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The electrochemical synthesis of hydrogen peroxide (H2O2) from two-electron oxygen reduction reaction (2e- ORR) is a promising alternative for producing chemicals on demand, but its widespread application is still hampered by the low efficiency. Here, we successfully prepared a boron and nitrogen co-doped porous carbon (B/N C) aerogel with a tunable B, N co-doped configuration by the gelation of PVA-graphene, borax and PANI, followed by pyrolysis. Due to a hierarchical porous structure and optimized B, N co-doping, B/N C aerogel showed an excellent electrocatalytic performance for H2O2 production in alkaline solution with a high H2O2 selectivity (94.16%) at positive applied potential (0.6 V vs. RHE), superior than most of the other reported electrocatalysts. Density functional theory (DFT) calculations reveal that the hexagonal boron nitride (hBN) coupled with neighboring pyridinic-N species act as the active sites to lower free energy barrier for formation of HOO* intermediate, thus facilitating H2O2 production. Practically, B 2p electron plays an important role for the adsorption of HOO* intermediates. B and N co-doping into carbon materials provides an effective and facile method to reasonably construct carbon-based catalysts for electroreduction of O2 to H2O2.

This paper studies the optimal investment-consumption decision under the constant elasticity of variance (CEV) model for an individual seeking to maximize the expected utility from cumulative consu...

Traditional metal–organic frameworks (MOFs), although have the ability to accumulate some chemicals from solution, are usually electrochemically inert. Here, spherical MIL-53(NiFe) MOFs have been synthesized via a simple solvothermal method. A series of characterization methods including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectrophotometry, energy dispersive X-ray spectroscopy (EDS), and element mapping were used to investigate this material. An MIL-53(NiFe)/AB/GCE-modified electrode was constructed using acetylene black (AB) as the conductive substrate, which can make up for the electrochemical inertness of metal in the MOFs to some extent. Moreover, the bimetallic center can coordinate with the azo functional group in Sudan I to some extent, which is beneficial to the binding of the molecules to the electrode. Thus, the sensitive and rapid detection of Sudan I can be realized. The quantitative determination of Sudan I was carried out via the differential pulse voltammetry (DPV) method in a wider linear range (0.005–10 μM) and lower detection limit (0.002 μM, S/N = 3). The developed method can be successfully applied to the detection of Sudan I in chilli powder and tomato paste with satisfactory results.

Background The biosafety concern of silica nanoparticles (SiNPs) is rapidly expanding alongside with its mass production and extensive applications. The cardiovascular effects of SiNPs exposure have been gradually confirmed, however, the interaction between SiNPs exposure and atherosclerosis, and the underlying mechanisms still remain unknown. Thereby, this study aimed to explore the effects of SiNPs on the progression of atherosclerosis, and to investigate related mechanisms. Results We firstly investigated the in vivo effects of SiNPs exposure on atherosclerosis via intratracheal instillation of ApoE−/− mice fed a Western diet. Ultrasound microscopy showed a significant increase of pulse wave velocity (PWV) compared to the control group, and the histopathological investigation reflected a greater plaque burden in the aortic root of SiNPs-exposed ApoE−/− mice. Compared to the control group, the serum levels of total triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C) were elevated after SiNPs exposure. Moreover, intensified macrophage infiltration and endoplasmic reticulum (ER) stress was occurred in plaques after SiNPs exposure, as evidenced by the upregulated CD68 and CHOP expressions. Further in vitro, SiNPs was confirmed to activate ER stress and induce lipid accumulation in mouse macrophage, RAW264.7. Mechanistic analyses showed that 4-PBA (a classic ER stress inhibitor) pretreatment greatly alleviated SiNPs-induced macrophage lipid accumulation, and reversed the elevated CD36 expression induced by SiNPs. Conclusions Our results firstly revealed the acceleratory effect of SiNPs on the progression of atherosclerosis in ApoE−/− mice, which was related to lipid accumulation caused by ER stress-mediated upregulation of CD36 expression in macrophage. Graphical abstract

The occurrence of acesulfame (ACE) in two full-scale drinking water treatment plants (DWTPs) in Zhejiang Province, China, was investigated. The results showed that ACE was commonly detected in the ...

To deal with the multi-objective optimization problems (MOPs), this study proposes a new Multi-Objective Multi-Agent Complex Network Optimization Algorithm called MOMCNA based on the idea of Cellular genetic algorithm (CGA) and the Multi-agent complex network. Compared with the traditional CGA for multi objective problem, the individuals in the population of MOMCNA have more features of intelligent agent, the new form of neighborhood for the population, private archive for individuals, the new strategy of “local-global” genetic operator and the chaotic mutation are proposed in the new algorithm to balance the convergence and diversity of the algorithm. Seventeen unconstrained multi-objective optimization problems and seven many-objective problems are introduced and tested to evaluate the new algorithm, in addition, the classical traffic assignment problem based on different system optimum principle is also established to evaluate the new algorithm. The comparison between MOMCNA and other classical algorithms shows that the proposed MOMCNA proves to be competitive in dealing with multi-objective and many-objective optimization problems and the structure of the complex network made up of population also has effect on algorithm’s performance.

To analyze the effect of customer enterprises’ behavior on freight transport markets with various products, a bi-level programming model for freight pricing is developed. The transport companies make decisions in the upper level, a large number of customer enterprises make decisions at the lower level. Cumulative prospect theory is adopted to depict customers’ bounded rationality. The complex network model is introduced to construct the interactions among customer enterprises where the changes in their risk attitudes are depicted by dynamic evolution of their heterogeneous reference points. The existence of the generalized Nash equilibrium is proved and verified. A comparison of the optimal solutions of the new model and the traditional logit based choice model is conducted. The results show that (1) the new model fully embodies the characteristics of cumulative prospect theory and can also improve customers’ utility; (2) the equilibrium freight price and the total profits of transport companies increase with increases in the customers’ interaction intensity.

The development of hydrogels with excellent mechanical properties is highly desirable in both fundamental studies and practical applications. But it is difficult to construct hydrogels that are both tough and stiff at the same time as these properties often contradict each other. Here, we report a facile and efficient method for producing ultrastiff and tough poly(N-isopropylacrylamide) (PNIPAM)/clay plastic-like hydrogels (PHs) by immersing PNIPAM/clay hydrogel into NaCl aqueous solution. The optimized PH-2-6 presented superior strength, modulus, and toughness (4.1 ± 0.2 MPa, 41.6 ± 8 MPa, and 15.85 ± 0.8 MJ m-3, respectively). The unique mechanical properties are attributed to the synergistic effect of the osmotic pressure and the strong affinity between Na+ ion and the PNIPAM chain, which lead to a high degree of PNIPAM chain entanglement and fixing. Note that the PHs were molded into any required shape under an applied force, and retained permanently their shapes even if the load was removed, thus displaying typical plasticity. However, the deformed PHs could return to their original size and softness of hydrogel when immersed in pure water, which is a kind of shape-memory effect. The reversible conversion of elasticity and plasticity and shape memory arise from a kind of dynamic physical across-linking of Na+ and PNIPAM molecular chains, which could exist in the salt aqueous and disintegrate in water reversibly. Moreover, the mechanical properties of hydrogel can be tuned by adjusting the salt concentration and immersion time. The facile strategy may provide further avenue in developing hydrogels with such versatile dynamic behaviors to expand their applications.

