•An ultrafast method was applied to prepare tellurium nanorods on nickel foam.•This Te@Ni materials can be used as cathode without any binders and carbon additives.•Carbon cloth used as interlayer can further improve the battery performance.Recently, tellurium has been regarded as a promising cathode material for rechargeable lithium-ion batteries due to its high theoretical volumetric capacity. However, a plethora of research are focusing on impregnating the tellurium into porous carbon materials by the thermal-diffusion method, which would consume large amounts of energy and take prolonged time. Herein, a carbon and binder-free cathode with 100% Te is fabricated by a facile galvanic replacement method on a nickle foam. Driven by the large electrochemical potential difference between Ni and Te, desirable amounts of Te can be obtained in just 10 min with no need of energy input. Li-Te batteries constructed by the as-obtained cathode show relatively good performance in DMSO solvent. To further elevate the performance of this battery especially at low current density, commercial carbon cloth is added between the separator and Te electrode as an interlayer. The cell with interlayer delivers a gravimetric capacity of 116.2 mAh g−1 after 70 cycles at the current density of 100 mA g−1, which is 2.8 times as high as that of a cell without interlayer (40.4 mAh g−1).

•An efficient synthetic route to 3-halo-3-arylacrylonitriles (including Cl-, Br- and I-) is described.•High regio- and stereoselectivity is achieved, only Z-isomers are observed.•Halogen atoms are sourced from readily available inorganic salts.•First systematic study on the addition of cyanoalkynes with metal halides.An efficient synthesis of 3-halo-3-arylacrylonitrile is described from the direct addition between cyanoalkynes and inorganic alkaline metal halides such as LiCl, LiBr and KI in good to satisfactory yields. No transition metal is needed for the synthesis of iodo- and bromo-products, although Pd catalyst is used to accelerate the chloro-product.Synthetic pathway towards 3-halo-3-arylacrylonitriles with high efficiency, versatility and excellent regio- and stereoselectivity.Download high-res image (76KB)Download full-size image

AbstractSolar-driven activation of molecular oxygen, which harnesses light to produce reactive oxygen species for the removal of pollutants, is the most green and low-cost approach for environmental remediation. The energy coupling between photons, excitons, and oxygen is the crucial step in this reaction and still remains a challenge. In this study, a dual-purpose strategy for enhanced molecular oxygen activation is established by in situ carbon homogeneous doping on ultrathin Bi2MoO6 nanosheets for the first time. The C-doped ultrathin 2D material exhibits an enlarged bandgap straddling the electrochemical potential of O2 /•O2− and H2O /•OH, without any attenuation of light absorption. An internal electric field and shortened carrier-transportation distance are also found in the longitude orientation of the nanosheets ([001] axis), leading to a higher density of effective photogenerated carriers localized on the exposed {001} surface. As applied for the nitric oxide removal, the reactive rate over the ultrathin C-doped Bi2MoO6 nanosheets is 4.3 times higher than that over the bulk counterparts as a result of the increasing reactive oxygen species. This new proof-of-concept strategy not only realizes the band structure engineering and charge transportation regulation but also paves a new way to construct highly efficient photocatalytic materials.

Solar-driven reduction of dinitrogen (N2) to ammonia (NH3) is severely hampered by the kinetically complex and energetically challenging multielectron reaction. Oxygen vacancies (OVs) with abundant localized electrons on the surface of bismuth oxybromide-based semiconductors are demonstrated to have the ability to capture and activate N2, providing an alternative pathway to overcome such limitations. However, bismuth oxybromide materials are susceptible to photocorrosion, and the surface OVs are easily oxidized and therefore lose their activities. For realistic photocatalytic N2 fixation, fabricating and enhancing the stability of sustainable OVs on semiconductors is indispensable. This study shows the first synthesis of self-assembled 5 nm diameter Bi5O7Br nanotubes with strong nanotube structure, suitable absorption edge, and many exposed surface sites, which are favorable for furnishing sufficient visible light-induced OVs to realize excellent and stable photoreduction of atmospheric N2 into NH3 in pure water. The NH3 generation rate is as high as 1.38 mmol h−1 g−1, accompanied by an apparent quantum efficiency over 2.3% at 420 nm. The results presented herein provide new insights into rational design and engineering for the creation of highly active catalysts with light-switchable OVs toward efficient, stable, and sustainable visible light N2 fixation in mild conditions.

