New Insights into Improving the Photovoltaic Performance of Dye-Sensitized Solar Cells by Removing Platinum from the Counter Electrode Using a Graphene-MoS2 Composite or Hybrid.

Photovoltaic systems, such as dye-sensitized solar cells (DSSCs), are one of the useful tools for generating renewable and green energy. To develop this technology, obstacles such as cost and the use of expensive compounds must be overcome. Here, we employed a new MoS2/graphene hybrid or composite instead of platinum in the DSSCs. Furthermore, the correctness of the preparation of the MoS2/graphene hybrid or composite was evaluated by field emission scanning electron microscope (FESEM), and the results showed that the desired compound was synthesized correctly. Inexpensive organic dyes were used to prepare the DSSCs, and their chemical structure was investigated by density functional theory (DFT) and cyclic voltammetry (CV). Finally, the DSSCs were fabricated using MoS2/graphene composite or hybrid, and to compare the results, the DSSCs were also prepared using platinum. Under the same conditions, the DSSCs with MoS2/graphene composite illustrated better efficiency than MoS2/graphene hybrid or/and graphene.

Significance of Zn Complex Concentration on Microstructure Evolution and Corrosion Behavior of Al/WS2.

Corrosion is a harmful processes which by definition is a chemical or electrochemical reaction between a substance (usually a metal) and the environment which leads to a change in the properties of the substance and has destructive effects. In this study, new composites consisting of Al/WS2/ZnTerp-2TH with 5 and 10 wt.% ZnTerp-2TH were prepared and the results were fully compared. Al/WS2 played the role of matrix and ZnTerp-2TH played the role of reinforcement. In other words, as a novelty to prevent the corrosion of Al/WS2, ZnTerp-2TH is designed and synthesized and showed good results when the corrosion ratio was reduced by the existence of ZnTerp-2TH. Furthermore, the NMR and mass analysis of ZnTerp-2TH were carried out, and the thermal properties, X-ray diffraction, Fourier-transform infrared (FTIR) spectroscopy, morphology, energy-dispersive X-ray spectroscopy (EDX) analysis and corrosion behavior of the composites were also discussed in detail. The crystal size values of composites were calculated by the modified Scherrer method 34, 26 and 27 nm for Al/WS2, Al/WS2/5 wt.% ZnTerp-2TH and Al/WS2/10 wt.% ZnTerp-2TH, respectively. The microstructural examination of the specimens showed that the reinforcing phase (ZnTerp-2TH) has a favorable distribution on the surface of Al/WS2 when it covers the cracks and holes. In addition, the corrosion investigation results showed that the addition of ZnTerp-2TH to Al/WS2 can improve the corrosion resistance when the Ecorr and Icorr values of Al/WS2/10 wt.% ZnTerp-2TH were recorded in tandem -724 mV/decade and 5 uA cm-2.

In quest for improvement of dyeing properties using agriculture waste: utilization of Oleaster as new bio-mordant for wool yarns.

Agricultural waste is an unwanted material that is not only unmarketable, but also has secondary costs such as environmental pollution. Oleaster, also known as olive Russian fruit, has various uses, but it also produces waste such as seeds and peels. Oleaster fruit and all its parts are tannin rich, which can be utilized as natural mordant. Improvement of fastness and color properties of natural dyed fibers is obtained by using mordant. The employing of this mordant is effective in reducing agricultural waste and the production of dyeing chemical waste. Reseda extract was utilized as natural dye to investigate the color characteristics. The study of the phenolic percentage of different components of the Oleaster fruit, including peel, seed, and flesh, showed that each of these materials can be used as natural mordant. The formation of physical bonds in the presence of all kinds of mordant was investigated using the FTIR method, and the results showed that their performance is similar and they are effective in surface treatment of wool. Investigation of color characteristics of the yarns showed that the color strength increases in the presence of mordant. Studying the fastness of yarns dyed with ISO methods showed that the samples have high washing fastness.

Nanocomposite Based on HA/PVTMS/Cl2FeH8O4 as a Gas and Temperature Sensor.