Mass production of manganese-doped silica nanowires (Mn-SiONWs) have been achieved by a simple method of thermal evaporation of SiO and Mn powders. Tunneling electron microscope studies reveal manganese silicide nanodots with an average diameter of 3.52 nm embedded in the SiONWs. Based on the characterizations of the novel microstructures, a plausible growth mechanism for the Mn-SiONWs was proposed by considering the catalytic role of SiO and Ostwald Ripening process during the growth. Quantitative simulation was then performed to understand the narrow size distribution of the nanodots, and the critical radius about 1 nm for the nanodot formation was obtained. Finally, the photoluminescence properties and their relationship with the microstructures were studied.

As an important issue in the field of computer vision, object detection has broad application prospects. Recent researches using convolutional neural networks (CNN) have shown the state-of-the-art results in the challenge competition. Most of them focused on improving the precision under ideal imaging conditions. However, it is hard to ensure that the optical imaging system works in the focused state in practice. In this study, we examine the impact of defocus on detection accuracy. The results show that even the state-of-the-art network is sensitive to a different defocus situation. Thus we put forward wavefront coding (WFC) technique for improving the performance over a large range of depth of field (DOF). Simulation results indicate the improvement on average precision of detection results by applying WFC. In addition, we propose a novel WFC method for overcoming the defects of the traditional one. Then the optical imaging system is designed under the guidance of the proposed theory. Experiments are conducted to suggest that the detection accuracy rate can be enhanced considerably with WFC.

In this study, mild temperature was applied to enhance norfloxacin (NOR) degradation in nanoscale zero-valent copper (nZVC) activated persulfate (PS) process and the underlying activation mechanism was detailedly elaborated. Results showed that the activation performance of nZVC was far superior than that of micro zero-valent copper (mZVC), and almost complete elimination of 31.32 μM NOR was achieved within only 5 min in the condition of 0.05 g/L nZVC and 1.0 mM PS at 40 °C. The in-situ generated Cu+ was found to be the pivotal active copper species for PS activation and the presence of dissolved oxygen was favorable for its release. Mild temperature not only accelerated the Cu+ release from the nZVC corrision, but provided more opportunity for intermolecular collision to quickly form reactive oxygen species. SO4−∙ and ∙OH played the primary role for NOR destruction, while O2−· and H2O2 served as the mediators for copper cycling. The higher PS concentration favored NOR removal, whereas overdosing nZVC exerted the negative impact. Further increasing reaction temperature significantly accelerated the elimination of NOR in nZVC/PS process. The satisfactory removal of NOR was achieved under the acidic and neutral conditions. The NOR oxidation in the tested process was found to follow four routes and the cleavage of piperazine ring was determined to be the primary one. These encouraging results demonstrated that mild temperature enhanced nZVC/PS process was a promising strategy for the treatment of refractory and non-biodegradable industrial wastewater.

Multi-objective pricing of high-speed rail (HSR) passenger fares becomes a challenge when the HSR operator needs to deal with multiple conflicting objectives. Although many studies have tackled the challenge of calculating the optimal fares over railway networks, none of them focused on characterizing the trade-offs between multiple objectives under multi-modal competition. We formulate the multi-objective HSR fare optimization problem over a linear network by introducing the epsilon-constraint method within a bi-level programming model and develop an iterative algorithm to solve this model. This is the first HSR pricing study to use an epsilon-constraint methodology. We obtain two single-objective solutions and four multi-objective solutions and compare them on a variety of metrics. We also derive the Pareto frontier between the objectives of profit and passenger welfare to enable the operator to choose the best trade-off. Our results based on computational experiments with Beijing–Shanghai regional network provide several new insights. First, we find that small changes in fares can lead to a significant improvement in passenger welfare with no reduction in profitability under multi-objective optimization. Second, multi-objective optimization solutions show considerable improvements over the single-objective optimization solutions. Third, Pareto frontier enables decision-makers to make more informed decisions about choosing the best trade-offs. Overall, the explicit modeling of multiple objectives leads to better pricing solutions, which have the potential to guide pricing decisions for the HSR operators.

In this study, a mitochondria-targeted dual-reactable fluorescent probe was developed, which can rapidly react with H2S in physiological buffer (pH = 7.4) to give red emission. This probe exhibited good selectivity to H2S over other biologically relevant species based on dual-reactable groups (7-nitro-1,2,3-benzoxadiazole amine and aromatic azide). Furthermore, the probe could be used to image chiral cysteine-induced endogenous mitochondrial biosynthetic of H2S in HEK293A cells, and could also be applied to detect H2S in mice.

A series of Co3O4-CeO2 mixed metal oxides were synthesized by co-precipitation method and successfully used to activate persulfate for diclofenac removal. The effects of Co:Ce mole ratio, calcination temperature and calcination time on the catalytic activities were investigated. Results showed that the activity of Co3O4-CeO2 catalysts increased with Co:Ce mole ratio from 1:9 to 7:3, and decreased with the calcination temperature from 300 to 800 °C. 90% diclofenac was removed with Co7Ce3-300-1 catalyst (Co:Ce = 7:3, calcinated at 300 °C for 1 h) after 15 min. Moreover, short calcination time and low temperature resulted in smaller crystallite size, more structural defects, more active crystal surfaces and larger surface area of the catalyst, which led to higher removal efficiency of diclofenac. The high ratios of Co2+/Co3+, Ce3+/Ce4+ and Oads/Olatt were very important to enhance the catalytic activity. Finally, a potential reaction mechanism was proposed based on characterization of the fresh and spent catalysts.

A pilot carbon emissions trading scheme (ETS) has been launched for three years in the Guangdong (GD) Province in China, with the power industry contributing nearly 66% of the covered CO2 emissions...

A novel two-photon HNO fluorescent probe (TP-HNO) was easily constructed and prepared by combining 6-acetyl-2-naphthol and 2-(diphenylphosphino)-benzoate. TP-HNO exhibited high selectivity (more than 140-fold off–on fluorescence response) and high sensitivity (the detection limit is 78 nM) to HNO in solution. TP-HNO was also applied for two-photon imaging of HNO in living cells and in tissues.

