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International audience; In this study, we compare two independent paleoenvironmental proxies for a loess sequence in northern Serbia, in the southern Carpathian Basin: novel n-alkane biomarkers and traditional land snail assemblages. Both are associated with other, more widely used proxy data for loess sections, such as environmental magnetism, grain size, and geochemical indices. Together, these paleoenvironmental proxy records provide evidence for the continued dominance of grasslands during the Late Pleistocene in the Southern Carpathian Basin. It is contrary to other European loess provinces, which are characterized by high diversity of Late Pleistocene environments (ranging from tundra-like to deciduous forest habitats). These findings highlight the southeastern part of Carpathian Basin as an important, but still insufficiently investigated, biogeographical refugium, and biodiversity preservation zone. The reason for this is a mostly stable paleoclimate for much of the Late Pleistocene.

Sulfate radical-based photo-Fenton (SR-photo-Fenton) reaction, assisted by visible light irradiation, was achieved by CuBi2O4 and its composites with α-Bi2O3 for refractory chemical degradation in aqueous solution. Herein, this catalyst was fabricated by a sol-gel method and the fabrication conditions, including calcination temperature and molar ratio of Cu/Bi, were optimized according to the crystal phase composition, catalytic activity and toxic copper ion leaching. The optimal calcination temperature was 500 °C and molar ratio of Bi to Cu was 2.0. The catalyst containing CuBi2O4 and α-Bi2O3 showed a higher density of surface OH which might be the key surface active site than pure CuBi2O4. The influence of initial solution pH, PMS concentration, catalyst dosage and catalyst reuse on rhodamine B (RhB) degradation was investigated. Importantly, calcination at 500 °C reverted the catalytic activity of catalyst. Results of electron paramagnetic resonance, competitive radical experiments and surface chemical property characterization demonstrated that the reaction mechanism of this novel SR-photo-Fenton reaction is a combination of interface and solution reactions. In the interface reaction, the transfer of photogenerated electron/hole pairs drives the decomposition of PMS to produce SO4 − and OH. Furthermore, the cycling of Cu(I)/Cu(II) facilitated effective PMS activation to generate free radical that was responsible for the degradation of RhB. The second order reaction rate constant between RhB and SO4 − was determined to be 0.595–6.436 × 1010 M−1 S−1 based on the chemical reaction kinetics of radical, which was a first and important report for SO4 − chemistry.

The requirement for enhanced, less expensive, and eco-friendly nanocomposites as an adsorbent is highly preferred for removal of heavy metals and in the major applications of environmental remediat...

Different amounts of nickel were loaded on carbon nanotubes (CNTs) by an impregnation method and characterized by N2 adsorption/desorption isotherms, X-ray diffraction, X-ray photoelectron spectros...

Wavy carbon nanotubes (CNTs) are ubiquitously present in high-aspect-ratio CNT arrays used in advanced device applications. This paper investigates the effective modulus and natural frequency of wavy CNTs that have random, sinusoidal, or helical structures. Parameters such as loading deviation angle, boundary condition, and low shear modulus are considered. It was found that loading deviation could cause 3–4 orders modulus reduction for sinusoidal and helical CNTs at small waviness ratio. In contrast, there is slight modulus enhancement by a small loading deviation for randomly wavy CNTs. By applying pined or fixed boundary condition at the loading end, the moduli of wavy CNTs may be enhanced by up to 4 orders in magnitude. As another critical parameter, low shear modulus (∼50 MPa) may cause significant modulus reduction only for helical CNTs, about 2 orders of magnitude due to large shear and torsional deformation. The natural frequencies of wavy CNTs were also computed, showing that helical CNTs generally have lower frequency than other wavy CNTs. Furthermore, very low shear modulus could result in significant frequency reduction for helical CNTs, but has limited effect on random or sinusoidal CNTs. With the high sensitivity to shear modulus, helical CNTs are thus more desirable in the electric-field-induced resonance testing used for CNT property characterization. The findings on the properties of wavy CNTs can provide fundamental guidelines for the design of CNT arrays or CNT-based composites.

Chirality is a fundamental property of biochemical molecules and often dictates their functionality. Conventionally, molecular chirality is studied by linear optical activity effects. However, poor contrast and artifacts due to anisotropy limit such studies to purified molecules not in their original microenvironments, potentially modifying their conformations. Here, we demonstrate that resonant second-harmonic-generation circular dichroism (SHG-CD) microscopy provides not only tissue imaging with improved chiral contrast, but also molecular chirality information of collagen, the most abundant protein in mammals, at its native state. Gradual protein denaturation shows that the resonant SHG-CD is dominated by the microscopic chirality related to collagen structures smaller than the spatial resolution of the microscope, i.e. to the protein conformation and microfibril organization, while the effects due to fiber orientation/anisotropy are mostly responsible of the non-resonant part. This result agrees well with a simple and intuitive model we propose to explain the resonant behavior and the consequent numerical SHG-CD simulations. Our results demonstrate the possibility to study molecular chirality in intact bio-tissues with nearly-unity contrast and sub-micrometer resolution, which will be useful in a broad range of biological and biochemical applications acceptedVersion

The novel supported CoAlOx/CeO2 catalysts have been synthesized via four preparation processes [impregnation (IWI), microwave in-situ grown (MW), impregnation-combustion (CS) and plasma treatment (P)], and investigated for methane catalytic combustion. The results indicated that preparation method played a vital role in controlling structural properties of the catalysts, resulting in a significant difference in catalytic performance. The activities of synthesized catalysts increased and optimised in the following order: CoAlOx/CeO2-IWI

Oxidation of pure Ti coated with a thin Si layer was investigated to clarify the role of titanium silicide phases in improving oxidation resistance of titanium alloys. The system initially reacted to form a two-layer structure with Ti5Si3 and SiO2. Oxidation proceeded by upward diffusion of Ti to form TiO2 wedge-like crystals on the surface and inward oxidation of Ti5Si3 into a mixed nanocrystalline TiO2 and SiO2 internal scale that was locally layered. The Ti5Si3 phase inhibited oxygen inward diffusion, thereby limiting oxygen ingress into Ti and retarding inward Ti oxidation until the silicide layer was completely oxidized.

