Search

Three-dimensional (3D) porous networkstructural BiOI-graphene hydrogel-FTO (BiOI/GH/FTO) electrode with remarkably superior photoelectrocatalytic degradation activity and photoelectrocatalytic mineralization ability was successfully prepared by a two-step electrodeposition method. The BiOI nanosheets were electrodeposited into the architectures of 3D porous graphene hydrogel which was prepared by the electrochemical reduction of GO in aqueous dispersion. The morphology and amount of BiOI can be controlled by the electrochemical deposition. With the deposition time of BiOI for 60 s and the working voltage at 1.0 V, the photoelectrocatalytic activity of the 3D BiOI/GH/FTO achieved to the maximum. The removal rate of phenol can be up to about 83% in 5 h, which was 13.8 times higher than that of BiOI/FTO electrode. The degradation rate and mineralization rate of phenol in the solution absence of Na 2 SO 4 electrolyte were 76.8% and 56.8%, respectively, which were 13.2 times and 33.4 times as high as that of the BiOI/FTO. The enhanced photoelectrocatalytic degradation activity of 3D BiOI/GH/FTO is due to the 3D porous architecture and a larger surface area of graphene hydrogel which is favorable for reactant diffusion, and the superior electrical conductivity which promotes the charges to transfer excited by BiOI. The BiOI/GH/FTO electrode has the excellent stability. The degradation rates of phenol nearly unchanged after 4 cyclic degradations in static system and a long-term degradation for 72 h in dynamical system. Trapping experiment shows that the hole might be the main active species in photoelectrocatalytic degradation. This research provides new insights in the development of a new photoelectrocatalytic material for the removal of organic compound. [ABSTRACT FROM AUTHOR]

• ZnAl-LDH with rich OVs (E-CZA-LDH) was prepared by Co doping and alkali etching. • The unique OVs structures can organically couple the photocatalytic reaction and PMS oxidation. • E-CZA-LDH exhibits the synergistic effect of photocatalysis and PMS activation for CIP degradation. • Both radical and non-radical processes are jointly involved in CIP degradation. In this paper, ZnAl-LDH with rich oxygen vacancies (E-CZA-LDH) was prepared by two steps of Co doping and alkali etching. Both methods are conducive to the formation of oxygen vacancies (OVs) to form the unique defect structure (Co-OVs or Co-OVs-V Zn) with high electron delocalization in E-CZA-LDH. The OVs structures can organically couple the photocatalytic reaction and peroxymonosulfate (PMS) oxidation due to its efficient electron capture performance and high PMS adsorption capacity. As a result, E-CZA-LDH exhibits highly efficient degradation activity for ciprofloxacin (CIP) under the synergism of photocatalysis and PMS oxidation, which is 4.98 and 2.81 times higher than that in the photocatalytic and PMS systems, respectively. The oxidation process is the combined action of radical and non-radical species, the active species like SO 4 ·-, O 2 ·-, ·OH, h+, and 1O 2 are jointly involved in CIP degradation. Liquid chromatography-mass spectrometry (LC-MS) gives the primary oxidation intermediates of CIP degradation, and toxicity assessment shows that the oxidation process decreases the environmental risks of CIP. The E-CZA-LDH demonstrates outstanding stability and reusability, making it suitable for practical application. This study might provide an excellent reference for designing and constructing low-cost and high-efficiency catalysts for pollutant degradation in the actual environment. [ABSTRACT FROM AUTHOR]

[Display omitted] Designing a semiconductor-based heterostructure photocatalyst is very important way to enhance the hydrogen production activity. Here, a novel 2D/2D CoAl-LDHs/ZnIn 2 S 4 S-scheme heterostructure with an ultrathin structure was synthesized by electrostatic attraction between CoAl-LDHs and ZnIn 2 S 4 nanosheets. The presence of oxygen vacancies in the monolayer CoAl-LDHs nanosheet promotes the formation of Co-S X bonds, which serve as charge transfer channels at the interface of the CoAl-LDHs/ZnIn 2 S 4 heterostructure. The ultrathin CoAl-LDHs/ZnIn 2 S 4 exhibits broadened light absorption in the near-infrared range due to the occurrence of Co-S X chemical bonds. The CoAl-LDHs/ZnIn 2 S 4 with a mass ratio of 1:2 demonstrated the highest photocatalytic hydrogen evolution activity (1563.64 μmol g−1 h−1) under the simulated sunlight, which is 4.6 and 9.7 times than that of the ZnIn 2 S 4 and CoAl-LDHs/ZnIn 2 S 4 (bulk), respectively. The enhanced photocatalytic activity of ultrathin 2D/2D CoAl-LDHs/ZnIn 2 S 4 should attributed to the shorter carriers path that benefit from the ultrathin structure and the quicker photogenerated charge transfer and the S-scheme migration pathway accelerated by the charge channel of Co-S X bonds. These new ideas should be inspiring for the design and construction of heterostructures for higher photocatalytic hydrogen evolution activity. [ABSTRACT FROM AUTHOR]

A 3-dimensional (3D) ZnIn 2 S 4 /TiO 2 Z-scheme system has been designed and constructed for photocatalytic reduction of CO 2 into renewable hydrocarbon fuels without the use of a solid-state electron mediator. The unique 3D morphology, achieved by assembling 2D ZnIn 2 S 4 nanosheets onto 1D TiO 2 nanobelts, not only provides large surface area but also improves the separation and transfer efficiency of photogenerated electrons and holes. The 3D ZnIn 2 S 4 /TiO 2 Z-scheme photocatalysts show excellent light-harvesting properties demonstrated in photocatalytic reduction of CO 2 , resulting in generation of desired hydrocarbons. The CH 4 production rate of the 3D ZnIn 2 S 4 /TiO 2 can reach up to 1.135 μmol g −1 h −1 , which is about 39-times higher than that of bare ZnIn 2 S 4 (0.029 μmol g −1 h −1 ). The enhanced photocatalytic activity is attributed to effective separation of the charge carriers between ZnIn 2 S 4 and TiO 2 through the direct Z-scheme instead of a type-II heterojunction. The photogenerated electrons in TiO 2 nanobelts recombine with the holes in ZnIn 2 S 4 nanosheets, and the unrecombined electrons/holes on different active sites have stronger reduction/oxidation abilities, leading to higher photocatalytic activity for CO 2 reduction. [ABSTRACT FROM AUTHOR]

A novel visible-light 3D-3D Bi 2 WO 6 /graphene hydrogel (BWO/GH) photocatalyst with the synergistic effect of adsorption and photocatalysis has been successfully synthesized by a facile one-step hydrothermal method and is applied in environment remediation. 3D porous graphene hydrogel, in which 3D-structured flower-like BWO as an efficient photocatalyst is homogenously distributed, not only exhibits the great absorption toward the organic pollution, but also provides multidimensional quality and electron transfer channels. The 3D-3D structure of BWO/GH composite is beneficial to light refraction and reflection, which highly improves the utilization rate of light. The synergistic effect of the 3D-3D BWO/GH composite greatly enhanced the removal rates of organic pollutants and it is ease of separation and recycling in water purification. The removal rate of methylene blue (MB) by BWO/GH composite is about 2.3 times as that of the pure BWO in static systems, and the removal rates of MB and 2, 4-dichlorophenol (2, 4-CDP) are about 1.3 and 3 times as these of the pure BWO in dynamic system. When the irradiation time lasted for 74 h, the removal rate of MB is nearly unchanged and still kept at 36.1%, indicating that the 3D BWO/GH composite has a high stability. The construction of BWO/GH composite resolved the adsorption saturation problem of GH and improved the photocatalytic activity of BWO, thus greatly improved the removal rate of water pollutants. [ABSTRACT FROM AUTHOR]

