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An efficient method that utilizes simple techniques, easy operation, and low‐cost production to create flexible graphene‐based materials is a worthy practical challenge. A rapid strategy for preparing flexible, functional graphene oxide (GO) is introduced using GO‐ethanol dispersion filtration. The filtration process is highly efficient and drying time is significantly reduced by employing ethanol as solvent, due to the fact that ethanol is a volatile liquid. Freestanding GO papers can be harvested with ultralarge size (700 cm2), color variety, and writable characteristics. After reduction, N‐doped graphene (NDG) papers still maintain good foldability with improved electric conductivity and porous structure. When used as an electrode for a supercapacitor, the flexible NDG paper device demonstrates good electrochemical performance even with size expansion and extreme double folding. Moreover, this NDG paper capacitor device shows a good electrosorption performance for capacitive deionization of sulfate and chromate in groundwater system. These flexible GO and NDG papers promise potential to facilitate the production of graphene‐based materials for practical applications in energy and environmental related fields.

We propose two techniques to improve the power generating performance of the “thermoelectric power generating paper” based on carbon nanotube (CNT) that we reported in our previous study. First, we remove the excess amount of dispersant (sodium dodecyl sulfate; SDS) in the sample by immersing the sample in nitric acid under a suitable condition (e.g., only SDS is expected to be decomposed and removed, but CNT and pulp are retained), thus improving the conductivity of the paper. Second, we dope the contained CNT in the composite paper by adsorbing KOH and 18-Crown-6 molecule physically so that it exhibits an n-type characteristic. In thermoelectric power generation, a large electromotive force can generally be obtained by combining p-type and n-type semiconductors. The semiconducting CNT is known to exhibit a p-type property normally because of O2 adsorption in the air, so we tried to make an n-type semiconducting paper. As a result, we succeeded in obtaining the n-type semiconducting paper, and the paper maintained the property for at least 45 days. Finally, we multi-staged the modified paper for a demonstration of power generation and measured the performance. The results showed that the multi-staged thermoelectric power generating paper had up to 10.0 mV of electromotive force and 0.31 mA of short-circuit current. This unique thermoelectric power generating paper has great potential for use in daily life by combining it with existing products made from paper.

A novel nacre-like flame-retardant paper based on graphene oxide (GO), and phytic acid (PTA) is fabricated via evaporation-induced self-assembly. This facile method is time saving and low energy consuming. A facile approach is proposed to improve thermal oxidative stability of GO paper by in situ phosphorus doping during flame exposure. Then fire-alarm system is designed based on the high-temperature thermal reduction characteristic of GO. The GO paper functionalized with PTA (GO-PTA) can provide ultrasensitive, reliable and longtime fire early-warning signal. Fire alarm can be triggered at approximately 0.50 s when GO-PTA samples are attacked by fire. Phosphorus atoms are in situ doped into graphene layers during fire exposure, endowing GO-PTA paper with outstanding thermal oxidative stability, and thus alarm duration time of GO is greatly improved. The work develops advanced fire detection and early-warning sensors that provide reliable and continuous signals, which provide more available time for fire evacuation.

Vapor phase polymerization has been used for the synthesis of polypyrrole-coated filter paper (PPy-FP) using a simple experimental setup. In addition, we have doped the polymer-coated filter papers...

The development of actuators for power sources is essential for the efficient manipulation of fluids in microfluidics systems. In this work, a capacitor-type three-layer paper actuator was fabricated by sandwiching a polyelectrolyte layer between two films of poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT/PSS). The paper actuator exhibited stable large electromechanical deformations in bilateral symmetry under alternating square-wave electric field. The actuation properties were examined in a function of voltage (±0.5, ±1, ±1.5, ±2, and ±2.5 V) and frequency (1, 0.5, 0.2, and 0.05 Hz). In addition, the PEDOT/PSS electrode films with different thicknesses were prepared, and the effects of actuator thickness on actuation properties were examined. As a result, it was found that the actuator displacement increased considerably with reducing actuator thickness. In addition, the actuator with a thickness of 48 μm demonstrated a maximum displacement of 5.8 mm at a voltage of 1.5 V and a frequency of 0.05 Hz. The proposed actuator can be potentially used in the development of power sources for micropumps and check valves of microfluidic devices.

A rewritable photonic crystal (PC) paper as an environmentally friendly and low-resource-consuming material for information storage and spreading has gradually become a research hotspot. In this work, a novel rewritable PC paper with inkless writing and double-sided rewritability properties was developed. A double-sided epoxy resin PC paper exhibiting an inverse opal structure and a bright structural color was fabricated using the sacrificial template method. Carbon black was doped into the material to increase color saturation and purity while preventing light transmission and protecting the double-sided structural color from interference. The force of sliding friction and deformation triggered by capillary pressure as well as swelling-triggered recovery of the inverse opal structure led to an easy rewriting of the PC paper. The PC paper exhibited excellent rewritability even after 50 runs of the rewriting process. Given the inkless and double-sided rewriting, this study provides a new method for the preparation of rewritable PC papers.

