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The g-C3N4-BiOBrxI1-x nanocomposites were successfully prepared using solvothermal methods. The obtained g-C3N4-BiOBrxI1-x composites had tunable band structures and displayed preferable photocatalytic performance for CO2 reduction irradiated by visible light. Moreover, comparing to pure g-C3N4 and corresponding BiOBrxI1-x, all the obtained g-C3N4-BiOBrxI1-x nanocomposites exhibited distinctly higher activity for CO2 reduction, with 5% g-C3N4-BiOBr0.25I0.75 nanocomposites displaying the best photocatalytic performance. Enhanced photocatalytic performance of g-C3N4-BiOBrxI1-x nanocomposites may arrive from their advantages of high efficiency of electron-hole separation, tunable band structures, and rapid charge transfer. Moreover, a possible visible light induced photocatalytic mechanism on g-C3N4-BiOBrxI1-x nanocomposites was further proposed.

A simple and versatile strategy for controlled production of monodisperse ethyl cellulose (EC) microcapsules by a single-stage emulsification method has been developed. Monodisperse oil-in-water emulsions, obtained by a microfluidic device, are used as templates for preparing EC microcapsules. Oil-soluble ethyl acetate (EA) is miscible with water, so the interfacial mass transfer between EA and water occurs sufficiently, which leads to water molecules pass through the phase interface and diffuse into emulsion interior. Water molecules aggregate at the interface, and some merge into a large water drop in the central position of the emulsion. After evaporation of EA solvent, monodisperse EC microcapsules create large numbers of pits on the surface with a hollow structure. Curcumin is used as a model drug and embedded in the hollow structure. EC microcapsules have good, sustained drug release efficacy in a simulated intestinal environment, and the release process of EC microcapsules containing 6.14% drug-loaded capacity is fully consistent with the vitro drug release model. Such simple techniques for making EC microcapsules may open a window to the controlled preparation of other multifunctional microcapsules. Besides, it offers theoretical guidance for the study of EC microcapsules as drug carriers and expanding clinical application of curcumin.

AgIO₃/Ag₂O/Ag nanocomposites with enhanced photocatalytic activities were synthesized by a onestep coprecipitation method at room temperature. The optimum hybrid of AgIO₃/Ag₂O = 1.25:1 with Ag nanoparticles (Ag NPs) loading (denoted as AA125) exhibited superior photocatalytic activity, demonstrating 97.19% tetracycline (TC) degradation within 60 min under simulated solar irradiation. This was approximately 10.44 and 2.63 times higher than that of pure Ag₂O and AgIO₃, respectively. The advanced photocatalytic activity can be ascribed to the synergetic effects of the heterostructured AgIO₃/Ag₂O/Ag and the strong surface plasmon resonance (SPR) effect of Ag NPs generated on the surface, which improved the separation and transfer efficiency of photoinduced electron-hole pairs. The results from radical scavenger experiments indicated that the degradation of TC was driven mainly by the participation of superoxide radical (·O-₂).

BiOCl/diatomite composite with enhanced photocatalytic property for the degradation of liquid Tetracycline hydrochloride (TC) and gaseous formaldehyde (HCHO) were successfully prepared by a facile hydrothermal method at different pH value. The structure and morphology characterizations of BiOCl/diatomite composite exhibit that diatomite not only acts as a natural porous support of photocatalyst but also acts as dominant facets regulator at pH = 3 when the doping amount is change, owing to the surface electrical property of the diatomite and interaction between diatomite and BiOCl. This interaction is certified by XPS and FT-IR which indicate that Bi in layer structure of [Bi2O2]2+ group interacts with the O in Si O Si bond when the formation of BiOCl with the participation of diatomite. The BET characterization confirms that the increasing amount of diatomite enables the composite with more reaction points for light harvest and molecule adsorption than pure BiOCl. Furthermore, TC and formaldehyde are targeted as degradation objects to test the photocatalytic property of BiOCl/diatomite composite. The optimum photocatalytic property are BiOCl(3–1.2) and BiOCl(12–0.6) at TC degradation and BiOCl(3–0.3) and BiOCl(12–0.6) at formaldehyde elimination, which is much better than that of pure diatomite or BiOCl. The difference of optimum photocatalysts in liquid and gaseous phase systems can be attributed to the photoelectric performances of BiOCl/diatomite composite, which were characterized by DRS, PL, transient photocurrents and the electrochemical impedance spectroscopy technique.

Constructing heterojunction is an effective way to enhance the catalytic activities of semiconductor photocatalyst owing to its special synergistic effect. In this study, a novel p-n heterostructured CdWO₄/BiOCl nanocomposites were synthesized by a facile hydrothermal and subsequently chemistry bath method. The photocatalytic performance of CdWO₄/BiOCl heterojunctions was investigated by degrading phenol and RhB under simulated solar light irradiation. Highly improved photocatalytic activities were achieved on all CdWO₄/BiOCl heterojunctions compared with both pure CdWO₄ and BiOCl. The CdWO₄/BiOCl heterojunction with optimal mole ratio of 25% CdWO₄ displayed the highest photoactivity with RhB and phenol being completely degraded in 15 min and 6 h, respectively. Mechanism analysis revealed that the interface of p-n heterojunction of CdWO₄/BiOCl composites can produce spontaneously electric field which can effectively separate photogenerated electrons and holes. Moreover, the active species research demonstrated that holes and superoxide radicals proved to be the principal active species during the photocatalytic process. This work demonstrated that the CdWO₄/BiOCl photocatalyst may be a promising material for purifying the organic contaminant in practical application.