A commercial calcium carbonate particle as hard template is employed to synthesize mesoporous carbon nitride (mpg-C 3 N 4 ) by a thermal polycondensation process using dicyandiamide as a precursor, then it can be easily removed using diluted hydrochloric acid. Compare with the other hard templates, such as SiO 2 and porous anodic aluminium oxides (Al 2 O 3 ), the industrially available calcium carbonate particles are not only low-cost, but also environment friendly. A certain amount of carbon dopants were generated in the resulting mpg-C 3 N 4 matrix, and the concentration of carbon dopants can be controlled by the amount of calcium carbonate particle. The synthesized mpg-C 3 N 4 not only possesses high specific surface area, but also has the enhanced visible light absorption range from 460 nm to 800 nm. The photocatalytic activity increases as the mass ratio of template to dicyandiamide increases, when the mass ratio is 1.0, the photocatalytic performance is up to the maximum, which is 12.3 times higher than that of bulk g-C 3 N 4 . The enhancement of the photocatalytic performance of mpg-C 3 N 4 is contributed to its improved specific surface areas and the enhancement of the visible light absorptions from 450 nm to 800 nm. [ABSTRACT FROM AUTHOR]

Bismuth molybdate photocatalysts with different phase structures and morphologies were controllably synthesized via a refluxing method by adjusting the pH in the reaction system. Bi2MoO6 nanosheets were easily obtained under acidic conditions, while Bi3.64Mo0.36O6.55 nanoparticles were formed in circumneutral and basic solutions. The mechanism for the formation and phase transition of these two bismuth molybdates is based on tuning the pH value, which can control the growth rate along different crystal axes and the formation of different hydrolysis products that act as the initial seeds of the crystallographic phases. The photocatalytic activity of the Bi2MoO6 nanosheets for MB and MO degradation was higher than that of the Bi3.64Mo0.36O6.55 nanoparticles under visible light irradiation, and the highest photocatalytic activity was observed for the Bi2MoO6 nanosheets prepared at pH 6.0. The high visible-light photocatalytic activity of the Bi2MoO6 nanosheets arises from the easy separation and transfer of photogenerated electron–holes in the nanosheet’s structure as well as the narrow band gap, which leads to an improvement in the visible absorption ability. Electron spin resonance (ESR) and a photogenerated carrier trapping experiment suggested that both Bi2MoO6 and Bi3.64Mo0.36O6.55 had the same photocatalytic mechanism and the main oxidative species for these samples was the hydroxyl radical. [ABSTRACT FROM AUTHOR]

A series of visible-light-induced Ag/AgBr/g-C 3 N 4 nanocomposites were fabricated vis a one-pot and simple approach. The ionic liquid 1-octyl-3-methylimidazolium bromide ([Omim]Br) was introduced into the synthesis system, and served not only as the Br source but also as a dispersant. The Ag/AgBr nanoparticles were found to be highly dispersed on the sheets of g-C 3 N 4 . The Ag/AgBr/g-C 3 N 4 nanocomposites showed much higher visible-light-driven photocatalytic activity than individual g-C 3 N 4 and Ag/AgBr for organic compound degradation. The optimal Ag/AgBr content with the highest photocatalytic activity is determined to be 40%, which is almost 2.4 and 1.9 times higher than that those of individual g-C 3 N 4 and Ag/AgBr for the degradation of methylene blue (MB), and 18.8 and 1.6 folds for the degradation of phenol. The enhancement in photocatalytic activity should be assigned to the extended light-absorption range and efficient charge separation as a result of the surface plasmon resonance effect of Ag 0 and the well-matched overlapping band-structure between Ag/AgBr and g-C 3 N 4 . Finally, the possible mechanism for the charge separation and transformation among Ag, AgBr and g-C 3 N 4 ternary system under the visible light is proposed. [ABSTRACT FROM AUTHOR]

Photocatalytic degradation is an environmentally friendly way to eliminate environmental pollution. Exploring a photocatalyst with high efficiency is essential. In the present study, we fabricated a Bi2MoO6/Bi2SiO5 heterojunction (BMOS) with intimate interfaces via a facile in situ synthesis method. The BMOS had much better photocatalytic performance than pure Bi2MoO6 and Bi2SiO5. The sample of BMOS-3 (3:1 molar ratio of Mo:Si) had the highest removal efficiency by the degradation of Rhodamine B (RhB) up to 75% and tetracycline (TC) up to 62% within 180 min. The increase in photocatalytic activity can be attributed to constructing high-energy electron orbitals in Bi2MoO6 to form a type II heterojunction, which increases the separation efficiencies of photogenerated carriers and transfer between the interface of Bi2MoO6 and Bi2SiO5. Moreover, electron spin resonance analysis and trapping experiments showed that the main active species were h+ and •O2− during photodegradation. BMOS-3 maintained a stable degradation capacity of 65% (RhB) and 49% (TC) after three stability experiments. This work offers a rational strategy to build Bi-based type II heterojunctions for the efficient photodegradation of persistent pollutants. [ABSTRACT FROM AUTHOR]

A series of CdS/BiPO 4 heterojunction photocatalysts with the visible-light response were synthesized by the solvothermal method. The resulting products were characterized by X-ray diffraction, Transmission electron microscopy, X-ray photoelectron spectroscopy, and UV–vis diffuse reflection spectroscopy. CdS nanoparticles with the size at range of 5–7 nm were immobilized on the surface of BiPO 4 nanorods. The CdS/BiPO 4 composite exhibited much higher photodegradation rate of methylene blue under visible light irradation compared to the pure CdS and BiPO 4 . The optimal mass ratio of CdS to BiPO 4 was 0.5, the photodegradation rate of which is 2.1 times higher than that of CdS. The enhancement of photocatalytic activity is attributed to the heterojunction structure of CdS/BiPO 4 composite which induced the effective electron–hole separation between CdS and BiPO 4 . [ABSTRACT FROM AUTHOR]

Cu (II) meso-Tetra (4-carboxyphenyl) porphyrin (CuTCPP) hybridized g-C 3 N 4 (CuTCPP/g-C 3 N 4 ) composites have been facilely synthesized through the ethanol dispersion method. CuTCPP molecules as a sensitizer could easily assemble on the surface of g-C 3 N 4 nanosheets mainly through π–π stacking interaction. The CuTCPP/g-C 3 N 4 composites show much higher photocatalytic activity for phenol degradation than pure g-C 3 N 4 under visible light irradiation. The optimum photocatatlytic activity of the CuTCPP/g-C 3 N 4 composites with weight ratio of CuTCPP at 0.75% is almost 2.2 times as high as that of pure g-C 3 N 4 under the visible light. The enhancement of the visible light photocatalytic activity comes from the efficient electrons transfer from photoexcited CuTCPP molecules to g-C 3 N 4 sheets and more efficiently visible-light harvesting due to the CuTCPP sensitization. Both the holes and ·O 2− are main oxidative species of CuTCPP/g-C 3 N 4 for phenol degradation under visible light irradiation. Finally, the possible charge transfer mechanism of enhanced visible light photocatalytic activity was proposed. [ABSTRACT FROM AUTHOR]