This work reports a modification of a fibrous cellulose material (paper) by the addition of polyacrylonitrile (PAN) fibres doped with 10,12–pentacosadiynoic acid (PDA). The fibres are sensitive to ultraviolet (UV) light. When the paper containing PAN–PDA is irradiated with UV light it changes colour to blue as a consequence of interaction of the light with PDA. The colour intensity is related to the absorbed dose, content of PAN–PDA fibres in the paper and the wavelength of UV radiation. The features of the paper are summarised after reflectance spectrophotometry and scanning microscopy analyses. All the properties of the modified paper were tested in accordance with adequate ISO standards. Moreover, a unique method for assessing the unevenness of the paper surface and the quality of printing was proposed by using a Python script (RGBreader) for the analysis of RGB colour channels. The modification applied to the paper can serve as a paper security system. The modified paper can act also as a UV radiation indicator.

Made available in DSpace on 2019-10-06T17:04:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-06-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Development and application of a new, simple, inexpensive, and eco-friendly method is presented for the quantification of bumetanide in human urine samples for the detection of doping in sports. The method involves the use of a paper platform and digital image detection and is based on the reaction between bumetanide, p-dimethylaminocinnamaldehyde (p-DAC), and HCl in a methanolic medium, yielding a colored compound in a delimited area on a qualitative filter paper. The concentrations of p-DAC and HCl were optimized by a chemometric experimental design. After the addition of the reagents to the paper, digital images were obtained by scanning in a multifunctional printer and analyzed using the RGB pattern. The linear bumetanide concentration range was 6.90 × 10 −5 –1.37 × 10 −3 mol L −1 with R 2 = 0.993 and the limits of detection (LOD) and quantification (LOQ) were 3.60 × 10 −4 and 1.09 × 10 −4 mol L −1 , respectively. A SPE clean-up step for the samples were required to eliminate the interference of urinary urea. The recoveries obtained varied from 94% to 105%, indicating the absence of significant matrix effects or interferences in urine samples after clean-up step. The proposed method was successfully applied to the analysis of bumetanide in human urine samples. Instituto de Química Universidade Estadual Paulista “Júlio de Mesquita Filho” UNESP, R. Prof. Francisco Degni 55, P.O. Box 355 Instituto de Química Universidade Estadual Paulista “Júlio de Mesquita Filho” UNESP, R. Prof. Francisco Degni 55, P.O. Box 355 CAPES: 001 FAPESP: 2015/21733-1

Cellulose fiber (CF) paper is a low-cost, sustainable, and flexible substrate, which has gained increasing interest recently. Before practical usage, the functionalization of the pristine CF paper is indispensable to meet requirements of specific applications. Different from conventional surface modification or physical mixing methods, we report in situ growth of ultralong hydroxyapatite nanowires (HAPNWs) with lengths larger than 10 μm on the CF paper. HAPNWs are radially aligned on the surface of CFs, creating a micro/nanoscale hierarchical structure. By means of the excellent ion exchange ability of HAP and the hierarchical structure, the functions of the CF paper can be easily customized. As a proof-of-concept, we demonstrate two kinds of functional CF paper: (1) the photoluminescent CF paper by doping Eu3+ and Tb3+ ions into the crystal lattice of HAPNWs and (2) the superhydrophobic CF paper by coating poly(dimethylsiloxane) on the HAPNW hierarchical structure, which can be applied for self-cleaning and oil/water separation. It is expected that an in situ growth of ultralong HAPNWs will provide an instructive guideline for designing a CF paper with specific functions.

Nano-sized Sr1−xAgxTiO3 system was prepared using modified Pechini method (x = 0, 0.02, 0.05 and 0.07). XRD, TEM and DRS are utilized for the prepared sample characterization. The doping impact on the structural and the antimicrobials properties was studied. The undoped SrTiO3 has cubic-like perovskite structure while Ag-doped samples have traces of metallic silver in addition to the cubic-like perovskite structure. Doping of SrTiO3 with silver resulted in red shift of the absorption to the visible light range. Antimicrobial properties were detected for nano-sized undoped and Ag-doped SrTiO3, whereas the parent SrTiO3 has not clear zone. Different concentrations of silver were applied in matrices of polymer to be utilized as active coating materials on paper sheets. Physico-mechanical properties of coated paper, thickness, water absorption, tensile, elongation at break and short span, were investigated. Active nanocomposite coating enhanced the mechanical and short span behaviors. Interested throughout assessment was presented for nanocomposites coating and its uses on packaging materials.

