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It is a practical way to raise the efficiency of photocatalysis by using oxygen vacancy defect modified materials. In this experiment, a Z‐scheme BOA composite photocatalyst with defect structure was prepared by hydrothermal in situ precipitation method. The optimal ratio of 1.5 BOA showed excellent photocatalytic degradation performance for MO, TC and CIP under visible light irradiation, and maintained good structural stability and circulation rate after five cycles. The increased photocatalytic activity of the composite can be explained to the heterojunction interface's synergistic effects and the quicker electron hole transit rate caused by the surface oxygen vacancy defect. XPS and EPR confirmed the existence of anoxic structure in the composite, PL and photocurrent confirmed the high electron hole transfer rate. The active species that contributed to the degradation process were validated by the active species capture experiment and ESR. LC–MS speculated the possible degradation path of CIP. Finally speculated the reaction mechanism of Z‐scheme BOA composite photocatalyst. Using the anoxic structure of BiO2−X to form a Z‐scheme heterostructure with Ag3PO4, the oxygen vacancy as the electron capture center and active site is conducive to improving the photogenerated electron transfer rate, thereby improving the structural stability and photocatalytic performance of the complex. [ABSTRACT FROM AUTHOR]

An excellent ternary Z-scheme photocatalytic heterojunction of g-C3N4 nanosheet/WO3/graphene oxide (CWG) was prepared by in-situ growth of WO3 during thermal exfoliation bulk g-C3N4 to g-C3N4 nanosheet, followed by electrostatic self-assembly of graphene oxide (GO) and g-C3N4 nanosheet in the HNO3 solution. The photocatalytic performance was evaluated by the degradation of rhodamine B (RhB) under visible light irradiation. The CWG heterojunction exhibited outstanding photocatalytic efficiency for RhB degradation, which was about 4.6 and 23 times that of CN and WO3, indicating the introduction of GO and WO3 improved the capability of the photocatalysis due to an efficient charge separation and transfer between g-C3N4 nanosheets and WO3. In addition, the possible for the enhancing photocatalytic mechanism was revealed based on the active species trapping and ESR analysis. [ABSTRACT FROM AUTHOR]

A new type of visible light Z‐scheme Bi2O3‐Ag3PO4 composite photocatalyst was created in this work using a simple in‐situ precipitation process. On this basis, the morphology, optical properties and electrochemical performance of the photocatalyst were studied by N2 adsorption‐desorption analysis and XRD, FT‐IR, XPS, SEM, TEM, UV‐vis DRS, PL, EIS, and other characterization methods. To further explore the photocatalytic performance of the composites, visible light degradation experiments were carried out on the antibiotic TC and the organic dyes MB and MO. The results show that the 0.025BA composite material exhibits higher photocatalytic performance than other comparative samples. In addition, the 0.025BA composite after five cycles of experiments also has a satisfactory photodegradation rate. The active species capture experiment and ESR showed that the active species h+, ⋅O2− are the main factors affecting the photocatalytic degradation, and ⋅OH played a minor role. The intermediates and possible decomposition pathways of TC were illustrated through LC–MS technology. Finally, the possible photocatalytic reaction mechanism was speculated. On the whole, the high photocatalytic activity of the 0.025BA composite is perhaps the result of the formation of its Z‐scheme heterojunction, which enables fast transfer and high separation of photogenerated carriers at the heterojunction interface, and also accelerates the rate of redox reactions on electron‐hole pairs. [ABSTRACT FROM AUTHOR]

A novel binary ZnO/g‐C3N4 nanosheets (ZCN)‐X (X=10, 20 and 30 wt% of ZnO) composites were prepared by a simple hydrothermal method. The properties of the samples were characterized by XRD, FT‐IR, SEM, UV‐vis, PL, XPS and electrochemistry, and the photodegradation effect of the samples on MO were evaluated. The FT‐IR spectra revealing that the conjugated system between g‐C3N4 and ZnO was generated. The UV‐vis diffuse reflectance spectra showed that the introduction of CNNs reduces the band gap of binary composites and broadens the visible light absorption range of the samples. The fluorescence analysis results suggested that the conjugated system between g‐C3N4 and ZnO was generated. The phtotcatalysis results showed that ZCN‐20 has strong photodegradation activity and lower luminescence intensity. After irradiation for 120 min under visible light, it gives a degradation rate of 98.5 % with good stability. The construction of heterojunction between CNNs and ZnO nanoparticles accelerates electron transfer and inhibits the recombination of photogenerated electron hole pairs, and the synergistic effect of CNNs and ZnO greatly enhanced the photocatalytic performance of samples. [ABSTRACT FROM AUTHOR]

