Synthesis and optical properties of polyvinylidene difluoride nanocomposites comprising MoO3/g-C3N4

The present study describes the optical properties for prepared polymer nanocomposites of PVDF at different content of MoO3/g-C3N4. The structural properties of polymer films were analysed via XRD, FTIR and ESEM techniques. The XRD diffraction patterns of PVDF with different concentrations of MoO3/g-C3N4 have two characteristic peaks at 2 θ = 18.4° and 20.3° where first peak was assigned to α-phase, while last peak was attributed to β-phase. The ESEM micrographs of PVDF-MoO3/g-C3N4 nanocomposites have shown smooth surface topography. According to the UV–visible absorption spectra, the UV absorption of PVDF was increased when adding MoO3/g-C3N4 nanoparticles where distinct peak was appeared in the UV region at 310 nm and its edges become more intense and moved towards higher wavelength after MoO3/g-C3N4 incorporation. The optical values of (Edir) and (Eind) energies have decreased with increasing the nanoparticle composites content. The optical band gap energy (Eopt) was decreasing from 5.66 eV to 4.56 eV as increasing the content of MoO3/g-C3N4. The refractive index (n) was increased with increasing the concentration of MoO3/g-C3N4 in nanocomposites samples, except for the sample with 0.25 wt%. The distinctive optical characteristics of PVDF-MoO3/g-C3N4 qualify such polymer nanocomposites for optoelectronic applications

Synthesis of Sulfur@g-C₃N₄ and CuS@g-C₃N₄ Catalysts for Hydrogen Production from Sodium Borohydride

In this work, the S@g-C3N4 and CuS@g-C3N4 catalysts were prepared via the polycondensation process. The structural properties of these samples were completed on XRD, FTIR and ESEM techniques. The XRD pattern of S@g-C3N4 presents a sharp peak at 27.2° and a weak peak at 13.01° and the reflections of CuS belong to the hexagonal phase. The interplanar distance decreased from 0.328 to 0.319 nm that facilitate charge carrier separation and promoting H2 generation. FTIR data revealed the structural change according to absorption bands of g-C3N4. ESEM images of S@g-C3N4 exhibited the described layered sheet structure for g-C3N4 materials and CuS@g-C3N4 demonstrated that the sheet materials were fragmented throughout the growth process. The data of BET revealed a higher surface area (55 m2/g) for the CuS-g-C3N4 nanosheet. The UV–vis absorption spectrum of S@g-C3N4 showed a strong peak at 322 nm, which weakened after the growth of CuS at g-C3N4. The PL emission data showed a peak at 441 nm, which correlated with electron–hole pair recombination. The data of hydrogen evolution showed improved performance for the CuS@g-C3N4 catalyst (5227 mL/g·min). Moreover, the activation energy was determined for S@g-C3N4 and CuS@g-C3N4, which showed a lowering from 47.33 ± 0.02 to 41.15 ± 0.02 KJ/mol

Processing of new efficient Cr1-xNaxO3 catalysts for sodium borohydride methanolysis

This study reports the development of a novel Cr1-xNaxO3 catalyst using a simple cost-effective method for hydrogen production from NaBH4 methanolysis. The properties of the nanocomposites were investigated by employing XRD, FTIR, SEM and XPS characterization techniques. The XRD diffraction peaks confirmed the rhombohedral crystal structure of Cr1.xNaxO3 nanoparticles. The average crystal size of these nanoparticles was found to be ranging from 25.0 to 20 nm. FTIR analysis showed the characteristic absorption bands of Cr1.xNaxO3 nanoparticles. The SEM images of Cr2O3 and Cr1.7Na0.3O3 demonstrated that the nanoparticles are irregular in shape, while Cr1.4Na0.6O3 has a porous surface texture. XPS spectra of Cr2O3, Cr1.7Na0.3O3 and Cr1.4Na0.6O3 confirmed the presence of chromium, oxygen, and sodium in the samples. The optical band gaps of Cr2O3 Cr1.7Na0.3O3 and Cr1.4Na0.6O3 nanoparticles were approximately 3.28 eV, 1.61 and 0.81 eV, respectively. Cr1.4Na0.6O3 exhibited the most significant level of activity in terms of hydrogen production of 19144 mL/g.min

Synthesis of CaCO₃/Cu₂O/GO Nanocomposite Catalysts for Hydrogen Production from NaBH₄ Methanolysis

The synthesis of CaCO3/Cu2O/GO nanocomposites was developed by sol-gel auto-combustion method. The analysis of structure was completed on X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and environmental scanning electron microscopy (ESEM). The XRD spectra of the nanocomposites matched the crystal structure of CaCO3/Cu2O. The average crystal size was 20 nm for Cu2O and 25 nm for CaCO3 nanoparticles. FTIR data showed the absorption bands of Cu2O and GO. Raman spectroscopy data confirmed the formation of GO sheets. ESEM micrographs displayed spherical nanoparticles dispersed in GO sheets. X-ray photoelectron spectroscopy showed the peaks of Cu 2p, O 1s, C 1s, Cu 3s, and Ca 2p. The spectra of optical absorption revealed an absorption band of around 450 nm. The calcium content increase led to a decrease in the optical energy gap from 2.14 to 1.5 eV. The production of hydrogen from NaBH4 across the methanolysis reaction was accelerated by the CaCO3/Cu2O/GO nanocomposites. Therefore, these nanocomposites are superior in catalytic hydrogen production systems