In this paper, a novel nanocrystalline composite material of hydroxyapatite (HA)/polyvinyltrimethoxysilane (PVTMS)/iron(II)chloride tetrahydrate (Cl2FeH8-O4) with hexagonal structure is proposed for the fabrication of a gas/temperature sensor. Taking into account the sensitivity of HA to high temperatures, to prevent the collapse and breakdown of bonds and the leakage of volatiles without damaging the composite structure, a freeze-drying machine is designed and fabricated. X-ray diffraction, FTIR, SEM, EDAX, TEM, absorption and photoluminescence analyses of composite are studied. XRD is used to confirm the material structure and the crystallite size of the composite is calculated by the Monshi-Scherrer method, and a value of 81.60 ± 0.06 nm is obtained. The influence of the oxygen environment on the absorption and photoluminescence measurements of the composite and the influence of vaporized ethanol, N2 and CO on the SiO2/composite/Ag sensor device are investigated. The sensor with a 30 nm-thick layer of composite shows the highest response to vaporized ethanol, N2 and ambient CO. Overall, the composite and sensor exhibit a good selectivity to oxygen, vaporized ethanol, N2 and CO environments.

Green miles in dyeing technology: metal-rich pumpkin extracts in aid of natural dyes.

To reduce environmental pollution, it is essential to use green processes in dyeing and meet its requirements. Most natural dyes have a low affinity to be used in the dyeing process. To refine this limitation, the mordanting flow is necessary for many dyeing cases. Pumpkin extract as a natural, metal-rich source can be used as a bio-mordant in green dyeing of natural yarns such as wool. Two natural dyes native to Iran, Reseda luteola and madder, were employed in this study. The effectiveness of bio-mordant presence on yarns was evaluated by FTIR-ATR test from mordanted and mordanted-dyed wool samples. The study of K/S (color strength) content of dyed samples showed that increasing the dye concentration increases the amount of K/S. Fastness performance of wool dyed with pumpkin alternated from good to excellent depending on natural dye type and concentration, due to the formation of complex structures.

Environmental-friendly extraction of Peepal (Ficus Religiosa) bark-based reddish brown tannin natural dye for silk coloration.

The present study aims to extract a natural reddish brown colorant from Peepal (Ficus religiosa) for silk dyeing using the microwave radiation process (MW). The colorant was isolated in aqueous and acidic media, and MW treatment for 1, 2, 3, 4, and 5 min has been given to both fabric and extract to observe changes in color intensity. The dye variables have been optimized, and for sustainable shade making process with good fastness, 1.0-5.0 g/100 mL of sustainable chemical and bio-mordants has been employed. It has been found that after microwave treatment for 3 min, under selected conditions, the irradiated aqueous extract has given high color intensity onto silk fabric. The utilization of 3% of Al, 4% of Fe, and 2% of tannic acid (T.A.) as pre chemical mordant whereas 4% of Al, 4% of Fe, and 3% of tannic acid as post chemical mordant have given good color characteristics. In comparison, 4% of acacia and 3% of turmeric and pomegranate while 3% of acacia and turmeric and 4% of pomegranate extracts as post-bio-mordant have given excellent color characteristics. It is concluded that MW treatment has an excellent sustainable efficacy to isolate colorant from Peepal bark for silk dyeing, whereas the inclusion of bio-mordants has not only made the process more sustainable and environmental friendly but also best K/S, and L*a*b* values have been acquired.

Enhanced thermal stability of anthocyanins through natural polysaccharides from Angum gum and cress seed gum.