3D hierarchical structure BiOX(X ═ Cl, Br)-(CMC) assembled from 2D nanosheets with {010} facets exposed have been successfully synthesized by the assistance of biomass solvent CMC-Na. All the nitrogen adsorption isotherms and photoelectrochemical results reflected that BiOX(X Cl, Br)-(CMC) exhibit higher specific surface area, superior optical absorption efficiency and separation efficiency of photoinduced electron-hole than BiOX(X═Cl, Br) 2D nanosheets exposed with {001} facets. Besides, 96.5% and 60.3% of tetracycline hydrochloride (TC) were photodegradated in 60 minutes under the visible light irradiation catalyzed by BiOBr-(CMC) and BiOCl-(CMC), which is much better than BiOBr and BiOCl. The formation and enhanced photocatalytic activity of 3D hierarchical structure BiOX-(CMC) may be ascribe to the bi-functional groups of CMC, which can affect the crystallization process and morphology of BiOX. According to the merit of environmental friendly and improved photocatalytic activity of the 3D hierarchitecture, we believe that this work broadens the possibility of designing efficient BiOX photocatalyst with {010} facets exposed.

A series of novel BiPO4–BiOBrxI1−x p–n heterojunctions were successfully prepared by a facile solvothermal method. The morphology, structure and optical properties of photocatalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and ultraviolet visible diffuse reflectance spectroscopy. The visible light photocatalytic activities of BiPO4–BiOBrxI1−x heterojunctions were investigated by photocatalytically reducing CO2. After 4 hours of irradiation, the 5% BiPO4–BiOBr0.75I0.25 heterojunction showed the highest photocatalytic activity with the yields of CO and CH4 up to 24.9 and 9.4 μmol gcat−1 respectively. The improved photocatalytic activity may be due to the formation of BiPO4–BiOBrxI1−x p–n heterojunctions which can effectively restrict the recombination rate of the photoexcited charge carriers. Moreover, the energy band structure of BiPO4–BiOBrxI1−x heterojunctions could be easily adjusted by changing the mole ratio of I and Br. The possible mechanism of the enhancement of the photocatalytic performance was also proposed based on experimental and theoretical analysis. The present study may provide a rational strategy to design highly efficient heterojunctions with an adjustable energy band for environmental treatment and energy conversion.

The BiOBrxI1−x solid solutions were successfully synthesized both in water and ethylene glycol (EG), using a facile solvothermal method. The as-prepared BiOBrxI1−x solid solutions were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), UV–vis spectrometer and so on. SEM images revealed that BiOBrxI1−x solid solutions formed 2D plate-like shape in water, and formed microspheres in EG solvent; except that BiOI formed nanoparticles in EG solvent. The photocatalytic performance of all the BiOBrxI1-x solid solutions samples were investigated by degrading phenol under visible light irradiation (λ > 420 nm). The BiOBr0.5I0.5 microspheres with highly exposed {1 1 0} facets showed the highest photocatalytic activity with phenol completely degraded within 80 min under visible light irradiation. In addition, a reasonable mechanism for the enhanced photocatalytic performance was also discussed in detail.

Bi2MoO6-BiOCl nanoplate composites were successfully synthesized by a simple solvothermal process. The morphology, microstructure and optical properties of the as-prepared Bi2MoO6-BiOCl nanocomposites were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-Vis diffuse reflection spectroscopy (DRS). A noteworthy enhancement in the visible-light-responsive photocatalytic degradation of RhB was observed over the Bi2MoO6-BiOCl nanocomposites compared to its individual components. The enhanced photocatalytic performance of Bi2MoO6-BiOCl nanocomposites could be attributed to the heterojunction interface in the composite, which can both efficiently separate photogenerated electron-hole pairs and also restrain the recombination of photoinduced charges.

The g-C₃N₄-BiOBr

An electrochemical palladium/ferric oxide (Pd/Fe2O3) nanocomposite modified glassy carbon electrode (GCE) was fabricated by hydrothermal method of Fe2O3 and electrochemical deposition of palladium nanoparticles, respectively. As-prepared Pd/Fe2O3 composite modified electrode exhibits enhanced electrocatalytic activity towards the catalytic oxidation of nitrite compared to Fe2O3, PdNPs modified electrodes and bare electrode. The parameters such as the influence of amount of Pd nanoparticles deposition onto the Pd/Fe2O3 modified electrode (ME) and effect of solution pH were investigated and discussed in detail. Under the optimal conditions, the Pd/Fe2O3 modified GCE can be used to detect nitrite concentration in a wide linear range of 10 and 1000 μM with the detection limit of 0.1 μM. The presence of Cu2+, Na+, Cl-, PO3-4 SO2-4, Mg2+ K+, NO-3, and NH+4 showed a trivial effect on the response of nitrite determination, revealing that developed modified electrode has an excellent anti-interference ability to common ions. It also shows good stability and reproducibility.