The three novel acceptor–donor–acceptor (A–D–A) conjugated small molecules were synthesized, each featuring a benzodithiophene (BDT) core presenting lateral flexible side chains: TB-BDT6T substituted with 2-ethynyl-5-octylthiophene, TS-BDT6T substituted with 2-(octylthio)thiophene, and TT-BDT6T substituted with 2-(2-ethylhexyl)thieno[3,2-b]thiophene groups. The lateral incorporation of functionalized π-conjugated flexible side chains, without altering the end-capped acceptor (cyanoacetate) moieties, amended the optoelectronic properties of these BDT-based small molecules. X-ray diffraction spectroscopy revealed that these small molecules possess high crystallinity; moreover, the optimized blend film morphologies, recorded using atomic force microscopy, revealed miscibility with PC61BM, and turn out nanoscale phase separations. The energy levels of the highest occupied and lowest unoccupied molecular orbitals of these small molecules were allowed, leading to high open-circuit voltages (Voc) for their solar...

High performance copper-based catalysts (CuNiZnO/γ-Al2O3) for hydrogen production from methanol decomposition were successfully synthesized by the method of microwave-assisted thermal hydrolysis of urea. The ICP-OES, N2 adsorption–desorption, SEM, TEM, XRD and H2-TPR were applied to characterize the physicochemical properties of the prepared materials. These experiment results reveal that the higher thermal treatment temperature can improve the catalytic performance by enlarging the content of promoters (Zn and Ni) and promoting the dispersion of deposited particles. Moreover, the addition of Ni can significantly improve the catalytic performance of the copper-based catalysts, which is ascribed to the regulation of reaction process and inhibition of Cu Zn alloy. Among the obtained catalysts, the MW-Cu/Ni-95 developed at 95 °C exhibits a higher catalytic activity, which reaches 91.7% conversion at 250 °C. Most significantly, it shows the excellent catalytic performance as compared with the commercial catalyst under the same test conditions.

In this study, SiC supported Pd nanoparticles were found to be an efficient catalyst in acetylene selective hydrogenation reaction. The ethylene selectivity can be about 20% higher than that on Pd/TiO2 catalyst at the same acetylene conversion at 90%. Moreover, Pd/SiC catalyst showed a stable catalytic life at 65 °C with 80% ethylene selectivity. With the detailed characterization using temperature-programmed reduction (H2-TPR), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2 adsorption/desorption analysis, CO-chemisorption and thermo-gravimetric analysis (TGA), it was found that SiC owns a lower surface area (22.9 m2/g) and a broad distribution of meso-/macro-porosity (from 5 to 65 nm), which enhanced the mass transfer during the chemical process at high reaction rate and decreased the residence time of ethylene on catalyst surface. Importantly, SiC support has the high thermal conductivity, which favored the rapid temperature homogenization through the catalyst bed and inhabited the over-hydrogenation of acetylene. The surface electronic density of Pd on Pd/SiC catalyst was higher than that on Pd/TiO2, which could promote desorption of ethylene from surface of the catalyst. TGA results confirmed a much less coke deposition on Pd/SiC catalyst.

Early Upper Paleolithic sites in the Danube catchment have been put forward as evidence that the river was an important conduit for modern humans during their initial settlement of Europe. Central to this model is the Carpathian Basin, a region covering most of the Middle Danube. As the archaeological record of this region is still poorly understood, this paper aims to provide a contextual assessment of the Carpathian Basin’s geological and paleoenvironmental archives, starting with the late Upper Pleistocene. Subsequently, it compiles early Upper Paleolithic data from the region to provide a synchronic appraisal of the Aurignacian archaeological evidence. It then uses this data to test whether the relative absence of early Upper Paleolithic sites is obscured by a taphonomic bias. Finally, it reviews current knowledge of the Carpathian Basin’s archaeological record and concludes that, while it cannot reject the Danube corridor hypothesis, further (geo)archaeological work is required to understand the link between the Carpathian Basin and Central and Southeastern Europe.

Hierarchical structures are commonly observed in nature and possess unique properties. The fabrication of hierarchical structures with well-controlled sizes in different length scales, however, is still a great challenge. To further understand the morphologies and properties of the hierarchical structures, here we present a novel strategy to prepare hierarchical polymer structures by combining the modified breath figure method and the template method. Poly(methyl methacrylate) (PMMA) honeycomb films with regular micropores are first prepared using the modified breath figure method by dipping PMMA films into mixtures of chloroform and methanol. The polymer chains on the honeycomb films are then annealed and wetted into the nanopores of anodic aluminum oxide templates via capillary forces, resulting in the formation of hierarchical polymer structures. The morphologies of the polymer structures, which can be controlled by the molecular weights of the polymers and the concentrations of the polymer solutions, are characterized by scanning electron microscopy. The surface wettabilities of the polymer structures are also examined by water contact angle measurements, and the hierarchical structures are observed to be more hydrophobic than the flat films and honeycomb films. This work not only provides a feasible approach to fabricate hierarchical polymer structures with controlled sizes but also gives a better understanding of the relationship between surface morphologies and properties.

Nickel doped defective h-BN nanosheets and their potential application on hydrogen storage were explored by density functional theory (DFT) calculation. Three types of defective h-BN (SW defect, VB and VN substrates) were modeled. In comparison with the SW defect, the B or N vacancy can improve the interaction between Ni atom and h-BN nanosheet strikingly. Furthermore, the Ni-doped SW defect sheet shows chemisorption on H2 molecules, and the H H bond is partially dissociated. While on the VB sheet, Ni adatom interacts with H2 in the range of physisorption. However, the Ni-functionalized VN sheet exhibits a desirable adsorption on H2, and the corresponding energy varies from −0.40 to −0.51 eV, which is favorable for H2 adsorption and release at ambient conditions. As a result, the VN substrate is expected to a desirable support for H2 storage. Our work provides an insight into H2 storage on Ni-functionalized defective h-BN monolayer.