A new method for immobilizing nano-scaled TiO 2 on the surface of montmorillonite (Mt) clay has been developed. First, cationic surfactants were introduced into the Mt galleries through ion exchange and physical adsorption processes. Next a titanium precursor with negative charges was allowed to hydrolyze and condense around the nature clay to form meso-phase assemblies on the external and internal surface of the Mt. After the removal of the surfactant, a highly porous TiO 2 pillared clay with mesopores was formed. The cationic surfactant has a templating role, which not only tailored the formation of TiO 2 but also controlled the TiO 2 content in the composite. The photocatalytic performances of these new porous materials were evaluated by using methylene blue degradation. The photocatalytic activity of these TiO 2 composite is higher than that of P25 although TiO 2 only accounts for about one-third of the sample's mass in the composite samples. [ABSTRACT FROM AUTHOR]

Highlights: [•] ZnO@mpg-C3N4 core–shell photocatalysts were prepared via ultrasonic dispersion method. [•] The ZnO@mpg-C3N4 showed remarkably UV and visible light photocatalytic activity. [•] The core–shell structure favors the transport of both electrons and holes. [•] The enhanced UV activity can be attributed to the hybridization of ZnO and mpg-C3N4. [•] The enhanced visible light activity is due to core–shell structure induced by the match of lattice and energy level. [Copyright &y& Elsevier]

Abstract: A microfibrous TiO2–CdS/palygorskite (TiO2–CdS/Pal) nanostructured material was prepared following a colloidal route based on the controlled hydrolysis of alkoxides in the presence of cetyltrimethylammonium-palygorskite gel. The cationic surfactant coating on the surface of Pal as a template assured organophilic environment for the formation of TiO2 nanoparticles. The presence of CdS on the surface of TiO2/Pal not only extended its photoresponse to the visible-light region, but also accelerated the photogenerated electron transfer from the inorganic sensitizer (CdS) to TiO2. The new photocatalysts were characterized by XRD, N2 adsorption–desorption, SEM, TEM, XPS, FTIR and UV–vis spectroscopy and their photocatalytic activities were evaluated by the degradation of methylene blue (MB) under visible light irradiation. This TiO2–CdS/Pal nanocomposite exhibited much higher visible light photocatalytic activity than TiO2/Pal and CdS/Pal. The apparent rate constant (kapp) for TiO2–CdS/Pal nanocomposites, TiO2/Pal and CdS/Pal were calculated and TiO2–CdS/Pal-0.4 showed the highest rate constant (3.00×10−3 min−1) among all the prepared samples. [Copyright &y& Elsevier]

Highlights: [•] TiO2 pillared Mt was prepared with the small surfactant CTAB as an expand agent. [•] The structure of this composite was the delaminated TiO2 pillared clay. [•] Introducing CTAB significantly increases the porosity and surface area of the composite. [•] The composite exhibited superior photocatalytic property. [ABSTRACT FROM AUTHOR]

Abstract: A magnetically separable adsorbent, named chitosan/montmorillonite–Fe3O4 (CTS/MMT–Fe3O4) microsphere is prepared by microemulsion process and characterized by infrared spectroscopic analysis (IR), X-ray Powder Diffraction (XRD) and scanning electron microscope (SEM). The microspheres are applied as adsorbents for the removal of Cr (VI) from aqueous solution. The effects of MMT content (wt%), the initial concentration of Cr (VI) solution (C 0), initial pH value (pH0) of Cr (VI) solution and the adsorption dose on the adsorption capacity of the microspheres are investigated. The adsorption experiments show that the adsorption capacity of CTS/xMMT–Fe3O4 microspheres for Cr (VI) is higher than the mean value of those of CTS and MMT. The optimum pH value for Cr (VI) adsorption is found at pH=2, and the adsorption capacity increased with the increase in adsorption temperature. The adsorption kinetics is better described by the pseudo-second order equation, and their adsorption isotherms are better fitted to the Langmuir equation. Thermodynamic parameters such as ΔH ∘, ΔS ∘ and ΔG ∘ were calculated to understand the adsorption mechanism for Cr (VI). The adsorption–desorption experiments implied that CTS/MMT–Fe3O4 can be used as promising adsorbents for the removal of Cr (VI) from wastewater. [Copyright &y& Elsevier]

Abstract: The europium-doped mesoporous titanium dioxide nanoparticles (Eu-doped TiO2) with the different Eu/Ti rations were prepared using sol–gel method in the presence of tir-block copolymer pluronic P123. The as-prepared catalysts were characterized by low-angle and wide-angle X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), N2 absorption–desorption, ultraviolet visible light spectroscopy (UV–vis) and X-ray photoelectron spectroscopy (XPS), respectively. The XRD analysis indicated that all as-prepared TiO2 samples were mainly anatase phase and mesoporous. The crystallite sizes were in the range 6–11nm, in consistent with the results obtained form TEM images. HRTEM and XPS showed that the europium atoms were doped into the lattice of anatase TiO2. Eu doping can not only increase the stability of mesoporous TiO2, but also make the absorption edge position move toward shorter wavelength. The photodecomposition experiments showed that the photodegradation activity of Eu-doped TiO2 was higher than that of undoped TiO2. [Copyright &y& Elsevier]

Abstract: TiO2 pillared clay materials were prepared by montmorillonite (Mt) and acidic solutions of hydrolyzed Ti alkoxides in the presence of high-molecular-weight polyoxypropylene (POP)-backboned di-quaternary salts (POP). The as-prepared materials were characterized by means of XRD, FTIR, TG–DTA, XRF, specific surface area and porosity determinations, TEM and SEM, respectively. The experiments showed that the resulting material was a porous delaminated structure containing pillared fragments and nano-scaled TiO2 particles well dispersed among each other. Introducing polymer surfactant POP as an expanding agent of Mt cannot only promote the formation of the delaminated structure, but significantly improve the porosity and surface area of the composites. The resulting TiO2 pillared Mt exhibited a good thermal stability as indicated by its surface area after calcination at 800°C. No phase transformation from anatase to rutile was observed even under calcination at 900°C. The grain size of anatase in as-prepared sample decreased with the increase of the POP concentration, but increased with the increment of calcination temperature. The photocatalytic performances of these new porous materials were evaluated by using methylene blue degradation. The composite solid exhibited superior photocatalyic property and the maximum removal efficiency was up to 98% within 90min. [Copyright &y& Elsevier]

Abstract: Anion–cationic, anionic and cationic surfactants modified montmorillonite (MMT) are prepared by incorporating cationic surfactants cetyl trimethyl ammonium bromide (CTMAB), anionic surfactants sodium stearate (SSTA) and their mixture to montmorillonite. The modified samples are characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and Thermogravimetry–differential thermal analysis (TG–DTA). XRD result shows that both the anionic and cationic surfactants can be intercalated into the MMT, making the interlayer spaces of MMT expand. TG–DTA studies indicate the organic carbon contents of anion–cationic surfactants modified MMT are higher than the montmorillonite modified by anionic or cationic surfactants solely. The adsorption experiments indicate that CTMAB/10SSTA–MMT had the largest adsorption capacity compared with CTMAB–MMT and 10SSTA–MMT due to the formation of a highly effective partition medium by anion–cationic surfactant micelle. The adsorption kinetic of methyl orange onto the modified MMT samples can be best described by the pseudo-second-order model, and the adsorption isotherm is in good agreement with the Langmuir equation. The activation energy, change of free energy, enthalpy and entropy of anion–cationic modified MMT are also evaluated for the adsorption of methyl orange. Thermodynamic results indicate that the adsorption is a spontaneous and exothermic process. [Copyright &y& Elsevier]