Ga-, Y- co-doped Li7La3Zr2O12 ceramic electrolytes with composition of Li7-3xGaxLa3-yYyZr2O12 (x = 0.2 and y = 0, 0.125, 0.25, 0.5) were prepared via conventional solid-state reaction in air and characterized using X-ray diffraction (XRD), Raman spectra, scanning electron microscopy (SEM) and AC impedance spectroscopy. XRD analysis and Raman spectra showed that all samples formed a single cubic phase with garnet-type structure. Among the materials investigated, Li6.4Ga0.2La2.75Y0.25Zr2O12 sample presented the highest lithium-ion conductivity of 1.61 mS cm−1 at room temperature, a minimum activation energy of 0.281 eV along with the maximum relative density of 96.6%. The stability of Li6.4Ga0.2La2.75Y0.25Zr2O12 material was also investigated in liquid electrolyte, air, LiCl solution, deionized water and LiOH solution. Although the Li+/H+ exchange was confirmed by XRD, Raman spectra, Fourier Transform infrared spectroscopy (FTIR) and thermo-gravimetric analysis (TGA), the garnet-type cubic structure was found to be stable for the sample after immersion in organic liquid electrolyte, in LiCl solution, deionized water, at room temperature for two weeks. The lithium-ion conductivity was more or less decreased in the sample treated in air, LiCl solution, deionized water and LiOH solution. However, no decrease in conductivity was observed in the sample upon organic liquid electrolyte treatment for a long time, making it a suitable alternative in fabricating hybrid lithium-ion batteries. Therefore, through construction of the symmetric Li/Garnet/Li cells, the interfacial resistance decreases from 970 to 205 Ω cm2 by adding liquid electrolyte as a buffer layer. Meanwhile, the full cells consisting of hybrid electrolyte, lithium-metal anode, and LiCoO2 cathode demonstrate a high initial discharge capacity of 140 mAh g−1 and excellent cycling stability with 130 mAh g−1 retained after 100 cycles at a charge/discharge rate of 15 mA g−1 at room temperature.

The remediation of water polluted by fluroquinolones antibiotics remains an important issue. Although zero-valent copper (ZVC) coupled with molecular oxygen can destruct refractory organic pollutants, the activation efficiency still needs to be further improved. In this study, the introduction of ascorbic acid (AA) in ZVC/air process maintained a high-concentration of Cu(Ⅰ), which can efficiently activate molecular oxygen to generate reactive oxygen species (ROSs). Superoxide radicals and hydroxyl radicals coexisted in nZVC/AA/air system. The former contributed to the yield of H2O2 and also acted as a mediator for Cu(Ⅱ)/Cu(Ⅰ) redox cycles, the latter was the pivotal ROSs for ciprofloxacin (CIP) destruction. The CIP degradation decelerated through the addition of excessive nZVC and AA, and the optimum dosages of nZVC and AA were determined to be 0.2 g/L and 1 mM, respectively. The developed nZVC/AA/air process could efficiently operate in a relative broad pH range of 3.0–7.0, which was due to the fact that AA prevented the precipitation of copper ions in solution via forming stable chelates. The coexistence of Cl− severely retarded the CIP removal. According to the results of UPLC-MS/MS analysis and density functional theory calculations, the plausible degradation pathways including the decarboxylation, defluorination, hydroxylation and cleavage of C–C bond in piperazine ring were proposed.

The extensive application of silica nanoparticles (SiNPs) brings about inevitable occupational, environmental, and even iatrogenic exposure for human beings. The liver, which is rich in mitochondria, is one of the target organs of SiNPs, but the underlying mechanisms by which these nanoparticles (NPs) interact with liver mitochondria and affect their functions still remain unclear. In the present study, we examined silicon nanoparticle (SiNP)-induced mitochondrial dysfunction, and further revealed its negative effects on mitochondrial quality control (MQC) in the human liver cell line L-02, including mitochondrial dynamics, mitophagy and biogenesis. Consequently, SiNPs induced cellular injury, accompanied by mitochondrial dysfunction, including mitochondrial reactive oxygen generation and mitochondrial membrane potential collapse. In line with the transmission electron microscopy (TEM)-observed abnormalities in the mitochondrial morphology and length distribution, a fission phenotype was manifested in the mitochondria of SiNP-exposed cells, and up-regulated DRP1 and FIS1, and down-regulated MFN1, were detected. Furthermore, the enhanced LC3II level, colocalization of the mitochondria and lysosomes, activated PINK1/Parkin signaling, and accumulated p62 in the SiNP-exposed cells suggested mitophagy disorder triggered by SiNPs. In addition, SiNPs inhibited mito-biogenesis, as evidenced by the reduced mitochondrial mass and mtDNA copy number, as well as the suppressed PGC1α-NRF1-TFAM signaling pathway. Overall, the study demonstrates that SiNPs trigger hepatocytotoxicity through interfering with the MQC process, bringing in excessive mitochondrial fission, mitophagy disorder and suppressed mito-biogenesis, leading to mitochondrial dysfunction and ensuing cell damage, and ultimately contributing to the occurrence and development of liver diseases. Our research could provide important experimental evidence related to safety assessments of SiNPs, especially in the field of biomedical applications.

Magnetic ferrites were used as heterogeneous peroxymonosulfate (PMS) activators for bisphenol A (BPA) degradation, in which activation performance, mechanism and application feasibility were investigated in depth. The results demonstrated that BPA depletion in ferrites activated PMS processes could be described by pseudo-first-order kinetic model and the BPA degradation was in the sequence of CoFe2O4 > MnFe2O4 > CuFe2O4 > Fe3O4. Comprehensive consideration of activation performance, operating cost and toxicity risk, MnFe2O4 might be the most ideal PMS activator. MnFe2O4/PMS process could efficiently work in wide pH range of 4.0–10.0 and acidic pH was more favorable for the oxidation. The introduction of natural organic matter, sulfate, bicarbonate and low concentration of chloride retarded BPA removal. Contrastingly, the presence of high level of chloride greatly stimulated the degradation. A reasonable mechanism for PMS activation by MnFe2O4 was evidenced by free radical identification and XPS measurements, illustrating that the cycles of Mn(II)-Mn(III)-Mn(II) and Fe(III)-Fe(II)-Fe(III) were involved during the oxidation and sulfate and hydroxyl radicals were both responsible for BPA degradation. MnFe2O4 showed excellent reusability and long-term stability, which was testified by the detailed characterizations of fresh and spent catalysts. MnFe2O4/PMS process not only achieved efficient degradation of different emerging organic pollutants in ultrapure water, but gained high-efficient depletion of low concentration of BPA in surface waters. More importantly, potential risk derived from BPA degradation could be effectively controlled by MnFe2O4/PMS process.