The photodegradation of 4-chlorophenol (4-CP) by using 3,3′-Pt(dcbpy)(bdt), 33Pt(bdt), sensitized platinized titanium dioxide, Pt-TiO2, under 420 nm light irradiation while bubbling O2 has been studied in this research. The 84% degradation efficiency was reached in 3 h, and this efficiency was much better than that assisted by 4,4′-Pt(dcbpy)(bdt), 44Pt(bdt), under the same conditions using 420 nm light. The possible reason is due to the difference in UV–vis absorption spectra of these two dyes around 420 nm. The 33Pt(bdt) dye which has been first synthesized in this study and has the twisted geometry shows larger open circuit voltage, higher molar extinction coefficient of π–π* transition around 420 nm and much better in 4-CP photodegradation than its 4,4′-analogue under blue light. Under 580 nm light irradiation for 6 h, both 33Pt(bdt) and 44Pt(bdt) sensitized Pt-TiO2-catalyzed 4-CP degradation with O2 bubbling could reach 94% photodegradation efficiency based on metal ligand charge transfer, MLCT, mechanism. Fluorescence quenching experiments have been carried out to affirm the enhanced photo-induced charge separation and transmission during 33Pt(bdt)-assisted reaction. To our knowledge, this is the first time to show that under blue or yellow light irradiation dye-sensitized Pt-TiO2-catalyzed 4-CP degradations have different mechanisms and are tunable by light wavelength. Dye 33Pt(bdt) is more robust and better sensitizer in 4-CP degradation than 44Pt(bdt) under blue light. Thus, by the careful selection of light wavelength and using the robust dye, one can tune the system to efficiently harvest specific visible light for the photodegradation of small organic pollutants.

Controlling circularly polarized (CP) states of light is critical to the development of functional devices for key and emerging applications such as display technology and quantum communication, and the compact circular polarization-tunable photon source is one critical element to realize the applications in the chip-scale integrated system. The atomic layers of transition metal dichalcogenides (TMDCs) exhibit intrinsic CP emissions and are potential chiroptical materials for ultrathin CP photon sources. In this work, we demonstrated CP photon sources of TMDCs with device thicknesses approximately 50 nm. CP photoluminescence from the atomic layers of tungsten diselenide (WSe2) was precisely controlled with chiral metamolecules (MMs), and the optical chirality of WSe2 was enhanced more than 4 times by integrating with the MMs. Both the enhanced and reversed circular dichroisms had been achieved. Through integrations of the novel gain material and plasmonic structure which are both low-dimensional, a compac...

A superparamagnetic graphene oxide (GO)/Fe3O4 nanocomposite (MGO) was prepared by a facile in situ co-precipitation strategy, resulting in a prospective material for the application of graphene oxide in wastewater treatment. MGO was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The prepared adsorbent showed a high adsorption efficiency relevant to the purification of dye-contaminated wastewater and could be readily magnetically separated. The maximum adsorption capacity was ca. 546.45 mg g−1 for the common cationic dye methylene blue (MB) and ca. 628.93 mg g−1 for the anionic dye Congo red (CR). The adsorption processes fit the pseudo-second-order kinetic model well, which revealed that these processes may involve the chemical interaction between adsorbate and adsorbent. The thermodynamic parameters indicated that the adsorption reaction was an endothermic and spontaneous process. Furthermore, the prepared magnetic adsorbent had a wide effective pH range from 5 to 11 and showed good stability after five reuse cycles. The synthetic MGO showed great potential as a promising adsorbent for organic contaminant removal in wastewater treatment.

N-doped TiO2 (NT) was proven to be efficient for monuron decay via peroxymonosulfate (PMS) activation under visible LED (Vis LED). The activation mechanism revealed that OH and SO4− have a critical role in the monuron decay with a ratio of about 3 to 1, respectively; and the holes at the catalyst surface are the main precursors in forming SO4− . The NT/PMS/Vis LED hybrid process was found to be an effective approach under a wide solution pH range of 2.5–9.2 (>80% decay). Interestingly, the highest efficiency was observed at pH 9.2 due to the contribution of PMS/Vis LED process by generating both OH and SO4− at alkaline pH. However, the decay rate of monuron was inhibited at pH 11.6 due to the dissociation of OH into O− and the electrostatic repulsion among reagents. The process was also suitable for ion-rich wastewater since no significant reduction in the performance was induced in the presence of high concentrations of inorganic anions. Furthermore, the process was proven to be a promising approach for mineralization of monuron and its intermediates. Twenty reaction intermediates were detected and five of them are newly reported. A novel mathematical model was established based on reaction intermediates using a parallel-serial-irreversible reaction approach, which is helpful in predicting the detoxification extent of hazardous intermediates.

A synergistic UV/TiO2/Fenton (PCF) process is investigated for the degradation of ibuprofen (IBP) at circumneutral pH. The IBP decay in the PCF process is much faster than that with the conventional UV, UV/H2O2, Fenton, photo-Fenton, and photocatalysis processes. The kinetics analysis showed that the IBP decay follows a two-stage pseudo-first order profile, that is, a fast IBP decay (k1) followed by a slow decay (k2). The effects of various parameters, including initial pH level, dosage of Fenton's reagent and TiO2, wavelength of UV irradiation, and initial IBP concentration, are evaluated. The optimum pH level, [Fe2+]0, [Fe2+]0/[H2O2]0 molar ratio, and [TiO2]0 are determined to be approximately 4.22, 0.20 mmol/L, 1/40, and 1.0 g/L, respectively. The IBP decay at circumneutral pH (i.e., 6.0–8.0 for wastewater) shows the same IBP decay efficiency as that at the optimum pH of 4.22 after 30 min, which suggests that the PCF process is applicable for the treatment of wastewater in the circumneutral pH range. The lnk1 and lnk2 are observed to be linearly correlated to 1/pH0, [IBP]0, [H2O2]0, [H2O2]0/[Fe2+]0 and ln[TiO2]0. Mathematical models are therefore derived to predict the IBP decay.

Ni loaded mixed metal oxides (MMO) catalysts were systematically synthesized with different Ni/Al ratios through layered double hydroxides (LDH) decomposition, fully characterized using various techniques, and tested in catalytic methane decomposition reaction to study the properties of active nickel species on supports. H2 chemisorption indicated the Ni metallic surface areas on Ni0.5Al-MMO and Ni1Al-MMO were 17.1 and 21.1 m2/g, respectively, which were much higher than those on Ni0.5/Al2O3 and Ni1/Al2O3 impregnated catalysts (at 8.8 and 8.5 m2/g, respectively). However, the MMO catalysts gave the lower carbon nanotubes (CNTs) yield compared with the impregnated catalysts. Form the XPS, XRD and H2-TPR characterizations, it were found that there existed a strong metal and support interaction, leading to less NiO being reduced as the active sites. When Ni/Al ratios increased to 2 and 3, the CNT yields for the NixAl-MMO catalysts were much higher than those of impregnated Ni catalysts, up to 2.02 gc/gcat. and 4.55 gc/gcat., vs 1.36 gc/gcat. and 1.29 gc/gcat., respectively. From H2 chemisorption, we found that NixAl-MMO (x = 2 or 3) catalysts had much higher metallic surface areas (22.3 m2/g and 24.6 m2/g), while they were only 4.9 m2/g and 4.3 m2/g on the impregnated catalysts at the same Ni loadings. It suggests MMO catalysts have more reduced Ni active sites available for methane decomposition reaction, attributing to the proper metal-support interactions. SEM and TEM results display the uniform Ni particle sizes existing on MMO catalysts, giving a nice correlation to the inner diameter of CNTs produced.