Submitted by Eduardo Luiz Rossini (eduardo.rossini@unesp.br) on 2020-02-27T15:12:46Z No. of bitstreams: 1 rossini_el_dr_araiq.pdf: 2590313 bytes, checksum: 64d9f340eb5c633e6fa6c028150b8a1b (MD5) Approved for entry into archive by Ana Carolina Gonçalves Bet null (abet@iq.unesp.br) on 2020-03-02T13:10:34Z (GMT) No. of bitstreams: 1 rossini_el_dr_araiq_par.pdf: 703386 bytes, checksum: 96b74b148702167b3e4e332064b9fbf4 (MD5) Made available in DSpace on 2020-03-02T13:10:35Z (GMT). No. of bitstreams: 1 rossini_el_dr_araiq_par.pdf: 703386 bytes, checksum: 96b74b148702167b3e4e332064b9fbf4 (MD5) Previous issue date: 2020-02-14 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) A primeira parte deste trabalho foi desenvolvida no laboratório Fritz Feigl-UNESP/CAr, na qual foi descrito um novo carbon dot (CD) sintetizado a partir de ácido cítrico e tiramina usando uma rota em única etapa por meio de aquecimento por micro-ondas doméstico. O CD sintetizado apresenta emissão no azul quando irradiado com luz UV, que foi suprimida na presença de H2O2 e peroxidase. O CD foi utilizado para desenvolver metodologias para quantificar glicose em amostras biológicas utilizando plataforma de papel. O método desenvolvido foi aplicado em amostras de soro e urina certificadas, e não há diferenças estatisticamente significativas entre os resultados obtidos usando o dispositivo de papel com adição de padrão e as amostras certificadas. Também foram desenvolvidas metodologias utilizando 3D-µPAD com o reagente fluorescente e enzimas oxidase para quantificação de glicose e lactato em amostras de saliva. O preparo de amostra foi simples e rápido e o método foi validada utilizando adição de padrão e recuperação, além de ser aplicado em amostras de soro certificadas, não houve diferenças estatisticamente significativas entre os resultados obtidos e os valores de referência. A segunda parte deste trabalho foi desenvolvida no Badu’s research group na The Ohio State University durante o período sanduiche com bolsa da FAPESP, na qual foi desenvolvida a quantificação direta de agentes dopantes em amostras de urina sem tratamento da amostra por PS-MS. Paper-spray mass spectrometry é um método de ionização em condições ambientes que combina as vantagens das plataformas de papel com a confiabilidade das análises de espectrometria de massas, reduzindo o tempo de análise e o consumo de reagente e de solventes orgânicos. O uso de substâncias ilícitas para aumentar a desempenho de atletas em esportes é proibido e considerado doping. A superfície do papel foi tratada com triclorometilsilano utilizando reação em fase gasosa para aumentar a ionização dos compostos alvo. Essa abordagem foi aplicada para análise de dois agentes anabólicos (trembolona e clembuterol) e dois diuréticos (furosemida e hidroclorotiazida) em amostras de urina. Após a otimização das condições experimentais, os métodos desenvolvidos apresentaram repetibilidade satisfatória e boa correlação linear entre concentração e intensidade absoluta. Foram alcançados limites de detecção na faixa de sub-ng mL-1, abaixo dos níveis de desempenho mínimos requeridos pela WADA, utilizando o método de PS-MS com papel hidrofóbico sem nenhuma etapa de preparo ou clean-up da amostra. Os métodos propostos foram aplicados em amostras de urina fortificadas com os agentes dopantes e se mostraram rápidos, simples, sensíveis, exatos e precisos. The first part of this work was developed on the Fritz Feigl-UNESP/CAr laboratory, in which a novel carbon dot synthesized from citric acid and tyramine was described using a one-step microwave heating route. Under UV irradiation, the CD displayed blue emission that was quenched in the presence of H2O2 and peroxidase. This property was used to develop a method to quantify glucose in biological samples using a paper platform. The method developed was applied in the analysis of certified serum and urine samples, and there were no statistically significant differences between the certified concentrations and the results obtained using the paper device with standard additions. In addition, it was developed method using 3D-µPAD, the CD fluorescence reagent and oxidase enzymes to quantify glucose and lactate in saliva samples. The sample preparation used was simple and fast. The method was validated in saliva samples utilizing standard addition and recovery, and applied in the analysis of certified serum samples, and there were no statistically significant differences between the certified concentrations and the results obtained using the 3D-µPAD. The second part of this work was developed at the Badu’s research group at The Ohio State University during the internship period funded by FAPESP, in which a direct quantification of doping agents in urine samples with no sample preparation by PS-MS was developed. Paper-spray mass spectrometry (PS-MS) is an ambient ionization method that combines the advantages of the paper platform with the reliability of MS analysis, reducing the consumption of time, reagent, and organic solvent. The use of illicit substances to improve enhance athletic performance in sport is forbidden and considered doping. The paper surface was treated with trichloromethylsilane (TCMS) using a gas-phase reaction to increase the target compounds ionization. This approach was applied for the analysis of two anabolic agents (trenbolone and clenbuterol) and two diuretics (furosemide and hydrochlorothiazide) in urine samples. Under optimized conditions, the developed methods presented satisfactory repeatability and a good correlation between concentration and absolute intensity. Highly sensitive detections as low as sub-ng mL 1 which is below the minimum required performance levels (MRPL) proposed by the WADA has been reached using the hydrophobic PS-MS without any pre-concentration and clean-up step. The proposed methods were applied in fortified urine samples with doping agents and showed to be fast, simple, sensitive, accurate and precise. FAPESP n. 2016/20847-6 FAPESP n. 2018/05993-1 CNPq n. 140503/2016-1

Paper plays an important role in various aspects of human life. However, most of the paper materials are vulnerable to both flame and water, which seriously restrict their performance in many applications. Here, we report a new kind of flame-retardant paper with high-temperature-resistant hydrophobicity. This kind of paper was fabricated by vacuum filtration of electrospun fluorinated SiO2 fibers and methyl silicon resin. It is mechanically flexible. Its Young’s modulus is 94 MPa, similar to normal printing paper. The optimized paper demonstrated a water contact angle (WCA) of 151°, which can be maintained as high as 126° even after 30 min of annealing at the temperature of 600 °C. Finally, writing with inorganic ink can be performed on this paper with inhibited ink diffusion. The written paper can maintain its integrity after 5 min of firing by alcohol flame. The flame-retardant and hydrophobic paper here may extend the applications of paper in wide range of fields.