Abstract: YVO4:Eu3+,Bi3+ phosphors have been prepared by the high-temperature solid-state (HT) method and the Pechini-type sol–gel (SG) method. Spherical SiO2 particles have been further coated with YVO4:Eu3+,Bi3+ phosphor layers by the Pechini-type SG process, and it leads to the formation of core–shell structured SiO2/YVO4:Eu3+,Bi3+ phosphors. Therefore, the phase formations, structures, morphologies, and photoluminescence properties of the three types of as-prepared YVO4:Eu3+,Bi3+ phosphors were studied in detail. The average diameters for the phosphor particles are 2–4μm for HT method, 0.1–0.4μm for SG method, and 0.5μm for core–shell structured SiO2/YVO4:Eu3+,Bi3+ particles, respectively. Photoluminescence spectra show that effective energy transfer takes place between Bi3+ and Eu3+ ions in each type of as-prepared YVO4:Eu3+,Bi3+ phosphors. Introduction of Bi3+ into YVO4:Eu3+ leads to the shift of excitation band to the long-wavelength region, thus the emission intensities of 5D0–7F2 electric dipole transition of Eu3+ at 615nm upon 365nm excitation increases sharply, which makes this phosphor a suitable red-emitting materials that can be pumped with near-UV light emitting diodes (LEDs). [Copyright &y& Elsevier]

Abstract: In order to utilize visible light more efficiently in the photocatalytic reaction, N-doped TiO2 (N-TiO2) nanoparticles sensitized by Zn porphyrin including [tetrakis(4-carboxyphenyl)porphyrinato]zinc(II) (ZnTCPP) and [tetraphenyl-porphyrinato]zinc(II) (ZnTPP) were prepared, and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic absorption spectrometry (AAS), Fourier transform infrared spectroscopy (FT-IR) and UV–vis spectroscopy, etc. The characterization results show that the ZnTCPP is chemisorbed on the surface of TiO2 through an Oh name="sbnd" />Owhile the ZnTPP is physically adsorbed. N-TiO2 sensitized by Zn porphyrin exhibits higher absorption in the visible-light region and photocatalytic degradation efficiency of methylene blue under visible-light irradiation than N-TiO2 and TiO2 sensitized by ZnTCPP. Moreover, their visible-light photocatalytic mechanism was discussed. [Copyright &y& Elsevier]

In this paper, we study the two weight commutators theorem of Riesz potential on an arbitrary homogeneous group H of dimension N. Moreover, in accordance with the results in the Euclidean space, we acquire the quantitative weighted bound on homogeneous group. [ABSTRACT FROM AUTHOR]

• 2D/2D ultrathin S-scheme BiOCl-OV/CoAl-LDH heterojunction were constructed. • OV reduced electron occupation of the Co 3d-orbital. • S-scheme heterojunction accelerates the photogenerated electrons transfer. • The designed system shows high removal capability for the actual wastewater. Sustainable and rapid production of high-valent cobalt-oxo (Co(IV)=O) species for efficiently removing organic pollutants is challenging in permoxymonosulfate (PMS) based advanced-oxidation-processes (AOPs) due to the limitation of the high 3d-orbital electronic occupancy of Co and slow conversion from Co(III) to Co(II). Herein, S-scheme BiOCl-OV/CoAl-LDH heterojunction were constructed by ultrathin BiOCl with the oxygen-vacancy (OV) self-assembled with ultrathin CoAl-LDH. OV promoted the formation of charge transfer channel (Bi-O-Co bonds) at the interface of the heterojunction and reduced electron occupation of the Co 3d-orbital to facilitate the generation of Co(IV)=O in the BiOCl-OV/CoAl-LDH/PMS/Visible-light system. S-scheme heterojunction accelerated the photogenerated electrons to allow rapid conversion of Co(III) to Co(II), promoting the fast two-electron transfer from Co(II) to Co(IV)=O. Consequently, the developed BiOCl-OV/CoAl-LDH/PMS/Visible-light system showed excellent degradation efficiency for most of organic pollutions, and exhibited very high removal capability for the actual industrial wastewater. This study provides a new insight into the evolution of Co(IV)=O and the coordinative mechanism for photocatalysis and PMS activation. This study finding that the introduction of oxygen-vacancy (OV) significantly promotes the formation of chemical bonds (Bi-O-Co) at the heterointerface of 2D/2D ultrathin S-scheme BiOCl-OV/CoAl-LDH heterojunctions, leading to the electronic delocalization around Co sites and reducing the occupancy of the Co 3d-orbital. Additionally, the ultrathin S-scheme heterojunction facilitates the migration of photogenerated electrons from BiOCl-OV to Co sites in the CoAl-LDH, accelerating conversion of Co(III) to Co(II) and realizing a smooth cycle of Co(II)-Co(IV)-Co(II). [Display omitted] [ABSTRACT FROM AUTHOR]

Ni3Si2O5(OH)4 rods (NS) were synthesized via a hydrothermal method, employing natural wollastonite as a template. The hierarchical Ni3Si2O5(OH)4 rods exhibited vertically oriented nanosheets, resulting in a substantial increase in the specific surface area (from 2.24 m2/g to 178.4 m2/g). Subsequently, a CdS/Ni3Si2O5(OH)4 composite photocatalyst (CdS/NS) was prepared using a chemical deposition method. CdS was uniformly loaded onto the surface of the Ni3Si2O5(OH)4 nanosheets, successfully forming a heterojunction with Ni3Si2O5(OH)4. The CdS/NS photocatalyst in the presence of lactic acid as a sacrificial agent demonstrated an impressive H2 production rate of 4.05 mmol h−1 g−1, around 40 times higher than pure CdS. The photocorrosion of CdS was effectively solved after loading. After four cycles, the performance of CdS/NS remained stable, showing the potential for sustainable applications. After photoexcitation, electrons moved from Ni3Si2O5(OH)4 to the valence band of CdS, where they interacted with the holes via an enhanced interface contact. Simultaneously, electrons in CdS transitioned to its conduction band, facilitating hydrogenation. The enhanced performance was attributed to the improved CdS dispersion by Ni3Si2O5(OH)4 loading and efficient photogenerated carrier separation through the heterojunction formation. This work provides new perspectives for broadening the applications of mineral materials and developing heterojunction photocatalysts with good dispersibility and recyclability. [ABSTRACT FROM AUTHOR]

Combining plasmonic noble metals with semiconductor materials has been considered to be an effective way to improve catalyst performance. In the present paper, Au nanoparticles (NPs) were decorated onto CVD-grown β-Ga2O3 nanowires (NWs) through a chemical reduction method. Different quantity of HAuCl4 solution was used to control the size and density of Au NPs. The photocatalytic activity of the Au-Ga2O3 NWs is evaluated by degrading rhodamine B (Rh B) under UV and visible light irradiation. It is found that the size and density of the Au NPs had a great influence on the photocatalytic efficiency of β-Ga2O3 NWs. And Ga2O3 NWs with Au NPs of ~ 5.7 nm size and ~ 420/μm2 density shows the best catalytic efficiency. Moreover, Au NPs attachment on the Ga2O3 could extend its photocatalytic activity towards the visible light irradiation, which is significant to efficient utilization more solar light. A jointly effect of both the interfacial Schottky potential field between Au NPs and β-Ga2O3 NWs and local surface plasma resonance excitation is proposed to contribute the enhancement effects. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The F- Bi 2 MoO 6 can be easily synthetized by a hydrothermal method. • F- Bi 2 MoO 6 show much higher photocatalytic activity than pure Bi 2 MoO 6. • F doing can increase the band gap of Bi 2 MoO 6 and concentration of OH radicals. • The enhanced photocatalytic activity is due to higher charge separation efficiency. Abstract The fluorine substitution on Bi 2 MoO 6 (F-Bi 2 MoO 6) can be easily synthesized by a hydrothermal method. Based on the XRD result, it could be speculated that fluorine ion can substitute oxygen ion in the crystal lattice of Bi 2 MoO 6. The photodegradation activity of F-Bi 2 MoO 6 almost is 1.9 times as high as the single Bi 2 MoO 6 for degradation of RhB and 1.7 times for decomposition of 2, 4-CDP under the visible light. The enhanced catalytic activity of F-Bi 2 MoO 6 should be attributed to the wider band gap, the more positive VB potential and the higher concentration of OH radicals due to the F doping. Additionally, F doping formed the donor state below the Fermi energy, which can trap the electrons and increase the efficiency of charge separation remarkably. [ABSTRACT FROM AUTHOR]

