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Obesity is a complex disorder associated with immense health consequences including high risk of cardiovascular diseases, diabetes, and cancer. Abnormality in the thyroid gland, genetics, less physical activity, uptake of excessive diet, and leptin resistance are critical factors in the development of obesity. To determine the treatment strategy, understanding the pathophysiology of obesity is crucial. For instances, leptin resistance mediated obesity defined by the presence of excessive leptin hormone (Lep) in the systemic circulation is very common in diet induced obesity. Therefore, our hypothesis is that quantitative measurement of Lep from blood can help to identify individuals with Lep resistant mediated obesity and thereby guide toward a proper treatment strategy. In this work, we aim to utilize an electrochemical immunosensing platform for diagnosis of obesity by measuring the Lep content in systemic circulation. A porous carbon confined FeNi bimetallic system was synthesized with three different ratios of Fe and Ni ions using high temperature pyrolysis technique. The suitability of the sensor for detecting Lep was studied using both CV and EIS techniques. The limit of detection (LOD) for GCE was recorded as 157.4 fg/mL with a wide linear concentration range of 500 fg/mL to 80 ng/mL, while for SPCE the LOD was 184.9 fg/mL with a linear range of 500 fg/mL to 50 ng/mL. Finally, the feasibility and applicability of the sensor for Lep detection was tested with serum collected from high fat diet induced obese rats. The selectivity, sensitivity, storage, and experimental stability and reproducibility tests showed potential for this biosensor platform as a point-of-care Lep detection device.

Blending TiO2and cement to create photocatalytic composites holds promise for low-cost, durable water treatment. However, the efficiency of such composites hinges on cross-effects of several parameters such as cement composition, type of photocatalyst, and microstructure, which are poorly understood and require extensive combinatorial tests to discern. Here, we report a new combinatorial data science approach to understand the influence of various photocatalytic cement composites based on limited datasets. Using P25 nanoparticles and submicron-sized anatase as representative TiO2photocatalysts and methyl orange and 1,4-dioxane as target organic pollutants, we demonstrate that the cement composition is a more influential factor on photocatalytic activity than the cement microstructure and TiO2type and particle size. Among the various cement constituents, belite and ferrite had strong inverse correlation with photocatalytic activity, while natural rutile had a positive correlation, which suggests optimization opportunities by manipulating the cement composition. These results were discerned by screening 7806 combinatorial functions that capture cross-effects of multiple compositional phases and obtaining correlation scores. We also report •OH radical generation, cement aging effects, TiO2leaching, and strategies to regenerate photocatalytic surfaces for reuse. This work provides several nonintuitive correlations and insights on the effect of cement composition and structure on performance, thus advancing our knowledge on development of scalable photocatalytic materials for drinking water treatment in rural and resource-limited areas.

The rational design of multifunctional catalysts that use non-noble metals to facilitate the interconversion between H2, O2, and H2O is an intense area of investigation. Bimetallic nanosystems with highly tunable electronic, structural, and catalytic properties that depend on their composition, structure, and size have attracted considerable attention. Herein, we report the synthesis of bimetallic nickel–copper (NiCu) alloy nanoparticles confined in a sp2carbon framework that exhibits trifunctional catalytic properties toward hydrogen evolution (HER), oxygen reduction (ORR), and oxygen evolution (OER) reactions. The electrocatalytic functions of the NiCu nanoalloys were experimentally and theoretically correlated with the composition-dependent local structural distortion of the bimetallic lattice at the nanoparticle surfaces. Our study demonstrated a downshift of the d-band of the catalysts that adjusts the binding energies of the intermediate catalytic species. XPS analysis revealed that the binding energy for Ni 2p3/2band of the Ni0.25Cu0.75/C nanoparticles was shifted ∼3 times compared to other bimetallic systems, and this was correlated to the high electrocatalytic activity observed. Interestingly, the bimetallic Ni0.25Cu0.75/C catalyst surpassed the OER performance of RuO2benchmark catalyst exhibiting a small onset potential of 1.44 V vs RHE and an overpotential of 400 mV at 10 mA·cm–2as well as the electrochemical long-term stability of commercial RuO2and Pt catalysts and kept at least 90% of the initial current applied after 20 000 s for the OER/ORR/HER reactions. This study reveals significant insight about the structure–function relationship for non-noble bimetallic nanostructures with multifunctional electrocatalytic properties.