Beginning with an introduction of the concept, situation, and application of big data, the authors discuss current challenges and propose a data-objective spectrum-based technology. They also propose the idea of a model group along two dimensions: the transition from a qualitative concept and unstructured data to a quantitative value in one dimension, and the Pareto optimal frontier of generalization ability in another. In the end, the feasibility of the framework proposed is illustrated based on the example of peoples behavior pattern acquisition.

In this work, five different metal-oxide additives (metal = Ba, Co, Fe, Li, and Mn) were examined as sintering aids and SiO2 impurity scavengers for Ce0.8Sm0.2O1.9 (SDC). 2 mol% additives were loaded into the SDC with ∼150 ppm (moderately impure) and ∼2000 ppm (highly impure) SiO2. Ba-, Co-, Fe- and Mn-oxides showed comparative sintering-aid effect on both moderately- and highly-impure SDC specimens, but the sintering-assisting effect of Li-oxide was completely neutralized in highly impure SDC. Regarding electrical property, the deleterious effect of 2000 ppm SiO2 impurity on the grain-boundary conduction of SDC can be effectively alleviated by adding Ba-, Co-, Fe-, or Mn-oxides. Microstructure analysis revealed that Ba-oxide reacted directly with SiO2 and consequently enhanced grain-boundary conduction. By contrast, with the addition of Co-, Fe-, and Mn-oxides, the improved grain-boundary conductions of impure SDC were related to the scavenging reactions between Si, Ca (another original impurity) and Sm components.

Designing and fabricating cheap and active bifunctional materials is crucial for the development of renewable energy technologies. In this article, three-dimensional nitrogen-doped porous carbon materials (NDPC-X, in which X represents the pyrolysis temperature) were fabricated by simultaneous carbonization and activation of polypyrrole-coated paper towel protected by a silica layer followed by acid etching. The material had a high specific surface area (1,123.40 m2/g). The as-obtained NDPC-900 displayed outstanding activity as a catalyst for the oxygen reduction reaction (ORR) as well as an electrode with a high specific capacitance in a supercapacitor in an alkaline medium. The NDPC-900 catalyst for the ORR exhibited a more positive reduction peak potential of −0.068 V (vs. Hg|HgCl2) than that of Pt/C (−0.121 V), as well as better cycling stability and stronger methanol tolerance. Moreover, the NDPC-900 had a high specific capacitance of 379.50 F/g at a current density of 1 A/g, with a retention rate of 94.5% after 10,000 cycles in 6 mol/L KOH electrolyte when used as an electrode in a supercapacitor. All these results were attributed to the effect of a large surface area, which provided electrochemically active sites. This work introduces an effective way to use biomass-derived materials for the synthesis of promising bifunctional carbon material for electrochemical energy conversion and storage devices.

Polymorphism in functional materials offers an excellent platform for comparative investigations of the structure–property relationship and thus the rational design of functional materials with enhanced performances. Here, we report a facile and selective fluorination route to phase-pure gadolinium oxyfluorides crystallizing in orthorhombic (O-GdOF) and rhombohedral (R-GdOF) structures. The phase selectivity can be achieved simply by controlling the reaction temperature and the amount of the fluoridizer (polytetrafluoroethylene). A reversible phase transition from R-GdOF to O-GdOF was observed around 600 °C upon heating and cooling, which was further confirmed by the in situ X-ray diffraction results. Trivalent rare-earth ion (RE3+) doping makes O- and R-GdOF potential bifunctional materials for optical imaging and magnetic resonance imaging (MRI) applications. Under near infrared (NIR) irradiation (980 nm), both RE3+-doped O- and R-GdOF exhibit intriguing visible upconversion (UC) emissions with a tunable G/R ratio (RE = Yb/Ho), near single-peak red emissions around 660 nm (RE = Yb/Er) and NIR emissions around 800 nm (RE = Yb/Tm). RE3+-doped O- and R-GdOF also show discrepant UC profiles in terms of emission intensity, peak shape and G/R ratios attributed to the subtle symmetry differences of the RE3+ doping sites. Besides, the ability of RE3+-doped O- and R-GdOF to serve as T2 weighted MRI contrast agents was evaluated. The results show that R-GdOF performs better than O-GdOF in T2 weighted MRI with higher r2 relaxivity values and r2/r1 ratio. The exploration of more RE oxyfluorides with multimorphism and the comparative studies of their optical performances will provide deep insight into their structure–property relationship and accelerate the rational design of better multifunctional materials.

As a typical iron-based oxide semiconductor with abundant reserves, α-Fe2O3 has been widely used in the domain of photocatalysis and environmental remediation. Here, sulfur doped α-Fe2O3 (S-α-Fe2O3) has been successfully fabricated through coprecipitation, hydrothermal and calcination processes and applied to activate persulfate (PS) for carbamazepine (CBZ) degradation under UV irradiation. Systematic characterizations were conducted to analyze the morphology, structure and chemical composite of S-α-Fe2O3. UV/PS/S-α-Fe2O3 process showed remarkably enhanced photocatalytic performance for CBZ degradation. The degradation rate constant (7.78 × 10−2 min−1) was about 2.2 and 14.1 times as high as that of UV/PS/α-Fe2O3 (3.60 × 10−2 min−1) and UV/PS (5.53 × 10−3 min−1) processes, respectively. With increasing PS concentration and photocatalyst dosage, the removal efficiency of CBZ both increased. UV/PS/S-α-Fe2O3 process can efficiently and steadily operate in a wide pH range of 3.0–8.0. The introduction of water matrix species (i.e. chloride, bicarbonate, nitrate and humic acid) exerted different effects on CBZ degradation. S-dopant was doped via forming ≡FeIII-SO42- bond on S-α-Fe2O3 surface, and doped sulfur functioned as surface electrons trapping centers derived from DFT study. The band gap value of S-α-Fe2O3 was reduced and the separation efficiency of photogenerated electrons and holes was improved. Hydroxyl radicals, sulfate radicals, superoxide radicals and holes all contributed to CBZ destruction. Furthermore, two major routes of CBZ degradation were proposed as hydroxylation and deamination, then followed by decarbonxylation, ketonization and ring cleavage based on the results of HPLC-MS and DFT calculation.