Preparation and Optical Properties of PVDF-CaFe₂O₄ Polymer Nanocomposite Films

In this work, a synthesis technique for highly homogeneous PVDF-CaFe2O4 polymer films direct from solution was developed. The structural characterizations were conducted using XRD, FTIR, and ESEM experimental techniques. The XRD characteristic peaks of CaFe2O4 nanoparticles revealed a polycrystalline structure. The average crystallite size for CaFe2O4 was calculated to be 17.0 nm. ESEM micrographs of PVDF nanocomposites containing 0.0, 0.25, 0.75, and 1.0 wt% of CaFe2O4 showed smooth surface topography. The direct Edir and indirect Eind band gap energies for the PVDF-CaFe2O4 nanocomposites were decreased with the additions of 0.0–1.0 wt% CaFe2O4. In addition, the refractive index (n0) increased from 3.38 to 10.36, and energy gaps (Eg) decreased from 5.50 to 4.95 eV. The nonlinear refractive index (n2) for the PVDF-CaFe2O4 nanocomposites was improved with the addition of CaFe2O4 nanoparticles, exceeding those reported in the literature for PVC, PVA, and PMMA nanocomposites. Therefore, the PVDF-CaFe2O4 nanocomposites are expected to take the lead in optoelectronic applications because of their unusual optical properties

Direct synthesis of sodium doped Cu2O/GO nanocomposites for catalytic hydrogen production from NaBH4

In this work, Cu2O/GO doped Na nanocomposites were prepared via sol-gel auto-combustion procedure. The material structure was analysed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and environmental scanning electron microscopy (ESEM). The crystal structure of the Cu2O/GO, Cu1.7Na0.3O/GO and Cu1.4Na0.6O/GO nanocomposites was found to be cubic as evidenced by XRD patterns. The complexing of copper oxide and GO was confirmed by FTIR and Raman spectroscopy. ESEM micrographs showed that Cu2O nanoparticles are integrated into GO nanosheets. The surface area of these nanocomposites decreased from 122 to 59 m2/g. The optical energy gap was found to decrease from 2.14 to 1.72 eV with increasing sodium content. The addition of sodium to Cu2O/GO nanocomposites accelerated the hydrogen evolution from NaBH4. The maximum rate of hydrogen (10,981 mL/g·min) was achieved for the Cu1.4Na0.6O/GO nanocomposite sample. These findings confirm that the prepared nanocomposites could be used as efficient hydrogen catalysts

Survey of awareness of diabetes mellitus among the Arar population, Northern Border Region of Saudi Arabia

Background: Diabetes Mellitus (DM) is one of the most widely prevalent diseases in Saudi Arabia. Health education is considered an essential component to improve knowledge and change behavior. People affected by diabetes often have inadequate knowledge about the nature of diabetes, its risk factors and associated complication. Objectives: The aim of this study was to assess the awareness of the Arar population with various aspects of diabetes mellitus. Methods: A cross-sectional study was carried out in Arar city, the capital of the Northern Province of Kingdom of Saudi Arabia (KSA). The study was carried out on Saudi nationals from different age groups that were selected by systematic random sampling. Data was collected by means of personal interview with the participants using a pre-designed questionnaire which was administered by the medical students for each diabetic patient. Data were analyzed by SPSS version 15, using descriptive statistics and Chi-square test. Results: A total of 702 participants were interviewed, among them 201 (28.6%) males and 501 (71.4%) females, and most of them (77.8%) had high educational level, 10.4% were diabetics, 78.9% did not have regular checkup visits to the doctor and 58.5% did not perform any regular exercises, including walking, 60% thought that DM was due to partial or total decrease in insulin secretion and 12.4% thought that it was due to excess sweet eating. Additionally, 48.7% of the respondents thought that lack of exercise and obesity were the major risk factors of DM, 33.2% thought that it was a genetic disease. The majority (86.3) of the participants believed that the treatment of DM was a combination of healthy diet, exercise and medication and more than half (63.1%) said that weight loss and modification of life style were the most important preventive measures of DM. Regarding participants’ knowledge about DM complications, 24.5% knew about retinopathy and loss of vision, 8.3% knew about retinopathy, loss of vision, low sensation and numbness in extremities, 24.9% said that symptoms of DM were thirst and frequent urination. Conclusion: This study recommends that health policy makers conduct more effective health education sessions to increase knowledge of diabetic patients and their caregivers about diabetes and the importance of compliance with its treatment

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population