Pd-Fe 3 O 4 hybrid nanostructures were prepared using a simple one-pot hydrothermal method. The prepared materials were characterized by Fourier transform-infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, inductively coupled plasma, N 2 adsorption-desorption, and vibrating sample magnetometry. This self-assembled nanosystem acted as an efficient magnetically recyclable noble metal-based multi-functional nanocatalyst. It showed excellent catalytic activity and stability for the Heck reaction of iodobenzene and styrene under mild conditions. The methods used to prepare the Pd-Fe 3 O 4 catalysts were simple and low-cost, which will be useful for the large-scale development and application of a magnetically recoverable Pd catalyst.

The rapid development of perovskite solar cells (PSCs) has triggered a quest for lead (Pb)-free alternatives to improve their commercial viability. One such non-lead material, the methylammonium antimony iodide zero-dimensional dimer (CH3NH3)3Sb2I9, was reported recently, but with a low photo conversion efficiency (PCE) resulting from its poor surface morphology (many pinholes; amorphous nature). In this study, we employed anti-solvent treatment to improve the surface morphology of the Sb-based dimer by speeding up heterogeneous nucleation. We also incorporated an interlayer that acted as a favorable hydrophobic scaffold for the growth of large-grain (CH3NH3)3Sb2I9 crystals, thereby decreasing the number of the voids and increasing the film quality. We achieved a champion efficiency of 2.77%—a large improvement over the efficiencies reported previously. Using the techniques employed herein to prepare new perovskite-like materials, Sb-based photoabsorbers might become promising replacements for Pb-based perovskites.

A homogeneous better-dispersed ultrathin nanosheets (ca. 5 nm) of cobalt-nickel layered double hydroxides (LDH) supported on nickel foam scaffold was synthesized using controllable electrodeposition approach for high efficiency electrode materials of new supercapacitor. The morphology and electrochemical performances of the samples can be controlled by adjusting the precursor ratio, i.e., Ni(OAc)2/Co(NO3)2 molar ratio in the electrodeposition approach. With the increase of this molar ratio, the electrochemical performances give a volcano trend. When the optimized molar ratio is 0.64/0.36, the hybrid delivered a high specific capacitance of 1587.5 F g−1 at a current density of 0.5 A g−1, with good rate capability (1155 F g−1 was retained even at 10 A g−1) and a robust recycle stability (remaining 91.5% after 1000 cycles at 5 A g−1). The good performance could be attributed to the enlarged interlayer spacing, ultrathin nanosheets and synergistic effects between Co(OH)2 and Ni(OH)2. Furthermore, an asymmetric supercapacitor with a high energy density of 34.5 Wh kg−1 at 425 W kg−1 and excellent cycling stability of 85.4% after 5000 charge-discharge cycles at 2 A g−1 was fabricated. We believe that this fantabulous new electrode material would have encouraging applications in electrochemical energy storage and a wide readership.

In this study, eco-friendly PTCDI-C8–based organic thin film transistors (OTFTs) were fabricated by incorporating polymers from renewable sources as gate dielectrics and substrates. Chitosan, a polysaccharide obtained from the deacetylation of chitin, and natural rubber (NR), extracted from natural rubber tree, have good dielectric properties, biocompatibility, and biodegradability. To examine the practical applicability of these materials, we fabricated OTFTs using bilayer PVPy/NR and chitosan/NR films as gate dielectric materials. NR not only improved the insulation properties of the dielectric film but also acted as a surface modifier. The fabricated OTFT incorporating chitosan/NR dielectric operated under a low driving voltage, with values of μ and Vth of 0.027 cm2V−1s−1 and 0.83 V, respectively. It also displayed an electrical response in the presence of DNA at different concentrations. Because, chitosan possesses high transparency and good mechanical properties, it can be readily cast to form transparent flexible substrates. Accordingly, a flexible disposable OTFT device was fabricated using PVPy/NR as the dielectric material on chitosan as the substrate. The disposable device exhibited a carrier mobility of 0.011 cm2V−1s−1, a value of Vth of 0.83 V, and an on/off ratio of 103, while being workable over 100 bending cycles.

The adsorption of acetylene molecules on the ordered NixAg1-x/Ni (111) (x = 1, 0.75, 0.5, 0.25) bimetallic surfaces was investigated by using the density functional theory (DFT). Among the model systems, Ni atom was replaced by Ag atom only on the top surface layer. The results show that, as the Ag concentration increases, the interaction between Ag-modified NixAg1-x/Ni (111) and acetylene molecules decreases gradually. Additionally, the adsorption processes of acetylene molecules on different considered surfaces are all exothermic thermodynamically. Furthermore, the Partial density states (PDOS) and the differential charge density properties suggest that an increase in atomic concentration of Ag in the upmost layer decreases the electron transfer between the acetylene molecule and surface. Our results could provide useful information to increase the activity of Ni-based catalysts for acetylene hydrogenation.

The NiFe layered double hydroxide (LDH) with lamellar structure is beneficial to exposure more active sites. It shows high OER catalytic activity and stability under alkaline conditions, which makes it one of the hot spots in OER catalysts. The intrinsic electrocatalytic activity of the NiFe LDH can be further improved via doping to tailor surface electronic structure and valence state. The NiFe-Vx catalysts were prepared by one-step hydrothermal method. Compared with that of undoped NiFe LDH, the oxygen evolution overpotential of NiFe-V1.0 was reduced by 37 mV at a current density of 10 mA cm−2, the Tafel slope is decreased by 43.37 mV dec−1. The results demonstrated that V doping can enhance the electron transfer of LDH, and increase the electrochemical active surface area, leading to the enhanced OER activity.