The ternary ZnIn 2 S 4 -Au-TiO 2 Z-scheme heterostructure photocatalysts has been fabricated by selecting effectiveness Au NPs as a solid electron mediator, via a chemical-deposition process for water splitting under simulated solar light irradiation. The designed photocatalysts exhibit high surface area and wide light absorption range, which significantly enhance photocatalytic efficiency. At an optimal ratio of 24 wt% Au NPs and 60 wt% ZnIn 2 S 4 , the obtained ZnIn 2 S 4 -Au-TiO 2 photocatalysts achieve the highest H 2 production with the rate of 186.3 μmol g −1  h −1 , and the O 2 production rate is reached to 66.3 μmol g −1  h −1 . It showed that the ZnIn 2 S 4 -Au-TiO 2 composite structures exhibit significantly better photocatalytic activity than ZnIn 2 S 4 -TiO 2 and Au-ZnIn 2 S 4 -TiO 2 structure. Such an excellent performance should be attributed to the Au NPs in the Z-scheme system structure which favor to enhance the transfer rate of the photogenerated electrons and holes and remain strong redox ability of the photocatalysts. It is worth pointing out that the unique Z-scheme ZnIn 2 S 4 -Au-TiO 2 heterostructure shows great solar activity toward water splitting into renewable hydrocarbon fuel. [ABSTRACT FROM AUTHOR]

As 2D heterojunction photocatalysts, lateral heterojunctions (LHs) formed based on chemical bonding generally exhibit much higher photocarrier separation efficiency than vertical heterojunctions (VHs) formed by van der Waals bonds. However, little is known about the different detailed interfacial structures and photocarrier separation mechanisms of the two heterojunctions. Herein, 2D BiOCl and Bi 4 O 5 I 2 were selected as model building blocks to construct BiOCl/Bi 4 O 5 I 2 VHs and LHs. The LHs with direct charge carrier transport channels show stronger interfacial electric field and higher charge transfer efficiency than the VHs. The photogenerated charge carrier migration pathway in the LHs follows a Z-scheme model, while the VHs fits a type II model. As a result, the BiOCl/Bi 4 O 5 I 2 LHs exhibited higher redox performance than the VHs, which is 1.55, 1.56 and 2.1 times better for H 2 production, Cr(VI) photoreduction and phenol photodegradation, respectively. This study demonstrates a new approach to constructing highly efficient facet-dependent 2D heterojunction photocatalysts. [Display omitted] • BiOCl/Bi 4 O 5 I 2 LHs and VHs were successfully fabricated by a two-step hydrothermal method. • LHs with small lattice mismatch (4.8%) shows that perfect lateral epitaxial heterojunction. • Bi 4 O 5 I 2 epitaxially grown on the BiOCl (110) facet to form LHs and grown on the BiOCl (001) facet to form VHs. • The photogenerated charge migration pathway of LHs follows a Z-scheme model, the VHs fits a type II model. [ABSTRACT FROM AUTHOR]

Cr(VI) is a common heavy metal pollutants present in the aquatic environment, which possess toxic and carcinogenic properties. In this study, a solvothermal reaction was used to prepare porphyrin (TCPP)-modified UiO-66-NH2 (UNT). The UNT integrated adsorption and photocatalytics in the application for dealing with Cr(VI). The photocatalytic reduction activities of UNT for Cr(VI) were investigated under visible light illumination. We found that the TCPP doping amount of 15 mg UNT (15-UNT) had a 10 times higher reduction rate of Cr(VI) than pristine UiO-66-NH2. The optimal 15-UNT photocatalyst demonstrated the highest photocatalytic activity, and Cr(VI) was completely removed within 80 min. In addition, the introduction of porphyrin not only enhanced the absorption of light but also enabled the transport of photogenerated electrons from porphyrin to UiO-66-NH2, which promoted the separation of charge carriers. Furthermore, the effects of factors such as porphyrin content, pH and light source on the photocatalytic reduction performances of UNT were also explored. Overall, this work presented a possible relationship between the crystal structures and the performance of UNT. [ABSTRACT FROM AUTHOR]

Heterostructured Bi 2 Ti 2 O 7 /Bi 4 Ti 3 O 12 nanocomposites were successfully synthesized through a facile calcination method. The composition and band gap of the Bi 2 Ti 2 O 7 /Bi 4 Ti 3 O 12 nanocomposites were controlled by tuning the calcination temperature. The morphology of the Bi 2 Ti 2 O 7 /Bi 4 Ti 3 O 12 composite changed from worm-like nanosheets to spherical particles when the calcination temperature increased from 500 to 800 °C. The structural features of the heterojunction were confirmed using characterization techniques such as XRD, SEM, HRTEM, ESR, and SPV. The Bi 2 Ti 2 O 7 /Bi 4 Ti 3 O 12 nanocomposite calcined at 600 °C had the highest visible light photocatalytic activity, which was almost 2.0 times as high as that of the pure Bi 2 Ti 2 O 7 for Rhodamine B (RhB) photodegradation, and 2.5 times the rate of 2,4–dichlorophenol (2,4–DCP) removal under simulated sunlight irradiation. The enhanced photocatalytic activity is due to the heterojunction interfaces induced by the match of lattice and energy levels between Bi 2 Ti 2 O 7 and Bi 4 Ti 3 O 12 , which is helpful for the separation and transfer of electron-hole pairs. The photocatalytic mechanism was elucidated via active species trapping experiments and electron spin resonance. The photogenerated holes played a key role in the degradation reaction via the Bi 2 Ti 2 O 7 /Bi 4 Ti 3 O 12 composites. Finally, a possible charge transfer mechanism for the enhanced photocatalytic activity was proposed. [ABSTRACT FROM AUTHOR]

High photoelectrochemical water oxidation efficiency can be achieved through an efficient photogenerated holes transfer pathway. Constructing a photoanode semiconductor heterojunction with close interface contact is an effective tactic to improve the efficiency of photogenerated carrier separation. Here, we reported a novel photoanode p-n junction of Ti:Fe2O3/Cu2O (n-Ti:Fe2O3 and p-Cu2O), Cu2O being obtained by in situ reduction in CuAl-LDH (layered double hydroxides). The Ti:Fe2O3/Cu2O photoanode exhibits a high photocurrent density reaching 1.35 mA/cm2 at 1.23 V vs. RHE is about 1.67 and 50 times higher than the Ti:Fe2O3 and α-Fe2O3 photoanode, respectively. The enhanced PEC activity for the n-Ti:Fe2O3/p-Cu2O photoelectrode is due to the remarkable surface charge separation efficiency (ηsurface 85%) and bulk charge separation efficiency (ηbulk 72%) formed by the p-n junction and the tight interface contact formed by in situ reduction. Moreover, as a cocatalyst, CuAl-LDH can protect the Ti:Fe2O3/Cu2O photoanode and improve its stability to a certain extent. This study provides insight into the manufacturing potential of in situ reduction layered double hydroxides semiconductor for designing highly active photoanodes in the field of photoelectrochemical water oxidation. [ABSTRACT FROM AUTHOR]

