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The persistence of pharmaceutical and personal care products (PPCPs) such as norfloxacin (NFX) poses a serious threat to the water environment, and the development of efficient and cost-effective advanced oxidation catalysts is an important step toward resolving this issue. Herein, Fe and N co-doped graphene (FeNGO) was synthesized from graphene oxide (GO), urea, and iron salt via simple impregnation pyrolysis, and applied for activating peroxymonosulfate (PMS) to degrade NFX. FeNGO possessed a two-dimensional porous sheet structure and was rich in defects, nitrogen species, and active sites. Compared with the control catalyst doped with N or Fe alone, FeNGO/PMS system showed the best degradation performance with 97.7% removal of NFX after 30 min, the rate constant was 7.1 and 1.7 times than that for NGO and FeGO, respectively. Fe 3 N was the main active site of FeNGO, and it is confirmed that singlet oxygen (1O 2) and superoxide radical (O 2 •-) were the primary oxidation active species (ROS) during NFX degradation. The formation of 1O 2 came from the transformation of O 2 •- and PMS decomposition. FeNGO showed strong pH adaptability, and also exhibited stale degradation performance in saliferous water matrices. It is believed that this work will offer theoretical and practical guidance for PMS activation by non-radical pathways. [Display omitted] • The FeNGO was prepared and the Fe 3 N were the main active sites. • The FeNGO exhibited good pH flexibility and had low Fe leaching. • O 2.•- and 1O 2 were primary cause of norfloxacin degradation. • Possible degradation pathway of norfloxacin was proposed. [ABSTRACT FROM AUTHOR]

Adsorption and advanced oxidation technology are important means to remove organic pollutants, and the combination of adsorption and catalytic degradation to construct a multi-field coupled system can realize valid adsorption and degradation of organic contaminants. In this paper, CuBi 2 O 4 supported by a nonmetallic element-modified graphene hydrogel composite structure CuBi 2 O 4 /X-rGH (X = N, P, S, B) was synthesized and applied to the efficient removal of organic pollutants. We found that the doping of nonmetallic elements enhances the graphene conjugated large π-bond system, which not only improves the adsorption performance of pollutants but also increases the graphene conductivity and builds more carrier transport channels, which is beneficial to the photocatalytic Fenton synergistic degradation activity. Among them, CuBi 2 O 4 /P-rGH could achieve 90 % degradation of phenol (50 ppm) after 20 min of turning on the light, which was nearly 2 times more than the degradation activity of CuBi 2 O 4 /rGH. Electron paramagnetic resonance (EPR) and quenching experiments proved that ·OH was the main active species in the synergistic degradation process, and the mechanism of adsorption of nonmetallic modified graphene hydrogel hybrid catalysts and in situ photocatalytic Fenton degradation of pollutants was proposed. [ABSTRACT FROM AUTHOR]

Adsorption and advanced oxidation technology are important means to remove organic pollutants, and the combination of adsorption and catalytic degradation to construct a multi-field coupled system can realize valid adsorption and degradation of organic contaminants. In this paper, CuBi 2 O 4 supported by a nonmetallic element-modified graphene hydrogel composite structure CuBi 2 O 4 /X-rGH (X = N, P, S, B) was synthesized and applied to the efficient removal of organic pollutants. We found that the doping of nonmetallic elements enhances the graphene conjugated large π-bond system, which not only improves the adsorption performance of pollutants but also increases the graphene conductivity and builds more carrier transport channels, which is beneficial to the photocatalytic Fenton synergistic degradation activity. Among them, CuBi 2 O 4 /P-rGH could achieve 90 % degradation of phenol (50 ppm) after 20 min of turning on the light, which was nearly 2 times more than the degradation activity of CuBi 2 O 4 /rGH. Electron paramagnetic resonance (EPR) and quenching experiments proved that ·OH was the main active species in the synergistic degradation process, and the mechanism of adsorption of nonmetallic modified graphene hydrogel hybrid catalysts and in situ photocatalytic Fenton degradation of pollutants was proposed. [ABSTRACT FROM AUTHOR]

A CoO/3D graphene composite synthesized via hydrothermal method was used as an anode material for Li-ion batteries. X-ray diffraction, scanning electron microscopy, thermogravimetry, energy-dispersive X-ray spectroscopy, transmission electron microscope, cyclic voltammetry, electrochemical impedance spectroscopy, and charge/discharge measurement were conducted to evaluate the physical and electrochemical properties of the CoO/3D graphene composite. Results showed that the composite delivered high rate capacities of 1481.1, 657.7, 472.5, 423.8, and 391.2 mAh g −1 , at 50, 100, 200, 300, 400, and 500 mA g −1 , respectively. The capacity after 100 cycles was 860 mAh g −1 at 50 mA g −1 , thereby indicating excellent cycle stability. The excellent electrochemical performance was ascribed to 3D graphene sheets that were formed in the composite structure. [ABSTRACT FROM AUTHOR]