•1,4-Diethynylbenzene-based conjugated polymer photocatalysts are synthesized.•Some of these organic semiconductors can absorb light even up to ∼750 nm.•The highest AQY of 4.2% at 420 nm is obtained without a co-catalyst.•The properties of conjugated polymers can be promoted by structural fine tuning.Some conjugated polymer organic semiconductors with linear or network structures and tunable band gaps are found to be efficient metal-free photocatalysts for H2 production. In the present work, three 1,4-diethynylbenzene-based linear conjugated polymer organic semiconductors (named P7-E, B-BT-1,4-E, and P17-E) were synthesized by palladium-catalyzed Sonogashira–Hagihara cross-coupling polycondensation. Compared with three reported 1,4-benzene-based linear conjugated polymer organic semiconductors (P7, B-BT-1,4, and P17), the ethynyl group is introduced into their backbones and the absorption edge is extended by 150–190 nm to the red/NIR light region (up to ∼750 nm). Importantly, a negative shift of LUMO levels and enhanced photocurrent intensity are also observed, and their visible-light-induced H2 production activity is improved dramatically. P7-E exhibits the highest H2 production rate of 180.7 μmol/h under λ > 420 nm irradiation even without Pt co-catalyst loaded. Moreover, the apparent quantum yield (AQY) value of P7-E is 4.2% at 420 nm, which is much higher than that reported so far for P7. The present result indicates that small changes in the chemical structure of conjugated polymers can significantly tune their optical and photocatalytic properties, which provides a new direction for attaining more efficient organic conjugated polymer photocatalysts.Download high-res image (88KB)Download full-size image

•Versatile halogenation method for terminal alkynes is proposed.•39 successful examples vary from chlorination, bromination to iodination are presented, up to 99% yields.•Catalyst is recyclable, 99% yield achieved even after 5 runs.•Mild reaction conditions.Direct halogenation, including chlorination, bromination and iodination of terminal alkynes, are of great importance in organic synthesis. Here an efficient and recyclable nano-Ag/g-C3N4 catalyst system was developed and proved to be remarkably active with 39 examples varied from chlorination, bromination to iodination, of which 14 runs have yielded more than 95% of the product. Recycling of the catalyst was also achieved without obvious activity loss after several runs: 99% yield was observed even after 5 runs in the bromination of phenylacetylene. The catalysts system is of low cost and easy to be prepared, making this procedure versatile, convenient and economic.Download high-res image (101KB)Download full-size image

•Electrostatic complementarity between relatively electron-deficient perylenediimide and relatively electron-rich porphyrin•Zipper-like heteroaggregates of perylenediimide and porphyrin could stablize the GNA duplex significantly.•Chromophores can lead to remarkable variation for the CD spectra and bathochromic shift occurred upon duplex formation.Relatively electron-deficient perylenediimide (PDI) and relatively electron-rich porphyrin (Por) were introduced into the middle of 16-mer glycol nucleic acid (GNA), and up to five consecutive chromophores were arranged in the zipper-like interstrand alternating fashion. Remarkable variation for the CD spectra ascribed to chromophores was observed, and bathochromic shift in the UV/Vis absorption region of chromophores occurred upon duplex formation. Interestingly, zipper-like heteroaggregates of chromophores inside had marvelous positive effects on the stabilization of the duplex, Tm of Por-PDI-Por sandwich-type modified GNA duplex was increased by 24 °C in comparison with three A-T base pairs, moreover, Por-PDI-Por-PDI-Por interstrand modified GNA duplex was even stabilized by 25 °C in replacement of five A-T base pairs. The specificity of high duplex stability might be driven by the strong hydrophobic electrostatic complementarity between PDI and Por face-centered stacking.Download high-res image (143KB)Download full-size image