The work obtained mesoporous TiO 2 white pigments using titanyl sulfate as titanium source with a simple, low-temperature method simplifying the synthesis process and reducing the energy consumption. We investigated the effects of the aging temperature and aging time on the structure and pigments properties of the samples. The structure and morphology of mesoporous samples were characterized by X-ray diffraction and transmission electron microscopy. The obtained mesoporous TiO 2 showed excellent pigments properties of whiteness (93.91%), hiding power (12.37 g m −2 ), and lightness value (97.89), respectively. Moreover, such materials showed outstanding photodegradation performance of organic dyes under UV light irradiation. The current research provided an alternative route to prepare mesoporous TiO 2 micspheres white pigments with well photocatalytic performance for indoor purification on industrial scale. It has great significance in titania white pigments field. [ABSTRACT FROM AUTHOR]

A wollastonite-nanoTiO 2 composite (WOT-PC) was prepared by a facile mechanochemistry method, which is expected to improve the photocatalytic performance and its recycling ability. According to the results of photocatalytic degradation, the degradation extent of the 10 ppm (10 mg/L) methyl orange solution was 99% after 20 min UV irradiation, indicating the good photocatalytic performance of WOT-PC. The XPS results suggests that stable Ca– O –Ti and Si– O –Ti bind wollastonite and nanoTiO 2 together chemically. Furthermore, Ca– O –Ti may promote the separation efficiency of photoinduced electrons and holes during irradiation. To study the bending of energy structures of nanoTiO 2 , UPS was used. The results showed a negative shift of the energy structure bands and a positive shift of the Fermi level to TiO 2 , revealing that electrons more easily move to the surface of TiO 2 after wollastonite supports nanoTiO 2. The WOT-PC coating exhibits great self-cleaning ability because of its superhydrophilicity and photocatalytic performance, reflecting the promise of WOT-PC as an outdoor wall coating in practical applications. [ABSTRACT FROM AUTHOR]

A novel 3D porous reduced graphene oxide/montmorillonite composite hydrogel (rGO–MMT) was prepared by solvent method, where the MMT nanosheets were homogenously dispersed in 3D rGO hydrogel. The porous 3D structure and the high dispersion of MMT nanosheets can promote the adsorption capacity. The effects of MMT content (wt%), the initial concentration of Cr(VI) solution (C0), pH value (pH0), the adsorption dose and temperatures on the adsorption capacity of rGO–MMT for Cr(VI) ions have been investigated. The optimum pH value for Cr(VI) adsorption is 2, and the adsorption capacity increases with MMT content and adsorption temperature. The rGO–MMT composite hydrogel displays the excellent adsorption property for both the heavy metal and organic pollutants. The adsorption capacity of rGO–MMT composite hydrogel is obviously higher than those of single rGO hydrogel and MMT due to the synergistic adsorption of rGO hydrogel and MMT. The adsorption of Cr(VI) ions on the rGO–MMT composite hydrogel follows linear pseudo-second-order kinetics, and the Langmuir model describes the adsorption process much better. Thermodynamic parameters indicate that adsorption is spontaneous, favorable and endothermic in nature. [ABSTRACT FROM AUTHOR]

• A simple method to prepare 3D porous rGO-Ag@Ag 3 PO 4 hydrogel photocatalyst. • 3D rGO as a reductant and a supporter can increase the photostability of Ag 3 PO4. • The rGO-Ag@Ag 3 PO 4 hydrogel photocatalyst has the synergistic effect of adsorption photocatalytic degradation. • The rGO-Ag@Ag 3 PO 4 hydrogel photocatalyst has good stability. A novel visible-light driven 3D porous network structure rGO-Ag@Ag 3 PO 4 (RAA) hydrogel composite photocatalyst with a synergistic effect of adsorption enrichment and photocatalysis degradation has been synthesized by a facile method and characterized by XRD, SEM, TEM, EDS, FTIR, DRS, UV–vis, TG, Raman, and XPS. RAA hydrogel photocatalyst with 3D porous network structure is not only favorable to increasing the absorption property for organic pollutants owing to a larger surface area and π-π conjunction property, but also promotes the separation and transformation of electron-hole pairs due to the good conductivity performance. The RAA hydrogel composite photocatalyst has exhibited the excellent removal capacity of organic pollutants which were about 1.94 and 1.10 times higher than those of bare Ag 3 PO 4 for the removal of MB and 2, 4-CDP in the dynamic system, respectively. The enhancement of removal efficiency was due to a synergistic effect of adsorption enrichment and photocatalysis degradation. The removal rate of RAA hydrogel composite photocatalyst has only a little decrease from 76.04% to 68.51% for 60 h of the photoreaction, showing the relatively good stability. The trapping experiment and ESR showed the main active species were holes. [ABSTRACT FROM AUTHOR]

Abstract: Novel Eu2+-doped bromosilicate phosphors, (CaO–CaBr2–SiO2):0.03Eu2+, were prepared by the traditional solid-state method under a different calcination temperature. The as-prepared (CaO–CaBr2–SiO2):0.03Eu2+ phosphors obtained under various reaction temperatures all indicated a broad excitation in the near ultraviolet region (350–450nm). The phosphor system exhibits bluish-green light with a peak wavelength at 498nm when the calcination temperature is below 800°C, while it shows a strong blue emission light with a peak wavelength at 474nm as the calcination temperature is above 800°C, and it also gives an interesting greenish-yellow long-lasting phosphorescence with a peak wavelength at 540nm in the dark. [Copyright &y& Elsevier]

Abstract To improve the solar energy utilization and photodegradation efficiency of ZnO and α-MnO 2 , ZnO/MnO 2 composite materials were prepared by a facile method. The materials are characterized by XRD, Raman spectra, X-ray photoelectron spectroscopy, scanning electronic microscopy, transmission electron microscopy, and UV–vis diffuse reflection spectroscopy. The photocatalytic activity and microwave-assisted photocatalytic activity of the composite are much higher than that of ZnO or α-MnO 2. The main active species in the reaction progress were confirmed by electron paramagnetic resonance spectra and trapping experiments. According to the DFT calculation result and photothermal images, the enhanced catalytic activity is attributed to the photothermal and microwave-assisted effect. The addition of α-MnO 2 improves the absorption of light and microwave by the composite, which can further heat up the catalysts. As a result, the separation of photogenerated charge carriers is accelerated. Finally, a mechanism for the enhanced catalytic performance of the composite materials was proposed. Graphical abstract Image 1 Highlights • ZnO-MnO 2 composites are prepared by a facile method. • The composite showed higher photocatalytic and microwave-assisted photocatalytic activity. • The solar energy utilization is improved and the secondary pollution of microwave oxidation is avoided. • The mechanism of photothermal assisted photocatalysis was proposed. [ABSTRACT FROM AUTHOR]