In this study, the degradation of antibiotic ciprofloxacin (CIP) over Bi 2 O 3 /(BiO) 2 CO 3 heterojunctions under simulated solar light irradiation (SSL-Bi 2 O 3 /(BiO) 2 CO 3 ) was examined for the first time. The results showed that the Bi 2 O 3 /(BiO) 2 CO 3 heterojunctions dramatically improved CIP decay efficiency. The effect of parameters showed that the CIP decay was optimized with the Bi 2 O 3 /(BiO) 2 CO 3 dosage of 0.5 g/L and a wide pH range of 4.0–8.3, based on which, a kinetic model was derived to predict the remaining CIP concentration. It was found that the presence of anions like SO 4 2− , NO 3 − and HCO 3 − decelerated the CIP decay, while the co-existence of Cl − accelerated the CIP decay. Six degradation intermediates were identified by ultra-performance liquid chromatography coupled with mass analyzer (UPLC/MS) and ion chromatographic (IC) analysis, and the decay pathways and degradation mechanism of CIP were proposed by combining the experiment data with theoretical calculation of frontier electron densities. Hydroxyl radical’s reaction, photo-hole (h + ) oxidation and reductive defluorination were found to involve in the CIP decay. The efficient alleviation on total organic carbon (TOC) and toxicity indicated that the complete mineralization and de-toxicity are possible by this system with sufficient reaction time.

The presence of toxic lead (Pb) remains a major obstruction to the commercial application of perovskite solar cells. Although antimony (Sb)-based perovskite-like structures A3M2X9 can display potentially useful photovoltaic behavior, solution-processed Sb-based perovskite-like structures usually favor the dimer phase, which has poor photovoltaic properties. In this study, we prepared a layered polymorph of Cs3Sb2I9 through solution-processing and studied its photovoltaic properties. The exciton binding energy and exciton lifetime of the layer-form Cs3Sb2I9 were approximately 100 meV and 6 ns, respectively. The photovoltaic properties of the layered polymorph were superior to those of the dimer polymorph. A solar cell incorporating the layer-form Cs3Sb2I9 exhibited an open-circuit voltage of 0.72 V and a power conversion efficiency of 1.5%-the highest reported for an all-inorganic Sb-based perovskite.

Oxygenated functionalized carbon nanotube (oCNT) supported LaOx-promoted Ni nanoparticles (10Ni-xLa/oCNT) were prepared by the co-impregnation method and tested for synthetic natural gas from the CO2 reduction reaction. Several advanced characterization methods, including atomic resolution scanning transmission electron microscopy (STEM), temperature programmed experiments (TPSR, CO2-TPD, and H2-TPR) and X-ray photoelectron spectroscopy (XPS), were applied to explore, for the first time, the origin of structure modulation of LaOx species on oCNT supported Ni-LaOx hybrids and the structure–activity relationship over the CO2 reduction reaction. The Z-contrast STEM-HAADF results revealed that the LaOx species are mostly in the size of the sub-nano scale and highly dispersed on the surface of Ni nanoparticles and oCNT, and consequently no diffraction peak of LaOx was observed from XRD results. TEM analysis showed that the Ni nanoparticle sizes were similar among all samples either after reduction or after reaction due to the relatively strong interaction between Ni and oxygenated groups on CNT supports, regardless of the influence of the La mass loading. It was suggested that the catalytic performance trend was due to the structural variation rather than the size effect. The LaOx modulation catalyst with 2 wt% of La metal loading not only presented low CO2 activation temperature at only 163 °C, but also resulted in extremely high CH4 selectivity (100%) compared with the initial supported Ni catalyst (52.7% of CH4 selectivity at 300 °C).

Nanostructured carbon materials have served as potent electrode materials and crucial components for energy storage; however, multi-function integration of the synthesis route is hugely challenging. Consequently, we report herein a facile and general methodology for the synthesis of multifunctional materials, specifically mesoporous onion-like carbon (OLC) and core–shell Fe2O3@N-doped carbon hybrids, derived from water soluble gelatin and ferric nitrate precursors, which could function as high-performance electrodes for supercapacitors (SCs) and Li-ion batteries (LIBs). Owing to the strong chelation effect between the abundant functional groups of gelatin chains and metal ions, in situ-formed uniform confined nanoparticles (NPs) in a three-dimensional (3D) carbon framework could exert the triple roles of templates, graphitizing catalysts, and active materials via controllable annealing. Mesoporous OLC-3 with hollow core size of 5–8 nm, high specific surface area of 418 m2 g−1, thin shells of 3–5 graphitic layers, and rich oxygen content (18.62%) exhibited a remarkable specific capacitance (251.2 F g−1 at 0.5 A g−1), surpassing most OLC state-of-the-art SC electrodes. Besides, the as-obtained core-shelled Fe2O3@N-doped carbon annealed at 500 °C composed of a gelatin-derived carbon-coating layer (ca. 4 nm) and uniform Fe2O3 core (ca. 30 nm) greatly enhanced the rate capability (achieving an average reversible capacity of 735.9 mA h g−1 at 0.1 A g−1 and 480.6 mA h g−1 at a large current density of 2 A g−1) and demonstrated an excellent cycling life (372 mA h g−1 after 500 cycles at 1 A g−1, or 0.39 mA h g−1 decay per cycle) for Li storage. This method is quite flexible and could be also extended to the synthesis of other metal-based functional materials.

Anatase titanium dioxide (an-TiO2) is often used as the electron transporting material (ETM) in planar-heterojunction perovskite solar cells (PSCs) because of its excellent semiconductor characteristics, outstanding optical transmittance, and suitable band structure. Herein, we report an inexpensive method for mass-scale production of TiO2 ETMs at room temperature (RT ∼ 30 °C), involving the grinding of large clumps of an-TiO2 to form a suspension of TiO2 nanoparticles (NPs) in isopropyl alcohol for meso-superstructured PSCs. This process does not involve any chemical synthesis; it is a purely physical process. The lowest unoccupied molecular orbital (LUMO) of ground an-TiO2 NPs, estimated using ultraviolet photoelectron spectroscopy (UPS), was ca. 4.06 eV, which is a salient feature for the active layer. A regular perovskite solar cell (PSC) based on a CH3NH3PbI3 absorber and ground an-TiO2 ETL exhibited a champion power conversion efficiency (PCE) of 17.43% with an active area of 0.1 cm2. The same ground an-TiO2 NPs were used to fabricate a large-area (designated area: 25.2 cm2) PSC and a PCE of 14.19% was achieved. PSC devices incorporating the ground an-TiO2 NP ETLs exhibited an attractive long-term device stability, with the PCE retaining approximately 85% of the initial values after 80 days.

