Langhuan Huang

Large‐Scale Fabrication of Pseudocapacitive Glass Windows that Combine Electrochromism and Energy Storage

Multifunctional glass windows that combine energy storage and electrochromism have been obtained by facile thermal evaporation and electrodeposition methods. For example, WO3 films that had been deposited on fluorine-doped tin oxide (FTO) glass exhibited a high specific capacitance of 639.8 F g(-1). Their color changed from transparent to deep blue with an abrupt decrease in optical transmittance from 91.3% to 15.1% at a wavelength of 633 nm when a voltage of -0.6 V (vs. Ag/AgCl) was applied, demonstrating its excellent energy-storage and electrochromism properties. As a second example, a polyaniline-based pseudocapacitive glass was also developed, and its color can change from green to blue. A large-scale pseudocapacitive WO3-based glass window (15×15 cm(2)) was fabricated as a prototype. Such smart pseudocapacitive glass windows show great potential in functioning as electrochromic windows and concurrently powering electronic devices, such as mobile phones or laptops.

Fabrication of a High-Stability Cross-Linked Quaternized Poly(epichlorolydrin)/PTFE Composite Membrane via a Facile Route

A novel cross-linked quaternized composite anion-exchange membrane based on poly(epichlorohydrin) (PECH) was prepared by a facile route. First, PECH was cross-linked with 2-methylimidazole and combined with a poly(tetrafluoroethylene) (PTFE) membrane to form cross-linked PECH/PTFE (CPECH/PTFE). Then, CPECH/PTFE was quaternized by 1-methylimidazole to obtain cross-linked quaternized PECH/PTFE (CQPECH/PTFE). (1)H NMR and Fourier transform infrared spectroscopic data indicated that CQPECH was successfully synthesized, and the CQPECH/PTFE membrane had a dense and homogeneous structure demonstrated by the field-emission scanning electron microscopy. The results showed that the use of 2-methylimidazole as the cross-link agent could avoid the solubility of the composite membrane in water and dimethyl sulfoxide. With an increase of 2-methylimidazole, the solubility of the PECH ionomer was decreased. M-3, one of the CQPECH/PTFE membranes, showed good thermal properties (stable below 250 °C under an N2 atmosphere), excellent mechanical strength (a tensile strength of 67.3 MPa), moderate water uptake of 45.3%, and very low swelling degree of 9.01% at 30 °C. Besides, M-3 showed a hydroxide conductivity of up to 27 mS/cm and good long-term stability in a 1 M KOH solution at 60 °C for 15 days. In addition, a single H2/O2 fuel-cell test using M-3 at 50 °C indicated a peak power density of 23 mW/cm(2). These results suggested that the CQPECH/PTFE membrane had a good perspective for application in an alkaline fuel cell.

Easy one-step hydrothermal synthesis of nitrogen-doped reduced graphene oxide/iron oxide hybrid as efficient supercapacitor material

AbstractHybrid material consisting of α-Fe2O3 and nitrogen-doped reduced graphene oxide (N-rGO/Fe2O3) for supercapacitor electrode material has been synthesized via an easy one-step hydrothermal method, where urea serves as nitrogen source, reducing agent and precipitant. As a result, the reduction and nitrogen doping of graphene oxide and the in situ formation of α-Fe2O3 are achieved simultaneously. The results show that the synthesized N-rGO/Fe2O3 composite exhibits much better electrochemical performance than the sample without nitrogen doping. Moreover, thanks to the positive synergetic effect between N-rGO and α-Fe2O3, the N-rGO/Fe2O3 composite shows superior electrochemical property, including high capacitance, excellent rate capability, and good cycle life. Consequently, the easy preparation approach in this work will be considered as an efficient pathway for the development of metal oxide or hydroxide/N-rGO electrode material for high-performance supercapacitors. Graphical AbstractNitrogen-doped reduced graphene oxide/α-Fe2O3 (N-rGO/Fe2O3) composite was prepared via easy one-step hydrothermal method, where urea served as nitrogen source, reducing agent, and precipitant. The presence of N-rGO was favored for the smaller size and more homogenous distribution of Fe2O3 nanoparticle. Due to the nitrogen doping and positive synergistic effect between N-rGO and Fe2O3, the obtained composite exhibited superior electrochemical performance.

