Nano

Pure and La-doped titania nanoparticles are prepared by the chemical precipitation method. The stoichiometry of prepared samples is confirmed by EDAX whereas XRD analysis showed rutile tetragonal phase of synthesized pure TiO₂ and La (2%, 4%, 6% and 8%)-doped titanium dioxide nanoparticles. The crystallite size of all samples lies below 50nm as calculated from XRD. All the samples show cuboid/ellipsoidal polyhedral kind of morphologies of nanoparticles except La 2% TiO₂ which exhibits nanoflex morphology as seen in TEM images. Raman spectra recorded from low temperature to room temperature have shown $B_{1g}$, $A_{1g}$ and $E_g$ fundamental modes supporting the rutile tetragonal structure as reported in XRD. The absorption edge in the UV-Visible spectra of doped samples is shifted towards higher values of wavelength with increase of La in TiO₂. Photoluminescence spectra at various excitation energies showed the changes in PL intensity as La content is increased. Photocatalytic activity for the constant time interval for pure TiO₂ shows better photodegradation efficiency in comparison to the La-doped TiO₂. Antibacterial activity of pure TiO₂ is seen to be improved with La doping of 8%-doped TiO₂ nanoparticles.

In order to conveniently and rapidly detect Cr³⁺ ions in aqueous solution, novel functionalized gold nanoparticles (AuNPs) were designed with 4-mercaptobenzoic acid (4-MBA) and polyethyleneimine (PEI). In addition, we also compared the response signal of various functional AuNPs to Cr³⁺ ions on the detection system. The modifiers included 4-MBA, 4-nitrobenzene mercaptan (4-NTP) and PEI, respectively. The results showed that 4-MBA and PEI co-functionalized had better sensitiveness than others. Cr³⁺ ions in aqueous solution could be detected by naked eye and UV-Vis absorption spectrum and the limit of detection was 1 μM. The response was found to be proportional to Cr³⁺ ions concentration in the range from 2 μM to 10 μM. The developed platform with high selectiveness was successfully utilized to detect Cr³⁺ ions in simulated samples.

With the rapid development of the chemical industry, oil/ water emulsion separation is receiving global attention. It is particularly important to find a low-cost, convenient, economical and environmentally friendly method to prepare superhydrophilic/ underwater superoleophobic membranes for oil/ water emulsion separation. In this paper, discarded cigarette butts were used as raw materials, combined with chitosan to form a superhydrophilic/ underwater superoleophobic membrane through a phase inversion method. The performance of CA/CS membrane is controlled by adjusting the ratio of cellulose acetate and chitosan. The cigarette butts are washed in ethanol solution to remove impurities to obtain cellulose acetate, and then chitosan and polyvinylpyrrolidone (PVP) are added to build the micro–nano structure on the surface of the membrane. The prepared CA/CS composite membrane was superhydrophilic/ underwater superoleophobic. For the oil-in-water emulsion, the filtrate of the CA/CS membrane can hardly see the oil droplets through electron microscope. CA/CS membrane has a higher emulsion permeation flux (more than 340 L m${}^{-2}$ h${}^{-1})$ and a higher separation efficiency (more than 97.1%). In addition, the membrane has good reusability within 10 cycles. This method can reduce the harm of cigarette butts to nature and can also be used for oil–water separation. The method of turning discarded cigarette butts into treasure is worthy of social advocacy.

In this work, the antibacterial activities of natural Ethiopian honey and iron (Fe)-/nickel (Ni)-doped ZnO nanoparticles against Gram-positive and Gram-negative bacteria were investigated. The test strains used were Staphylococcus aureus (S. aureus ATCC25923) and Escherichia coli (E. coli ATCC25922). The co-precipitation method was used to prepare Fe- and Ni-doped ZnO nanoparticles (NPs). The X-ray diffraction (XRD) study revealed that the prepared samples have hexagonal crystal structure with a preferred orientation along the (101) plane. The average crystal sizes for iron and nickel-doped NPs were 39.09nm and 34.30nm, respectively. The energy dispersive analysis of X-ray spectra (EDX) analyses confirmed the presence of Zn, O, Fe and Ni elements in the prepared NPs samples. A strong emission peak at 454nm was observed in the photoluminescence spectra of the NPs. In order to characterize the honey’s composition, variety of physico-chemical and optical approaches were used. The absorption spectra of the three samples of honey are comparable and exhibited a noticeable peak about 260nm. The FTIR analysis confirmed that the honey samples contained the expected functional groups. The agar well diffusion technique was used to investigate the antibacterial efficacy of Fe- and Ni-doped ZnO NPs as well as Ethiopian natural honey. The results show that against E. coli strains and S. aureus strains, respectively, Fe-doped and Ni-doped ZnO NPs had average inhibitory zones of 17.1mm, 15.7mm, 15.5mm and 14.7mm, respectively. Against the S. aureus strain, the natural honey displayed a maximal inhibition zone of 12.6mm and no inhibition zone at all for E. coli.