Highly ordered, multi-layered, regular hexagonally patterned and size controlled honeycomb magnetic chitosan hydrogel beads were successfully fabricated by a facile method combining breath-figure templating and co-precipitation processing. The chitosan honeycomb beads were characterized and the unique structure formation mechanism was outlined. The diameter of pores in the hexagonally patterned structure was ∼10 μm, and the saturation magnetization of the chitosan honeycomb containing Fe3O4 nanoparticles (ca. 5 ± 2 nm) was around 12 emu/g.

In this study, the double-edge role of permanganate in sulfamethoxazole (SMX) photodegradation with a recyclable catalyst was revealed for the first time. The role of the catalyst under different UV wavelength, the role of permanganate in the treatment process, the effects of permanganate dosage and solution pH on the removal efficiency were investigated. Moreover, the transformation products, TOC reduction and the toxicity of the treated final product to Chlorella vulgaris and Artemia salina were determined. Sole permanganate showed no effect in SMX degradation, while its introduction to the photocatalytic process doubled the reaction rate at the optimal dosage. It is interesting to find that the reaction rate showed a fluctuation trend in terms of permanganate dosage due to the summation of positive effect of permanganate oxidation and the negative effect of the formed MnO2 at the surface of the catalyst, as well as the light attenuation due to overdosed permanganate. The determined intermediates, the higher inorganic ions release and TOC reduction provided a clue on a higher mineralization compared to SMX degradation in the same process without permanganate. Permanganate above 1 μM may pose a threat to the algae growth, therefore a good monitoring and control of residual permanganate dosage should be incorporated into the process design. A good toxicity reduction to A. salina was observed in the treated effluent; a longer detention is suggested for the complete removal of toxicity.

A supramolecular toolbox approach for multivalent ligand-receptor recognition was established based on β-cyclodextrin vesicles (CDVs). A series of bifunctional ligands for CDVs was synthesised. These ligands comprise on one side adamantane, enabling the functionalisation of CDVs with these ligands, and either mannose or sulphate group moieties on the other side for biological receptor recognition. The physicochemical properties of the host-guest complexes formed by β-cyclodextrin (β-CD) and adamantane were determined by isothermal titration calorimetry (ITC). Ligand-lectin interactions were investigated by surface plasmon resonance experiments (SPR) for the mannose ligands and the lectin Concanavalin A (ConA). Microscale thermophoresis (MST) measurements were applied for sulphate-dependent binding to L-selectin. In both cases, a multivalent affinity enhancement became apparent when the ligands were presented on the CDV scaffold. Furthermore, not only the clustering between our supramolecular mannosylated complex and Escherichia coli (E. coli), expressing the lectin FimH, was visualised by cryo-TEM, but also the competitive character to detach bound E. coli from a cell line, representing the uroepithelial cell surface, was demonstrated. In summary, a facile and effective supramolecular toolbox was established for various ligand-receptor recognition applications.

Pd nanoparticles (NPs) supported on polyaniline (PANI)-coated carbon nanotubes (CNTs) were synthesized using a low-cost and simple method for application in the Heck reaction. The effects of the PANI/CNT coating weight ratio on the catalytic stability and recyclability of the composite were determined by using a combination of experimental and computational methods. The results show that through coordination of the N-species in PANI with the Pd NPs, the nitrogen-rich PANI@CNT provides a strong support for the Pd NPs. The thickness of the PANI layer is the key in determining the stability of the catalyst. PANI becomes protonated in the presence of CNTs, as electron transfer from the former to the latter creates strong interactions between the two. Thus, PANI becomes more stable in nanocomposites with a higher CNT content, e.g., PANI/CNT = 0.5 : 1. The catalyst with a PANI/CNT ratio of 0.5 : 1 exhibited the best recycling performance, and only a small loss of activity was observed after 10 cycles. However, upon increasing the PANI content (e.g., PANI/CNT = 4 : 1), the PANI units tend to form bulk structures that are less stable than those that wrap around the CNTs. Such a structure is unstable; therefore, the PANI layers can easily deform or break away from the CNT backbones. Hence, these catalysts deactivate during recycling. Thus, our study demonstrates that the assembly of noble-metal NPs on CNTs bearing a thin coaxial PANI coating is a powerful technique to prepare reusable catalysts for the Heck reaction. Coating thickness is also a key factor affecting the efficiency and stability of the catalyst.

Zn2+ plays fundamental roles in cellular metabolism and apoptosis, as well as neurotransmission. However, how to fast detect Zn2+ in biology is still challenging and meaningful. In this study, we rationally synthesized a simple OFF–ON fluorescent probe for fast detection of Zn2+ based on intramolecular charge transfer and chelation-enhanced fluorescence. Addition of Zn2+ into the probe induced a significant fluorescence enhancement with a bathochromic shift of 55 nm. Moreover, the probe demonstrated excellent sensitivity (detection limit = 0.072 μM) and outstanding selectivity toward Zn2+ and an ultra-fast response rate of two seconds. The recognition mechanism of the probe toward Zn2+ was fully confirmed by HRMS and 1H NMR spectra, as well as TDDFT calculations. Furthermore, the probe could rapidly visualize Zn2+ in living cells and zebrafish models in bioimaging experiments with low cytotoxicity and good biocompatibility.

This study was aimed to boost the catalytic ability of carbon nanotubes (CNTs) supported Fe-based catalysts, prepared by using wet-impregnation and followed by nitrogenization, for carbon-free hydrogen production from NH3 decomposition at a low temperature. The nitrogenization temperature and iron loading had significant effects on the size of the well-dispersed Fe2N crystallites. The Fe3O4/CNTs catalysts at a higher nitrogenation temperature under NH3 flow with a suitable Fe content led to the formation of the stable and uniformly distributed Fe2N species, which played an active role in the enhanced catalytic ability of the Fe3O4/CNTs catalysts. However, the nitrogenization of the Fe3O4/CNTs catalyst under either H2 or Ar led to the formation of the Fe4N and Fe2N species. In the presence of the Fe4N phases, the Fe3O4/CNTs catalyst exhibited an enhanced catalytic activity. In brief, the collaborative interaction of the active site Fe2N and carbon nanotubes in the Fe2N/CNTs catalysts resulted in a significant increase in the catalytic activity and durability up to 40 h. The effective control of the density of the active sites Fe2N and the synergism between the carrier and the crystallite composition of iron nitrides are the key aspects for the efficient design of the transition nitride catalysts for carbon-free hydrogen production via ammonia decomposition.