Electrochemical immunosensor for interferon-γ based on disposable ITO detector and HRP-antibody-conjugated nano gold as signal tag

Tuberculosis is the most frequent cause of infection-related death worldwide. A new disposable electrochemical immunosensor with low cost and simple fabrication was proposed to detect interferon-γ (IFN-γ). Diallyldimethylammonium chloride (PDDA) and Au nanoparticle (AuNP) composite were used to provide an efficient biointerface, horseradish peroxidase (HRP)-labeled antibody-conjugated AuNP (HRP-Ab2-AuNP) bioconjugates were used as a novel signal tag. The large amounts of HRP on the signal tag can catalyze the oxidation of Hydroquinone (HQ) by H2O2, which can induce an amplified reductive current. The catalytic reduction current was related to the amount of HRP immobilized on the surface, which itself was related to the concentration of IFN-γ. Under optimized conditions, the proposed immunosensor showed a high sensitivity and a linear range of 0.1-10,000pg/mL with a detection limit of 0.048pg/mL. The assay results of clinical serum samples obtained by the immunosensor were in acceptable agreement with the reference values. Therefore, the immunosensor possessed excellent clinical value in early diagnosis and control of tuberculosis.

Preparation of montmorillonite-pillared graphene oxide with increased single- and co-adsorption towards lead ions and methylene blue

To prevent the aggregation of graphene oxide (GO) during storage or application, montmorillonite (MMT) was used as the modifier, and MMT-pillared GO (GM) was prepared. The features of GM were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, energy dispersion X-ray spectrometry, atomic force microscopy and X-ray diffraction measurements. Then, a batch system was applied to study the adsorption behaviors of lead ions (Pb2+) and methylene blue (MB) by GM in single and binary systems. The results showed that GM possessed a higher Brunauer–Emmett–Teller (BET) specific surface area than GO. In a single system, the maximum adsorption capacities of GM for MB and Pb2+ were 350 and 285 mg g−1, respectively. With increasing the storage days, the BET specific surface area and the maximum adsorption capacity of GM remained approximately unchanged, while that of GO dramatically decreased. For a binary system, the presence of MB in water provides additional binding sites for Pb2+, promoting the adsorption of Pb2+ on GM. The presence of Pb2+ in water would compete with MB on GM during the adsorption process, resulting in a decrease in the adsorption of MB. The adsorption results recorded under different conditions indicated that this experiment was capable of the simultaneous removal of Pb2+ and MB using GM as the adsorbent. In addition, the pillared structure of GM greatly enhanced the noncovalent adhesion.

A colon targeted drug delivery system based on alginate modificated graphene oxide for colorectal liver metastasis

A major problem associated with colon cancer is liver metastasis. A colon-targeted drug delivery system is one way to address this problem after the resection of colorectal cancer. However, traditional drug delivery systems face many challenges, such as an inability to control the release rate, inaccurate targeting, susceptibility to the microenvironment and poor stability. Here, we report the development of a graphene oxide (GO)-based, sodium alginate (ALG) functionalized colon-targeting drug delivery system, that is loaded with 5-fluorouracil (5-FU) as the anti-cancer drug (denoted as GO-ALG/5-FU). Our results demonstrate that the as-prepared drug delivery system possesses a much lower toxicity and better colon-targeting controlled-release behaviours. We show that GO-ALG/5-FU significantly inhibited tumour growth and liver metastasis and prolonged the survival time of mice. We anticipate that our assay will help improve basic research of colon-targeted drug delivery systems and provide a new way to treat colon cancer liver metastasis.