As a globally important artificial sweetener, sucralose (SUC) is a persistent emerging contaminant in global aquatic environments. This research comprehensively track the fate and transport of SUC throughout an urban water cycle; to perform laboratory experiments to determine chlorinated disinfection by-products (DBPs) of SUC sebsequent to advanced oxidation with ozone; and to perform a risk evaluation of SUC related DBPs.; The results demonstrated that SUC was consistently present throughout the urban water cycle, including consumer's tap water. The inluent to the municipal wastewater treatment plant contained 1033.4-2626.3 ng/L SUC, and as expected for this non-biodegradable artificial sweetener, the concentration in the effluent was slightly reduced to 917.6-2031.2 ng/L. The concentration of SUC varied in surface waters with a peak value of 2070.0 ng/L. In finished drinking water 288.1–505.3 ng/L SUC was found, and values of 177.7–409.7 ng/L were present in the distribution system. Up to 16.3% of SUC concentration discharged as municipal wastewater was delivered to residents in their drinking water. While conventional treatment little removed SUC, the mean removal efficiency of SUC with ozonation followed by activated carbon filtration was 39.6% at a full-scale drinking water treatment plant. The fate and transformation of SUC in drinking water treated by ozonation and chlorination were investigated in laboratory experiments. Ozonation partially degraded SUC; however, intermediates reacted with chlorine to generate DBPs, including trichloromethane (TCM), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA). Peak 7-days potential formation of TCM, DCAA and TCAA were 0.016, 0.51 and 23.34 μ g/mg SUC, respectively. DBP yields increased with increasing chlorine dosage, chlorination time, temperature, and solution pH. The presence of ammonia nitrogen in water facilitated dichloroacetonitrile (DCAN) production up to 0.78 μ g/mg SUC, while simultaneously reducing the yield of TCM, DCAA and TCAA. Human exposure analysis revealed that carcinogenic risks of DBPs caused only by SUC ozonation were in the range of 1.86 × 10−12-6.12 × 10−9, while non-carcinogenic risks were in the range of 6.0 × 10−9-4.37 × 10−6. The pervasive occurrence of SUC in an urban water cycle, couple to its resistance to biological and chemical treatment, confirms that SUC is a persistent contaminant in the aquatic system, including tap water.

The anti-oxidation behavior of boron aluminosilicate glass-ceramic materials with different MoO3 content deposited on titanium in temperatures range 850–1050 °C were investigated. The experimental results showed that in comparison with the bare titanium, the weight gain of specimen without MoO3 decreased from 18.7 to 0.6 mg/cm2 after 100 h oxidation at 850 °C.The addition of MoO3 was able to provide further decrease on the oxidation rate of titanium from 0.6 to 0.1 mg/cm2. The 20 wt.% MoO3 system measured the least weight gain and maximum tensile strength which was between the substrate and the coating for 30.1 MPa at 850 °C for 100 h whilst led to the peak retained strength value with 8.7 MPa after 30 times thermal cycles to 700 °C. The EDS line scanning images revealed that a molybdenum rich interlayer was detected in between the substrate and coating layer with average width of about 2 μm and it was believed that it did play an essential part in blocking the inward diffusion of oxygen to titanium.

The multi-channel fully convolutional networks is designed.We segment liver tumors from multiphase contrast-enhanced CT images.We train one network for each phase of CT images and fuse their high-layer features together.This method can make full use of the characteristics of different enhancement phases of CT images.The results showed our model provided greater accuracy and robustness than previous methods. This paper presents a novel, fully automatic approach based on a fully convolutional network (FCN) for segmenting liver tumors from CT images. Specifically, we designed a multi-channel fully convolutional network (MC-FCN) to segment liver tumors from multiphase contrast-enhanced CT images. Because each phase of contrast-enhanced data provides distinct information on pathological features, we trained one network for each phase of the CT images and fused their high-layer features together. The proposed approach was validated on CT images taken from two databases: 3Dircadb and JDRD. In the case of 3Dircadb, using the FCN, the mean ratios of the volumetric overlap error (VOE), relative volume difference (RVD), average symmetric surface distance (ASD), root mean square symmetric surface distance (RMSD) and maximum symmetric surface distance (MSSD) were 15.64.3%, 5.83.5%, 2.00.9%, 2.91.5mm, 7.16.2mm, respectively. For JDRD, using the MC-FCN, the mean ratios of VOE, RVD, ASD, RMSD, and MSSD were 8.14.5%, 1.71.0%, 1.50.7%, 2.01.2mm, 5.26.4mm, respectively. The test results demonstrate that the MC-FCN model provides greater accuracy and robustness than previous methods.

A facile electrochemical sensor for dopamine detection was successfully fabricated by the modification of gold nanoparticles (AuNPs) and poly(hydroquinone) film on three-dimensional nickel foam. The results of scanning electron microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry measurements demonstrated the successfully preparation of the sensor. The effect factors of electrodeposition time of AuNPs, polymerization pH, cycles of polymerization and rate of polymerization were optimized for the sensor preparation. Under the optimized conditions, the prepared sensor exhibited selective and sensitive detection capacities toward dopamine. The linear response to dopamine ranged from 1.0 × 10 − 7 mol/L to 1.0 × 10 − 5 mol/L with a detection limit of 4.19 × 10 − 8 mol/L. Moreover, the sensor could be applied in the detection of dopamine in real samples with satisfactory results.

In this work, a visible-light-driven catalyst of Ag/g-C3N4/Chitosan (Ag/g-C3N4/CS) was developed by a facile soniation-assisted method at room temperature. The surface morphology, crystal structure and chemical composition of the as-prepared catalyst was systematically characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and electrochemical impedance spectra (EIS). The photocatalytic activity of Ag/g-C3N4/CS nanocomposite was evaluated on the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by sodium borohydride (NaBH4) without separating AgNPs/RGO nanocomposite from the synthesis systems. The result shows that the as-prepared nanocomposite exhibits enhanced photocatalytic activity.

Well-dispersed zinc oxide/cyclized polyacrylonitrile (ZnO/CPAN) nanocomposites were prepared by a facile in-situ precipitation method. The mixture solution of dimethyl sulfoxide containing zinc nitrate and polyacrylonitrile (PAN) was added dropwise into ammonia water under vigorous magnetic stirring. Accompanied by the precipitation of PAN in water, zinc hydroxide were simultaneously formed via in-situ reaction of zinc nitrate with hydroxyl ions, leading to the uniform dispersion of zinc hydroxide nanoparticles in the precursor of ZnO/PAN nanocomposites. Then ZnO/CPAN nanocomposites were prepared by calcining the obtained precursor at 250 °C in nitrogen atmosphere via cyclization/dehydrogenation reaction of PAN and decomposition reaction of Zn(OH)2. The as-prepared ZnO/CPAN nanocomposites were characterized by XRD, SEM, XPS, UV–vis DRS, PL, etc. Results show that CPAN molecules in ZnO/CPAN nanocomposites significantly decrease the mean size of ZnO nanocrystals, increase the quantity of oxygen defects in ZnO particles, improve the absorbance of ZnO in the whole wavelength range especially in the visible-light range, and obviously reduce the recombination probability of photo-generated electron/hole pairs. The photocatalytic activity of ZnO/CPAN nanocomposites was evaluated by photodegradation of methyl orange (MO) solution under visible light irradiation. Experiment results reveal that the apparent rate constant k of MO photodegradation under visible light irradiation photocatalyzed by ZnO/CPAN (0.361 h−1) is 1.28, 5.84 and 25.8 times of that by AgBr (0.282 h−1), Ag3PO4 (0.0618 h−1) or g–C3N4 (0.0140 h−1), respectively, meaning that ZnO/CPAN exhibits much higher visible-light photocatalytic activity than these typical visible-light photocatalysts. The visible-light photocatalytic mechanism has been discussed.