In this study, the composite catalysts with the heterojunction between DUPG and BiOBr were used to degrade methyl orange (MO), and a g‐C3N4‐based ternary composite catalyst was developed. In our previous work, we prepared a D‐C3N4/U‐C3N4 isotype heterojunction with ordered mesoporous (DUPG) by co‐mixed calcination and hard template method. On this basis, we prepared DUPG/BiOBr nanoparticle uniformly distributed on DUPG nanosheets by coprecipitation self‐assembly method. The hybrids form a tightly coupled heterojunction that enhances the photoactivity and photostability of the DUPG/BiOBr composites. The results show that this tight coupling is beneficial, which facilitates the charge transfer between DUPG and BiOBr, thus promoting the effective separation of photogenerated electron hole pairs. Under visible light irradiation, the methyl orange conversion of the sample has higher photocatalytic reduction activity than BiOBr and DUPG, and its excellent photocatalytic activity is improved by light‐harvesting ability, increased specific surface area, active species and target pollution. [ABSTRACT FROM AUTHOR]

Bismuth SBA-16 catalyst was synthesized by the hydrothermal method. Four kinds of p-toluenesulfonic acid functionalized imidazole ionic liquids were prepared by a two-step method and their molecular structures were characterized by 1H NMR and MS. The post-synthesis impregnation method was used to functionalize the Bi(10)-SBA-16 silicon mesoporous material with the ionic liquids and the obtained materials were characterized by FT-IR, XRD, BET, XPS, and TG. The results show that the volume and pore size of SBA-16 were changed by loading Bi and ionic liquids, while the three-dimensional cubic pore structure of SBA-16 was not destroyed. The composite catalyst was evaluated in Friedel–Crafts acylation of anisole with acetic anhydride. The effects of reaction temperature and the ratio of anisole and acylating agent on the acylation of anisole were investigated by experimental design. The results showed that 1.2ILc@Bi(10)-SBA-16 was used as the catalyst, the conversion of anisole was 85.41% and the yield of aromatic ketone was 69.19% under the conditions of a reaction temperature of 100 °C, a catalyst dosage of 0.5 g, a time period of 4 h and a molar ratio of 1 : 1.5. After 5 recycling runs, the reduction in the overall ratio of reactant conversion and product yield did not exceed 7.5%, indicating that 1.2ILc@Bi(10)-SBA-16 has good stability and reusability. [ABSTRACT FROM AUTHOR]

The BiOI/Bi2O2CO3 p–n junctions were constructed by anion exchange method with Bi2O2CO3 in situ growth on BiOI. Then, the surfaces of BiOI/Bi2O2CO3 samples were modified by negative charge with (3-aminopropyl) triethoxysilane (APTES) in an ethanol solution. Finally, the ami-BiOI/Bi2O2CO3/graphene (RGO) ternary composites were fabricates by the simple hydrothermal reaction. The obtained photocatalysts were well characterized with the various characterization techniques to study their morphological, physical, optical, and photocurrent properties, and have been evaluated by investigating the degradation of Rhodamine B and tetracycline under visible irradiation. Compared with single BiOI, the BiOI/Bi2O2CO3 photocatalysts displays higher photocatalytic activity, due to the formation of the electric fields between p–n heterojunction to promote the migration of photogenerated carriers. Moreover, the ami-BiOI/Bi2O2CO3/RGO composites with the best photocatalytic activities can be attributed to that the positively charged ami-BiOI/Bi2O2CO3 were coupled with the negatively charged graphite oxide (GO) by electrostatically attraction to form the effectively interfacial contacts, causing the photocatalytic reaction sites increased, the range of light response expanded, the separation of photogenerated charge further improved. This work provides a feasible strategy for the construction of high efficiency semiconductor and RGO nanocomposite photocatalyst. [ABSTRACT FROM AUTHOR]

