A New CuSe-TiO2-GO Ternary Nanocomposite: Realizing a High Capacitance and Voltage for an Advanced Hybrid Supercapacitor

A high capacitance and widened voltage frames for an aqueous supercapacitor system are challenging to realize simultaneously in an aqueous medium. The severe water splitting seriously restricts the narrow voltage of the aqueous electrolyte beyond 2 V. To overcome this limitation, herein, we proposed the facile wet-chemical synthesis of a new CuSe-TiO2-GO ternary nanocomposite for hybrid supercapacitors, thus boosting the specific energy up to some maximum extent. The capacitive charge storage mechanism of the CuSe-TiO2-GO ternary nanocomposite electrode was tested in an aqueous solution with 3 M KOH as the electrolyte in a three-cell mode assembly. The voltammogram analysis manifests good reversibility and a remarkable capacitive response at various currents and sweep rates, with a durable rate capability. At the same time, the discharge/charge platforms realize the most significant capacitance and a capacity of 920 F/g (153 mAh/g), supported by the impedance analysis with minimal resistances, ensuring the supply of electrolyte ion diffusion to the active host electrode interface. The built 2 V CuSe-TiO2-GO||AC-GO||KOH hybrid supercapacitor accomplished a significant capacitance of 175 F/g, high specific energy of 36 Wh/kg, superior specific power of 4781 W/kg, and extraordinary stability of 91.3% retention relative to the stable cycling performance. These merits pave a new way to build other ternary nanocomposites to achieve superior performance for energy storage devices

Design and Development of Defect Rich Titania Nanostructure for Efficient Electrocatalyst for Hydrogen Evolution Reaction in an Acidic Electrolyte

Cost-effective, efficient and stable electrocatalyst for water splitting in the acidic electrolyte medium has been developed. The acidic electrolyte could be a support for the high purity hydrogen production via water splitting. Accordingly, we have prepared the defect-rich titania nanostructure via electrochemical anodization and cathodization routes using the titanium plate, which showed highly effective and durable electrocatalyst of hydrogen evolution reaction (HER) in an acidic medium. This hybrid compound showed a low onset potential of −0.17 V for HER with a current density of −150 mA cm−2 in 1 M H2SO4. Moreover, the stability test has been performed with the defect-rich titania nanostructure as cathode for 6 h in the two electrodes system. © 2021 The Author(s).The authors extend their appreciation to the Deanship of Scientific Research, King Saud University for funding this work through Research Group no RG-1441-043 and funded by the Taif University Researchers Supporting Project number (TURSP-2020/04), Taif University, Taif, Saudi Arabia. One of the author Dr G. Murugadoss would like to thank Chancellor, President and Vice Chancellor, Sathyabama Institute of Science and Technology, Chennai for providing lab facilities and encouragement

Use of Fe3O4 Nanoparticles and Ultrasound-assisted Dispersive Liquid-liquid Microextraction of Lead in Water, Tobacco, and Fertilizer Samples for FAAS Determination

A Fe3O4 nanoparticle and ultrasonic coupled dispersive liquid-liquid microextraction (NPsU-DLLME) method was developed for the preconcentration of lead from water, tobacco, and fertilizer samples. Imidazole-2,4-dicarboxylic acid was used as the chelating agent and carbon tetrachloride as the extractor solvent. Addition of certain amounts of Fe3O4 nanoparticles and specific exposure periods to ultrasonic waves were optimized. Maximum recovery (%) was obtained using the following conditions: 17.5 mL sample volume, sample pH 6, 100 mu L of carbon tetrachloride as the extraction solvent, 70 mu L of ethanol as the dispersing solvent, 100 mu L of 0.1% imidazole-2,4-dicarboxylic acid as the chelating agent, 100 mu L of a 0.1% Fe3O4 nanoparticle suspension, and a 1-minute exposure to ultrasonic waves. This method was validated using an SPS-WW2 Wastewater certified reference material. The limit of detection (LOD) was 5.3 mu g L-1, the limit of quantification (LOQ) 15.8 mu g L-1, and the relative standard deviation (RSD) 2.6%. The method was applied to the determination of lead in some water, tobacco, and fertilizer samples