The novel ternary cyclized polyacrylonitrile (CPAN)/Ag/AgCl composites were successfully synthesized by a facile precipitation and photo-assistant reduction method. The CPAN/Ag/AgCl particles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectroscopy, UV–vis diffuse reflectance spectroscopy (UV–vis DRS), photoluminescence spectroscopy (PL), electrochemical impedance spectra (EIS) and photocurrent time (EI) measurement. The photocatalytic activities of the samples were investigated through the decomposition of methyl orange (MO) and rhodamine B aqueous solution under visible-light irradiation. The results showed that the CPAN/Ag/AgCl photocatalysts displayed much higher visible-light photocatalytic activity than Ag/AgCl, and the reaction rate constant of the MO degradation catalyzed by CPAN/Ag/AgCl is about 3 times of that by Ag/AgCl. It is proposed that the photogenerated holes h+ and O2− played important roles in the photocatalytic degradation of MO in the presence of CPAN/Ag/AgCl composites under visible light irradiation.

Free amino acids (FAAs) are key components of the global nitrogen cycle and important disinfection byproduct (DBP) precursors. The knowledge gap of FAA occurrence in source and engineered water is discussed in this paper. Solid phase extraction and post column derivatization was combined with gas chromatography&ndash, mass spectrometry to simultaneously detect &mu, g/L concentrations of FAAs. This method efficiently detects alanine (Ala), threonine (Thr), serine (Ser), valine (Val), leucine (Leu), isoleucine (Ile), proline (Pro), aspartic (Asp), phenylalanine (Phe), and glutamic acid (Glu) with good linearity, accuracy, and precision. An investigation of FAAs in surface waters in Zhejiang Province found concentrations of 1.48&ndash, 14.73 &mu, g/L Ala, 0.20&ndash, 2.39 &mu, g/L Thr, 0.41&ndash, 7.84 &mu, g/L Val, 0.21&ndash, 6.86 &mu, g/L Ser, 0.11&ndash, 4.16 &mu, g/L Leu, 0.57&ndash, 1.54 &mu, g/L Ile, 0.24&ndash, 8.06 &mu, g/L Pro, 0.42&ndash, 4.73 &mu, g/L Asp, 0.30&ndash, 3.01 &mu, g/L Phe, and 0.12&ndash, 3.83 &mu, g/L Glu. Phe and tyrosine (Tyr) exhibited higher trichloromethane (TCM) formation (1029&ndash, 1148 &mu, g/mmolAA) than dichloroacetonitrile (DCAN) formation (333&ndash, 347 &mu, g/mmolAA). Asp and Glu demonstrated the opposite trend: higher DCAN (570&ndash, 1106 &mu, g/mmolAA) formation than TCM (137&ndash, 506 &mu, g/mmolAA).

Nitroxyl (HNO) plays an important role in multiple physiological and pathological processes, but the detailed generation mechanism of the endogenous HNO still remained to explore and perfect further. There is an urgent need to develop an excellent fluorescent probe for selective recognition and sensitive detection of HNO in biological systems. Near-infrared (NIR) fluorescent probes with a large Stokes shift are an ideal tool for bioimaging applications. Here, we have developed a NIR fluorescent probe with a large Stokes shift, namely, NIR-HNO, to monitor HNO in cells and zebrafish. NIR-HNO consists of an isophorone-fused NIR fluorescence reporter and a diphenylphosphinobenzoyl HNO-responsive unit. Based on an aza-ylide intramolecular ester aminolysis reaction, NIR-HNO showed a rapid selective NIR fluorescent turn-on response for HNO, high sensitivity (detection limit was 39.6 nM), and large Stokes shift (265 nm). The biological imaging results indicate that NIR-HNO is a good candidate for imaging of endogenous HNO in living systems.

Hydrazine (N2H4) has been classified as a potential carcinogen with its high toxicity, which can be readily absorbed through the skin or via breathing directly. Although some fluorescent probes have been developed for imaging of N2H4, very little can be used for imaging of N2H4 in vivo because of its short emission wavelength. In this study, a new colorimetric and near-infrared (NIR) fluorescent probe CF-1 based on a seminaphthorhodafluor dye was successfully designed and used for hydrazine determination. Upon reaction with N2H4, probe CF-1 showed obvious off-on NIR emission spectrum centered at 657 nm, as well as a distinct color change that can be distinguished by the naked eye. The results of fluorescence spectrum experiments indicated that probe CF-1 has high selectivity and low detection limitation (40.6 nM in the solution). Probe CF-1 has low cytotoxicity and was applied to imaging hydrazine in mitochondria of HeLa cells and in zebrafish.

The environmental impact and health risk of carbamazepine (CBZ) in water environment has been continuously reported. Ultraviolet C (UVC)/persulfate (PS) and UVC/chlorine (NaClO) processes were confirmed to be able to efficiently eliminate CBZ through the oxidation by reactive radicals (52.82% SO4−· and 44.21% ·OH in UVC/PS system, 53.47% RCS and 43.84% ·OH in UVC/chlorine process, pH 7.0). The second-order rate constants of CBZ reacted with ·OH, SO4−· and RCS were determined to be 8.2 × 109, 9.1 × 108 and 4.2 × 1010 M−1 s−1, respectively. In both processes, increasing oxidants dosage and rising temperature was favorable for elimination, while increasing CBZ concentration retarded its degradation rate. The coexisting of NOM, SO42− and CO32–/HCO3– presented the inhibitory effect, while NO3– promoted the removal. NH4+ exerted an inhibitory effect in UVC/chlorine process, while exerted no obvious influence in UVC/PS system. Cl− posed a promoting role in UVC/PS treatment and a dual effect in UVC/chlorine process. pH affected the quantum yield of chlorine photolysis and the formation of RCS and ·OH. The degradation of CBZ oxidation via UVC/chlorine process was more pH dependent. 12 and 14 CBZ oxidation products were identified in UVC/PS and UVC/chlorine systems, respectively. SO4−·, RCS and ·OH were readily to attack C = C in CBZ molecule, mainly yielding hydroxylated CBZ, epoxy CBZ, pyridine aldehydes and ketones. Of the disinfection by-products (DBPs) assessed, both processes controlled the formation of haloacetic acids, while increased the generation of trichloromethane, especially via UVC/chlorine process. UVC/chlorine process was more economical and effective (EEO UVC/chlorine = 0.2213 kWh L−1), whereas UVC/PS process was safer in terms of DBPs and toxicity control.

