyst for the efficient purification of flowing wastewater

The development of recyclable photocatalysts with broad-spectral photoresponse has drawn much attention for the practical application in flowing wastewater treatment. Herein, we have reported the construction of BiOBr/Ag/AgBr junctions on carbon fiber cloth (CFC) as broad-spectral-response filter-membrane-shaped photocatalyst that is efficient and easily recyclable. With CFC as the substrate, BiOBr nanosheets (diameter: 0.5–1 μm) were firstly synthesized by a hydrothermal method, and then Ag/AgBr nanoparticles (size: 100–300 nm) were prepared on the surface of CFC/BiOBr by using a chemical bath deposition route. CFC/BiOBr/Ag/AgBr presents superior flexibility and wide UV–Vis-NIR photoabsorption (from 200 to 1000 nm). Under visible light irradiation, CFC/BiOBr/Ag/AgBr (area: 4 × 4 cm2) can remove 99.8% rhodamine B (RhB), 99.0% acid orange 7 (AO7), and 93.0% tetracycline (TC) after 120 min, better than CFC/BiOBr (95.4% RhB, 55.0% AO7 and 91.2% TC). Interestingly, when CFC/BiOBr/Ag/AgBr is served as a filter-membrane in a photoreactor to purify the flowing sewage (RhB, rate: ~1.5 L h−1), the degradation rate of RhB goes up to 90.0% after ten filtering grades. Therefore, CFC/BiOBr/Ag/AgBr has great potential to purify the flowing wastewater as a novel filter-membrane-shaped photocatalyst.

Preparation and Photocatalytic Performance for Degradation of Rhodamine B of AgPt/Bi4Ti3O12 Composites.

Loading a noble metal on Bi4Ti3O12 could enable the formation of the Schottky barrier at the interface between the former and the latter, which causes electrons to be trapped and inhibits the recombination of photoelectrons and photoholes. In this paper, AgPt/Bi4Ti3O12 composite photocatalysts were prepared using the photoreduction method, and the effects of the type and content of noble metal on the photocatalytic performance of the catalysts were investigated. The photocatalytic degradation of rhodamine B (RhB) showed that the loading of AgPt bimetallic nanoparticles significantly improved the catalytic performance of Bi4Ti3O12. When 0.10 wt% noble metal was loaded, the degradation rate for RhB of Ag0.7Pt0.3/Bi4Ti3O12 was 0.027 min−1, which was respectively about 2, 1.7 and 3.7 times as that of Ag/Bi4Ti3O12, Pt/Bi3Ti4O12 and Bi4Ti3O12. The reasons may be attributed as follows: (i) the utilization of visible light was enhanced due to the surface plasmon resonance effect of Ag and Pt in the visible region; (ii) Ag nanoparticles mainly acted as electron acceptors to restrain the recombination of photogenerated electron-hole pairs under visible light irradiation; and (iii) Pt nanoparticles acted as electron cocatalysts to further suppress the recombination of photogenerated electron-hole pairs. The photocatalytic performance of Ag0.7Pt0.3/Bi4Ti3O12 was superior to that of Ag/Bi4Ti3O12 and Pt/Bi3Ti4O12 owing to the synergistic effect between Ag and Pt nanoparticles.

Green route to Prussian blue nanoparticles with high degradation efficiency of RhB under visible light

Prussian blue nanoparticles (PBNPs) have been synthesized by using β-cyclodextrin (β-CD) as a surfactant and ethyl alcohol as a green solvent. The products were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), X-ray photoelectron spectrometer (XPS) and Brunauer–Emmett–Teller (BET) to analyse the structure, morphology, surface elements, specific surface area and porosity, respectively. It was found that the specific surface area of PB-120 was 90.527 m2 g−1. When the as-prepared PBNPs were applied as heterogeneous photo-Fenton catalysts, they exhibit high catalytic efficiency and stability of degrading Rhodamine B (RhB) under visible light in neutral system. The catalytic degradation of 25 mg L−1 RhB by PB-120 only needed 15 min, while the high degradation rate (83%) of RhB after 4 cycles of degradation could be achieved. The as-prepared PBNPs may be employed as excellent catalysts to degrade organic pollution.