In order to enhance the photocatalytic performance of carbon nitride, mesoporous graphitic carbon nitride (mpg-C3N4) nanocomposite photocatalyst (mpg-C3N4/SnO2) with high photocatalytic activity was synthesized by in situ growth method in this paper. The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV–Vis diffuse reflectance spectra (DRS). Also, the photocatalytic properties of mpg-C3N4/SnO2 nanocomposite were studied by photocatalytic degradation of Rhodamine B (RhB) solution under visible light irradiation. After 120 min of visible light irradiation, the photocatalytic activity of the synthesized mpg-C3N4/SnO2 nanocomposite increased significantly, the degradation effect of the mpg-C3N4/SnO2 composite sample can reach up to 93%, and higher than that of pure mpg-C3N4 and SnO2. The mesoporous structure of mpg-C3N4/SnO2 nanocomposite could enlarge the contact area with dye and increase light absorption, and the presence of heterojunction on the interface between mpg-C3N4 and SnO2 further enhanced the separation efficiency of photogenerated electron hole pairs, sequentially improves the photocatalytic performance of the mpg-C3N4/SnO2 nanocomposite. [ABSTRACT FROM AUTHOR]

In order to improve the photocatalytic activity of graphitic carbon nitride, we prepared a g-C3N4 isotype heterojunction with ordered mesopores through simple one-step calcination. Ordered mesoporous structures were prepared by directly condensing uniform mixtures of precursors and an SBA-15 sacrificial template. After the removal of SBA-15, the physical and chemical properties of the resulting samples were characterized via XRD, TEM, XPS, FT-IR, UV-vis, PL and N2 physical adsorption studies. Significantly, the samples serve as more efficient photocatalysts for the removal of methyl orange than pure g-C3N4 and a g-C3N4 isotype heterojunction without ordered mesopores. The optimum photocatalytic activity of DUPG2 is almost 3 times higher than bulk g-C3N4. After irradiation for 120 min under visible light, it gives a degradation rate of 82% with good stability. The enhanced photocatalytic activity could be attributed to the fact that the isotype heterojunction and ordered mesopores accelerate the separation of photogenerated electron–hole pairs and enhance the efficiency of visible light utilization. [ABSTRACT FROM AUTHOR]

Ternary heterostructure composites are promising photocatalysts for degrading organic pollutants in water. In this study, a series of mesoporous carbon nitride (mpg‐C3N4) decorated with different amounts of carbon quantum dots (CQDs) and cadmium sulfide quantum dots (CdSQDs) were synthesized with a few simple and feasible steps. Under visible‐light irradiation, the optimal catalyst resulted in a more than 6.16 times faster reaction rate for methyl orange (MO) photodecomposition than pure mpg‐C3N4 and 3.1 times faster than pure cadmium sulfide. The carbon dots and cadmium sulfide quantum dots could be observed on the layers of carbon nitride pore walls through transmission electron microscopy (TEM) and high‐resolution transmission electron microscopy (HRTEM). The physicochemical properties of selected samples were characterized by X‐ray diffraction (XRD), Fourier transform infrared (FT‐IR), X‐ray photoelectron spectroscopy (XPS), Brunauer‐Emmett‐Teller (BET), UV‐vis diffuse reflection spectroscopy (DRS), the photoluminescence (PL) and the photocurrent (PC). Probable mechanism of enhanced visible‐light photocatalytic activity was investigated. The properties of combined ternary composites, such as high specific surface area of mpg‐C3N4, good visible‐light harvest ability of CdSQDs and excellent electron storage capacity of CQDs, cooperatively contributed to the final enhancement. A series of mesoporous carbon nitride decorated with different amounts of carbon quantum dots and cadmium sulfide quantum dots were produced through a few simple and feasible steps. Methyl orange was selected as target degradation to measure photoactivities of catalysts under visible light. The mechanism of photo‐degradation process was investigated based on free radicals and holes trapping experiments, fluorescence spectra analysis and photocurrent measurement. The results provide new thinking of designing photocatalyst with stable structure and improved activity. [ABSTRACT FROM AUTHOR]