To address the problem of traditional surface illuminated detectors being of low responsivity, this work proposes a large-size interdigitated “finger-type” germanium-on-silicon (Ge-on-Si) photodetector (PD) based on the surface illumination approach. For 1550 nm light with a surface incident power of -20 dBm at room temperature, the best responsivity of the PD achieved is ∼0.64 A/W at 0.5 V. At the same time, the optimal bandwidth reaches 1.537 MHz with 3.5 V applied voltage. In order to suppress the dark current induced noise, a Ge-on-Si avalanche photodiode (APD) with the interdigitated structure is designed. The avalanche voltage is designed ∼13.3 V at room temperature, and the dark current density in linear region is at mA/cm2 order. We believe this type of device can be applied in weak light detection condition.

Developing efficient electrocatalysts for CO2 conversion into value-added chemicals is highly desirable, but it still remains a great challenge to achieve scalable production of these catalysts that displays simultaneously the high product selectivity and large current density at a low overpotential. Here, we develop a universal domino reaction strategy for mass production of metal single atoms anchored on N-doped carbon nanosheets (M-SA/NC), including Fe, Co, Ni, Mn, Mo, Pd and combinations thereof (among FeCo, FeNi, FeCoNi) SA/NC by ball-milling of polyaniline (PANI) with appropriate salts (e.g., NiCl2, NaCl and NaNO3), followed by pyrolysis. During pyrolysis, NaNO3 is decomposed in-situ to release gases capable of blowing PANI, then carbon sheets from carbonized PANI is etched by O2 to create microporous and the aggregated metal particles is etch by CO. The as-prepared Ni-SA/NC exhibits an extraordinary catalytic activity for CO2 reduction to CO, yielding a large current density of 213.2 mA cm−2 with CO Faradaic efficiency up to 96.9% at a low overpotential of 0.55 V in a flow cell. DFT calculations reveal that N atoms in NiN4 species act as the active sites for CO2RR, rather than conventional Ni atoms, since the neighboring pyrrolic-N induces electrons of Ni 4s orbitals shift to adjacent N 2s orbitals in NiN4, leading to a high N 2s electron density for facilitating the COOH* formation. This work provides not only a rational design concept for mass preparation of M-SA/NC heterogeneous electrocatalyst for CO2 reduction and beyond, but also a deep insight of an electron transfer mechanism for CO2RR.

Pre-magnetized Fe0/persulfate (pre-Fe0/PS) process was innovatively employed for controlling the pollution of p-arsanilic acid (p-ASA). This process showed favorable removal performance, achieving almost complete elimination of 10 mg/L p-ASA within 30 min at the reaction conditions of 0.2 g/L pre-Fe0 and 1 mM PS. The increase of PS concentration and pre-Fe0 dosage was conducive to the degradation. The coexistence of Cl−, NO3− and SO42− accelerated the removal, however the presence of HCO3− and HA presented the opposite trend. The p-ASA degradation decelerated gradually with increasing pH from 5 to 9. Its removal was caused by the attack of reactive oxygen species (i.e., SO4− , OH, O2− ), which could be continuously formed via the Fe2+/Fe3+ cycle in solution and on pre-Fe0 surface. In pre-Fe0/PS system, SO4− in solution, surface-bound SO4− , OH, OH in solution, O2− in solution and Fe(IV) contributed to the p-ASA degradation. A plausible transformation route related to the break of C-N and As-C bonds, the substitution of OH group was put forward. More importantly, the released inorganic arsenic during p-ASA decomposition could be effectively controlled through multiple functions including the precipitation, co-precipitation and sorption, which was well confirmed by XPS, FTIR and XRD analysis. Pre-Fe0/PS and Fe0/PS pretreatments both reduced the generation of C-DBPs except for chloral hydrate, while increased the formation of N-DBPs except for trichloroacetamide.

The mass production of waste activated sludge in wastewater treatment plants may lead to environmental pollution and sludge dewatering is an essential process during its treatment. The oxidation of extracellular polymeric substances (EPS) was the core step to achieve deep sludge dewatering. In this study, thermally-activated sodium persulfate (SPS) process was managed to improve the dewaterability of waste activated sludge (WAS) and its internal mechanism was systematically elaborated. Experimental results showed that with 2.0 mmol/g VSS SPS at 80 °C, capillary suction time (CST) was roughly 59.74% of that in raw sludge. Under this condition, 14.66 ± 0.10 × 1011 kg/m of specific resistance to filtration (SRF) and 61.8% ± 0.1% of water content (WC) was determined, respectively. A solubilization/oxidation process was proposed to unravel the mechanism of the enhanced dewaterability of WAS in thermally-activated SPS process. Mild temperature efficiently disrupted the sludge flocs and broke cell walls, releasing large amounts of EPS into bulk phase. Meanwhile, mild temperature accelerated the decomposition of SPS to generate sulfate radicals (SO4 −) and hydroxyl radicals ( OH) for oxidizing EPS, facilitating the conversion of bound hydrated water into free water and achieving solid-water separation. The higher reaction temperature favored sludge dewatering, whereas overdosing SPS posed no significant impact. Further analysis illustrated that tyrosine protein-like, tryptophan protein-like, fulvic acid-like and humic acid-like substances in various EPS fractions together exerted the influence on sludge dewatering. Furthermore, the synergy process could alter the secondary structure of protein, which caused a loose structure of EPS and the exposure of hydrophobic sites, facilitating the dehydration of sludge flocs. The details of how thermally-activated SPS process enhanced sludge dewaterability provided the theoretical and technical basis for the application of the process under a real-world situation.

As an emerging semiconductor different from regular white TiO2, black TiO2 has attracted intensive attention on visible light driven photocatalysis for degrading dyes, but rarely for degradation of antibiotics. In this study, black anatase-TiO2 was demonstrated to be an effective catalyst for tetracycline (TC) visible light photodegradation. 66.2% removal efficiency of TC was achieved over black TiO2 under visible light illumination, while white TiO2 and N-doped TiO2 exhibited 43.4% and 59.6% removal efficiencies, respectively. Furthermore, only ⋅O2− radicals played an important role in TC photodegradation over white TiO2, whereas both ⋅O2− and h+ were responsible for the degradation over black TiO2 and N-doped TiO2. Different from white TiO2 for visible light photocatalytic TC degradation that follows photosensitization, the visible light photodegrataion over black TiO2 is due to photoexcitation.