Abstract

Herein we present a modified iodine clock experiment which replaces starch with cellulose paper. This provides the reaction with a white solid surface in which color change can be clearly observed and reduces reagent amounts required to 540 μL per group. After data acquisition, students are required to calculate reaction orders and the reaction constant k, culminating in their ability to discern the rate equation for this reaction. This experiment is ideal for teaching kinetics in high school and undergraduate settings, particularly if liquid waste disposal is not readily available or if high importance is placed upon minimizing their environmental impact.

Herein, we report a facile method for the synthesis of sulfonated coffee waste (CW-SO3H). The biosorbent was characterized using Scanning Electron Microscopy (SEM), Energy-dispersive X-ray Spectroscopy (EDS), Fourier-transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, Thermogravimetric analysis (TGA) and Zeta potential measurements. The biosorbent was used for the biosorption of endocrine disrupting chemicals such as bisphenol A (BPA) and antibiotics such as sulfamethoxazole (SMX) from water. The calculated biosorption capacities of CW-SO3H were 271 mg/g and 256 mg/g towards the removal of BPA and SMX, respectively. The as synthesized biosorbent is capable to form π–π interaction and electrostatic interaction that allow the efficient biosorption of BPA and SMX. The Temkin isotherm model fits the experimental data better for BPA biosorption process, whereas the Temkin and Langmuir models explain the experimental data better for SMX biosorption process. The kinetic studies showed that the biosorption of BPA and SMX by CW-SO3H follows pseudo-second order kinetic model. The thermodynamic studies showed that the biosorption processes were spontaneous as well as exothermic in both cases. Therefore, CW-SO3H could be used as a promising biosorbent for the rapid removal of BPA and SMX from the wastewater.

Fullerene Stabilized Gold Nanoparticles Supported on TiO2for Enhanced Photocatalytic Degradation of Methyl Orange and the Catalytic Reduction of 4-nitrophenol.

In this study, we report a facile method for the preparation of sulfonic acid functionalized carbonaceous adsorbent (TW-SO3H) from tea leaves. The adsorbent was characterized using Fourier-transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy-dispersive X-ray Spectroscopy (EDS), Thermogravimetric analysis (TGA), Raman Spectroscopy and Zeta potential measurements. The adsorbent was utilized for the adsorptive removal of antibiotics such as sulfamethoxazole (SMX) and endocrine disrupting chemicals such as bisphenol A (BPA) from water. The calculated adsorption capacities of TW-SO3H were 258.87 mg/g and 236.80 mg/g towards the removal of SMX and BPA, respectively at 25 °C. The new adsorbent has the ability to form electrostatic interaction and π–π stacking that allow the efficient adsorption of SMX and BPA. The Langmuir and Temkin isotherm models best fit the experimental data for the BPA and SMX adsorption processes, respectively. The results of the kinetic studies showed that the removal of SMX and BPA by TW-SO3H followed pseudo-second order kinetic model. A thermodynamic study indicated that the adsorption process was spontaneous as well as exothermic. The adsorbent was facilely regenerated and recycled for three cycles with a nominal loss of adsorption capacity. Our results indicated that TW-SO3H could be utilized as a promising adsorbent for the rapid removal of SMX and BPA from the contaminated water.

Conversion of waste tire rubber into a high-capacity adsorbent for the removal of methylene blue, methyl orange, and tetracycline from water.

Herein, we report a novel benzoylated-cotton and multiwalled carbon nanotubes (BC-MWCNT) composite that exhibits efficient electrocatalytic properties to produce reactive oxygen species (ROS) in water. The BC-MWCNT was deposited on a fluoride-doped tin oxide (FTO) electrode to probe its electrochemical properties. The ROS produced through this approach were exploited towards the degradation of Methyl Orange (MO) dye. The BC-MWCNT electrode produced ROS at a −1.0 V potential, as indicated by the electrochemical degradation of MO dye solutions by 96% at pH 7.4 in 60 min. Experiments performed by varying the pH and electrolyte concentrations produced dramatic changes in the kinetics of the reaction, increasing degradation to 100% and shortening reaction time to 4 min with optimal conditions at pH 3.

