Natural bio-waste-derived 3D N/O self-doped heteroatom honeycomb-like porous carbon with tuned huge surface area for high-performance supercapacitor.

Supercapacitor electrodes (SCs) of carbon-based materials with flexible structures and morphologies have demonstrated excellent electrical conductivity and chemical stability. Herein, a clean and cost-effective method for producing a 3D self-doped honeycomb-like carbonaceous material with KOH activation from bio-waste oyster shells (BWOSs) is described. A remarkable performance was achieved by the excellent hierarchical structured carbon (HSC-750), which has a large surface area and a reasonably high packing density. The enhanced BWOSs-derived HSC-750 shows an ultrahigh specific capacitance of 525 F/g at 0.5 A g-1 in 3 M KOH electrolyte, as well as high specific surface area (2377 m2 g-1), pore volume (1.35 cm3 g-1), nitrogen (4.70%), and oxygen (10.58%) doping contents. The SCs also exhibit exceptional cyclic stability, maintaining 98.5% of their capacitance after 10,000 charge/discharge cycles. The two-electrode approach provides a super high energy density of 28 Wh kg-1 at a power density of 250 W kg-1 in an alkaline solution, with remarkable cyclability after 10,000 cycles. The study demonstrates the innovative HSC synthesis from BWOSs precursor and cost-effective fabrication of 3D N/O self-doped heteroatom HSC for flexible energy storage.

Bimetal-organic frameworks derived redox-type composite materials for high-performance energy storage.

Electrodes and electroactive materials are crucial components in the development of supercapacitors due to their geometric properties. In this study, bimetal-organic frameworks (Bi-MOFs, ZIF-8@ZIF-67) were utilized as electrode materials for a high-performance hybrid supercapacitor (HSC) by designing a novel synthesis of metallic carbonate hydroxide/oxides. In particular, the Bi-MOFs function as a sacrificial precursor in the synthesis of hollow NiMn(CO3)0.5·0·.11H2O/ZnO@Co3O4 CNCs (NM-CH/ZnO@Co3O4 CNCs) cubic composite materials by a straightforward low-temperature treatment. The NM-CH/ZnO@Co3O4 CNCs exhibited exceptional electrochemical performance with high specific capacity of 196.3 ± 0.08 mAh/g, specific capacitance of 1179 ± 0.10 F g-1 at 0.5 A g-1, and outstanding cycling stability of 98% after 25,000 cycles compared to the other electrode materials. The porous and hollow structure, along with a large surface area, contributed to the enhanced electrochemical properties of the composite material. An HSC was constructed using NM-CH/ZnO@Co3O4 CNCs as the cathode and activated porous carbon (APC) as the anode, resulting in a device with a specific energy of 33 ± 0.12 Wh kg-1 and a power density of 19354 ± 0.07 W kg-1. The use of Bi-MOF electrodes presents new avenues for the development of high-performance energy storage materials, with the potential for industrial energy storage application demonstrated though the successful powering of portable lightbulbs.

Characteristics of hydrogen energy yield in steam gasification of coffee residues.

Coffee residues (CRs) were gasified using a laboratory-scale fluidized bed gasifier with an air/steam mixture as the carrier gas. The gasification was conducted at an equivalence ratio (ER) of 0.3, and different operation temperatures (700, 800, and 900 °C) and steam-to-biomass (S/B) ratios (0, 0.75, and 1.5) were applied. Increasing temperature without steam boosted H2 and CO concentrations in producer gas, raising lower heating value (LHV) and cold gas efficiency (CGE) through endothermic reactions like Boudouard, tar cracking, and water-gas formation. At 900 °C, gas had LHV of 3.76 MJ/Nm3 and CGE of 22.47%. It was elevating temperature from 700 to 900 °C and S/B ratio to 1.5 raised H2 and CO concentrations from 2.04 to 8.60% and from 9.56 to 11.8%, respectively. This also increased LHV from 2.23 to 3.89 MJ/Nm3 and CGE from 11.28 to 25.08%. The steam gasification reaction was found to increase the H2 concentration and was thus considered effective in converting CRs to syngas and increasing energy production. Overall, the study successfully demonstrated the feasibility of steam gasification as a means of converting coffee residues to syngas and increasing energy production. The results also highlighted the importance of operating temperature and S/B ratio in improving the gasification process.