Mesoporous silica materials (MCM-41) with different pore sizes were synthesized by using 1,3,5-trimethylbenzene as a micelle expander and used as support material for preparation of containing sulfonic acid ionic liquid catalysts. The -SO3H functionalized Brønsted acid ionic liquids ([Ps-mim]HSO4) were loaded on MCM-41 with different pore sizes by impregnation method and the three composites [1-IL@MCM-41 (2.4, 3.6 and 4.8 nm)] were obtained. Their physicochemical properties were characterized by FT-IR, TG-DSC, N2 adsorption technique, XRD and TEM. Also, the catalytic performances of 1-IL@ MCM-41 (2.4, 3.6 and 4.8 nm) were evaluated by the alkylation of phenol with tert-butyl alcohol. The effects of reaction temperature, pore size of MCM-41and the recyclability of catalysts on the conversion of phenol and selectivity to products were investigated. The 1-IL@MCM-41 (4.8 nm) exhibited the best phenol conversion up to 78.7% at temperature as low as 80 °C among the three composite catalysts, and the recyclability of 1-IL@MCM-41 (3.6 nm) is much better than the catalysts of1-IL@MCM-41 (2.4 nm) and 1-IL@MCM-41 (4.8 nm). [ABSTRACT FROM AUTHOR]

A series of polylactic acid/hydroxyapatite/graphene oxide composite (PLA/HA/GO) were fabricated via solution blending and casting method using N,N-dimethyl-formamide (DMF) and CH2Cl2 as mutual solvents. The physicochemical properties of the resulting composites were characterized by means of FT-IR, SEM, TEM, Raman spectra, XRD and N2-physisorption. Particularly, the thermal stabilities, hydrophobic and mechanical properties of PLA/HA/GO composites were systematically investigated. The influences of GO content on thermal stabilities, hydrophobic and mechanical properties of the composites were also evaluated. The results showed that the addition of GO and HA not only improved the thermal stability of PLA, but also improved the hydrophobic property of PLA-based composites. By compared with the PLA/HA/GO composite, the tensile strength of pristine PLA is slight high. The tensile strength and hardness of PLA/HA/GO composites increased with the increase of GO content. The obtained PLA/HA/GO composite may be a promising material for load-bearing orthopedic implants. [ABSTRACT FROM AUTHOR]

Three different mesoporous molecular sieves, including MCM-41, MCM-48, and SBA-15, were synthesized by hydrothermal process and characterized by XRD, BET and TEM. The chlorine-aluminate acidic ionic liquid of 1-butyl-3-methylimidazolium chloride-aluminum chloride ([Bmim]Cl-AlCl, denoted as Al-ILs) was prepared by two-step method. The immobilized ionic liquid (SBA-15/Al-ILs, MCM-41/Al-ILs, MCM-48/Al-ILs) was prepared through impregnating Al-ILs. The structures of composite catalysts were characterized by XRD, BET, FT-IR, TEM and XPS. The amounts of aluminum present in the resulting composite catalysts were detected by ICP-AES to calculate the amount of AL-ILs impregnated. The ketalization between cyclohexanone and ethanediol was used as the model reaction to test the catalytic activities of the composite catalysts. The effects of molar ratio of the reactants, reaction time, the catalyst dose, as well as the addition of cyclohexane were discussed in detail. Also, catalytic activities of three catalysts with different pore sizes were compared. Under comparable conditions, the SBA-15/Al-ILs composite catalyst exhibited much high catalytic activity and gave a maximum yield that was ca. 85.1%. [ABSTRACT FROM AUTHOR]