Herein, a novel visible-light-driven heterojunction AgI/WO3 nanocomposite was successfully prepared using a facile two-step hydrothermal-precipitation process and applied for photodegradation of organic pollutants. The information of phase structures, morphology, optical properties of the asprepared samples was analysed in detail by XRD, TEM, EDS, STEM, DRS measurement and so on. Formation of the heterostructure and intimate interactions between AgI and WO3 can promote highly effective photogenerated electron-hole pairs separation, which enable the heterojuctions to perform excellent photocatalytic activity as greatly enhanced photocatalysts compared to that of pristine AgI and WO3 for decomposing Rhodamine B (RhB) dye under visible light irradiation. In addition, the AgI/WO3 (1:1) nanocomposites exhibit optimal photocatalytic activity. Moreover, the as-prepared samples exhibit good stability, which is favorable for its potential application. Additionally, we have an analysis on a possible photocatalytic mechanism based on trapping experiments together with other experimental results.

In this paper, a series of Ag 3 PO 4 -BiOCl 1−x Br x composites with adjustable band gap has been fabricated by using a facile two-step synthetic method. The photocatalytic activity of Ag 3 PO 4 -BiOCl 1−x Br x was evaluated by photocatalytic decomposition of phenol aqueous solution under simulated solar light irradiation. The result shows that Ag 3 PO 4 -BiOCl 0.75 Br 0.25 (1:5) composite possesses the best photocatalytic activity among all the as-prepared samples. The photocatalytic activity of Ag 3 PO 4 -BiOCl can be enhanced mainly owing to the strong light absorption ability by loading Ag 3 PO 4 on the surface of BiOCl, while the photocatalytic activities of Ag 3 PO 4 -BiOCl 1−x Br x (x = 0.25, 0.5, 0.75 and 1) composites could be enhanced by restraining the recombination of photo-generated electron-hole pairs. The enhanced solar-light photocatalytic activities of Ag 3 PO 4 -BiOCl 1−x Br x composites could be ascribed to the adjustable energy band structure, which facilitates the separation of photoinduced carriers. In addition, superoxide radicals ( O 2 − ), holes (h + ) and OH are considered to dominate the photocatalytic degration process. Moreover, a possible mechanism of deep understanding on the base of experimental results was proposed.

An electrochemical sensor ground on nickel oxide (NiO) nanoparticles and multi-walled carbon nanotubes (MWCNTs) was exploited for the detection of nitrite. Scanning electron microscopy (SEM) ensure the morphology of the nanocomposite consisted of NiO nanoparticle and MWCNTs. High Resolution Transmission electron microscopy (HR-TEM) reveals that the structure of NiO nanoparticles and MWCNTs. Scanning transmission electron microscopy (STEM) persuasively verified presence of the C, Ni and O element. The electrochemical character of the nanocomposite were researched by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), and the behavior of electrochemical oxidation to nitrite on NiO/MWCNTs/CP was explored by chronoamperometry. In tests, the NiO/MWCNTs/CP shown a sensitive current response toward nitrite, the oxidation peak current are linearly related to nitrite concentration in the range from 10-6 M to 10-4 M (R = 0.997) with a sensitivity of 3.53 μA μM-1 and a detection limit of 0.25 μM (S/N = 3). The validity of utilizing the proposed electrode to determine nitrite in tap water was also demonstrated.

Au nanoparticles (Au NPs) were deposited onto BiOCl 1−x Br x nanosheets by using a facile ultrasonic treatment. The obtained Au-BiOCl 1−x Br x composites exhibit excellent photocatalytic property in the reaction of decomposing phenol aqueous solution under simulated solar light irradiation. There is a positive relationship exists in the surface plasmon resonance (SPR) of Au NPs and enhanced activities, which is contributed to the separation of photo-induced electrons and holes as well as facilitate the absorption of visible light. In addition, the tunable energy band structure might be beneficial to enhance the photocatalytic activities of Au-BiOCl 1−x Br x composites for optimizing the bandgap. And the OH and h + species were the main active species in photocatalytic reactions. In this paper, the Au-BiOCl 1−x Br x photocatalysts were demonstrated to be a promising material for practical applications in the purification of organic pollutants.

The highly effective g- $$\hbox {C}_{3}\hbox {N}_{4}$$ hybridized CdS photocatalysts were synthesized via a successive calcination and hydrothermal process. The as-prepared photocatalysts were characterized by X-ray powder diffraction, transmission electron microscopy and UV–Vis diffuse reflectance spectroscopy. The photocatalytic performance of the $$\hbox {C}_{3}\hbox {N}_{4}$$ /CdS nanocomposites was evaluated by the photodegradation of RhB under visible light irradiation. The results showed that photocatalytic ability of the $$\hbox {C}_{3}\hbox {N}_{4}$$ /CdS nanocomposites was higher than that of pure $$\hbox {C}_{3}\hbox {N}_{4}$$ and CdS. The enhanced photocatalytic activity could be attributed to the high separation efficiency of the photo-excited electron-hole pairs. A possible mechanism of the photocatalytic degradation of RhB on $$\hbox {C}_{3}\hbox {N}_{4}/$$ CdS nanocomposites was also proposed.