Enhanced thermal stability of anthocyanins from black barberry was obtained using an optimum concentration of Angum gum (AG) and cress seed gum (CSG). To this goal initially, the phytochemical characteristics, and the thermal stability of purified and non-purified anthocyanins were investigated to perceive the effect of the purification process. Then the effect of each gum and its concentration was evaluated on the thermal degradation kinetics of anthocyanins. Results demonstrated that both gums enhanced the thermal stability of anthocyanins, while CSG had a superior effect. Findings also revealed that the half-life of anthocyanin was increased at 60°C from 366 ± 22.8 to 432 ± 4.2 and 636 ± 52.8 min in presence of AG and CSG, respectively. TGA results confirmed that the presence of SF-AG and CSG in their optimum concentration enhanced the heat stability of anthocyanin extract. Also, physical molecular bondings were confirmed by the FTIR spectrums where some peaks attributed to both of the extract and the gums were shifted. Plateau or flake-like micro-particles were detected by SEM which correspond with the most freeze-dried microcapsules. PRACTICAL APPLICATION: The results of this study may contribute to the enhanced thermal stability of anthocyanins from barberry that can be used as a coloring agent in beverage and food systems. Moreover, it can be used in preparation of natural nutraceuticals and pharmaceuticals.

Cleaner colorant extraction and environmentally wool dyeing using oak as eco-friendly mordant.

Textile and dyeing are one of the most significant industries in many states. The employing of natural dyes in dyeing procedure is very important due to the environmental security of the area. To obtain a green, clean, and environmentally friendly dyeing of yarns, two natural dyes of madder and weld, which are native to Iran, were employed for dyeing yarns for carpet preparation. Due to the low affinity of natural dyes and maintaining the biocompatibility of the dyeing process, the oak was used as a new tannin rich mordant. The ultrasound-microwave-assisted method in water solution was used for extraction, and yield to the process was obtained about 27, 32, and 36% for madder, weld, and oak, respectively. The extractions were analyzed by UV-Visible and SEM techniques, and the ash, humidity, and density properties of these were investigated. The pre-mordanting method was employed for this study, and ferrous sulphate was used for compare of natural mordant performance. The washed, mordanted, and dyed yarns were investigated by analytical techniques, and the accuracy of these processes was confirmed. The fastness properties as well as the colorimetric characteristics of dyed yarns were assessed using related standards, and the dyed yarns have acceptable performance and could compete with metal mordant, colorimetrically.

Novel complex coacervates based on Zedo gum, cress seed gum and gelatin for loading of natural anthocyanins.

This study aimed to characterize novel complex coacervates based on Zedo gum and cress seed gum as natural polysaccharides with gelatin (type-A and type-B) as potential wall materials for encapsulation of anthocyanins. The coacervates were prepared under optimum conditions (pH and gum to gelatin ratio), freeze-dried, and the resulted powders were analyzed in terms of thermal stability, morphology, and molecular interactions. The thermogravimetric analysis revealed that molecular interaction between polysaccharides and gelatins led to enhance the thermal stability of gums. The morphology of coacervates showed that while ZG-gelatin and CSG-gelatin coacervates resulted in cubic and irregular particles, freeze-drying severely changed the morphology of coacervates. Moreover, SEM images at lower magnification showed big voids for lyophilized coacervates, while SEM images confirmed a compact and dense microstructure of coacervates at higher magnification and BET method. Also, the molecular interaction of polysaccharides and gelatin in aqueous media was assessed using Raman spectroscopy. Furthermore, findings showed that the type-A of gelatin is a more suitable protein to form coacervates with polysaccharides. In the next step, natural anthocyanins from barberry were encapsulated by proposed coacervates as wall material. The encapsulated extract had elevated thermal stability and showed a lower degradation rate.

Development and optimization of complex coacervates based on zedo gum, cress seed gum and gelatin.

The complexation mechanism of zedo gum and cress seed gum as nutraceutical polysaccharides with gelatin (type-A and type-B) was investigated as a function of pH, Protein to polysaccharide mixing ratio and ionic strength. Turbidity measurements were performed to achieve optimum reaction conditions. Furthermore, Zeta potential measurements along with measuring complex coacervation yield were carried out to support the turbidity results. The state diagrams representing complex coacervation formation limits were obtained for each system. FTIR analysis was performed on resulted complex coacervates which confirmed the molecular interactions between each gum and gelatin. Also, the coacervate phase of the suspensions showed shear-thinning behavior according to steady-state flows and represented higher values of storage moduli at lower frequencies in frequency sweep measurements. All systems which are assessed in this study have the potential to form particles, however, the one containing gelatin type-A had better performance in terms of pH stability.