Made available in DSpace on 2020-12-12T02:09:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-03 In this study, the direct analysis of doping agents in urine samples with no sample preparation by a modified paper spray mass spectrometry (PS-MS) methodology has been demonstrated for the first time. We have described a paper surface treatment with trichloromethylsilane using a gas-phase reaction to increase the ionization of target compounds. This approach was applied for the analysis of two classes of banned substances in urine samples: anabolic agents (trenbolone and clenbuterol) and diuretics (furosemide and hydrochlorothiazide). Under optimized conditions, the developed methods presented satisfactory repeatability, and an analysis of variance showed linearity without lack-of-fit. Highly sensitive detections as low as sub-nanogram per milliliter levels, which is below the minimum required performance levels proposed by the World Anti-Doping Agency, have been reached using the hydrophobic PS-MS analysis without any preconcentration and cleanup step. Department of Chemistry and Biochemistry Ohio State University, 100 West 18th Avenue Institute of Chemistry Department of Analytical Chemistry São Paulo State University (UNESP), Rua Professor Francisco Degni 55 ,P.O. Box 355 Institute of Chemistry Department of Analytical Chemistry São Paulo State University (UNESP), Rua Professor Francisco Degni 55 ,P.O. Box 355

Smart materials that reversibly change color upon light illumination are widely explored for diverse appealing applications. However, light-responsive color switching materials are mainly limited to organic molecules. The synthesis of inorganic counterparts has remained a significant challenge because of their slow light response and poor reversibility. Here, we report a seeded growth strategy for the synthesis of TiO2−x/WO3·0.33H2O hetero-nanoparticles (HNPs) with networked wire-like structure of ∼ 10 nm in diameters that enable the highly reversible light-responsive color switching properties. For the TiO2−x/WO3·0.33H2O HNPs, Ti3+ species self-doped in TiO2−x nanoparticles (NPs) act as efficient sacrificial electron donors (SEDs) and Ti-O-W linkages formed between TiO2−x and WO3·0.33H2O NPs ensure the nanoscale interfacial contact, endowing the HNPs enhanced photoreductive activity and efficient interfacial charge transfer upon ultraviolet (UV) illumination to achieve highly efficient color switching. The TiO2−x/WO3·0.33H2O HNPs exhibits rapid light response ( 180 times). We further demonstrate the applications of TiO2−x/WO3·0.33H2O HNPs in ink-free, light-printable rewritable paper that can be written on freehand or printed on through a photomask using UV light. This work opens an avenue for designing inorganic light-responsive color switching nanomaterials and their smart applications.

The use of polymer additives is effective for the fabrication of homogeneous single-walled carbon nanotube (SWCNT) films. However, the polymer chains located on the surface of SWCNT bundles act as barriers for electrical transport between SWCNTs and the chemical doping of SWCNTs. In this study, the combustion process of freestanding SWCNT/polymer films for the effective removal of the polymer additive and thermoelectric applications were investigated. By introducing the combustion process, high-performance p-type and n-type thermoelectric buckypapers were fabricated. The combusted and FeCl3-doped buckypapers with excellent electrical conductivity can be used as electrode materials in thermoelectric generators. Furthermore, a paper-based thermoelectric generator three-dimensional stacked for efficient energy harvesting using the vertical temperature difference was demonstrated. The thermoelectric generator with a thermal contact area of 1.2 cm2 exhibited a maximum output power of 2.48 μW with a vertical temperature difference of 30 K.

Heteroatom (boron) doped reduced graphene oxide (B-rGO) papers were prepared by the simple self-assembly process of graphene oxide through the deoxygenation in argon atmosphere at 400 °C. The phase purity and crystallinity of the B-rGO paper were studied by X-ray diffraction analysis. The wrinkled paper-like morphology was analyzed by scanning electron microscopy (SEM) and the homogeneity by the elemental mapping. The binding energy states of the B-rGO were confirmed by X-ray photoelectron spectroscopy. The shift in zeta potential values also confirms the heteroatom doping in the rGO paper. From the Raman spectra it was observed that the incorporation of boron into the rGO paper exhibits an improved conductivity and mobility. The current-voltage (J-V) characteristics revealed that the B-rGO paper can be effectively used as a hole transport material (HTM) for perovskite solar cells (PSCs). The largest conversion efficiency of 8.96% was achieved for the FTO/TiO2/CH3NH3PbI3/B-rGO/FTO sandwich structure with an active area of 1 cm2.

The Fe-N-C nanofibers (NFs) exhibit excellent electro-catalytic activity for oxygen reduction reaction (ORR), which is essential for energy conversion system. Compared with the traditional ink-based electrode, we synthesized the structured Fe-N-C ANFs/CP (activated NFs derived from polypyrrole(PPy) doped with iron atoms in situ grown on carbon paper) by electrochemical polymerization. Herein, we investigate the effect of the iron concentration on the electro-catalytic activity for ORR, revealing that the as-prepared 0.05-Fe-N-C ANFs exhibit superior electro-catalytic activity than 0.01-Fe-N-C ANFs, 0.03-Fe-N-C ANFs as well as 0.10-Fe-N-C ANFs and excellent durability in alkaline solution. It is shown that the better electro-catalytic activity of 0.05-Fe-N-C ANFs for ORR could be ascribing to the fluffy fibrous structure, higher Fe-N x concentration, and well-dispersed catalytic active sites.