•BBT is an organic semiconductor for photocatalytic H2 production and CIP degradation.•BBT/TiO2 heterojunction improves H2 evolution and CIP degradation activity.•The heterojunction interface enhances the photogenerated e−/h+ separation efficiency.•The catalyst can work under broad visible light region up to ∼700 nm.A π-conjugated microporous poly(benzothiadiazole) (hereafter denoted as BBT) is synthesized through palladium-catalyzed Sonogashira-Hagihara cross-coupling polycondensation, and used as a novel organic semiconductor photocatalyst for both photocatalytic H2 production and pollutant degradation under visible light (λ > 420 nm) irradiation. Furthermore, BBT/TiO2 heterojunction is conveniently fabricated through an in-situ polycondensation procedure of 4,7-dibromobenzo[c][1,2,5]thiadiazole and 1,3,5-triethynylbenzene in the presence of commercial TiO2. After optimizing the composition ratio, the resultant BBT/TiO2 heterojunction exhibited dramatically enhanced visible-light-responsive photocatalytic activities (∼18.0 and 20.4 times higher activity for H2 evolution and ciprofloxacin degradation, respectively) as compared BBT alone. Detailed investigations revealed that the BBT/TiO2 heterojunction interface can accelerate the photogenerated electron transferring from BBT to TiO2, and then improve the photoactivity. The present work exhibits some interesting points and dramatic improvement of photoactivity when an organic semiconductor is combined with an inorganic one, which provides a novel direction to exploit and fabricate photocatalyst for solar energy conversion and pollutant degradation.Download high-res image (318KB)Download full-size image

Fullerene C70 modified TiO2 (C70–TiO2) hybrids were fabricated through a hydrothermal method from titanium sulfate and functionalized C70. The structures of the synthesized hybrids were characterized by X-ray diffraction, UV-vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller surface area measurements, matrix-assisted laser desorption/ionization-time of flight-mass spectrometry and photoluminescence spectroscopy. The experimental results indicated that the introduction of C70 slightly reduces the crystallite size of TiO2 while extending its adsorption edge to the visible light region. C70 dispersed on the surface of TiO2 nanoparticles with covalent bonding, which generated strong interactions between the functionalized C70 and TiO2. The O2˙−, ˙OH and h+ are active species which were proved by the trapping experiment. The photocatalytic degradation efficiency of sulfathiazole over C70–TiO2 hybrids is higher than that over pure TiO2, C60–TiO2, and a mechanical mixture of C70 and TiO2 under visible light irradiation. The excellent visible light-induced activity is rationalized by the results of photoluminescence spectroscopy; i.e., the intensities of emissions from C70–TiO2 hybrids were found to be weaker than those from pure TiO2 and C60–TiO2 hybrid.

•PFCs were detected in fish from the Danjiangkou reservoir and Hanjiang river.•Total concentrations of PFCs in fish muscles ranged from 2.01 to 43.8 ng g−1 dw.•PFOS was the dominant PFC in the fish liver samples.•Hazard ratio of PFCs for all fish muscles was less than 1.0.•Frequent consumption of PFC contaminated fish may pose a risk to human health.Residues of eight perfluorinated compounds (PFCs) were investigated in 15 fish samples from the Danjiangkou reservoir and Hanjiang river (Xiangyang and Zhongxiang sections). The total concentrations of PFCs in fish muscles ranged from 2.01 to 43.8 ng g−1 dry weight. The mean concentration of total PFCs from related muscles showed the following trend in various regions: Zhongxiang section < Xiangyang section < Danjiangkou reservoir. Perfluorooctane sulphonate (PFOS) was the dominant PFC in the fish liver samples from the Danjiangkou reservoir. The calculated hazard ratio (HR) of PFCs, for all fish muscle samples, was less than 1.0, and could be classified at safe levels for the general population. However, yellow croaker fish from the Danjiangkou reservoir and Hanjiang river–Xiangyang section had HRs of 0.2, indicating that frequent consumption of this contaminated fish may pose an unacceptable risk to human health.