Strontium-doped hydroxyapatite nanowires with hierarchical interfaces were prepared in this study by a one-step hydrothermal method using Pluronic123 as a structural guide. The cytotoxicity and biocompatibility of the materials were detected by the MTT assay. The adhesion and growth of MG63 (osteosarcoma cells) on materials with different doping ratios were observed by scanning electron microscopy and fluorescence microscopy. Real-time polymerase chain reaction (RT-PCR) was used to detect the transcription levels of alkaline phosphatase (ALP), Runt-associated transcription factor 2 (Runx2), osteopontin (OPN), type I collagen (Coll-I) and osteocalcin (OCN). The protein expression levels of ALP, Runx2, OPN, Col-I and OCN were detected by western blotting (WB). The results showed that strontium-doped hydroxyapatite nanowires had good biocompatibility and osteogenic induction ability, and the strontium-doped hydroxyapatite nanowires with a 1% strontium content exhibited a better osteogenic induction performance. Therefore, it is expected to become a new, promising bone induction scaffold material.

Cu-$X$ CNTs composites ($X=0$, 1, 2vol.%) were successfully prepared through a combination of pre-treatment, powder metallurgy and multi-directional forging (MDF) processes. It provided a solution for the industrial production of structural composites with reticulated CNTs. The effect of CNTs contents on wear and electrical performance of the composites was investigated. The addition of CNTs results in a significant increase in the wear resistance of the composites. During the wear process, reticulated CNTs will carry the load barrier to high temperature softening and plastic deformation of the Cu-matrix, which protects the matrix eventually. In general, the addition of CNTs will reduce the conductivity of the composites. Under MDF process, the CNTs were organically linked together and formed a network structure as the volume fraction increased from 1% to 2%, resulting in a significant promotion of conductivity by providing paths for electron transfer. The contact resistance increased slightly when 2vol.% CNTs were added, with an average value of 5.87m$\mathrm{\Omega }$. The contact resistance volatility of the Cu-2vol.% CNTs was the most stable (variance of 1.485). Reticulated CNTs can effectively attenuate the erosive effect of molten pools and welding bridges on the anode material, and are ideal reinforcers for Cu-based electrical contact materials.

Catalytic materials at the nanoscale level have an enormous impact on sustainable environmental protection, which is important for the future. Therefore, the researchers will intensively carry out the design of catalytic materials with well-ordered surface structures. In more detail, morphology-controlled nanoparticles have special interactions with the reactants that increase catalytic performance and influence the selectivity for catalytic reactions. For those reasons, obtaining specifically surface structure-tuned nanocrystals having different surface arrangements is a significant priority that promises the best model relationship between well-oriented surface structure and catalytic performance. In this study, silver nanocrystals shaped with cubes, truncated octahedrons, and octahedrons were produced. Their catalytic behaviors were examined as an innovation for epoxidation/oxidation reactions of styrene in mild conditions. The morphological and surface characterizations of nanocrystals were determined by analytical and instrumental methods such as high-resolution transmission electron microscopy energy dispersive X-ray (HR-TEM-EDX), X-ray diffraction (XRD), as well as inductively coupled plasma mass spectroscopy optical emission spectrometry (ICP-OES), and gas chromatography-mass spectrometry (GC-MS). According to the results, nanoparticles having different surface-facets fractions can be employed to increase the selectivity of styrene epoxide.

The wide applications of Touch Mode Capacitive Pressure Sensors (TMCPS) have led the researchers working more on its performances. TMCPS have more acceptance due to their linearity, sensitivity, and ability to withstand more pressure which make them suitable for harsh environments. This study proposes a novel convex shape substrate to further improve the response of the TMCPS. This work provides a detailed mathematical and analytical modeling which upholds the proposed design. The analysis is compared with the simulation results from the software MATLAB. The simulated results have been compared with those reported in the existing literature. The linear operation range of the sensor is stretched more on the lower side (88KPa–2MPa) and the sensitivity is improved 2.85 times in touch mode, which completely fits in for the altimeter applications. This work also includes a detailed step-by-step process to be followed during the fabrication of the sensor. Sensor system characteristics such as nonlinearity, hysteresis and temperature dependence are also calculated in this work. The presented theory and simulation analysis fully supports the superior performance of the novel convex substrate square diaphragm TMCPS.

For lithium-ion batteries (LIBs) with high energy density, it is critical to develop reliable and high-capacity anode materials. In this work, d-Ti₃C₂T_x/h-BN hybrid layered nanocomposites with uniform distribution are synthesized using a simple liquid phase blending method and investigated as an anode material for LIBs. The results reveal that the uniformly dispersed h-BN anchored on the d-Ti₃C₂T_x nanosheets can effectively prevent the d-Ti₃C₂T_x nanosheets from restacking during charging and discharging processes, as well as improve the electronic conductivity. The studies show that the electrochemical performance, such as the capacity and cyclic stability, of d-Ti₃C₂T_x/h-BN electrode is better than that of pure d-Ti₃C₂T_x materials.

In this paper, the fabrication of PEDOT:PSS-doped graphene oxide (GO) as a hole transport conducting electrode has been discussed. GO has been synthesized by modified Hummer’s method. Formation of GO and structural changes in GO after PEDOT:PSS doping had been confirmed by Raman and XRD analyses. FESEM images depict the morphological changes in GO before and after doping. Bonds in the samples have been analyzed by FTIR. UV-Vis study shows that PEDOT:PSS-doped GO has good transparency in the visible region. Hall measurement indicates that the electrical conductivity in GO is due to the electron transport while the conductivity in PEDOT:PSS-doped GO is due to the hole transport. A new type of DSSC has been proposed with the fabricated hole transport PEDOT:PSS electrode without ITO. The working of the cell with the new hole transport electrode has been explained. Prepared electrodes have been used in the fabrication of DSSC, showing exciting initial results.