In this work, a novel time-resolved ratiometric fluorescent probe based on dual lanthanide (Tb: terbium, and Eu: europium)-doped complexes (Tb/DPA@SiO2-Eu/GMP) has been designed for detecting anthrax biomarker (dipicolinic acid, DPA), a unique and major component of anthrax spores. In such complexes-based probe, Tb/DPA@SiO2 can serve as a stable reference signal with green fluorescence and Eu/GMP act as a sensitive response signal with red fluorescence for ratiometric fluorescent sensing DPA. Additionally, the probe exhibits long fluorescence lifetime, which can significantly reduce the autofluorescence interferences from biological samples by using time-resolved fluorescence measurement. More significantly, a paper-based visual sensor for DPA has been devised by using filter paper embedded with Tb/DPA@SiO2-Eu/GMP, and we have proved its utility for fluorescent detection of DPA, in which only a handheld UV lamp is used. In the presence of DPA, the paper-based visual sensor, illuminated by a handheld UV lamp, would result in an obvious fluorescence color change from green to red, which can be easily observed with naked eyes. The paper-based visual sensor is stable, portable, disposable, cost-effective and easy-to-use. The feasibility of using a smartphone with easy-to-access color-scanning APP as the detection platform for quantitative scanometric assays has been also demonstrated by coupled with our proposed paper-based visual sensor. This work unveils an effective method for accurate, sensitive and selective monitoring anthrax biomarker with backgroud-free and self-calibrating properties.

Cu-doped zinc oxide (Cu–ZnO) nanostructure was prepared using Whatman filter paper as a template by combustion method. For the synthesis of porous Cu–ZnO nanostructures the stoichiometric amount of precursors were impregnated in the filter papers and processed, thermally. The formation of wurtzite phase having crystallite size in the range of 20–24 nm was confirmed by X-ray diffraction (XRD) analysis. The morphological study by field emission scanning electron microscopy (FESEM) and field emission transmission electron microscopy (FETEM) shows size of nanoparticles in the range of 25–50 nm. The optical study shows red shift i.e. extended absorbance in the visible region due to Cu doping. The photoluminescence study of Cu–ZnO results quenching in the photoluminescence peak as effect of Cu doping in ZnO lattice. Considering the extended band gap in the visible region of as synthesized Cu–ZnO, the photocatalytic dye degradation activity of methylene blue (MB) was executed in presence of sunlight irradiation. The effect of salt concentration and PH on dye degradation activity also studied. The highest photocatalytic activity was observed for Cu–ZnO with 4% doping as compared with other Cu–ZnO and ZnO nanostructure. The photocatalytic performance of Cu–ZnO shows complete degradation of MB dye within 30 min for 4% Cu–ZnO nanostructure. The photocatalytic activity obtained is much higher as compare to earlier reports. The synthesis of Cu doped ZnO by paper templated method and its photocatalytic activity is hitherto unattempted.

Large-sized graphene sheets (LG) and doping strategy were employed to fabricate lightweight and flexible graphene paper with exceptional electromagnetic interference (EMI) shielding performance. Compared with the smaller sized ones, LG with fewer defects and more conjugated carbon domain size as well as better alignment result in higher electrical conductivity and strength of graphene paper. The iodine doping further improves the carrier density of LG by formation of triiodide ( I 3 − ) and pentaiodide ( I 5 − ) through charge transfer process without deteriorating the mechanical property, thus leading to superior EMI shielding effectiveness (SE). The EMI SE of iodine doped LG film with thickness of 12.5 μm is up to ∼52.2 dB at 8.2 GHz, which is much higher than that of undoped LG with the same thickness (∼47.0 dB). More important, the improvements in EMI SE is contributed to the SE absorption, while the SE reflection is almost unchanged. The mechanisms of improved EMI shielding performance as well as mechanical property were investigated and discussed. The present study provides a facile way to fully develop graphene in lightweight and flexible EMI shielding materials and devices.

The effects of doping of ZnO and Nb2O5 solids with Fe2O3 (1.4 wt%) and Ag2O (1.4 wt%) on its surface and catalytic properties were investigated, as well as its photocatalytic performance on the degradation of a pulp and paper wastewater (PPW). The catalysts were characterized by XRD, SEM, photoacoustic spectroscopy (PAS), NH3-TPD and textural analysis. The results obtained revealed that Fe2O3 doping of Nb2O5 conducted at 500 °C resulted in an increase of about 116% for SBET while Ag2O treatment exerted a decrease of 33% for SBET of the doped adsorbents. Doping ZnO with Fe2O3 or Ag2O led to an increase of 80% for SBET. Iron and silver doping also led to a decrease in band gap energy of at least 6%. The addition of 1.4 wt% Ag2O on ZnO followed by calcination at 500 °C resulted in an increase of 11% in the value of the reaction rate constant (kap) for COD reduction under UV radiation. The treatment of Nb2O5 with 1.4 wt% Ag2O increased by a factor of 2.04 the value of kap for the reaction taking place under VIS radiation. The catalysts partially reduced the organic load and the real colour of the wastewater, allowing the achievement of the specifications for release into rivers, so photocatalysis could be an alternative for pulp and paper wastewater final polishing.