A two-step hydrothermal method is used to prepare N doped single-walled carbon nanotube–TiO2 (SWCNT–N/TiO2) hybrids with different contents of SWCNTs from 1.25 wt% to 10 wt%. The photocatalysts were characterized by X-ray diffraction analysis, UV-vis diffuse reflectance spectroscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The UV-vis diffuse reflectance spectra show an apparent enhancement of absorption throughout the visible light region. Raman spectroscopy further confirms the chemical interaction between N/TiO2 and SWCNTs in the hybrid. SWCNT–N/TiO2 hybrid presents a superior photocatalytic activity to DWCNT–N/TiO2 (N doped double-walled carbon nanotube–TiO2) and MWCNT–N/TiO2 (N doped multi-walled carbon nanotube–TiO2) based on the results of the photocatalytic degradation of sulfathiazole under visible light irradiation, which is attributed to the synergetic effects of SWCNT modification and N doping. N doping induces visible light absorption by either introducing localized electronic states within the band gap or contributing electrons to the valence band and metal-like SWCNT can act as an electron conductor to facilitate the fast injection of the photogenerated electrons into the conduction band of N/TiO2, leading to significantly enhanced visible-light-driven photocatalytic activity.

Hierarchical PbMoO4 microspheres were synthesized via a simple nitric acid-assisted hydrothermal process without the addition of a template or an organic directing reagent. The scheelite-type tetragonal PbMoO4 with various hierarchical microstructures can be controllably fabricated by adjusting the experimental conditions such as hydrothermal temperature, time and nitric acid concentration. Experimental results indicate that hierarchical PbMoO4 microspheres with a size of 5–10 μm, which are assembled by plate-like microcrystals with an average thickness of ∼230 nm, can be obtained from a hydrothermal treatment at 160 °C for 24 h in the presence of HNO3 solution, whereas only irregular particles and aggregations are obtained without HNO3 solution. The hierarchical PbMoO4 microspheres show better photocatalytic activity than the irregular PbMoO4 particles and the commercial photocatalyst (P25) for the degradation of rhodamine B (RhB) under UV light irradiation. Furthermore, a possible nitric acid-assisted formation mechanism for the hierarchical PbMoO4 microspheres is proposed, which might represent a new fabrication strategy for other nano/microstructures with desired morphologies.

•The C60–PbMoO4 was synthesized via a hydrothermal method.•The C60–PbMoO4 exhibits enhanced photocatalytic activity.•The C60–PbMoO4 possesses a strong binding between C60 and PbMoO4.•C60 increase the light absorption of PbMoO4 in the visible light region.In this study, fullerene-modified lead molybdate (C60–PbMoO4) was prepared via a hydrothermal method, and characterized by X-ray diffraction, UV–vis diffuse reflection spectroscopy, high-resolution transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. It was shown that the introduction of C60 reduces the crystallite size of PbMoO4, slightly influences the textual properties and optical characteristics (UV–vis absorption). The effect of C60 content on the photocatalytic activity of C60–PbMoO4 was studied in the photocatalytic degradation of rhodamine B under UV light and visible light irradiation. After modification with C60, the photocatalytic activity of PbMoO4 increased 3.8 times at a C60 weight ratio of 0.5 wt% under UV light irradiation, and 4.1 times at a C60 weight ratio of 5.0 wt% under visible light irradiation. The significant photocatalytic activity of C60–PbMoO4 was attributed to the excellent light absorption and charge separation on the interfaces between C60 and PbMoO4.