1-nitroso-2-naphthol impregnated multiwalled carbon nanotubes (NNMWCNTs) for the separation-enrichment and flame atomic absorption spectrometric detection of copper and lead in hair, water, and food samples

A novel enrichment-separation procedure based on solid phase extraction of copper(II) and lead(II) at ultratrace levels on 1-nitroso-2-naphthol impregnated multiwalled carbon nanotubes (NNMWCNTs) has been established. The effective critical parameters like pH and eluent type etc. on the quantitative recoveries of the analyte elements were optimized. The matrix effects are also investigated. The procedure was validated by analysing water certified reference materials and addition-recovery tests. The relative standard deviation of the presented procedure was below 10%. The application of the presented solid phase extraction procedure was successfully performed for copper and lead determination in some food and water samples

Ultrasound-assisted Supramolecular Microextraction of Copper in Water, Food, Hair, and Tobacco Samples Prior to Microsampling Flame Atomic Absorption Spectrometry

An analytical microextraction procedure was developed and applied for Cu(II) microextraction from natural waters, red pepper, black pepper, thyme, hashish, hair, and tobacco samples. The microextraction process was based on the chelation of Cu(II) from aqueous solutions with 4-(2-thiazolylazo) resorcinol, which is then moved to the organic supramolecular phase by ultrasonic waves. The organic phase, consisting of tetrahydrofuran and 1-decanol, was isolated by centrifugation. The extracted and preconcentrated copper was determined by microsampling flame atomic absorption spectrometry. The microextraction conditions and the operating parameters were optimized using the pH of 6, 200 mu L of 0.1% of 4-(2-thiazoly-lazo) resorcinol, and ultrasonic enhancement for 5 to 8 minutes. The ultrasound-assisted supramolecular solvent liquid phase microextraction procedure resulted in a limit of detection (LOD) of 1.13 mu g L-1 and was applied for Cu(II) determination in samples with different matrices

Dispersive liquid-liquid microextraction of lead(II) as tropaeolin ooo chelates from environmental samples prior to microsampling flame atomic absorption spectrometry

In the present work, lead(II) at trace level was extracted by a dispersive liquid-liquid microextraction procedure. The process was followed by flame atomic absorption spectrometry (FAAS) for trace determination of lead. Tropaeolin OOO was used as the chelating agent for lead(II). The analytical conditions for the quantitative recoveries of lead(II) were investigated. Lead (II) - Tropaeolin 000 chelate was quantitatively extracted to 200 mu L of CCl4 at pH 4. The limit of detection (LOD) was 11.4 mu g L-1. The recovery tests from the certified reference materials TMDA 64.2 and TMDA 53.3 Water Samples were in good agreement. The microextraction procedure showed applicability to wastewater and hair samples obtained from Kayseri, Turkey

Assessment of Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, and Pb Concentrations in Gluten-free Foods From Saudi Arabia by Inductively Coupled Plasma Mass Spectrometry

The levels of arsenic, cadmium, chromium, cobalt, copper, iron, lead, manganese, nickel, and zinc in some gluten-free food samples used for celiac disease patients have been determined after microwave digestion by inductively coupled plasma mass spectrometry (ICP-MS). The concentrations were found in the range of 0.09-0.66 (As), 2.9-6.6 (Cd), 4.7-100.3 (Cr), 866-2009 (Co), 0.043-0.26 (Cu), 3.2-17.4 (Fe), 1.4-10.5 (Pb), 12.9-41.3 (Mn), 0.35-0.46 (Ni) and 0.021-0.268 (Zn) mg kg(-1). The detection limits for As, Cd, Cr, Co, Cu, Fe, Pb, Mn, Ni, and Zn were 0.33, 0.009, 0.26, 0.041, 0.17, 1.36, 0.025, 0.061, 0.042, and 0.29 mg kg(-1), respectively. The accuracy of the method was confirmed by analysis of the standard reference material SRM 1568a Rice Flour. The results were compared with related works published for gluten-free foods used around the world and it was found that the Mn and Fe levels obtained in this study were at higher levels. The highest Ni, Co, Fe, and Cr levels were in Rice Flicks. The lowest Mn, Co, Zn, As, and Cd levels were in the Rice Thins samples