In this study, the degradation of carbamazepine (CBZ) was comparatively investigated by UV-LED/persulfate (PS) and UV-LED/H2O2 processes in the presence of trace Cu2+ at neutral pH. Results showed that the introduction of trace Cu2+ accelerated CBZ degradation and more favorable performance was achieved in UV-LED/PS process. As oxidants dosage raised from 0.2 to 1.0 mM, the pseudo-first-order rate constant (kobs) value of CBZ both linearly increased in UV-LED/PS/Cu2+ and UV-LED/H2O2/Cu2+ processes. The promotion effect of Cu2+ at low level was more significant than that at high level in both processes at neutral pH. With reducing solution pH from 7.2 to 3.1, the kobs value dramatically increased from 0.136 to 0.399 min−1 in UV-LED/PS/Cu2+ process, while its value exhibited the imperceptible change in UV-LED/H2O2/Cu2+ process. OH functioned as the major contributor to CBZ degradation in two processes in pH range of 3.1–7.2. The addition of humic acid (HA), HCO3− and Cl− impeded CBZ degradation in UV-LED/H2O2/Cu2+ process. As for UV-LED/PS/Cu2+ process, the kobs value significantly increased in the presence of Cl−, while the introduction of HA and HCO3− restrained the removal. Total eleven degradation intermediates of CBZ were identified and a reasonable degradation pathway was proposed based on HPLC-MS/MS analysis and the calculation of Gaussian program. The acute toxicities of reacted solution enhanced in both processes within 15 min, especially in UV-LED/PS/Cu2+ process. In terms of electrical energy per order value, UV-LED/PS/Cu2+ process was found to be more cost-effective than UV-LED/H2O2/Cu2+ process. It was also noticed that UV-LED/PS process was more effective for CBZ removal in natural water in the presence of trace Cu2+.

A new strategy based on sign-on and sign-off was proposed for propyl gallate (PG) determination by an electrochemical sensor. The successively modified poly(thionine) (PTH) and molecular imprinted polymer (MIP) showed an obvious electrocatalysis and a good recognition toward PG, respectively. Furthermore, the rebound PG molecules in imprinted cavities not only were oxidized but also blocked the electron transmission channels for PTH redox. Thus, a sign-on from PG current and a sign-off from PTH current were combined as a dual-sign for PG detection. Meanwhile, the modified MIP endowed the sensor with recognition capacity. The electrochemical experimental results demonstrated that the prepared sensor possessed good selectivity and high sensitivity. A linear ranging from 5.0×10(-8) to 1.0×10(-4)mol/L for PG detection was obtained with a limit of detection of 2.4×10(-8)mol/L. And the sensor has been applied to analyze PG in real samples with satisfactory results. The simple, low cost, and effective strategy reported here can be further used to prepare electrochemical sensors for other compounds selective recognition and sensitive detection.

Novel visible-light photocatalytic nanocomposites composed of cyclized polyacrylonitrile (CPAN) and CdS nanoparticles were prepared using a simple chemisorption and heat treatment approach. The as-prepared nanocomposites were systematically characterized by XRD, SEM, TEM (HRTEM), FTIR, XPS, UV–Vis DRS, PL, EIS, etc., and their visible-light photocatalytic performances were investigated by evaluating the photodegradation of methyl orange solutions under visible-light irradiation. The results show that the as-prepared nanocomposites display sphere-like morphology and their size is about 5 nm. A small amount of CPAN on the CdS surface can significantly enhance the absorption of CdS in the range of 500–800 nm and separation efficiency between the photogenerated electron/hole pairs in the nanocomposites. The investigated nanocomposites exhibit much higher visible-light photocatalytic activity than pure CdS and excellent photocatalytic stability. As the CPAN content increases, the visible-light photocatalytic activity of the nanocomposites increases first and then decreases, and the nanocomposite with the CPAN and CdS mass ratio of 1:50 shows the highest visible-light photocatalytic activity. A possible visible-light photocatalytic mechanism of the CPAN/CdS photocatalysts was proposed.

In this work, a sensitive and reliable electrochemical platform was developed for catechol (CC) and hydroquinone (HQ) individual and sensitive simultaneous detection. Due to the outstanding advantages of low cost, excellent flexibility, large surface area, and good conductivity, an exfoliated graphite paper (EGP) was used as a supported electrode for gold nanoparticles (AuNPs) electrodeposition to fabricate a sensor (AuNPs/EGP). Scanning electron microscope and cyclic voltammetry results revealed that AuNPs/EGP was successfully prepared with multi-layered structure and enhanced electron transfer ability. Under the optimized conditions, the sensor showed wide linear range for CC and HQ detection of 5.0 × 10 −7 - 1.0 × 10 −4 mol/L and 7.0 × 10 −8 - 1.0 × 10 −4 mol/L with limitation of detection (S/N = 3) of 4.13 × 10 −8 mol/L and 2.73 × 10 −8 mol/L, respectively. And the proposed sensing platform was successfully applied to the simultaneous determination of CC and HQ in real samples of three kinds of water with reliable recovery. The low cost, facile preparation, and attractive electrochemical performances made the graphite paper based sensor promise perspectives in the field of electroanalysis.

The authors report on a ratiometric electrochemical sensor for paracetamol (PR) which was fabricated by successively electropolymerizing a layer of Prussian blue (PB) and a layer of molecularly imprinted polypyrrole (MIP) on the surface of a glassy carbon electrode (GCE). The binding of PR molecules to the MIP has two effects: The first is an increase of the oxidation current for PR at 0.42 V (vs. SCE), and the second is a decrease in the current for PB (at 0.18 V) due to partial blocking of the channels which results in reduced electron transmissivity. Both currents, and in particular their ratio, can serve as analytical information. Under optimized conditions, the sensor displays enhanced sensitivity for PR in the 1.0 nM to 0.1 mM concentration range and a 0.53 nM lower limit of detection. The sensor was applied to the determination of PR in tablets and urines where it gave recoveries in the range between 94.6 and 104.9 %. This dual-signal (ratiometric) detection scheme (using electropolymerized Prussian Blue and analyte-specific MIP) in our perception has a wide scope in that it may be applied to numerous other electroactive species for which specific MIP can be made available.

Optical and electrical characteristics of solid materials are well-known to be intimately related to the presence of intrinsic or extrinsic defects. Hence, the control of defects in semiconductors is of great importance to achieve specific properties, for example, transparency and conductivity. Herein, a facile and controllable reduction method for modulating the defects is proposed and used for the case of p-type delafossite CuCrO2 nanoparticles. The optical absorption in the infrared region of the CuCrO2 material can then be fine-tuned via the continuous reduction of nonstoichiometric Cu(II), naturally stabilized in small amounts. This reduction modifies the concentration of positive charge carriers in the material, and thus the conductive and reflective properties, as well as the flat band potential. Indeed, this controllable reduction methodology provides a novel strategy to modulate the (opto-) electronic characteristics of semiconductors.