Abstract

Synthesis of high-capacity and regenerable adsorbent based on sulfonated resorcinol-formaldehyde microspheres for the removal of organic dyes from water.

Superatom molecular orbitals (SAMOs) are atom-like molecular orbitals that have been observed in the buckminsterfullerene C60molecule. We studied the ice-like water cluster (H2O)10that is expected to be ubiquitous in nature in nanoscale microenvironments at ambient temperatures due to the nanoconfinement effect. We report for the first time the theoretical prediction of the existence of SAMOs in the adamantanoid nanostructured water cluster (H2O)10. The geometry of the adamantanoid water cluster (H2O)10was optimized using the Restricted Hartree-Fock method and the ab-initio second-order Møller-Plesset perturbation theory (MP2) method, as well as the aqueous solvent phase polarizable continuum method (PCM). The optimized (H2O)10structure is a distorted adamantanoid that closely matches the crystal structure of (H2O)10that was previously reported. The theoretical studies using Hartree-Fock (HF), MP2, or Density Functional Theory (DFT) predict that the adamantanoid water cluster (H2O)10exhibits SAMOs in the low-lying LUMOs. The orbital energies calculated with these methods are reported. The lowest-lying SAMOs in the water cluster (H2O)10is the most intriguing SAMO due to its s-orbital character and potential to delocalize electrons in a large area that surrounds the cluster. The electron affinity of the water cluster (H2O)10was calculated using HF, MP2, and DFT methods and the values obtained from each method were (kJ/mol) +74.71, -770.58, and -48.57, respectively. The existence of SAMOs in low-lying LUMO levels indicate of possible supramolecular chemistry of the water clusters with interfacial implications in nanoconfined spaces. Overall, these theoretical results predict new fundamental properties of water clusters that may have deep implications and impact in biological and nanotechnology systems that involve nanostructured water in confined spaces.

The interaction of molecular hydrogen with a novel microporous dinuclear Cu(II) complex, [bis-μ-di(4-pyridyl)methanol-1,4,7-triazacyclononane copper(II)] triflate (1), and its derivatives formed from oxidation and solvent removal was studied with 2H NMR and density functional theory (DFT). The Cu-complex 1was characterized with X-ray diffraction methods and consists of a dinuclear macrocycle that forms one-dimensional channels of 9.55 Å in diameter. 2H NMR studies of deuterium gas adsorption by 1suggest that physisorption condensation of D2occurs within two distinct microenvironments: in the interior and in-between the microtubular structures. The assignment of NMR resonances to specific adsorption sites is supported by spectral decomposition and analysis of the line widths and integrated signal intensities of the components. The dynamics of the system are probed by spin−lattice relaxation time measurements and spectral hole-burn experiments as a function of temperature and pressure. NMR and DFT calculations suggest that hydrogen uptake is mediated through interactions with the Cu(II) centers via dipole−ion interactions.

The design of alternative earth-abundant van der Waals (vdW) nanoheterostructures for bifunctional oxygen evolution/reduction (OER/ORR) electrocatalysis is of paramount importance to fabricate energy-related devices. Herein, we report a simple metal–organic framework (MOF)-derived synthetic strategy to fabricate low-dimensional (LD) nanohybrids formed by zero-dimensional (0D) ZrO2nanoparticles (NPs) and heteroatom-doped two-dimensional (2D) carbon nanostructures. The 2D platforms controlled the electronic structures of interfacial Zr atoms, thus producing optimized electron polarization for boron and nitrogen-doped carbon (BCN)/ZrO2nanohybrids. X-ray photoelectron spectroscopy (XPS) and theoretical studies revealed the key role of the synergistic couple effect of boron (B) and nitrogen (N) in interfacial electronic polarization. The BCN/ZrO2nanohybrid showed excellent bifunctional electrocatalytic activity, delivering an overpotential (η10) of 301 mV to reach a current density of 10 mA–cm–2for the OER process and a half-wave potential (E1/2) of 0.85 V vs reversible hydrogen electrode (RHE) for the ORR process, which are comparable to the state-of-the-art LD nanohybrids. Furthermore, BCN/ZrO2also showed competitive performances for water-splitting and zinc–air battery devices. This work establishes a new route to fabricate highly efficient multifunctional electrocatalysts by tuning the electronic polarization properties of 0D–2D electrochemical interfaces.