A series of WO 3 -BiOCl x Br 1−x heterojunctions with tunable energy band structure were successfully synthesized via a hydrothermal method. The photocatalytic activities and reaction mechanism of WO 3 -BiOCl x Br 1−x composites were investigated by decomposition of Rhodamine B (RhB). The light absorption ability, energy band structure and photocatalytic activity in WO 3 -BiOCl x Br 1−x heterojunctions could be adjusted by changing the mole ratio of Br and Cl. The results revealed that the WO 3 -BiOCl x Br 1−x composites exhibited the highest photocatalytic activities than pure WO 3 and BiOCl x Br 1−x under visible light irradiation. The photocatalytic property of WO 3 -BiOCl can be strengthened mainly owing to the enhanced light absorption ability, while the photocatalytic activities of WO 3 -BiOCl x Br 1−x (x = 0, 0.25, 0.5 and 0.75) composites could be enhanced by restricting the recombination of photo-generated electrons and holes. Among them, 5% WO 3 -BiOCl 0.25 Br 0.75 heterojunction shows the highest photocatalytic activity with RhB completely decomposed in 6 min, this can be contributed to the synergetic effects of energy band structure and light absorption ability. Moreover, the holes and superoxide radical anions were considered as the active species during photocatalytic oxidation process, and the possible mechanism of the enhancement of the photocatalytic property was proposed.

The novel BiPO4-BiOClxBr1−x p–n heterojunctions with adjustable band gap are successfully constructed via a facile hydrothermal method. BiPO4-BiOClxBr1−x composites were fabricated by inlaying BiPO4 particles into BiOClxBr1−x hierarchical microstructure which is composed of nanosheets. Compared with BiPO4 and BiOClxBr1−x, they exhibited significant improvement of visible light photocatalytic properties toward the degradation of RhB. The results of transient photocurrent experiments demonstrated that the significant enhancement of photocatalytic activity can be ascribed to the surface p–n junction of BiPO4-BiOClxBr1−x composites which can effectively reduce the recombination rate of the photo-generated carriers during photocatalytic process. BiPO4-BiOClxBr1−x p–n heterojunctions were possessed of tunable band-gaps by decreasing the mole ratio of Cl/Br. The highest photoactivity of the 5% BiPO4-BiOCl0.75Br0.25 heterostructure could be attributed to the synergetic effect of optimized band structure, light absorption and effective separation of electron–hole pairs. In addition, holes and superoxide radicals (•O2−) were considered to dominate the photocatalytic process. Based on the theoretical and experimental results, the reasonable photocatalytic mechanism was proposed.

Ternary heterojunction photocatalyst Ag/AgIO3/BiOCl and Ag/AgIO3/BiOCl(CMC) were prepared to solve the contaminants of TC antibiotics residue in water and volatilizing HCHO in indoor air. Morphology modification, heterojunction construction, dominant facet controlling and surface plasma resonance strategies were merged into to modify the photocatalyst. First, biomass solvent assisted synthesis of AABC-CMC does a favor for harvesting the visible light and improving the adsorption of organic pollutants compared to AABC. In addition, Ag nanoparticles (NPs) have been successfully anchored on the surface of heterostructure to enhance the adsorption of visible light, and act as a visible light “trigger” for two wide band gap components of heterojunction. Non-centrosymmetric AgIO3 and band gap matching in heterostructure accelerates separating and transferring of electron-hole pairs, and reduces the probability of recombination. Besides, the IEF differing in BiOCl(CMC) and BiOCl results the difference of photocarriers migrating path when composited with AgIO3.The shorter transmission distance in the AABC-CMC reduces the recombination of photocarriers in the bulk and improve photocatalytic property of AABC-CMC. The possible charge transfer mechanism and key radicals differs in photodegradating process, O2− and OH plays a major role in photo-degrading TC and HCHO, respectively.

The efficient visible-light-driven AgIO3/AgBr photocatalyst was successfully synthesized by an in-situ anion-exchange method at room temperature. The scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflection spectroscopy (DRS) were used to characterize the obtained samples. The photocatalytic activities of the as-prepared heterojunctions were estimated by decomposing the organic dye RhB under visible-light irradiation (λ > 420 nm). Compared with pure AgBr and AgIO3, the AgIO3/AgBr compounds showed dramatically improved visible-light photocatalytic activity. Besides, the results also revealed that 20% AgIO3/AgBr exhibited the best photocatalytic activity, which could decompose the RhB completely in 24 min. The enhanced photocatalytic activity of the composites could be ascribed to the high separation rate of the photoinduced electron–hole pairs in the heterojunction structure. Moreover, the radical trap experiments were also carried out which confirmed that h+ played the major role in RhB photodegradation. The possible mechanism of RhB degradation on the AgIO3/AgBr composite was also discussed according to the results of the experiments and the performance of the obtained photocatalysts.