Ordered mesoporous carbon (CMK-3) was synthesized using SBA-15 mesoporous molecular sieve as a template and sucrose as carbon source. The materials were characterized by XRD, TEM and N physical adsorption technique. The resulting CMK-3 was used as adsorbent to remove Cd(II) ions from aqueous solution. The effect of pH, contact time and temperature on adsorption process was investigated in batch experiments. The results showed that the removal percentage could reach ca. 90% at the conditions of initial Cd(II) ions concentration of 20 mg/L, dose of 20mg, pH 6.5, contact time of 3h and 293K. Langmuir and Freundlich models were employed to describe the adsorption equilibrium. The kinetics data were described by the pseudo-first-order and pseudo-second-order models, respectively. The adsorption isotherm was well fitted to the Langmuir model, and the adsorption process was well described by the pseudo-second-order kinetic model. [ABSTRACT FROM AUTHOR]

A graphene oxide (GO)/β-FeOOH composite was prepared by the liquid insert method and was characterized by XRD, FT-IR, SEM and TEM. The adsorption capacity of the composite was evaluated by the removal of copper ions (Cu2+) from aqueous solution. The effect of initial pH, contact time and absorbent dose on the removal efficiency of Cu2+ was investigated by batch experiments. Langmuir and Freundlich models were employed to describe the adsorption equilibrium. The adsorption kinetics was investigated by both the pseudo-first-order and pseudo-second-order kinetics models. The results showed that the GO/β-FeOOH composite exhibited excellent adsorption capacity for Cu2+ and under the optimum experimental conditions, the removal rate of Cu2+ can reach ca. 93.8%. The adsorption isotherm was a good fit with the Langmuir model and the adsorption process was described by the pseudo-second-order kinetics model. [ABSTRACT FROM AUTHOR]

The degree of charge-transfer in Ag-4-mercaptopyridine (Mpy) and Ag2S-4-Mpy systems is investigated by use of surface-enhanced Raman spectroscopy (SERS). Ag2S and Ag2Se nanoparticles are prepared on the basis of the former formation of Ag nanoparticles to make the SERS analytical objects comparable. We utilize the intensity of the non-totally symmetric modes (either b1 or b2) as compared with the totally symmetric a1 modes to measure the degree of charge-transfer. We find ~25% of charge-transfer contribution for Ag-4-Mpy, whereas 81 ~ 93% for Ag2S-4-Mpy. It means that the charge-transfer resonance contribution dominates the overall enhancement in SERS of Ag2S-4-Mpy. Energy level diagram is applied to discuss the likely charge-transfer transition between Ag, Ag2S, Ag2Se and 4-Mpy. This article may point out the link among the three main resonance sources and could enable some insights into the electronic pathways available to the metal-molecule and semiconductor-molecule systems. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We propose a general approach for the preparation of graphene-metal sulfide quantum dots (QDs) composites by π-π stacking of pyridine-capped metal sulfide QDs and chemically converted graphene (CCG) in aqueous solution. CCG sheets disperse stably in water without the assistance of dispersing agents, only by electrostatic repulsion. The aromatic structures of pyridine capped on metal sulfide QDs make these QDs dispersible in ethanol or water, and further introduce a π-π stacking interaction between CCG and QDs, and extend the conjugated structure of CCG. The structural details, formation mechanism, and textural properties of the resultant graphene-metal sulfide QDs composites are characterized by X-ray diffraction, UV-vis absorption, electron microscopy, and Raman scattering studies. The CCG-metal sulfide composites disperse stably in aqueous solution, allowing them to be potentially used in biological tissues and easy-to-form filtered films for further research and application. [ABSTRACT FROM AUTHOR]

Gas phase methylation of methyltrichlorosilane with methyl chloride to high-valued dimethyldichlorosilane was carried out by using metallic aluminum as a chlorine acceptor in the co-presence of activated carbon, tin, and zinc. The addition of activated carbon in metallic aluminum significantly enhanced the methylation of methyltrichlorosilane, and dimethyldichlorosilane was dominantly produced. Activated carbon played a catalyst role in the methylation reaction. When active metals, such as tin and zinc, were added in the mixture of aluminum and activated carbon, the active metals and activated carbon synergistically catalyzed the methylation of methyltrichlorosilane with methyl chloride toward the formation of dimethyldichlorosilane. [ABSTRACT FROM AUTHOR]