We demonstrate fabrication of single-mode circular optofluidic waveguides in fused silica glass substrates using femtosecond (fs) laser assisted chemical etching based on slit beam shaping. The fabrication procedure consists of four steps: slit-assisted fs laser direct writing of fused silica, selective chemical etching, polydimethylsiloxane film bonding, and vacuum-assisted liquid filling. The combination of slit beam shaping and high numerical aperture objectives ensures very narrowly modified lines with nearly circular cross-sections during laser direct writing. Introduction of a string of extra-access ports allows production of uniform circular microchannels with the diameters of ~10 µm and the lengths at the centimeter scale due to the improvement of wet chemical etching process. By vacuum-assisted filling a mixture of liquid paraffin and decane into a microchannel structure, a single-mode circular optofluidic waveguide embedded in glass can be obtained.

In this paper, a new method for rapid oscillation suppression using phase delay motion of the movable pivot is designed. The pivot’s continuous motion control with a lagging phase difference is realized by taking the pendulum’s time delay angle as an input. Based on the intermittent motion control method, the pivot’s continuous motion is used as an auxiliary motion path to trigger the pivot’s intermittent action lagging behind the pendulum motion. The effects of time delay difference and pivot movement distance on the suppression efficiency are analyzed by setting up an experimental device. The principle of the pivot motion with time delay difference to suppress the oscillation is described. Moreover, the energy absorption factor is proposed to evaluate the quality of control methods. The effects of intermittent motion time and suppression efficiency are discussed. The proposed method can provide a practical, theoretical reference on rapid oscillation suppression of pendulum structure.

The search for stable alternative lead-free perovskites has identified all-inorganic antimony/bismuth halide derivatives as promising materials. Despite attractive optoelectronic properties, their wider band gaps and poor morphological control have greatly limited their solar device performance. In this study, we used the indacenodithiophene-based organic acceptor (ITIC) as a Lewis base to improve the morphology of Cs3Sb2I9 films and also as an electron transport layer to form a complimentary heterojunction, and, thereby, enhance the performance of Cs3Sb2I9 solar cells. The presence of cyano and carbonyl groups in ITIC modulated the rate of crystallization of Cs3Sb2I9 and improved its optoelectronic properties. The panchromatic absorption of the Cs3Sb2I9/ITIC heterostructure provided a power conversion efficiency of 3.25% in inverted solar cell structure under 1-sun irradiation. This enhanced performance when using a complimentary absorption strategy suggests a new pathway for developing wider-band-gap lead-free perovskite derivatives for solar cell applications. Moreover, the optimized Cs3Sb2I9/ITIC heterostructure–based solar cell achieved a PCE of 9.2% under indoor illumination at 1000 lx, highlighting the potential use of such devices in indoor applications.

A highly efficient electron transport layer (ETL) is an essential constituent for good performance and stability in planar perovskite solar cells. Among n-type metal oxide materials, zinc oxide (ZnO) is a promising candidate for an electron transport layer due to its relatively high electron mobility, high transparency, and versatile nanostructures. However, it was found that several disadvantages could occur at the ZnO/perovskite interface, such as decomposition of CH3NH3PbI3 and poorly aligned energy levels. To overcome these issues, we present a design based on staircase band alignment of a low-temperature solution-processed ZnO/Al-doped ZnO (AZO) bilayer thin film as electron transport layers in planar perovskite solar cells. Experimental results revealed that the power conversion efficiency (PCE) of perovskite solar cells was significantly increased from 12.3% to 16.1% by employing the AZO thin film as the buffer layer. Meanwhile, the short-circuit current density (Jsc), open-circuit voltage (Voc), a...

In this paper we describe a modified (AEG/CH) coated separator for Li-S batteries in which the shuttling phenomenon of the lithium polysulfides is restrained through two types of interactions: activated expanded graphite (AEG) flakes interacted physically with the lithium polysulfides, while chitosan (CH), used to bind the AEG flakes on the separator, interacted chemically through its abundance of amino and hydroxyl functional groups. Moreover, the AEG flakes facilitated ionic and electronic transfer during the redox reaction. Live H-cell discharging experiments revealed that the modified separator was effective at curbing polysulfide shuttling; moreover, X-ray photoelectron spectroscopy analysis of the cycled separator confirmed the presence of lithium polysulfides in the AEG/CH matrix. Using this dual functional interaction approach, the lifetime of the pure sulfur-based cathode was extended to 3000 cycles at 1C-rate (1C = 1670 mA/g), decreasing the decay rate to 0.021% per cycle, a value that is among the best reported to date. A flexible battery based on this modified separator exhibited stable performance and could turn on multiple light-emitting diodes. Such modified membranes with good mechanical strength, high electronic conductivity, and anti-self-discharging shield appear to be a scalable solution for future high-energy battery systems.