In this work, we report a bismuth oxide film electrode with oxygen defects and honeycomb multilevel structure prepared by one-step hydrothermal method. The control of raw materials enables to control the thickness and morphology of BiO electrodes. The photoelectrocatalytic of prepared electrodes were tested in various conditions. Under visible light irradiation (λ ≥ 420 nm) and 3 V bias, the sample BiO-2 has the highest photoelectrocatalytic activity, which is 4.95 times higher than the photocatalytic activity and 9.86 times higher than the electrocatalytic activity. The oxygen defects of bismuth oxide were confirmed by EPR and DFT calculation. The morphology and structure of prepared samples were tested by XRD, scanning electronic microscope (SEM), high-resolution transmission electron microscope (HRTEM) and X-ray photoelectron spectroscopy (XPS). The enhanced photoelectrocatalytic activity is attributed to the proper bias voltage, oxygen defects, and honeycomb multilevel structure. The results of tapping experiments showed that the main active species during the photoelectrocatalytic progress is superoxide radical and the mechanism of the photoelectrocatalysis was proposed. [ABSTRACT FROM AUTHOR]

In this work, Bi 2 O 3 /Bi 2 SiO 5 p-n heterojunction photocatalyst was successfully fabricated via a facile one-step synthesis using Bi(NO 3 ) 3 and nano-SiO 2 as precursors. With the increasing amount of SiO 2 , α-Bi 2 O 3 gradually transferred into β-Bi 2 O 3, and Bi 2 O 3 /Bi 2 SiO 5 p-n heterojunction was obtained at the same time. The as-prepared samples were systematically characterized by XRD, scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS). The Bi 2 O 3 /Bi 2 SiO 5 heterojunction photocatalysts exhibited higher photocatalytic activity than α-Bi 2 O 3 on the degradation of organic pollutants under simulated sunlight irradiation. The enhanced photocatalytic activity could be ascribed to the larger specific surface area, the larger contact angle, the formation of β-Bi 2 O 3 and construction of p-n heterojunction. More importantly, the phase transition mechanism of Bi 2 O 3 in Bi 2 O 3 /Bi 2 SiO 5 heterojunction photocatalyst was proposed, which is significant for the theoretical study and application of photocatalytic materials. [ABSTRACT FROM AUTHOR]

In this study, TiO 2 -coated CaCO 3 composite pigments were prepared by coating the modified CaCO 3 particles with modified TiO 2 in aqueous media according to the hydrophobic aggregation method. The experimental results revealed that the organic carbon chains of the modifiers adsorbed on the surfaces of the particles largely determined the formation of composite particles and the maintenance of the coating structure and pigment properties. The TiO 2 -coated CaCO 3 composite pigments could not be obtained until both the CaCO 3 and TiO 2 particles were modified with organic modifiers and exhibited hydrophobicity. The prepared TiO 2 -coated CaCO 3 composite pigments exhibited pigment properties equivalent to those of pure TiO 2 . The hiding power of the composite pigments with the mass ratio of TiO 2 of 60% prepared using sodium stearate and sodium oleate as the modifiers respectively reached 90.18% and 93.50% of that of pure TiO 2 , and the water contact angles of the prepared composite pigments were larger than 100°. Additionally, the binding mechanism analysis indicated that CaCO 3 and TiO 2 particles were combined together by the association among organic carbon chains on their surfaces. The results of ultrasonic experiments and binding force calculation showed that the binding force among particles was much stronger than Van der Waals force. [ABSTRACT FROM AUTHOR]

3D-hydrogels have broad potential for wastewater treatment, for they are separation-free and have excellent adsorption capacity. However, the process of adsorption is only the enrichment of pollutants rather than elimination. Development of 3D-hydrogel/photocatalyst composite materials is a promising strategy for achieving the enrichment and mineralization of organic pollutants. This paper describes a facile and environmentally friendly synthesis of separation-free polyacrylamide/bentonite/graphitic carbon nitride 3D-hydrogel. When the mass of graphitic carbon nitride is 1/10 of acrylamide, the composite hydrogel displays excellent removal of tetracycline in both static and flowing state. The total removal efficiency is higher than that of adsorption or degradation. The enhanced removal of organic pollutants is attributed to the synergistic effect of adsorption and photocatalytic degradation, the enhanced light absorption and the accelerated separation of photogenerated charge carriers. More importantly, it has excellent stability and can be easily separated from water and reused. This 3D-hydrogel/photocatalyst composite materials has broad application potential to the elimination of organic pollutants in water. [ABSTRACT FROM AUTHOR]

• A simple dipping method was employed to modify Mo:BiVO by the CoAl-LDH-u. • The CoAl-LDH-u accelerates hole-transport and promotes surface OER reaction. • The Mo:BVO/CoAl-LDH-u presents 5.8 mA/cm2 photocurrent density at 1.23 vs. RHE. Herein, Mo doping BiVO 4 /ultrathin-CoAl-LDH (Mo:BVO/CoAl-LDH-u) photoanode with self-healing property is firstly designed by using the atomic layer CoAl-LDH as cocatalyst to modify Mo:BVO through a simple dipping coating method. The Mo:BVO/CoAl-LDH-u photoanode presents a nearly 100% surface charge separation efficiency and extremely outstanding photocurrent density of 5.8 mA/cm2 at 1.23 V vs. reversible hydrogen electrode (V RHE) without any scavengers. The CoAl-LDH-u intimately contacted with BiVO 4 photoanode significantly improves the surface charge transfer efficiency by passivating the surface state and rapidly extracting holes from Mo:BiVO 4 , and promotes the oxygen evolution reaction (OER) rate by conversion of Co2+ to Co3+ species. Interestingly, the Mo:BVO/CoAl-LDH-u photoanode has the self-healing peculiarity, due to the easy reparation of oxygen defects in CoAl-LDH-u by the cycle of Co3+/Co2+, and hence the photoelectrochemical (PEC) performance can be restored naturally in the air. This work presents a facile approach to fabricate high-efficiency BiVO 4 photoelectrode for accelerating the PEC water splitting. [ABSTRACT FROM AUTHOR]

In our work, P doped Graphitic nitride (g-C 3 N 4 ) was prepared by the simple copolymerization of melamine and melamine phosphate. The melamine phosphate ester polymer is a complex of an s-triazine and phosphoric acid polymer, thus it will be favourable for P atom to incorporate into the C N network of g-C 3 N 4 . The doped P atoms may produce the delocalized lone electron and form the Lewis acid sites. The obtained P-doped g-C 3 N 4 showed the higher photocatalytic activity in photodegradation of MB and 2,4-Dichlorophenol than g-C 3 N 4 . The optimum photocatatlytic activity of P-C 3 N 4 with the weight ration of melamine phosphate and melamine at 0.06 is 2 times as higher as the pure g-C 3 N 4 in MB photodegradation, and 1.5 times higher in 2,4-Dichlorophenol photodegradation. The enhancement of photodegradation efficiency is due to the delocalization effect of lone electron, promoting the separation of photogenerated charges, and the larger band gap of P doped g-C 3 N 4 . [ABSTRACT FROM AUTHOR]