Yolk-shell silica dioxide spheres @ metal-organic framework immobilized Ni/Mo nanoparticles as an effective catalyst for formic acid dehydrogenation at low temperature.

The novel catalyst with yolk-shell SiO2 NiMo/SiO2 spheres immobilized by zeolitic imidazolate framework (ZIF-67) materials has been successfully prepared. The experimental results indicated that the prepared catalyst exhibits superior performance for hydrogen generation from Formic acid (FA) dehydrogenation without any additives at low temperatures. The catalytic performances of the NixMo1-x/ZIF-67@SiO2 yolk-shell increased with Ni addition ratio increasing. In this research, Ni0.8Mo0.2/ZIF-67@SiO2 yolk-shell could provide the highest catalytic conversion efficiency. This is due to the uniform dispersion of fine metal nanoparticles (NPs) and synergistic effect between the NiMo NPs and ZIF-67@SiO2 supporter. The turn over frequency (TOF) value was approximately 13,183 h-1 at 25 °C through complete FA conversion. H2 selectivity was also approximately 100% with obvious CO-free hydrogen production at 25 °C. Meanwhile, the prepared NiMo/ZIF-67@SiO2 yolk-shell catalyst also shows superior catalytic stability with corresponding 99% activity after 10 cycles. In summary, the catalyst preparation and hydrogen generated from FA dehydrogenation obtained from this research could provide the important information for application in catalyst innovation and waste FA recycling and recovery in the future.

Enantioseparation of ketoconazole and miconazole by capillary electrophoresis and a study on their inclusion interactions with ß-cyclodextrin and derivatives.

A chiral separation method coupled with capillary electrophoresis (CE) analysis for ketoconazole and miconazole enantiomers using chiral selectors such as ß-cyclodextrin (ß-CD) and hydroxypropyl-ß-CD (HP-ß-CD) was developed in this study, which included the optimisation, validation and application of the method on the antifungal cream samples. The formation of inclusion complex between the hosts (ß-CD and HP-ß-CD) and guests (ketoconazole and miconazole) were compared and analysed using ultraviolet-visible spectrophotometry, nuclear magnetic resonance (NMR) spectroscopy and molecular docking methods. Results from the study showed that in a concentration that ranged between 0.25 and 50 mg L-1 , the linear calibration curves of each enantiomer had a high coefficient of regression (R2 > 0.999), low limit of detection (0.075 mg L-1 ) and low limit of quantification (0.25 mg L-1 ). The relative standard deviation (RSD) of the intraday and interday analyses ranged from 0.79% to 8.01% and 3.30% to 11.43%, respectively, while the recoveries ranged from 82.0% to 105.7% (RSD < 7%, n = 3). The most probable structure of the inclusion complexes was proposed based on the findings from the molecular docking studies conducted using the PatchDock server.

Studies on the supramolecular complex of a guanosine with beta-cyclodextrin and evaluation of its anti-proliferative activity.

The behavior of the inclusion behavior of guanosine (GU) with beta-cyclodextrin (ß-CD) in the liquid, solid and virtual state were investigated. The absorption and fluorescence spectral were used to determine the inclusion behavior in liquid state. FT-IR, NMR, TGA, DSC, PXRD and FESEM techniques were used to investigate the inclusion behavior in solid-state, meanwhile the virtual state studies are done by molecular docking. The solid inclusion complex (GU: ß-CD) was prepared by using the co-precipitation method. The binding constant (K) of (GU: ß-CD) was calculated by using Benesi-Hildebrand. Besides that, the 1:1 stoichiometric ratio of inclusion complex was confirmed by using the Benesi-Hildebrand plot and Job's plot of continuous variation method. The most preferable model of GU: ß-CD that suggested via molecular docking studies was in good agreement with experimental results. The inclusion complex of GU: ß-CD exerted its toxicity effects towards HepG2 cell lines based on the reduced number of cell viability and lowest IC50 value compared to the GU and ß-CD viability.