A superior electrical conductivity of 38.5 S/cm and an electromagnetic shielding (EMS) effectiveness of −30 dB (−545 dB/mm) across a wide frequency range of 0–15 GHz, including the X-band, were achieved with thin organic paper of (55 μm) cellulose nanofiber (CNF)/polyaniline (PANI) doped with (±)-10-camphorsulfonic acid nanohybrid. Both electrical conductivity and EMS effectiveness of the PANI-coated CNF were strongly affected by the amount and type of dopant, which could be tunable after fabrication process via simple in situ oxidative polymerization of aniline. Flexible and free-standing film was obtained, since CNF provides good mechanical property without diminishing the electrical property of PANI.

Electrochemically active SnO2 materials are prospective alternatives for graphite toward better flexible LIBs. However, significant volume changes and structural pulverization restrict the cycling stability and high capacity of SnO2. Here, we report a binder and conductive additive free core-shell N-doped carbon @SnO2 hybrid paper by a subtle coaxial-electrospinning method. Core-shell N-doped C@SnO2 fibers not only offer rapid ionic transport and sufficient buffer space for the volume expansion during the Li insertion and extraction reactions, but also enable high flexibility against both compression and bending deformation. As an anode for LIBs, the hybrid materials delivered a large initial capacity of 1799 mAhg−1 with capacity retention of 729 mAhg−1 after 100 cycles at a current rate of 390.5 mAg−1. More importantly, flexible N-doped C@SnO2 fabrics exhibit excellent electrochemical performance even after a rough treatment, suggesting a facile strategy for the fabrication of electrochemically stable electrodes for flexible LIBs.

To evaluate the performance of Nanofibrillated cellulose (NFC) modified insulating paper under long term running process, 10 wt. % NFC modified insulating paper and ordinary insulating paper were subjected to accelerate thermal aging for 720 hours in a 130°C thermal aging chamber. The aging characteristics and electrical performance were measured during the aging process. Results show that NFC modification can delaying the thermal aging rate of oil immersed insulating paper and enhancing the electrical strength of oil immersed insulating paper during thermal aging process. NFC makes oil-impregnated insulating paper more compact during thermal aging process, resulting in higher polymerization degree and crystallinity. NFC modification can increase the relative permittivity and dielectric loss of the oil-impregnated paper during thermal aging process slightly. The AC and DC breakdown strength of the NFC modified paper are better maintained than the conventional oil-impregnated paper.

It is shown that the composition of the investigated alloy is nearly identical to the commercially available alloy MP35N (35Co-35Ni-20Cr-10Mo, wt%). However, the thermomechanical treatment of the experimental alloy is quite different from that used for the commercial one which consists of using cold work followed by annealing at temperatures below the recrystallization temperature. Here, depending on the amouunt of cold work, a tremendous hardening effect occurs, due to Suzuki hardening which allows to tune the mechanical properties in a range much larger than obtainable by the strategy used by the High Entropy Community by creating hierarchical microstructures.

The conductivity film of Poly(3,4-ethylenedioxythiophene): poly(styrene suffocate) (PEDOT:PSS) on ink-jet printing paper is prepared by gravure printing doped with dimethyl sulfide (DMSO), isopropyl alcohol (IPA) and methanol (Me). Comparing the effect of film-forming of the three doping solvents, IPA with relatively film uniformity is selected as the doping solvent to further explore the influence of different doping ratios on the uniformity of conductive film. In addition, methane sulfonic acid is employed to improve conductivity of PEDOT:PSS film. Meanwhile, the relationship between solvent doping ratio and film of uniformity and conductivity is discussed. Considering the uniformity and conductivity of film, the PEDOT:PSS film with uniform and low sheet resistance (373 Ω/□) is obtained. Then, the lower sheet resistance (273 Ω/□) can be further developed by the two-layer printing.

My comments concern the significant error in the crystallographic part of the commented paper. It was discovered that the studied crystals are of sillenite type and the correct formula should be Bi25FeO39:Ni,Ti instead of BiFeO3. Moreover, the type of unit cell is not correct. Due to the doping the new type of unit cell, previously unknown, was proposed for such crystals. It was found that the studied sample contains two slightly different phases of the sillenite type. The actual chemical composition of the studied crystals is not known.

My comments concern the sever error in the crystallographic part of the commented paper. It was found that the studied crystal is of the sillenite type and the correct formula should be Bi25FeO39:Cd,Ti instead of some kind of solid solution based on BiFeO3. Moreover, the type of unit cell is not correct. Due to the double doping the new type of unit cell, previously unknown, was proposed for such crystals. The actual chemical composition of the studied crystals is not known.

Over the last decade, interest in the utilization of solar energy for photocatalysis treatment processes has taken centre-stage. Researchers had focused on doping TiO2 with SiO2 to obtain an efficient degradation rate of various types of target pollutants both under UV and visible-light irradiation. In order to further improve this degradation effect, some researchers resorted to incorporate plasmonic metal nanoparticles such as silver and gold into the combined TiO2-SiO2 to fully optimize the TiO2-SiO2’s potential in the visible-light region. This article focuses on the challenges in utilizing TiO2 in the visible-light region, the contribution of SiO2 in enhancing photocatalytic activities of the TiO2-SiO2 photocatalyst, and the ability of plasmonic metal nanoparticles (Ag and Au) to edge the TiO2-SiO2 photocatalyst toward an efficient solar photocatalyst.