A series of heterojunction Ag 2 O/AgI photocatalysts with different Ag 2 O contents were successfully prepared though a facile two-step precipitation process at room temperature. The as-synthesized samples were measured in detail by XRD, EDS, XPS, SEM and DRS. The results showed that pherical Ag 2 O nanoparticles with diameter about 100–300 nm were uniformly distributed on the surface of AgI leading to the formation of Ag 2 O/AgI heterojunction. The photocatalytic activities of the obtained photocatalysts were evaluated by photocatalytic degradation of Rhodamine B (RhB) under visible light irradiation. The Ag 2 O/AgI with molar ratio of 1:1 showed the highest photocatalytic activities compared to the pure Ag 2 O and AgI with almost all RhB decomposed in 25 min. During photocatalytic process the visible light induced photogenerated electrons can be captured by Ag + ions on the surface lattice of heterojunction to form plasmonic Ag nanoparticles, which may promote the interfacial charge transfer. The enhanced photocatalytic activity was then largely attributed to the synergetic effects of heterojunction Ag 2 O/AgI/Ag and the efficient separation of photogenerated electron–hole pairs. This research may provide a novel Ag 2 O/AgI heterojunction with assistant of plasmonic Ag NPs to generate efficient, stable, and recyclable visible-light-driven plasmonic photocatalysts. The photocatalytic reaction kinetics and possible photocatalytic mechanism for this highly efficient photocatalysts were also proposed.

Ag nanoparticles decorated multi-walled carbon nanotubes (MWCNTs) composite was prepared by a simple electrochemical deposition approach. Transmission electron microscopy (TEM) and Energy dispersive spectroscopy (EDS) were employed to characterize the morphology and composition of the composite. The results showed that Ag nanoparticles with an average size approximately 20 nm were uniformly deposited on the MWCNTs surface. The electrochemical performance of the suggested sensor was investigated via differential pulse voltammetry (DPV) and chronoamperometry. Under optimum conditions, the AgNPs/MWCNTs/GCE displayed a rapid current response to nitrite, with the anodic peak current varying linearly with nitrite concentration in the range of 1 μM–100 μM (R = 0.9989) accompanying a low detection limit of 0.095 μM. The long-term stability and good reproducibility were also achieved on the proposed sensor. The determination of nitrite in tap water was studied and showed desirable recovery rate, signifying its possibility for practical application.

BiOCl 1− x Br x solid solutions with tunable structures and morphologies were successfully synthesized both in water and ethylene glycol (EG), via a facile solvothermal process. The microstructure and properties of composites were characterized by X-ray powder diffraction (XRD), Brunauer Emmet Teller (BET), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), UV–vis spectrophotometer, transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and so on. The effect on the innate character and light reaction mechanism on the photocatalytic activity of BiOCl 1− x Br x were investigated in detail by degradation of Rhodamine B (RhB). SEM revealed that rose-like BiOCl 1− x Br x solid solutions can be obtained in water and the sphere-like were synthesized in EG solvents. And the rose-like nanostructures showed superior photocatalytic properties. Furthermore, the rose-like BiOCl 0.5 Br 0.5 with high exposed {101} facets showed the highest photocatalytic activity with the RhB completely degraded within 12 min under visible light irradiation. In addition, a reasonable mechanism of the enhanced photocatalytic performance was also discussed according to the experimental results.

A novel heterojunction photocatalyst AgIO3/WO3 was fabricated through hydrothermal and chemical precipitation methods. The AgIO3/WO3 samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy dispersive X-ray detector, and UV–vis diffuse reflectance spectroscopy (UV-vis DRS). Moreover, the photocatalytic activities of AgIO3/WO3 samples were estimated by the decomposition of organic dye RhB under visible light irradiation (λ >420 nm). The result reveled that AgIO3/WO3 composite showed higher photocatalytic performance than pure AgIO3 and WO3 photocatalysts, and 50% AgIO3/WO3 heterojunction was recorded to have the optimum rate constant. The enhancement of the photocatalytic activity could be attributed chiefly to the effective separation and migration of photogenerated electron-hole pairs at the interface of AgIO3 and WO3. In addition, radical trap experiments confirmed that the ·OH was the primary reactive species during the photodecomposition of RhB. A possible photocatalytic mechanism of RhB decomposition over AgIO3/WO3 heterostructures was also presented.

A series of energy band adjustable Bi 2 W x Mo 1−x O 6 -BiOCl (x=0, 0.2, 0.4, 0.6, 0.8 and 1.0) heterojunctions were successfully synthesized through a solvothermal crystallization method. Characteristics and properties of the products were investigated using XRD, TEM, HRTEM, EDS, and DRS. Meanwhile, the photocatalytic activities of Bi 2 W x Mo 1−x O 6 -BiOCl composites were estimated by degrading Rhodamine B (RhB) under visible light irradiation. The results show that Bi 2 W 0.6 Mo 0.4 O 6 -BiOCl (1:14) composite displayed the best photocatalytic performance among all the as-prepared samples. The enhanced visible-light photocatalytic activities of Bi 2 W x Mo 1−x O 6 -BiOCl heterojunctions could be attributed to the generation of the adjustable energy band configuration, which has great influences on the generation of photoinduced carriers through inhibiting the recombination of electron-hole pairs. According to the active species trapping results and energy band calculation, the mechanism of the significant enhancement of the photocatalytic activity was proposed. This method may provide new insights into the energy band adjusting of photocatalysts used in environmental remediation and photocatalytic water purification.