A simple and fast method of low-density extraction solvent-based solvent terminated dispersive liquid–liquid microextraction (ST-DLLME) was developed for the highly sensitive determination of carbamate pesticides in the water samples by gas chromatography-tandem mass spectrometry (GC-MSMS). After dispersing, the obtained emulsion cleared into two phases quickly when an aliquot of acetonitrile was introduced as a chemical demulsifier into the aqueous bulk. Therefore, the developed procedure does not need centrifugation to achieve phase separation. It was convenient for the usage of low-density extraction solvents in DLLME. Under the optimized conditions, the limits of detection for all target carbamate pesticides were in range of 0.001–0.50 ng mL−1 and the precisions were in the range of 2.3–6.8% (RSDs, 2 ng mL−1, n = 5). The proposed method has been successfully applied to the analysis of real water samples and good spiked recoveries over the range of 94.5–104% were obtained.

Photocatalytic degradation of commercial phoxim emulsion in aqueous suspension was investigated by using La-doped mesoporous TiO2 nanoparticles (m-TiO2) as the photocatalyst under UV irradiation. Effects of La-doping level, calcination temperature, and additional amount of the photocatalyst on the photocatalytic degradation efficiency were investigated in detail. Experimental results indicate that 20 mg L−1 phoxim in 0.5 g L−1 La/m-TiO2 suspension (the initial pH 4.43) can be decomposed as prolonging the irradiation time. Almost 100% phoxim was decomposed after 4 h irradiation according to the spectrophotometric analyses, whereas the mineralization rate of phoxim just reached ca. 80% as checked by ion chromatography (IC) analyses. The elimination of the organic solvent in the phoxim emulsion as well as the formation and decomposition of some degradation intermediates were observed by high-performance liquid chromatography−mass spectroscopy (HPLC-MS). On the basis of the analysis results on the photocatalytic degradation intermediates, two possible photocatalytic degradation pathways are proposed under the present experimental conditions, which reveal that both the hydrolysis and adsorption of phoxim under UV light irradiation play important roles during the photocatalytic degradation of phoxim.

A new method was developed for the determination of cadmium in water samples using ionic liquid-based ultrasound-assisted dispersive liquid–liquid microextraction (IL-based USA-DLLME) followed by electrothermal atomic absorption spectrometry (ETAAS). The IL-based USA-DLLME procedure is free of volatile organic solvents, and there is no need for a dispersive solvent, in contrast to conventional DLLME. The ionic liquid, 1-hexyl-3-methylimidazolium hexafluorophosphate (HMIMPF6), was quickly disrupted by an ultrasonic probe for 1 min and dispersed in water samples like a cloud. At this stage, a hydrophobic cadmium–DDTC complex was formed and extracted into the fine droplets of HMIMPF6. After centrifugation, the concentration of the enriched cadmium in the sedimented phase was determined by ETAAS. Some effective parameters of the complex formation and microextraction, such as the concentration of the chelating agent, the pH, the volume of the extraction solvent, the extraction time, and the salt effect, have been optimized. Under optimal conditions, a high extraction efficiency and selectivity were reached for the extraction of 1.0 ng of cadmium in 10.0 mL of water solution employing 73 µL of HMIMPF6 as the extraction solvent. The enrichment factor of the method is 67. The detection limit was 7.4 ng L− 1, and the characteristic mass (m0, 0.0044 absorbance) of the proposed method was 0.02 pg for cadmium (Cd). The relative standard deviation (RSD) for 11 replicates of 50 ng L− 1 Cd was 3.3%. The method was applied to the analysis of tap, well, river, and lake water samples and the Environmental Water Reference Material GSBZ 50009-88 (200921). The recoveries of spiked samples were in the range of 87.2–106%.