The scalable and controllable preparation of carbon nanomaterial-based scaffolds with superior electromagnetic interference (EMI) shielding properties in addition to being ultrathin, robust, lightweight, flexible, and foldable is a challenging task. However, commonly used techniques such as integrating conducting moieties and high-temperature annealing cannot simultaneously meet the demands of high specific shielding effectiveness (SSE), robustness, and flexibility. Here, we adopted a novel PDA reduction technique to integrate various functionalities, including a nitrogen doping source, extended reduction of GO, and a large accessible area to accommodate multiwall carbon nanotubes (MWCNTs). The prepared ultrathin PDA-rGO/CNT composite sheet exhibited a low density (0.26 g/cm3), high flexibility, and superior shielding effectiveness (SE) under a wide range of microwave frequencies (i.e., the X band and Ku band). The total shielding effectiveness (SET) reached 47.6 dB and 48.7 dB in the X band and Ku band, respectively, at a thickness of 82 µm and a high SSE; in particular, the SE/density reached a maximum value of 183.3 and 187.3 dB cm3/g, respectively, which are superior to those of previously reported studies. This comprehensive study revealed the synergistic effect of PDA doping and MWCNTs, resulting in excellent shielding properties. Hence, this superior SSE and flexibility makes ultrathin lightweight PDA-rGO/CNT composite sheets a suitable candidate for replacing metallic counterparts for foldable and wearable electronic components.

This paper reports simultaneous modification of graphene oxide (GO) papers by functionalization with MgCl2. The Mg(2+) ions enhance both the interlayer cross-links and lateral bridging between the edges of adjacent GO sheets by forming Mg-O bonds. The improved load transfer between the GO sheets gives rise to a maximum of 200 and 400% increases in Young's modulus and tensile strength of GO papers. The intercalation of chlorine between the GO layers alters the properties of GO papers in two ways by forming ionic Cl(-) and covalent C-Cl bonds. The p-doping effect arising from Cl contributes to large enhancements in electrical conductivities of GO papers, with a remarkable 2500-fold surge in the through-thickness direction. The layered structure and the anisotropic electrical conductivities of reduced GO papers naturally create numerous nanocapacitors that lead to charge accumulation based on the Maxwell-Wagner (MW) polarization. The combined effect of much promoted dipolar polarizations due to Mg-O, C-Cl, and Cl(-) species results in an exceptionally high dielectric constant greater than 60 000 and a dielectric loss of 3 at 1 kHz by doping with 2 mM MgCl2. The excellent mechanical and electrical properties along with unique dielectric performance shown by the modified GO and rGO papers open new avenues for niche applications, such as electromagnetic interference shielding materials.

As good alternatives for conventional rigid piezoelectric materials, piezoelectric nanocomposites combining piezoelectric materials and flexible polymer matrix demonstrate great potential for flexible nanogenerators. Rational design of the hybrid structure is important for performance optimization of piezoelectric nanocomposite. Here, we designed a hybrid piezoelectric paper through uniform assembly of vanadium doped ZnO (V-ZnO) mircoflowers in bacterial cellulose (BC) matrix by a in situ synthesis method. Different from pure ZnO where the c-axis of crystalline need to be oriented in order to get improved piezoelectric output, V-ZnO demonstrate ferroelectric property, which is prerequisite for poling with external high voltage in enhancing the output performance. The resultant hybrid paper demonstrated excellent flexibility and was used to fabricate flexible piezoelectric nanogenerators (PENGs). With excellent mechanical strength and durability, the V-ZnO/BC hybrid paper-based PENGs can work as self-powered motion sensors, which are capable of monitoring page-turning motions when integrated with pages of books. The V-ZnO/BC hybrid paper based PENGs are lightweight and inexpensive, which demonstrate promising applications for self-powered sensor networks and wearable electronics.

In the long-term operation of power transformer, the traditional cellulose insulation paper undergoes aging phenomena, making it difficult for this type of paper to meet severe insulation requirements. In this study, cellulose is modified by doping with melamine-grafted nano-SiO2, and cellulose/water (C–H2O), nano-SiO2-modified cellulose/water (CN–H2O) and melamine-grafted nano-SiO2-modified cellulose/water (CAN–H2O) models are developed. The results show that the mechanical properties of CN–H2O and CAN–H2O are improved relative to those of C–H2O and that CAN–H2O exhibits the best mechanical properties. Furthermore, the glass transition temperatures of CN–H2O and CAN–H2O are, respectively, 39 and 69 K, higher than that of C–H2O. Near the glass transition temperature, the mean square displacement of the water molecules changes considerably. Therefore, increasing the glass transition temperature and thus the thermal stability of cellulose can be achieved by modifying cellulose with melamine-grafted SiO2 nanoparticles. Experimental studies show that with an increase in the aging time, the moisture content in the modified insulation paper will be less than that in the unmodified insulation paper, while the tensile strength, degree of polymerization (DP) and breakdown strength were greater than that in the unmodified insulation paper. In particular, the melamine-grafted nano-SiO2-modified insulation paper has the lowest moisture content and highest tensile strength DP and breakdown strength during the entire aging time. Thus, this study shows that the thermal stability and electrical characteristics of the melamine-grafted nano-SiO2-modified insulation paper is the highest at both the microscopic and macroscopic levels, indicating that this insulation paper could meet the insulation performance requirements of large transformers under high-temperature and high-pressure conditions.