AgI Nanoparticles Decorated Bi24O31Br10 Nanosheets: An Efficient 0D/2D Z-Scheme Heterojunction Photocatalyst for the Degradation of Rhodamine B

A novel 0D/2D Z-scheme AgI/Bi24O31Br10 photocatalyst was prepared through the simple solvothermal and coprecipitation method, in which AgI nanoparticles were decorated on the surface of Bi24O31Br10 nanosheets. The AgI/Bi24O31Br10 composites exhibited improved photocatalytic activity for the degradation of rhodamine B (RhB) in comparison with pristine Bi24O31Br10 and AgI under simulated sunlight irradiation. Specifically, AB-30 (mass fraction of AgI, 30%) composite exhibited remarkable photocatalytic activity of 97.6% towards RhB degradation under 120 min of simulated sunlight irradiation, and its RhB degradation rate constant (k) was approximately 20.7 and 2.9 times higher than that of pure Bi24O31Br10 and AgI, respectively. The improvement of photocatalytic performance of as-prepared AgI/Bi24O31Br10 heterojunction composites was ascribed to the synergistic effect of wide visible-light harvest capacity and the rapid transfer and separation efficiency of charge carriers. UV–vis diffuse reflectance spectra (DRS) analysis validated that the introduction of AgI could broaden the visible-light absorption of AgI/Bi24O31Br10 composite. The results of electrochemical impedance (EIS), photocurrent response and photoluminescence spectra (PL) tests showed that AgI/Bi24O31Br10 composite possessed the efficient separation and migration of photogenerated charge carriers. Trapping experiments of free radicals certified that ·O2− was the main reactive species in the process of degradation. And a probable photocatalytic mechanism of Z-scheme heterojunction between Bi24O31Br10 and AgI was proposed.

Photocatalytic Degradation and Antibacterial Properties of Fe3+-Doped Alkalized Carbon Nitride.

Discovering novel materials and improving the properties of existing materials are the main goals in the field of photocatalysis to increase the potential application of the materials. In this paper, a modified graphitic carbon nitride (g-C3N4) photocatalyst named Fe3+-doped alkalized carbon nitride, which couples the photocatalytic reaction with the Fenton reaction, is introduced to demonstrate its Rhodamine B (RhB) degradation and antibacterial properties. Under visible-light irradiation, the degradation rate of RhB was 99.9% after 200 min, while the antibacterial rates of Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli), and Staphylococcus aureus (S. aureus) after 300 min were 99.9986%, 99.9974%, and 99.9876%, respectively. Moreover, the repetitive experiments of RhB degradation demonstrate that the proposed photocatalysts have excellent stability and reusability. The active free radical trapping experiments reveal that the superoxide radical () is the dominant reactive oxygen species. In addition, the Fenton reaction is introduced into the photocatalytic system due to the doping of Fe3+, and the hydroxyl radical (·OH) produced from the Fenton reaction further enhances the photocatalytic performance. The remarkable improvement in photocatalytic performance of the proposed photocatalyst can be attributed to its broader UV–visible absorption characteristic and the occurrence of the Fenton reaction.

Biomimetic synthesis of 2D/2D mixed graphitic carbon nitride /carbonized polydopamine nanosheets with excellent photocatalytic performance

