Tungsten trioxide (WO₃) thin films are of great interest as counter electrodes in electrochromic (EC) devices such as ‘smart window’ for energy-efficient buildings. Uniform WO₃ nanoplates filmed as EC working electrodes were fabricated on seed-free fluorine-tin-oxide (FTO) coated glass via a facile and addictive agent-free hydrothermal process. The WO₃ nanoplates were characterised by scanning electron microscopy and the X-ray photoelectron spectroscopy. The morphological analysis of the film showed that the WO₃ nanoplates lying on the FTO glass uniformly. Fourier transform infrared spectroscopy was applied to study the vibrational information of the sample. Furthermore, uniform WO₃ nanoplates exhibit well performance of EC properties. Owing to the highly two-dimensional nanostructure, a fast switching speed of 12 and 3 s for colouration and bleaching are achieved for WO₃ film. These properties of the WO₃ nanoplates film endow its promising practical applications in smart windows.

Since there is currently no method to selectively fabricate superhydrophobic regions on superhydrophilic surfaces of metal substrates, wettability patterns on metal substrates are prepared via the three-step technique including superhydrophilic, superhydrophobic and selectively superhydrophilic modifications. Here, an innovative method that can selectively lower surface energy of superhydrophilic surfaces, and thereby makes it more convenient to fabricate the wettability patterns, is proposed. Chemical etching is used to formulate micro/nanoscale rough structures and fabricate superhydrophilic aluminium (Al) surface, which is then covered by patterned mask whose main composition is siloxane. Removing the mask after 80°C water bath heating for 20 s, the covered Al surface has been modified to become superhydrophobic (contact angles >165°, sliding angles <1.5°), while the uncovered region is still superhydrophilic, and wettability patterns are therefore obtained. Fourier transform infrared spectrophotometer and Raman spectra indicate that the change of wettability is induced by hydrophobic groups on the modified surfaces. The superhydrophobic surfaces fabricated by this method have excellent high-temperature resistance. The method proposed is simple, rapid and environmental-friendly.

Synthesising gold nanoprobes in the near infrared (NIR) region is of particular interest in developing nanosensors due to the minimal light attenuation from biomolecules. Here, the controlled synthesis and tunability of gold nanostars’ two distinct localised surface plasmon resonances (LSPRs) at around 700 and 1100 nm is reported. By using UV–Vis–NIR absorption measurements and finite-difference time-domain calculations, the induction of the LSPR and the multipolar nature of the resonances have been investigated experimentally and theoretically. Simulation results demonstrate that large electric fields are confined at the tips of the branches, where the LSPR can be induced specifically by controlling the polarisation of the incident electric field. The surface-enhanced Raman scattering (SERS) capability of these dual plasmonic gold nanostars (DPGNS) has also been demonstrated using a Raman reporter, diethylthiatricarbocyanine iodide and high SERS enhancement factor (EF) of 2 × 10⁷ is obtained with 785 nm excitation. With ease of synthesis, LSPR at NIR and high SERS EF, DPGNS demonstrated the capability to be an effective SERS substrate and the potential to elicit the highest SERS EF ever reported for gold nanoparticles, with further longer wavelength excitations at and beyond 1064 nm.

This paper investigated the green synthesis of silver nanoparticles (AgNPs) using aqueous extract of silky hairs of corn (Zea mays L.) which is a waste material of the crop, as both a reducing and stabilising/capping agent. The AgNPs were characterised by UV-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The average size of AgNPs was found to be 249.12 nm. The AgNPs displayed strong antibacterial activity against five different foodborne pathogenic bacteria with diameter of inhibition zones ranged between (9.23 − 12.81 mm). It also exhibited potent synergistic antibacterial activity together with standard antibiotics, kanamycin (10.6 − 13.65 mm inhibition zones) and rifampicin (10.02 − 12.86 mm inhibition zones) and anticandidal activity with amphotericin b (10.57 − 13.63 mm inhibition zones). The AgNPs exhibited strong antioxidant activity in terms of nitric oxide scavenging (IC₅₀ 91.56 µg/mL), ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging (IC₅₀ 115.75 µg/mL), DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging (IC₅₀ 385.87 µg/mL), and reducing power (IC_0.5 23.14 µg/mL). This study demonstrated the synthesis of spherical AgNPs with strong antibacterial, anticandidal and antioxidant properties that could potentially be utilised in the biomedical, cosmetic, food and pharmaceutical industries.

The biosynthesis of silver nanoparticles (AgNPs) has been proved to be a cost effective and environmental friendly approach toward chemical and physical methods. In the present study, biosynthesis of AgNPs was carried out using aqueous extract of Zea mays (Zm) husk. The initial colour change from golden yellow to orange was observed between 410 and 450 nm which confirmed the synthesis of AgNPs. Also, dynamic light scattering-particle size analysis confirmed the average size to be 113 nm and zeta potential value of −28 kV. The morphology of synthesised ZmAgNPs displayed flower-shaped structure, X-ray diffraction pattern revealed the strongest peaks at 2θ = 38.6° and 64° which proved that the nanoparticle has the face centred crystalline structure. The Fourier transform infrared spectroscopy results showed strong absorption bands at 1394.53, 2980.02 and 2980.02 cm⁻¹ due to the presence of alkynes, carboxylic acids, alcoholic and phenolic groups. The maximum zone of inhibition was observed against Salmonella typhi (22 mm) and Candida albicans (18 mm). The synthesised nanoparticles exhibited more free radical scavenging activity than the aqueous plant extract. This is the first report on the synthesis of AgNP from Zm husk, delivers the efficient and stable ZmAgNPs through simple feasible approach toward green biotechnology.