Constructing heterojunction is an effective way to enhance the catalytic activities of semiconductor photocatalyst owing to its special synergistic effect. In this study, a novel

A novel BiIO4/Ag3PO4 nanocomposite photocatalyst was synthesized through hydrothermal and chemical precipitation methods. The as-prepared samples were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and ultraviolet visible diffuse reflectance spectroscopy. Moreover, the photocatalytic activity was evaluated by degradation of phenol under visible light irradiation. BiIO4/Ag3PO4 nanocomposite exhibited higher photocatalytic activity than BiIO4 and Ag3PO4, with 5% BiIO4/Ag3PO4 nanocomposite displaying the highest activity. The enhanced photocatalytic performance may be due to the formation of BiIO4/Ag3PO4 heterojunction interface, which is beneficial to the separation and migration of the photogenerated electrons and holes. In addition, the active species trapping experiment demonstrated that •O2− and •OH were the major active species during the photocatalytic process.

In this work, BiOIO3 nanoplatelets were successfully prepared by a simple hydrothermal method. The as-prepared samples were characterised by energy-dispersive spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, X-ray powder diffraction and ultraviolet visible diffuse reflectance spectroscopy. The photocatalytic activities of the as-prepared BiOIO3 nanoplatelets were evaluated by photodegradation of rhodamine B (RhB) under simulated solar light. The results showed that the change of temperature within a certain range has almost no influence on the morphology and size of BiOIO3 nanoplatelets. However, it had an obvious effect on the photocatalytic performance of BiOIO3 nanoplatelets. The results showed that the BiOIO3 sample synthesised at 130 °C exhibited the highest photocatalytic activities compared to others, with RhB completely decomposed in 80 min. The products with proper crystallinity formed at 130 °C have the optimal rate of RhB photodegradation. It...

A novel heterojunction photocatalyst CdWO 4 /BiOBr was fabricated combining nano-rod CdWO 4 with flake-like BiOBr through a hydrothermal and subsequently chemical precipitation method. The samples were characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Energy dispersive X-ray detector (EDS), X-ray diffraction (XRD) and UV–vis spectrophotometer. Moreover the photocatalytic activities were evaluated by decomposing dye molecule RhB under visible light irradiation. The results showed that high photocatalytic performance can be achieved on the heterojunction photocatalysts with the 15% CdWO 4 /BiOBr composite displaying highest activity. The results of the study concluded that it was the introduction of BiOBr into the catalyst that mainly enhanced the activity of the photocatalyst by promoting the separation of electron–hole group on the interface of BiOBr and CdWO 4 .

In this study, the Ag3PO4 microcrystal was successfully prepared at different temperatures using precipitation and hydrothermal methods. The as-prepared products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (UV–vis DRS) and so on. It was found that the synthesized temperature had some effects on the morphologies and photocurrent of Ag3PO4. As the synthesized temperature increased from 20 °C to 120 °C, the ratio of exposed (110) facets increased, which are the active photocatalysis facets in Ag3PO4 crystals, along with a higher photocatalytic efficiency over RhB under visible light irradiation. And the Ag3PO4 microcrystals synthesized at 120 °C exhibited the highest photocatalytic activities with the degradation ratio of RhB rising up to 97.83% in 6 min due to the high separation efficiency of electron and hole pairs. In addition, the main active species and their roles were investigated by adding scavengers (isopropyl alcohol and EDTA) during the photocatalytic degradation of RhB and a possible mechanism was discussed.

A novel AgI/AgIO3 heterojunction photocatalyst was prepared through a mild ion-exchange method at room temperature. Their photocatalytic activities were assessed by the photodegradation of rhodamine B (RhB) under simulated solar light. The AgI/AgIO3 composites performed better photocatalytic activities than pure AgI and AgIO3 with 15 % AgI/AgIO3 heterojunction showing the highest photocatalytic efficiency among all the heterojunction samples. Moreover, the 15 % AgI/AgIO3 hybrid photocatalyst also showed excellent repeatability and stability during photocatalytic reaction. The improvement of photocatalytic performance can be attributed to effective separation of photoexcited electrons and holes at the interface of AgI/AgIO3 composites. Radical trap experiments determined that the O2·− radical was the main reactive species for the photodegradation of RhB.

In this article, the direct electrochemical behavior of nitrite at a Au nanoparticles (AuNPs)/carbon paper (CP) electrode made using a rapid electrochemical deposition method was investigated. The morphology of the AuNPs on the CP surface was characterized by scanning electron microscopy (SEM). The existence of the Au element was verified by energy dispersive spectroscopy (EDS). The crystal structure of the AuNPs was verified by X-ray diffraction (XRD). Cyclic voltammetry (CV) was applied to evaluate the electrochemical behavior of nitrite oxidation. Under the optimum conditions, the AuNPs/CP electrode exhibited a very strong response to nitrite; the oxidation peak current linearly increased with increasing nitrite in the ranges of 1 μM to 30 μM and 40 μM to 100 μM with correlation coefficients of 0.99883 and 0.99789, and a low detection limit of 0.093 μM. The suggested sensor demonstrated high sensitivity, good reproducibility and good recovery.