In recent years, exploring efficacious visible-light photocatalysis has been one of core concerns owing to potential applications for energy utilization and environmental remediation. Among all nanostructured photocatalysts, the nano-hierarchical material composed of two-dimensional (2D) nanosheets is terrific owing to abundant 2D coupling interfaces that can decrease the diffusion distance of photogenerated carriers and facilitate the interfacial electronic transfer. Herein, utilizing the biomimetic adhesion, 2D/2D graphitic carbon nitride nanosheet/carbonized polydopamine (CNNS/CPDA) nanocomposites were fabricated via the dopamine (DA) self-polymerization on the surface of graphitic carbon nitride (GCN) followed by carbonization and delamination. Wherein CPDA acts a crucial role for the reinforcement of photocatalytic degradation activity in CNNS/CPDA nanocomposites. On the one hand, CPDA has strong adsorption capacity that can accelerate the adsorption and degradation of rhodamine B (RhB) molecules. On the other hand, as one of carbon materials, CPDA has high conductivity and contacts with CNNS tightly, which is conducive to the transfer of photo-induced carriers. Hence, for the optimal CNNS/CPDA nanocomposite (CNNS/CPDA-2), the RhB degradation rate (0.0466 min−1) is 5.1 times as high as that of pure GCN. This kind of 2D/2D nanocomposites based on one-pot biomimetic strategy may hold significant promise in practical applications of water treatment.

Preparation of Ag2O/TiO2 nanocomposites by two-step method and study of its degradation of RHB

In order to solve the most difficult organic matter pollution in the water pollution problem, we successfully prepared a sample Ag2O/TiO2 heterojunction nanocomposite material using a two-step method, and used this material to test the degradation of rhodamine B (RhB). Compared with pure Ag2O and pure TiO2, Ag2O/TiO2 composites have improved degradation rate of RhB and enhanced photocatalytic activity under ultraviolet and visible light irradiation. Through SEM, UV–visible diffuse reflection, XPS and other characterizations, it can be seen that Ag2O nanoparticles are deposited on the inner and outer surfaces of TiO2 nanotubes, the absorption range of the sample has been significantly widened, and the heterojunction structure has been successfully constructed. These conclusions have a positive effect on the photocatalytic degradation of the sample.

Facile one-step sonochemical synthesis of AgCl quantum dots with enhanced photocatalytic activity and its size effects

In this work, a facile ultrasonic method for the fabrication of AgCl quantum dots (AgCl QDs) with an average diameter of about 2.5[Formula: see text]nm was reported for the first time. The material was analyzed by various techniques. In addition, effects of material’s size on its photocatalytic activities were studied. Results suggested that the AgCl QDs exhibited excellent photocatalytic activity to degrade Rhodamine B (RhB) and tetracycline (TC) under visible light illumination, and the degradation rate of RhB (TC) had reached up to 96.6% (72.2%) in 20 min, which was higher than that of AgCl nanoparticles (23[Formula: see text]nm) and AgCl nanospheres (114[Formula: see text]nm), respectively. Besides, the band gap of the material was increased when the size of material decreased from 23[Formula: see text]nm to 2.5[Formula: see text]nm. The significantly improved photocatalytic performance and increased band gap of AgCl QDs were mainly related to the quantum size effects of AgCl, which results in the more electron fluctuation in quantized energy levels and the lower recombination of electrons and holes.

A simple method for construction of Bi2O3/Bi6O6(OH)3(NO3)3·1.5H2O p–n junction photocatalyst with superior photocatalytic performance

In this work, a novel p-n junction Bi2O3(BO)/Bi6O6(OH)3(NO3)3·1.5H2O (BBN) photocatalyst (BBN-BO) with efficient photocatalytic activity have been prepared for the first time through simple grinding and calcinations method. Rhodamine B (RhB) was used to assess the photocatalytic activity of the as-prepared samples under the simulated solar light irradiation. Compared with pure Bi2O3 and BBN, the degradation rate of RhB by BBN-BO-20% (BBN/BO at a certain mass ratio: 20%) was effectively enhanced about 1.6 and 5.1 times, respectively. The photocatalytic activity of Bi2O3/Bi6O6(OH)3(NO3)3·1.5H2O was enhanced with the contribution to the reduced surface resistance, increased light absorption ability and inhibited the recombination of photogenerated electron hole pairs. In addition, the trapping experiment confirmed that h+ was the main active species in the photocatalytic degradation process of RhB.