A new kind of nonmetallic nanosensors based on surface-enhanced Raman spectroscopy (SERS) have been successfully prepared by the assembly of α-FeO nanoparticles (NPs) onto clean quartz surface via the cross-linker of hexamethylene diisocyanate (HDI). The resultant substrates have been characterized by electron micrographs, which show that the α-FeO NPs distribute on the modified surface uniformly with a monolayer or sub-monolayer structure. 4-mercaptopyridine (4-Mpy) and 2-mercaptobenzothiazole (2-MBT) molecules have been used as SERS probes to estimate the detection efficiency of the α-FeO thin films. The SERS experiments show that it is possible to record high quality SERS spectra from probe molecules on the α-FeO thin films at sub-micromolar ( < 10 mol/L) concentration. These results indicate that the highly ordered, uniformly roughed, highly sensitive and low-cost α-FeO thin films are excellent candidates for nonmetallic SERS-active nanosensors. [ABSTRACT FROM AUTHOR]

Uniform sized and integrated hollow silica spheres with porous shells were prepared by using sulfuric and carboxylic acid-functionalized polystyrene latex spheres as templates, sodium silicate as a precursor, and cetyltrimethylammonium bromide as a shell structure-directing agent. When polystyrene-methyl acrylic acid latex spheres were used as the templates, the pores in the shells of the resultant hollow silica spheres were composed of both micropores and mesopores. The pores in the shells of the hollow silica spheres were mainly composed of mesopores when sulfonated polystyrene-methyl acrylic acid latex spheres were used as the templates. The shell thickness and the specific surface area of the hollow silica spheres increased with the increase in the surface acidity of the latex spheres. [ABSTRACT FROM AUTHOR]

Ce-incorporated MCM-41 mesoporous molecular sieves (CeMCM-41) were synthesized by microwave irradiation method from sodium silicate and ammonium cerium (IV) nitrate precursors and using cetyltrimethyl ammonium bromide (CTAB) as template. The resulting samples were characterized by means of XRD, TEM, FT-IR, UV-Vis, XPS and N2 physical adsorption, respectively. The effect of the Si/Ce molar ratio on the textural properties of CeMCM-41 was investigated. The results reveal that the CeMCM-41 was successfully synthesized. The resultant mesoporous materials have specific surface areas in the range of 602–1,216 m2/g and pore sizes in the range of ca. 2.6–2.9 nm. The structural properties are related to the amount of cerium incorporation. The surface area and pore volume of the resulting CeMCM-41 were gradually reduced as the cerium content in the sample increased, and the mesoporous ordering diminished. [ABSTRACT FROM AUTHOR]

A series of Keggin type tungsten-substituted molybdophosphoric acids (H3PMo12− nW nO40·XH2O) were synthesized and characterized by ICP-AES, FT-IR, TG-DSC, and XRD. The tungsten substitution extent significantly affected their catalytic activity in the oxidation of cyclopentene and the selectivity of the resultant products. The tungsten-substituted molybdophosphoric acids with tungsten substitution numbers in a range of 3–6.8 exhibited high catalytic activity in the oxidation of cyclopentene. After reaction for 8 h, the conversion of cyclopentene was up to 97%; the oxidation products mainly consisted of glutaraldehyde, cis-1,2-cyclopentanediol and trans-1,2-cyclopentanediol with the yields of ca. 23%, 27%, and 45%, respectively. [ABSTRACT FROM AUTHOR]

Mesoporous titania was prepared by hydrothermal method and mesoporous titania solid superacid catalyst was prepared by wet impregnation method. The structure and property of the as-prepared catalysts were characterized by means of XRD, FT-IR and N2 physical adsorption. Isoamyl salicylate was synthesized by using concentrated sulfuric acid and solid superacid as catalyst, respectively. The effects of the molar ratio of raw material, the amount of catalyst, reaction time and reaction temperature on the yield of the product were systematically investigated. The results show that mesoporous titania solid superacid is a good catalyst for synthesizing isoamyl salicylate. The optimum conditions of isoamyl salicylate synthesized by using mesoporous titania solid superacid are the following: the molar ratio of salicylic acid to isoamyl alcohol is 1: 4, the quantity of catalyst is 1.6 g, the reaction time is 5 h, the reaction temperature is 130 °C and the yield can reach 94.6%. [ABSTRACT FROM AUTHOR]