In the present study, green synthesis and cost effective approach of silver nanoparticles using wild medicinal mushroom Ganoderma applanatum (Pers.) Pat. from Similipal Biosphere Reserve, Odisha, India is reported. The biosynthesised AgNPs were characterised using UV-visible spectroscopy, particle analyser and scanning electron microscopy studies. It was found by dynamic light scattering analysis, that the average size and charges of the AgNPs were 133.0 ± 0.361 nm and −6.01 ± 5.30 mV, respectively. Moreover, the Fourier transform infrared study was also conducted to identify the biomolecules or functional groups responsible for the reduction of Ag and stabilisation of the AgNPs. The potential biomedical application with reference to antimicrobial activity of the synthesised AgNPs was investigated against some pathogenic microorganisms viz. Escherichia coli, Bacillus subtilis, Staphylococcus epidermidis, Vibrio cholerae, Staphylococcus aureus and Shigella flexneri.

To eliminate the elaborate processes employed in other non-biological-based protocols and low cost production of silver nanoparticles (AgNPs), this study reports biogenic synthesis of AgNPs using silver salt precursor with aqueous extract of Aspergillus fumigates MA. Influence of silver precursor concentrations, concentration ratio of fungal extract and silver nitrate, contact time, reaction temperature and pH are evaluated to find their effects on AgNPs synthesis. Ultraviolet–visible spectra gave surface plasmon resonance at 420 nm for AgNPs. Fourier transform infrared spectroscopy and X-ray diffraction techniques further confirmed the synthesis and crystalline nature of AgNPs, respectively. Transmission electron microscopy observed spherical shapes of synthesised AgNPs within the range of 3–20 nm. The AgNPs showed potent antimicrobial efficacy against various bacterial strains. Thus, the results of the current study indicate that optimisation process plays a pivotal role in the AgNPs synthesis and biogenic synthesised AgNPs might be used against bacterial pathogens; however, it necessitates clinical studies to find out their potential as antibacterial agents.

Mesoporous nanocrystalline magnesium aluminate (MgAl₂O₄) particles with different surface area (70–230 m² g⁻¹) were synthesised via the homogeneous co-precipitation method using different surfactants (cationic, anionic and non-ionic). The obtained powders were used as the support to prepare 10.5 nickel (Ni)/MgAl₂O₄ catalysts, and the resulting samples were tested in the steam pre-reforming of natural gas. The obtained samples were characterised by Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller (BET), X-ray diffraction, thermogravimetric/differential thermal analysis, transmission electron microscopy and temperature programmed desorption (TPD) techniques. Experimental results showed that the shape, surface area and porosity of MgAl₂O₄ particles were strongly dependent on the type of surfactants used. In addition, the Ni catalyst supported on the MgAl₂O₄ with the highest surface area exhibited the smallest size of Ni particles (14.1 nm). This catalyst has over 97% of ethane and propane conversions in steam pre-reforming of natural gas under atmospheric pressure, 550°C, low steam to carbon molar ratio (S/C = 1.5) and high gas hourly space velocity (GHSV = 100,000 ml g⁻¹ _catalysth⁻¹).

Square-like nano-CeO₂ mingled with Ce(OH)₃ was successfully synthesised via a hydrothermal route using CeCl₃·7H₂O as cerium source, N₂H₄·H₂O as mineraliser, and ethylenediamine as complexant. The as-synthesised nanoparticles were characterised by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope, high-resolution transmission electron microscopy, Raman scattering, photoluminescence spectra (PL), and magnetisation measurements. It was found that nano-CeO₂ has a fluorite cubic structure, and there are defects and vacancies in the sample. PL spectrum showed excellent near-UV emission. M–H curve exhibited excellent room-temperature ferromagnetism with saturation magnetisation of 0.0300 emu/g, coercivity of 73.706 Oe, and residual magnetisation of 2.37 × 10⁻³ emu/g, which can be mainly associated with the surface Ce⁴⁺/Ce³⁺ pairs and oxygen vacancies in the nano-CeO₂.

Large-scale production of high-quality graphene nanosheets has been considered to be an interesting and significant challenge. A new approach is reported regarding the fabrication of high-quality graphene nanosheets via chemical reduction with the combination of reducing reagents from graphene oxide (GO). High-conducting reduced GO (RGO) was provided with the combination of hydrazine hydrate and hydroiodic acid. RGO was characterised by X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman, thermo gravimetric analysis, atomic force microscopy and four-probe conductivity tester. Characterisation results indicated that oxygenated functional groups were removed from GO, and high graphitisation has occurred in GO reduction process. The electrical conductivity of RGO was considerably improved and the C/O ratio of RGO was higher than that prepared by single reducing reagent. Combination of hydrate hydrazine and hydroiodic acid have showed high reduction efficiency and good synergistic effect in GO reduction process. The findings in this work can promote research on prepared graphene-based nanosheets composites by a quick and effective processing technique.