The photocatalytic degradation of a commercial methamidophos (MAP) emulsion in aqueous suspension containing mesoporous titania (m-TiO2) nanoparticles under UV irradiation was investigated. The mineralization rate of MAP went up steadily as prolonging the irradiation time and reached ca. 95% after 4 h irradiation based on determination of the end-products (NO3−, PO43−, and SO42−) of MAP through IC analysis. Moreover, the degradation kinetics of MAP followed the first-order reaction and has been monitored through GC-PFPD analysis, which also showed that MAP and the organic solvent as well as additive in the pesticide emulsion can be degraded readily and simultaneously. Photodegradation intermediates derived from two different concentrations of MAP were detected by GC-MS technique. The experimental facts indicated that the photodegradation mechanism of MAP mainly involves electron transfer process and hydroxylation process, and the dominant mechanism for MAP degradation in the initial steps can be attributed to the electron transfer process, which resulted in the formation of all intermediates containing P species detected in the initial photodegradation stage.

•This EC/EF process exhibited superior atrazine decholorination and mineralization rate.•Fe@Fe2O3 could activate molecular oxygen and accelerate the decholorination process.•Fe@Fe2O3 could be reused for the atrazine removal.•Atrazine was found to be decomposed via a triazinon ring opening mechanism.In this study, an electrochemical/electro-Fenton oxidation (EC/EF) system was designed to degrade atrazine, by utilizing boron-doped diamond (BDD) and Fe@Fe2O3 core-shell nanowires loaded active carbon fiber (Fe@Fe2O3/ACF) as the anode and the cathode, respectively. This EC/EF system exhibited much higher degradation rate, decholorination and mineralization efficiency of atrazine than the electrochemical (EC) and electrochemical/traditional electro-Fenton (EC/TEF) oxidation counterpart systems without Fe@Fe2O3 core-shell nanowires. Active species trapping experiment revealed that Fe@Fe2O3 could activate molecular oxygen to produce more OH through Fenton reaction, which favored the atrazine degradation. High performance liquid chromatography, high performance liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry were applied to probe the decomposition and mineralization of atrazine during this novel EC/EF process, which revealed that two intermediates of triazinons (the isomerization of hydroxylated atrazine) were generated during the electrochemical/electro-Fenton oxidation of atrazine in the presence of Fe@Fe2O3 core-shell nanowires. The experimental and theoretical calculation results suggested that atrazine might be degraded via a triazinon ring opening mechanism, while the presence of Fe@Fe2O3 notably accelerated the decholorination process, and produced more hydroxylated products to promote the generation of trazinons and the subsequent ring cleavage as well as the final complete mineralization. This work provides a deep insight into the triazine ring opening mechanism and the design of efficient electrochemical advanced oxidation technologies (EAOTs) for persistent organic pollutant removal.Download high-res image (320KB)Download full-size image

Fullerene C70 modified TiO2 (C70–TiO2) hybrids were fabricated through a hydrothermal method from titanium sulfate and functionalized C70. The structures of the synthesized hybrids were characterized by X-ray diffraction, UV-vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller surface area measurements, matrix-assisted laser desorption/ionization-time of flight-mass spectrometry and photoluminescence spectroscopy. The experimental results indicated that the introduction of C70 slightly reduces the crystallite size of TiO2 while extending its adsorption edge to the visible light region. C70 dispersed on the surface of TiO2 nanoparticles with covalent bonding, which generated strong interactions between the functionalized C70 and TiO2. The O2˙−, ˙OH and h+ are active species which were proved by the trapping experiment. The photocatalytic degradation efficiency of sulfathiazole over C70–TiO2 hybrids is higher than that over pure TiO2, C60–TiO2, and a mechanical mixture of C70 and TiO2 under visible light irradiation. The excellent visible light-induced activity is rationalized by the results of photoluminescence spectroscopy; i.e., the intensities of emissions from C70–TiO2 hybrids were found to be weaker than those from pure TiO2 and C60–TiO2 hybrid.