Lithium-sulfur (Li-S) batteries have remarkably high theoretical specific capacity as promising candidates for next-generation energy storage. However, the “polysulfides shuttle” effect hampers its commercial application. Here, we use a kind of rice paper as a raw material to get inorganic oxides doping carbon felt by the facile carbonization method, and then modified by a simple coating process using poly (fluorenyl ether ketone) and Super P slurry. The special structure of the carbon felt derived from rice paper and its modified layer endow the final electronic conductive interlayer with inherent polysulfides absorbents and ion Coulombic repulsion functions, respectively, which show synergistic effect for trapping polysulfides. As an interlayer of Li-S batteries, the obtained carbon felt/poly (fluorenyl ether ketone)& Super P (CFSS) interlayer shows excellent electrochemical performance in improving specific capacity and decreasing polarization. The batteries with CFSS interlayer exhibit a high capacity of 837 mA h g−1 at 2.0 C and a high initial capacity of 1073.4 mA h g−1 and good capacity retention of 824.5 mA h g−1 after 500 cycles at 0.5 C. CFSS interlayer also shows excellent anti-self-discharge performance. Therefore, the simple and economical CFSS interlayer can be considered as a promising component for high performance Li-S batteries.

Among numerous noble-metal-free electrocatalysts, molybdenum sulfides are recognized as promising candidates for hydrogen evolution reaction (HER). Owing to abundant under-coordinated sulfur atoms serving as catalytically active centers, intensive spectra studies have revealed that the HER property of amorphous molybdenum sulfide (a-MoSx) is superior to crystal molybdenum sulfide (c-MoS2). In this work, nitrogen-doped active carbon (NAC) is obtained through plasma treatment and amorphous MoSx/NAC hybrid catalyst films are electrodeposited on carbon fiber papers (CFP) which are employed as porous three-dimensional electrodes with low resistivity. The incorporation of NAC increases the electrochemically active surface area, enhances the electron transport, and facilitates the reaction kinetics. Moreover, the functionality durability benefits from synergistic effect between a-MoSx and NAC. Thus, the obtained hybrid catalyst delivers the excellent HER activity, requiring only 203 mV overpotential to achieve a geometrical current density of 100 mA cm−2 with a Tafel slope of ∼43.9 mV per decade.

The authors of the title paper (Optics and Laser Technology 83 (2016) 49–54) claim to have grown a ‘lithium sulphate doped l -threonine’ crystal by slow evaporation of an aqueous solution containing equimolar amounts of l- threonine and lithium sulphate. A reinvestigation of the crystal growth reaction reveals that fractional crystallization of l -threonine occurs. In this letter to the Editor, we prove that the so-called lithium sulphate doped l -threonine is a dubious crystal and not a ferromagnetic material

The preparation and application of heteroatom doped carbons have attracted lots of attention in the past years. In the current work, a facile synthesis of nitrogen doped carbon with filter paper as the carbon source and urea as the nitrogen source was presented. Filter paper was first impregnated with urea solution, and was then carbonized and activated. The carbons’ physical and chemical properties were studied. For the application in CO2 adsorption, impacts from porous characteristics and nitrogen doping were discussed and differentiated. The results suggested that nitrogen doping was beneficial to the improvement of CO2 uptake, but suitable porous properties were the most important factors. Nitrogen doping showed more significant effects on enhancing the adsorption heat and selectivity. The research of carbonaceous CO2 adsorbent should focus on nitrogen doped carbons with high porosity.

A flexible free-standing nitrogen-doped graphene paper (N-GP) is fabricated via a facile hydrothermal approach with doping reaction occurring at the solid/gas interface of graphene oxide and ammonia vapor. Ammonia not only facilitates the doping of oxidized graphene paper efficiently with a nitrogen doping level of ca. 6.81%, but also promotes its reduction. The electrochemical properties of N-GP as an anode of lithium ion batteries (LIB) are evaluated and N-GP delivers almost doubled reversible discharge capacity compared to the undoped graphene paper (GP) as well as a good cyclic stability and rate performance. The proposed strategy to realize simultaneous reduction and nitrogen doping of graphene oxide via hydrothermal approach at the solid/gas interface offers a green and facile solution to modify graphene paper with desired electrochemical performances for LIB application.

Osseointegration of biomedical implants as well as healing of broken bones are supported by novel bioceramic materials that, owing to their engineered ionic conductivity, in the presence of an electric field provide accumulation of negative electrical charges close to the interface between an implant and living bone tissue, thus stimulating the rate of bone growth. In this position paper, the structure as well as the chemical, electrical, and biomedical properties of Ca (Ti,Zr) hexaorthophosphates are reviewed. In addition, based on evaluation of the material’s properties, a conceptual configuration of a capacity-coupled bone growth stimulator will be presented. The advantage of the proposed novel device over already existing bone-growth stimulators is its provision of the intimate contact of a capacity-coupled electric field with the growing bone tissue as opposed to an externally applied inductively coupled electromagnetic field, which suffers substantial attenuation when transmitted through soft tissue covering the locus of bone growth. To achieve higher ionic conductivity in Ca (Ti,Zr) hexaorthophosphates, aliovalent doping with highly mobile Na or Li ions intercalated into the only partially occupied M1 sites appears to be a suitable route.