A visible-light-driven AgI/BiOIO3 nanohybrid photocatalyst was prepared via a successive hydrothermal-deposition process. The microstructures, morphologies, and composition of the obtained photocatalysts were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and energy-dispersive spectroscopy (EDS). The UV-vis diffuse reflectance spectrum (DRS) showed that the light absorption of the AgI/BiOIO3 nanohybrid is broadened from the UV to visible light region. The effect of AgI loading on BiOIO3 for photodegrading Rhodamine B (RhB) under visible light irradiation was investigated. The AgI/BiOIO3 nanohybrid exhibited superior photocatalytic activities to the bare AgI and BiOIO3, with the 30% AgI/BiOIO3 sample showing the highest photocatalytic degradation efficiency. Based on the energy band structure and the analysis of reactive species, the probable mechanism of enhanced photocatalytic reaction was discussed.

Novel, visible light-induced, Zn-doped BiOBr hierarchical nanostructures were successfully prepared by solvothermal methods. The photocatalytic activity of the samples was evaluated using RhB as the target pollutant. The Zn-doped BiOBr hierarchical nanostructures exhibited significantly enhanced visible light-induced photocatalytic efficiency for the degradation of RhB compared with pure BiOBr. The Zn-doped BiOBr with RZn = 0.1 (RZn is defined as the atomic ratio of Zn to Bi) showed the highest photocatalytic activity with decolorization efficiency of almost 100% after 15 min. The enhanced photocatalytic ability could be attributed to the efficient separation of photogenerated electron–hole pairs. Moreover, the role of the active species was also evaluated by adding different scavengers during the photodegradation of RhB. A possible mechanism for the enhancement of visible light performance of Zn-doped BiOBr photocatalysts was also proposed on basis of the experimental results.

A novel ferric oxide/multi-walled carbon nanotubes ( $$\hbox {Fe}_{2}\hbox {O}_{3}$$ /MWCNTs)-modified glassy carbon electrode (GCE) was prepared by drop casting $$\hbox {Fe}_{2}\hbox {O}_{3}$$ /MWCNTs onto the surface of GCE. Scanning electron microscopy (SEM) image shows that the $$\hbox {Fe}_{2}\hbox {O}_{3}$$ /MWCNTs has a nanostructure. Cyclic voltammetry (CV) results show that the $$\hbox {Fe}_{2}\hbox {O}_{3}$$ /MWCNTs-modified GCE presents excellent electrochemical activity in the presence of 1 mM nitrite in a 0.1 M phosphate-buffered saline (PBS) to compare the $$\hbox {Fe}_{2}\hbox {O}_{3}$$ and MWCNTs-modified GCE. Differential pulse voltammetry (DPV) results also show that the $$\hbox {Fe}_{2}\hbox {O}_{3}$$ /MWCNTs has excellent electrocatalytic performance to nitrite in a pH 7.0 PBS. The amperometric response result shows that the $$\hbox {Fe}_{2}\hbox {O}_{3}$$ /MWCNTs-modified GCE can be used to detect nitrite concentration in a wide linear range of $$10\textendash 1000\, \upmu \hbox {M}$$ with a detection limit of $$0.1\, \upmu \hbox {M}$$ .

Bi2MoO6-BiOCl nanoplate composites were successfully synthesized by a simple solvothermal process. The morphology, microstructure and optical properties of the as-prepared Bi2MoO6-BiOCl nanocomposites were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-Vis diffuse reflection spectroscopy (DRS). A noteworthy enhancement in the visible-light-responsive photocatalytic degradation of RhB was observed over the Bi2MoO6-BiOCl nanocomposites compared to its individual components. The enhanced photocatalytic performance of Bi2MoO6-BiOCl nanocomposites could be attributed to the heterojunction interface in the composite, which can both efficiently separate photogenerated electron-hole pairs and also restrain the recombination of photoinduced charges.

Herein, a novel visible-light-driven heterojunction AgI/WO3 nanocomposite was successfully prepared using a facile two-step hydrothermal-precipitation process and applied for photodegradation of organic pollutants. The information of phase structures, morphology, optical properties of the asprepared samples was analysed in detail by XRD, TEM, EDS, STEM, DRS measurement and so on. Formation of the heterostructure and intimate interactions between AgI and WO3 can promote highly effective photogenerated electron-hole pairs separation, which enable the heterojuctions to perform excellent photocatalytic activity as greatly enhanced photocatalysts compared to that of pristine AgI and WO3 for decomposing Rhodamine B (RhB) dye under visible light irradiation. In addition, the AgI/WO3 (1:1) nanocomposites exhibit optimal photocatalytic activity. Moreover, the as-prepared samples exhibit good stability, which is favorable for its potential application. Additionally, we have an analysis on a possible photocatalytic mechanism based on trapping experiments together with other experimental results.

The zinc-doped CdWO4 photocatalyst was successfully synthesized by a hydrothermal process. The influences of zinc doping on the phase structures, optical properties, morphologies and photocatalytic activities of the CdWO4 catalyst were investigated. The results showed that the zinc-doping can enhance the photocatalytic efficiency of CdWO4 with the highest activity obtained on the Zn-doped CdWO4 (Zn/Cd ratio of 0.1) for degradation of rhodamine B(RhB) under simulated solar light irradiation. The enhancement of photocatalytic activity may be attributed to the zinc doping which can change the band gap of the catalyst and subsequently inhibit the recombination of photogenerated electrons and holes.