We report the formation of two thermally stable supramolecular structures based on 2,6‐pyridyldicarboxylic acid bis‐4‐pyridylamide (PyI) and bis(hexafluoroacetylacetonato)manganese(II) that exhibits a microporous structure with cavities bearing hydrogen bonding motifs that can enclathrate acetone and methanol molecules via well‐positioned hydrogen bonding interactions. Single‐crystal x‐ray diffraction in combination with thermogravimetric analysis and X‐ray powder diffraction (XRPD) studies were utilized to study the structure and thermal behavior of trans‐[Mn(hfacac)2(PyI)2]·2(CH3)2CO (1) and trans‐[Mn(hfacac)2(PyI)2]·2CH3OH (2). Our studies indicated that 1and 2are isostructural with respect to their supramolecular assembly and trap solvent molecules along the crystallographic bdirection via the inwardly directed hydrogen bonding motifs of the PyI component. These solvent molecules can be thermally removed to generate a crystalline material with micropores bearing hydrogen bonding rich sites within an overall supramolecular matrix similar to 1and 2. The removal of the guest solvent molecules is reversible and can be followed with XRPD. Copyright © 2003 John Wiley & Sons, Ltd.

We report the formation of two thermally stable supramolecular structures based on 2,6-pyridyldicarboxylic acid bis-4-pyridylamide (PyI) and bis(hexafluoroacetylacetonato)manganese(II) that exhibits a microporous structure with cavities bearing hydrogen bonding motifs that can enclathrate acetone and methanol molecules via well-positioned hydrogen bonding interactions. Single-crystal x-ray diffraction in combination with thermogravimetric analysis and X-ray powder diffraction (XRPD) studies were utilized to study the structure and thermal behavior of trans-[Mn(hfacac)2(PyI)2]·2(CH3)2CO (1) and trans-[Mn(hfacac)2(PyI)2]·2CH3OH (2). Our studies indicated that 1 and 2 are isostructural with respect to their supramolecular assembly and trap solvent molecules along the crystallographic b direction via the inwardly directed hydrogen bonding motifs of the PyI component. These solvent molecules can be thermally removed to generate a crystalline material with micropores bearing hydrogen bonding rich sites within an overall supramolecular matrix similar to 1 and 2. The removal of the guest solvent molecules is reversible and can be followed with XRPD. Copyright © 2003 John Wiley & Sons, Ltd.

The development of low-dimensional (LD) supramolecular materials with multifunctional electrocatalytic properties has sparked the attention of the catalysis community. Herein, we report the synthesis of a new class of 0D–2D heterostructures composed of boron carbon nitride nanosheets (BCN NSs) and fullerene molecules (C60/F) that exhibit multifunctional electrocatalytic properties for the hydrogen evolution/oxidation reactions (HER/HOR) and the oxygen evolution/reduction reactions (OER/ORR). The electrocatalytic properties were studied with varying F:BCN weight ratios to optimize the intermolecular electron transfer (ET) from the BCN NSs to the electron-accepting C60molecules. The nanohybrid supramolecular material with 10 wt % F in BCN NSs (10% F/BCN) exhibited the largest Raman and C 1s binding energy shifts, which were associated with greater cooperativity interactions and enhanced ET processes at the F/BCN interface. This synergistic interfacial phenomenon resulted in highly active catalytic sites that markedly boosted electrocatalytic activity of the material. The 10% F/BCN showed the highest tetrafunctional catalytic performance, outperforming the OER catalytic activity of commercial RuO2catalysts with a η10of 390 mV and very competitive onset potential values of −0.042 and 0.92 V vs RHE for HER and ORR, respectively, and a current density value of 1.47 mA cm–2at 0.1 V vs RHE with an ultralow ΔGH*value of −0.03 eV toward the HOR process. Additionally, the 10% F/BCN catalyst was also used as both cathode and anode in a water splitting device, delivering a cell potential of 1.61 V to reach a current density of 10 mA cm–2.

Modification of peanut-shell into a high-capacity adsorbent using the sulfuric acid reflux technique for the removal of methylene blue and tetracycline from water.