A novel aptamer/graphene interdigitated gold electrode piezoelectric sensor was developed for the rapid and specific detection of Staphylococcus aureus ( S. aureus ) by employing S. aureus aptamer as a biological recognition element. 4-Mercaptobenzene-diazonium tetrafluoroborate (MBDT) salt was used as a molecular cross-linking agent to chemically bind graphene to interdigital gold electrodes (IDE) that are connected to a series electrode piezoelectric quartz crystal (SPQC). S. aureus aptamers were assembly immobilized onto graphene via the π – π stacking of DNA bases. Due to the specific binding between S. aureus and aptamer, when S. aureus is present, the DNA bases interacted with the aptamer, thereby dropping the aptamer from the surface of the graphene. The electric parameters of the electrode surface was changed and resulted in the change of oscillator frequency of the SPQC. This detection was completed within 60 min. The constructed sensor demonstrated a linear relationship between resonance frequency shifts with bacterial concentrations ranging from 4.1×10 1 −4.1×10 5 cfu/mL with a detection limit of 41 cfu/mL. The developed strategy can detect S. aureus rapidly and specifically for clinical diagnosis and food testing. [ABSTRACT FROM AUTHOR]

Abstract: Bimetallic palladium–silver nanoparticles (NPs) supported on reduced oxide graphene (RGO) with different Pd/Ag ratios (Pd–Ag/RGO) were prepared by an easy green method which did not use any additional reducing agents or a dispersing agent. During the process, simultaneous redox reactions between AgNO3, K2PdCl4 and graphene oxide (GO) led to bimetallic Pd–Ag NPs. The morphology and composition of the Pd–Ag/RGO were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetric analysis and Raman spectroscopy. Cyclic voltammetry and chronoamperometry were used to investigate the electrochemical activities and stabilities of these Pd–Ag/RGO catalysts for the electro-oxidation of methanol and ethanol in alkaline media. Among the different Pd/Ag ratios, the Pd–Ag (1:1)/RGO had the best catalytic activities and stability. So it is a promising catalyst for direct alcohol fuel cell applications. [Copyright &y& Elsevier]

• Graphene aerogel prepared at different freeze-casting temperatures yield unequal electromagnetic properties. • Modulate absorption/reflection shielding performance through the introduction of new skeleton. • Graphene aerogel with different pore structures reveal different mechanical properties. We report a comprehensive analysis of the Electromagnetic (EM) properties of graphene aerogel-based shielding materials prepared by freeze casting. Controlling the freeze casting temperature allows for tailoring the pore sizes of graphene aerogels, which further affects the permittivity and EM shielding properties. To protect the aerogel structures from collapsing during high temperature heat-treatment, we used Melamine sponge (MS) as a supporting strut. Through a comparison with bare aerogels, we find that the presence of MS can significantly modify both the reflection and absorption performances and that an absorption-dominated shielding material can be obtained. After heat-treatment at 1000 °C for two hours, the MS-supported aerogel sample (MS-aero) showed a shielding efficiency of 55.8 dB. Our work shows that the material composition and the microstructural architecture of aerogels crucially influence their electromagnetic shielding efficiency. [ABSTRACT FROM AUTHOR]

Abstract: Reduced graphene oxide/cadmium sulfide (RGO/CdS) hybrid material was synthesized by a one-step solvothermal method, wherein graphene oxide (GO) was a supporting material on which CdS nanoparticles were distributed homogeneously, and cadmium acetate (Cd(Ac)2·2H2O) was used as the CdS precursor. The supporting material RGO for CdS nanoparticles effectively enhanced their photocatalytic activities for the photodegradation of methylene blue in the aqueous solution. The optimum weight ratio of the GO to CdS in the hybrid material was 5.0%, which exhibited an excellent photodegradation efficiency (94%) and a better removal efficiency of total organic carbon (TOC) (57%), about 2.5 times and 5.1 times higher than that of pure CdS nanoparticles, respectively, under visible light (VL) irradiation. This improved photodegradation efficiency could be attributed to the increased adsorbability for methylene blue molecules, light absorption levels located in visible region, high charge transfer and separation ability, due to the introduction of a two-dimensional RGO network. [Copyright &y& Elsevier]