The black-pearl reduced graphene oxide–sodium alginate (rGO–SA) hydrogel microspheres are prepared by the external emulsification and thermal reduction method, which are characterized by scanning electron microscope (SEM) and X-ray Diffraction (XRD). Sodium alginate (SA) serves as a template to form a 3D porous network structure, which can prevent the agglomeration and restacking of rGO sheets efficiently. The size of hydrogel microsphere can be controlled by adjusting the size of the liquid drop. The effects of rGO content (wt%), contact time, initial concentration of phenol, adsorption temperature and adsorption dose on the adsorption capacity of rGO–SA microspheres are investigated. The kinetics and isotherm data are well described by the pseudo-second-order kinetic model and the Langmuir equation, respectively. Thermodynamic results demonstrate the spontaneous and endothermic nature of adsorption. This rGO–SA microsphere exhibits the favorable adsorption performance for phenol, BPA and tetracycline. The rGO–SA microsphere might be a potential candidate for efficient adsorbents in water treatment. [ABSTRACT FROM AUTHOR]

In this work, a novel C/Bi/Bi 2 O 3 composite photocatalyst was prepared by a facile one-pot method, using EDTA-Bi as a precursor. The C/Bi/Bi 2 O 3 composite photocatalyst exhibited higher photocatalytic activity than Bi 2 O 3 on the degradation of 2,4-dichlorophenol (2,4-DCP) under both simulated sunlight and visible light irradiation. Metallic Bi and the remaining organic carbon cannot only enhance the absorption of lights, but also accelerate the seperation of photogenerated charge carriers. As a result, the photocatalytic activity is enhanced. More importantly, this paper provides a facile method for the preparation of C/Bi/Bi 2 O 3 composite materials, which is suitable for mass production. [ABSTRACT FROM AUTHOR]

The spontaneously polarized electric field and Fe3+/Fe2+ cycle of tourmaline plays an artful synergism on optimizing the photocatalytic-driven persulfate activation system with tourmaline/g-C 3 N 4 composite. [Display omitted] • g-C 3 N 4 was coupled with Fe-containing tourmaline as polarized nanocomposites. • The hybrid demonstrates high photocatalytic activity for PMS activation. • The composite well outperforms individual components in CBZ degradation. • The polarized electric field promoted charge migration and separation in g-C 3 N 4. The peroxymonosulfate/peroxydisulfate (PMS/PDS) activation induced by photocatalytic reduction reaction is an economical and green means for oxidative degradation of organic pollutants in water. However, its efficiency is largely limited by the rapid recombination of photogenerated electron-holes. Herein, we report a graphitic carbon nitride (g-C 3 N 4)-based photocatalytic persulfate activation system fine-tuned by a natural polarized Fe-containing mineral, tourmaline. The tourmaline/g-C 3 N 4 composite photocatalyst was prepared to activate PMS for efficient carbamazepine (CBZ) degradation. In this system, the electrons and holes were produced by tourmaline/g-C 3 N 4 composites under light excitation. Subsequently, PMS was activated by photogenerated electrons from g-C 3 N 4 and Fe2+ on the surface of tourmaline to generate SO 4 •−, where partial SO 4 •− further reacted with H 2 O/OH– to produce •OH. Finally, the CBZ was oxidized by SO 4 •−, •OH and photo-induced holes. Under optimal conditions, with the presence of PMS, the degradation rate of CBZ conducted by tourmaline/g-C 3 N 4 is 6.2 and 7.7 times of pristine g-C 3 N 4 and tourmaline. It is revealed that the polarization electric field of tourmaline not only boosted the separation and migration of electron-hole of g-C 3 N 4 , but also optimized the electronic structure of g-C 3 N 4 for intensified light absorption and improved reduction ability. Moreover, the Fe2+/Fe3+ cycle of tourmaline also facilitated the utilization of photogenerated electrons from g-C 3 N 4 for PMS activation reactions. This study has innovatively constructed a photocatalytic PMS activation system enhanced by introducing natural Fe-containing polarized minerals, providing a new strategy for sustainable and low-cost advanced oxidation processes for water treatment. [ABSTRACT FROM AUTHOR]

A new CaCO3-SiO2 composite with core-shell structure was successfully prepared by mechano-chemistry method (MCM). SEM and FTIR indicated that SiO2 particles were homogeneously immobilized on the surface of CaCO3. The well dispersion of this CaCO3-SiO2 composite into silicone rubber can not only reduce the usage amount of SiO2, but also improve the mechanical properties of silicone rubber. By the calculation, the theoretical numbers of the SiO2 particles is about 10 times as large as that of CaCO3 particles in the CaCO3-SiO2 composite. Mixing CaCO3-SiO2 composite in silicone rubber can enhance the breaking strength of the silicone rubber about 18% as high as that when mixing the pure SiO2. And the elongation at break is about 14% less than that of adding the pure SiO2 sample. [ABSTRACT FROM AUTHOR]

[Display omitted] • A serials of BiOCl crystals with various surface oxygen vacancies (OVs) were prepared by one-step solvothermal method. • The enriched surface OVs can induce efficient charge separation, whole visible-light absorption, and photo-thermal effect. • The bandgap and electronic structure of BiOCl ware adjusted by OVS. • The OVs abundant BiOCl nanosheets show an excellent selective CO production rate of 15.33 μmol·g−1·h−1. A simple and controllable solvothermal method was used to synthesis a series of BiOCl nanosheets with various surface oxygen vacancies (OVs) concentration. The introduction of OVs on surface BiOCl nanosheets broaden the photo-absorption to the visible-light-region, induce a remarkable photothermal effect, and enormously promote efficient charge separation. The OVs abundant BiOCl nanosheets exhibit an outstanding selective CO generation rate of 15.33 μmol·g−1·h−1 under the simulated sunlight irradiation, without any sacrificing regent, which is roughly 20.1 times higher than that of pure BiOCl nanosheets. For the degradation of Rhodamine B and tetracycline hydrochloride under visible light, the activity of OVs enriched BiOCl nanosheets is about 43 and 19.5 times higher than that of pure BiOCl nanosheets. The improved photocatalytic activity is attributed to the strong photothermal effect, the tuned electronic structure and the excellent visible light absorption induced by oxygen vacancies. Furthermore, the possible photocatalytic mechanisms, including the separation and transport of carriers, generation process of reactive species and degradation intermediates of tetracycline hydrochloride, are revealed in-depth. Hence, this work may pave the way to illustrate the function of oxygen vacancies in the semiconductor photocatalysis process. [ABSTRACT FROM AUTHOR]

Abstract: A blue-emitting Ca2B5O9Br:Eu2+ phosphor for white light-emitting diodes was synthesized via a microwave calcination route. The phosphor powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectrophotometer, respectively. The obtained results revealed that the Ca2B5O9Br:Eu2+ phosphor prepared by the microwave calcination route possessed a rod-like morphology with the single phase orthorhombic structure. Based on the photoluminescence analysis, it was found that Ca2B5O9Br:Eu2+ phosphor exhibited a broad excitation band chiefly in the near ultraviolet region (270–420nm) and a blue broad emission band of main peak at 452nm under the strongest excitation of 411nm. Further investigation on concentration-dependent emission spectra indicated that Ca2B5O9Br:0.03Eu2+ phosphor exhibited the strongest luminescent intensity, and the concentration quenching for the two Eu-site emission centers was caused by dipole–dipole interactions. [Copyright &y& Elsevier]

Abstract: Nitrogen-doped TiO2 nanotubes with enhanced photocatalytic activity were synthesized using titanate nanotubes as raw material by a facile wet chemistry method. The resulting nanotubes were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectroscopy, and UV–vis absorption spectroscopy, etc. The photocatalytic activity of nitrogen-doped TiO2 nanotubes was evaluated by the decomposition of methylene blue under artificial solar light. And it was found that nitrogen-doped TiO2 nanotubes exhibited much higher photocatalytic activity than undoped titanate nanotubes. [Copyright &y& Elsevier]