In this study, BiOCl doped with different contents of zinc were successfully prepared via a facile ethylene glycol (EG)-assisted solvothermal process at 160 °C for 12 h. The as-synthesized samples were characterized in details by X-ray powder diffraction (XRD), energy dispersive X-ray analysis (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), UV–vis diffuse reflectance spectra (UV–vis DRS) and Brunauer Emmet Teller (BET) measurement. The photocatalytic performances were evaluated by the photocatalytic degradation of Rhodamine B (RhB) under visible light irradiation. The results showed that Zn doping did not change the morphologies and particle sizes of BiOCl. However, it had an obvious effect on the photocurrent and BET surface area of BiOCl and accordingly the photocatalytic performance of BiOCl was greatly improved. The Zn-doped BiOCl with RZn = 0.07 showed the highest photocatalytic activities with almost all of the RhB decomposed in 8 min. Moreover, repetitive tests imply the good recyclability and stability of the catalysts. The enhanced photocatalytic activity was largely ascribed to the efficient separation of photogenerated electron–hole pairs and high BET surface area of the catalysts. In addition, a possible mechanism on basis of the experimental results was discussed.

A novel BiOBr/ZnWO 4 p–n heterojunction catalyst was fabricated for the first time via a facile deposition method. The morphology and structure of the catalyst were characterized by SEM, TEM, HR-TEM, EDS, XRD, UV–vis DRS and BET. The results show that ZnWO 4 nanoparticles conjugated firmly with BiOBr nanoplates with the crystal structure of monoclinic ZnWO 4 and tetragonal BiOBr. The photocatalytic performance of the catalysts was evaluated through decolorization of rhodamine-B (RhB) in aqueous solution under visible light irradiation(λ > 420 nm). BiOBr/ZnWO 4 heterojunction catalyst shows much higher photocatalytic activity than that of BiOBr and ZnWO 4 . 30% BiOBr/ZnWO 4 heterostructure exhibits the highest photocatalytic activity with almost complete removal of RhB in 16 min. Moreover, good recyclability was also obtained from the BiOBr/ZnWO 4 heterojunction catalyst. The enhanced photocatalytic efficiency of the BiOBr/ZnWO 4 heterostructures may be related to the formation of p–n heterojunction interface between BiOBr and ZnWO 4 which reduced the recombination of electrons and holes.

In this study, Bi2WO6 doped with different barium contents were successfully prepared by a simple hydrothermal route at 180 °C for 12 h. The as-synthesized samples were characterized in detailed by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis diffusere flectance spectroscopy (UV–vis DRS) and Brunauer–Emmet–Teller (BET) theory. Their photocatalytic activities were evaluated by photodegradation of Rhodamine B (RhB) under simulated solar light. As a result, the photocatalytic properties were enhanced after Ba doping and the Ba-doped Bi2WO6 with RBa = 0.15 showed the highest photocatalytic activities of 96.3% RhB was decomposed in 50 min. Close investigation revealed that the proper Ba doped into Bi2WO6 could not only increases its BET surface area, decrease its crystalline size, but also act as electron traps and facilitate the separation of photogenerated electron–hole pairs. The mechanism of enhanced photocatalytic activities of Ba-doped Bi2WO6 were further investigated.

In this study, C3N4/Zn1−xCdxS (0 ≤ x ≤ 1) heterostructures with adjustment of the band gap were successfully prepared by calcination and a hydrothermal synthesis method. The photocatalytic properties of C3N4/Zn1−xCdxS composite photocatalysts were evaluated by the photocatalytic degradation of RhB under visible light irradiation. The results showed that the combination of the two semiconductor photocatalysts (C3N4 and Zn1−xCdxS) greatly enhanced the photocatalytic degradation efficiency of RhB compared to the pure C3N4 and Zn1−xCdxS under visible light irradiation. Among them, the 0.1C3N4/Zn0.8Cd0.2S composite photocatalyst exhibited the highest photocatalytic activities with the degradation efficiency of RhB arriving to 97.9% within 90 min. The remarkable photocatalytic activity of the 0.1C3N4/Zn0.8Cd0.2S composite photocatalyst was mainly attributed to the appropriate band structure and the effective separation of photogenerated electron–hole pairs. Additionally, a possible basic mechanism of the composite semiconductor photocatalytic process was also discussed. Moreover, it was also investigated that O2˙− and h+ were the main reactive oxidative species in this photocatalytic process of the degradation of RhB on the 0.1C3N4/Zn0.8Cd0.2S heterostructure photocatalyst.

A novel Fe3O4@SiO2@BiOBr photocatalyst was synthesized through a solvothermal method with the addition of core–shell Fe3O4@SiO2 nanoparticles. The results show that the photocatalyst is flower-like microspheres with diameters ranging from 2 μm to 3 μm. The as-prepared photocatalyst shows excellent photocatalytic performance in degradation of rhodamine B (RhB) under visible light irradiation (λ ≥ 420 nm) with superior stability and reusability. The introduction of the silica interlayer can suppress the direct contact of the Fe3O4 core and BiOBr to a great extent, resulting in the increased separation efficiency of the photo-induced electron–hole pairs and then higher photocatalytic performance. Furthermore, it can be completely recovered simply by applying an external magnetic field, indicating highly potential applications in wastewater treatment without secondary pollution.