Spectroscopic studies for the inclusion complexation of ketoprofen enantiomers with ß-cyclodextrin.

Inclusion complexes of R-ketoprofen and S-ketoprofen enantiomers with ß-cyclodextrin (ß-CD) in aqueous solution were studied using various spectroscopic techniques such as Raman, FTIR, UV and fluorescence. The different relative intensities and characteristic band shifts of the two enantiomers from Raman spectra suggests different interaction when complexed with ß-CD. Raman experiments revealed a noticeable diminishing of the CC vibration and ring deformation, which indicate the embedding of ketoprofen inside the ß-CD cavity. It's revealed that distinct differences between R- and S-ketoprofen in the presence of ß-CD at neutral pH. The stoichiometry ratio and binding constant of the inclusion complexes were calculated using Benesi-Hildebrand plot. Both enantiomers showed stoichiometry ratio of 1:1 inclusion complex with ß-CD. The binding constant of R-ketoprofen (4088 M-1) is higher than S-ketoprofen (2547 M-1). These values indicated that ß-CD formed inclusion complexes more preferentially with R-ketoprofen than S-ketoprofen. Results demonstrated that ß-CD can be used as a promising chiral selector for ketoprofen enantiomers.

A Facile Way to Form a Graded Halide Layer in Perovskite Solar Cells.

A light harvest layer composed of gradual change from formamidinium lead triiodide (FAPbI3) to methylammonium lead triiodide (MAPbI3) was fabricated using a novel two-step process. That is, a graded halide layer structure without extra processing steps is demonstrated. Conventionally, in the fabrication of MAPbI3 perovskite solar cells (PSCs) using two-step process, PbI2 layer was the first deposited on a mesoporous TiO2 coated substrate. The methylammonium iodide (MAI) solvent was then spin-coated on the surface of PbI2 layer and heated to form the MAPbI3 perovskite layer. Double perovskite layers such as FAPbI3 plus MAPbI3 requires twice of the second step which FAI and MAI should be spin-coated individually. This can be tedious and time consuming. We report here a facile way to form a graded perovskite layer, consisting FAPbI3 to MAPbI3, in a single step. FAI was first added into dimethylformamide (DMF) solution that was used to form PbI2 layer, then MAI solution was dripped on top of the FAI/PbI2 layer. The graded perovskite layer structure (FAPbI3/MAPbI3) in a gradient manner are readily formed, where the structure is confirmed by EDS to be FTO/compact TiO2/mesoporous TiO2/FAPbI3(thin)/MAPbI3/Spiro-OMeTAD/Ag. The Jsc, and Voc of solar cells with this graded perovskite layer are enhanced and the efficiency increases from 11.62% to 14.06%.

Preparation and characterization of host-guest system between inosine and ß-cyclodextrin through inclusion mode.

Inosine is a nucleoside that is formed when hypoxanthine is attached to a ribose ring (also known as a ribofuranose) via a ß-N9-glycosidic bond. Inosine is commonly found in tRNAs. Inosine (INS) has been used widely as an antiviral drug. The inclusion complex of INS with ß-CDx in solution phase is studied by ground and excited state with UV-visible and fluorescence spectroscopy, respectively. A binding constant and stoichiometric ratio between INS and ß-CDx are calculated by BH equation. The lifetime and relative amplitude of INS is increases with increasing the concentrations of ß-CDx, confirms the formation of inclusion complex in liquid state. The solid complexes are prepared by kneading method (KM) and co-precipitation method (CP). The solid complex is characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), powder X-ray diffraction (XRD) and differential scanning colorimetry (DSC). CP method gives the solid product with good yield than that of physical mixture and KM method. The structure of complex is proposed based on the study of Patch - Dock server.