Bisphenol A (BPA) is an industrial material used for many plastic products and is considered an endocrine disruptor. BPA can be released into the environment and can spread through the food chain. It is well known that BPA exposure leads to lesions, especially in the reproductive system. According to previous studies, BPA reduces newborn numbers in pregnant mice and affects placentation. The placenta is a special endocrine organ during pregnancy. It secretes important hormones, such as progesterone and estrogen, to maintain gestation. In steroid hormone synthesis, two specific enzymes are important: P450scc (CYP11A1) converts cholesterol to pregnenolone and aromatase (CYP19) induces androgen conversion to estrogen.To determine the effects of a low dose of BPA on hormone synthesis in the placenta, we used JEG-3 cells as a model. We found that the steroidogenic genes CYP11A1 and CYP19 were downregulated in human tissues by detectable concentrations of BPA (1-1000 nM), which do not affect cell viability. Furthermore, we demonstrated that BPA influenced the ERK signaling pathway and resulted in hormone reductions. An analysis of trophoblasts in primary culture from a term human placenta showed the same phenomena. Our data demonstrate that treatment with a low dose of BPA does not affect human placental cell survival, but decreases hormone production via to the downregulation of steroidogenic genes and ERK signaling pathway changes.

s Mo-based nanoparticles (MoO2 and Mo2C) embedded in porous carbon matrix have been synthesized by a successive hydrothermal and thermal treatment strategy. The synthesized materials were tested for COx-free H2 production via ammonia decomposition. Various characterizations, including N2-sorption, TGA, FTIR, TEM, XRD, EDX and XPS, were employed to investigate the morphology, component and structure of fresh and used catalysts. In terms of fresh Mo@C sample, tiny Mo-based nanoparticles (3–6 nm) are homogeneously dispersed in porous carbon matrixes, which were rapidly nitridized to MoN phases during reaction process. Most of MoN species were still embedded in carbon matrixes after 25 h stability test. For comparison, MoN@C sample was achieved via temperature-programmed ammonolysis of Mo@C sample, demonstrating the formation of MoN species and enhanced activities. The ammonia decomposition activity (∼90% conversion) is obtained over MoN@C catalyst at 600 °C and 15,000 h−1, which is higher than that of non-pretreated Mo@C catalyst. This embedded structure also endows them with a relatively stable performance even at high temperature.

Photogenerated electron/hole recombination greatly limits the catalytic efficiency of TiO 2 , and recently modification with graphene substance has been regarded as an effective way to enhance the photocatalytic performance of TiO 2 . When referring to the fabrication of graphene based materials, the reduction process of graphene oxide has been demonstrated to be a key step. Therefore, it is highly required to develop an efficient and simple route for the GO reduction and the formation of TiO 2 @rGO composites. In this study, we have demonstrated a facile and environmentally friendly strategy for in-situ preparation of the TiO 2 @rGO “dyade” hybrid and systematically investigated the photodegradation efficiency of the resultant composite by utilizing rhodamine 6G as the model pollutant. The obtained TiO 2 @rGO has a significant enhancement in photo energy adsorption leading to the effective photocatalytic degradation reactions. The results indicated that the best performance was conducted by the TiO 2 @rGO (10 wt%, 120 min’s irradiation), which exhibited more than triple the higher photodegradation rate than commercial TiO 2 (P25) nanoparticles mainly due to two aspects, the rapid separation of h + / e − and to improve adsorption. This work provides new insight into the synthesis of TiO 2 @rGO composites as a high performance photocatalyst for the degradation of organic contaminant.

Using a facile new synthesis method, the fabrication of cerium oxide doped birnessite MnO 2 (δ-MnO 2 ) catalysts has been operated, for the toluene catalytic combustion. These samples were investigated by XRD, Raman, TEM, BET, H 2 -TPR and XPS techniques and their catalytic activities were investigated and compared. The catalytic combustion of toluene was investigated as the model reaction for VOCs abatement. The several CeO 2 /MnO 2 based nano composites were accomplished via controlling the molar proportion of potassium permanganate and cerium acetate raw materials. The subtle CeO 2 doped δ-MnO 2 catalyst displayed better reducibility at lower reduction temperature, with the higher Mn 4+ /Mn 3+ ratio, which converts completely the 1000 ppm toluene to CO 2 and H 2 O at 318 °C and its T 90 is 277 °C. The excellent catalytic performance of Mn12Ce1O x catalyst might be resulted from the synergistic effect between the highly dispersed CeO 2 nanoparticles and the δ-MnO 2 substrate at their interface. These new observations provide a new perspective on the design of the high activity catalyst for decomposing the volatile organic compounds (VOCs abatement).

This paper explores the relations between riparian people and states in Southeast Asia’s Mekong-region hydropower projects. These relations are contested: the main actors have been wrestling for supremacy over the hydropower projects, and the struggles are rooted in the people’s relative disempowerment.

The doping effects of nitrogen or boron atom on the stability of defective graphene supported Ni n ( n = 1–6) clusters were explored using density functional theory (DFT) approaches, while the configurations of pyridinic-B and pyridinic-N doped defective graphene (PBG, PNG) were constructed. The binding energies of Ni n clusters on doped defective graphene are both higher than that of Ni n on pristine graphene (PG). It is indicated that the interaction between Ni n clusters and doped graphene is enhanced. PBG has a stronger interaction with Ni n clusters than PNG, and shows a more favorable ability to stabilize Ni n clusters. Further, both PBG and PNG carriers provide sufficient positions for binding Ni atoms. The binding site for Ni 1 and Ni 2 cluster on PBG shifts from the vacancy site to the five-membered ring for Ni 3 - Ni 6 clusters. For the PNG, the defects are the anchoring sites for depositing Ni n clusters. According to the Hirshfeld charge analysis, the Ni n -PBG system shows a different charge transfer way from Ni n -PNG.

The Congruent Matching Cells (CMC) method was invented at the National Institute of Standards and Technology (NIST) for accurate firearm evidence identification and error rate estimation. The CMC method is based on the principle of discretization. The toolmark image of the reference sample is divided into correlation cells. Each cell is registered to the cell-sized area of the compared image that has maximum surface topography similarity. For each resulting cell pair, one parameter quantifies the similarity of the cell surface topography and three parameters quantify the pattern congruency of the registration position and orientation. An identification (declared match) requires a significant number of CMCs, that is, cell pairs that meet both similarity and pattern congruency requirements. The use of cell correlations reduces the effects of “invalid regions” in the compared image pairs and increases the correlation accuracy. The identification accuracy of the CMC method can be further improved by considering a feature named “convergence,” that is, the tendency of the x–y registration positions of the correlated cell pairs to converge at the correct registration angle when comparing same-source samples at different relative orientations. In this paper, the difference of the convergence feature between known matching (KM) and known non-matching (KNM) image pairs is characterized, based on which an improved algorithm is developed for breech face image correlations using the CMC method. Its advantage is demonstrated by comparison with three existing CMC algorithms using four datasets. The datasets address three different brands of consecutively manufactured pistol slides, with significant differences in the distribution overlap of cell pair topography similarity for KM and KNM image pairs. For the same CMC threshold values, the convergence algorithm demonstrates noticeably improved results by reducing the number of false-positive or false-negative CMCs in a comparison.