Effect of oil extraction on properties of spent coffee ground–plastic composites

This study was aimed at evaluating the effect of oil extraction in spent coffee ground (SCG) on the properties of spent coffee ground–polypropylene composites. Coffee oil was removed from SCG by ultrasonication extraction. SCG and extracted spent coffee ground (ESCG) were used to reinforce the polypropylene (PP) in this research. Moisture uptakes, morphologies, mechanical properties, thermal properties, and accelerated aging test of composites were examined as a function of oil extraction. The results suggested that the extraction of coffee oil improved the water resistance of composites. The mechanical properties of spent coffee grounds–polypropylene composites (SCGPCs) were improved significantly after oil extraction, which suggested that the oil extraction was helpful to improve the interfacial adhesion and compatibility between filler and PP matrix. The moisture absorption of SCGPC showed a dramatic decrement after oil extraction. The results also revealed that the oil extraction improved the thermal property of composite.

Utilization of reduced graphene oxide for the enhancement of photocatalytic property of TiO2 nanotube

AbstractPhotocatalysts based on TiO2 nanotubes and reduced graphene oxide (TNTs-RGO) were prepared by the hydrothermal method. The resulting TNTs-RGO composite photocatalysts were characterized by X-ray powder diffraction, transmission electron microscopy, diffuse reflection spectrum, Fourier transform infrared spectroscopy, N2 adsorption–desorption isotherm, and fluorescence spectrum. The photocatalytic activity of TNTs-RGO was investigated through the degradation tests of Rhodamine B (RhB) and Cr(VI) under UV-light irradiation. The results showed that compared with TNTs or TiO2, TNTs-RGO possessed higher surface area, enhanced optical absorption in the visible-light region and improved separation efficiency of electron–hole pairs, leading to the remarkable increases in adsorption capacity and photocatalytic activity for RhB or Cr(VI), which was thanks to the introduction of RGO. On the basis of the experimental results, a possible photocatalytic degradation mechanism of RhB or Cr(VI) by TNTs-RGO was als...

Fabrication of quaternary phosphonium-intercalated vermiculite for reinforcing UV-curable epoxy acrylate coatings

In this study, UV-curable epoxy acrylate film was reinforced with benzyl triphenyl phosphorus chloride-intercalated vermiculite (BTPC-VMT). BTPC-VMT was prepared by intercalating benzyl triphenyl phosphorus chloride (BTPC) into vermiculite (VMT) and was used as reinforcing filler. Then, X-ray diffraction and Scanning electronic microscope results of hybrid films indicated that BTPC-VMT was well dispersed in the matrix. The hybrid films displayed enhanced tensile strength, impact strength, and pencil hardness without sacrificing elongation at break. Moreover, the thermal property of hybrid films was generally improved. The resulting hybrid films are promising for a number of applications, e.g. for metal and wood for their surface protection.

Study the photocatalysis activity of hydrothermal-synthesized BiVO4–graphene composite on methylene blue

AbstractA hydrothermal synthesis method was developed to prepare graphene-supported bismuth vanadate (BiVO4) particle (BiVO4–graphene) using graphene oxide, Bi(NO3)3·5H2O, and NH4VO3 as raw materials. The composite was characterized by various analytical methods, including X-ray powder diffraction, Fourier transform infrared spectroscopy, diffuse reflection spectra, transmission electron microscope, X-ray photoelectron emission spectroscopy, and fluorescence spectra. The photocatalytic activity of BiVO4–graphene composite was investigated by the degradation of methylene blue in an aqueous solution under visible light irradiation. It had been confirmed that the presence of graphene enhanced the photocatalytic activity of BiVO4 particle, and the BiVO4–1.0% graphene showed the best photocatalytic activity. The improved visible light activity of BiVO4–graphene was due to the enhancement of electron–hole separation by the electron trapping of graphene. Also, a possible mechanism was proposed to elucidate the r...