Vanadium phosphate (VPO) materials with high specific surface area prepared via a eutectic mixture as solvent and template with different lengths of time, i.e. 24, 72 and 144 h, were investigated in the oxidation of benzyl alcohol. The X-ray diffraction result indicated the initial VPO precursor was an amorphous phase due to the stronger incorporation of eutectic mixture. On subsequent reflux duration of 72 h, the precursor was composed of a crystallised VOHPO₄·H₂O phase. On further reflux duration of 144 h, the incorporated eutectic mixture gradually was leached out and the precursor became more crystalline. Interestingly the N₂ adsorption–desorption measurements Brunauer–Emmett–Teller studies showed that the VPO precursor incorporated eutectic mixture was mesostructured and the specific surface area first increased then decreased with increasing the reflux duration time. The growth process of the VPO nanostructures formed in a eutectic mixture with different lengths of time was investigated by scanning electron microscopic analysis. The influence of calcination temperature and lengths of reflux duration on the activity and selectivity of the VPO catalyst was studied and discussed.

A single pot, green method for platinum nanoparticles (Pt NP) production was devised with gum ghatti (Anogeissus latifolia). Analytical tools: ultraviolet–visible (UV-vis), dynamic light scattering, zeta potential, transmission electron microscope, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy were employed. Wide continuous UV-vis absorption and black solution colouration proved Pt NP formation. Face-centred cubic crystalline structure of NP was evidenced from XRD. NPs formed were nearly spherical with a mean particle size of 3 nm. NP demonstrated a myriad of properties including catalytic, peroxidase, polymerase chain reaction (PCR) enhancing and antioxidant activities. Catalytic action of NP was probed via NaBH₄ reduction of arsenazo-III dye. NP displayed considerable peroxidase activity via catalysis of 3, 3′, 5, 5′-tetramethylbenzidine oxidation by H₂O₂. NP showed exceptional stability towards varying pH (3–11), temperature (25–100°C), salt concentration (0–100 mM) and storage time duration (0–12 months). In comparison with horse radish peroxidase, its applicability as an artificial peroxidase is advantageous. NP caused a two-fold enhancement in PCR yield at 0.4 nM. Also showed significant 1′, 1′ diphenyl picryl-hydrazyle scavenging (80.1%) at 15 µg/mL. Author envisages that the biogenic Pt NP can be used in a range of biological and environmental applications.

The mesoporous CoTiO₃ nanoparticles, which have been successfully prepared by a fast, simple and low-cost hydrothermal method, show good decolourisation and degradation of methylene blue (MB). The synthesised samples can be recovered easily from solution by a magnetic mass. Surface morphology, structure, composition, and optical characteristics of the prepared CoTiO₃ were determined using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and ultraviolet–visible absorption measurements. The degradation percentage of MB was nearly 95% at an initial concentration of 10 ppm in 90 min. Such enhanced photocatalytic activities of synthesised CoTiO₃ were attributed to a large specific surface area (54.22 m² g⁻¹) and defects density, which was useful for restraining surface recombination of photo-generated charge carriers. The recovery of CoTiO₃ nanoparticles was about 85% and the degradation rate of MB remained 80% after five cycles. As a whole, the CoTiO₃ nanocomposites give a synergistic effect in photocatalytic and magnetic behaviour and indicate that the synthesised samples have a promising potential particularly for water purification and environmental remediation.

In this chapter, the main experimental results obtained to date on the selfhealing composite materials are reviewed. The review starts with the nanostructuration of the ruthenium Grubbs' catalyst (RGC) by means of the laser ablation process, followed by the encapsulation of the 5-ethylidene-2norbornene (ENB) liquid monomer into small capsules and the fabrication of three-dimensional (3D) microvascular nanocomposite beams by microfluidic infiltration. Special attention is given to the use of single-wall carbon nanotubes (SWCNT) material as reinforcement of the ENB healing agent from the perspective of obtaining a self-healing composite material with improved mechanical properties and, at the same time, having a fast ring-opening metathesis polymerisation (ROMP) reaction with high mechanical properties.

In this work, an Fe₃O₄/HZSM-5 nanocomposite was synthesised in the presence of Juglans regia L. leaf extract. Then, silver nanoparticles (Ag NPs) were immobilised on the surface of prepared magnetically recoverable HZSM-5 using selected extract for reduction of Ag⁺ ions to Ag NPs and their stabilisation on the surface of the nanocomposite. The reduction of Ag⁺ ions occurs at room temperature within a few minutes. Characterisation of the prepared catalysts has been carried out using fourier transform infrared (FT-IR), X-ray diffraction, field-emission scanning electron microscopy (FESEM), energy-dispersive spectroscopy, Brunauer–Emmett–Teller method, and a vibrating sample magnetometer. According to the FESEM images of the nanocomposites, the average size of the Ag NPs on the Fe₃O₄/HZSM-5 surface was >70 nm. The Ag/Fe₃O₄/HZSM-5 nanocomposite was a highly active catalyst for the reduction of methyl orange and 4-nitrophenol in aqueous medium. The utilisation of recycled catalyst for three times in the reduction process does not decrease its activity.

Hexagonal-like zinc oxide (ZnO)/silver (Ag) composite was successfully synthesised by a flux/solvothermal route, and Ag nanoparticles are loaded on ZnO. Compared with pure ZnO, the attachment of Ag on ZnO can significantly increase visible-light absorption and reduce photoluminescence emission intensity. The photocatalytic performance of ZnO/Ag composite was evaluated by the degradation of Rhodamine B solution under ultraviolet (UV) light and visible light irradiation. The degradation rate of ZnO/Ag composite is obviously improved compared with pure ZnO and the commercial TiO₂ (P25) and is more than 2.5 and 2.9 times faster than that of pure ZnO under the UV and visible light irradiation, respectively. The enhanced photocatalytic activity of ZnO/Ag composite under UV irradiation was ascribed to the formation of Schottky barriers between Ag particles and ZnO. However, the superior photocatalytic activity under visible light irradiation could be attributed to the surface plasmon resonance of Ag particles.

The growing increase of industrial wastewater, environmental contaminations, and the necessity of clean water has stressed the importance of removing pollutants. One of the effective means of removing pollutants from water and wastewater is by utilising zeolite. Zeolite, despite possessing unique photophysical properties (such as numerous fine cavities, the high capability to adsorb, and chemical–thermal stability), represents some limitations when being used. Depositing photocatalysts on zeolite particles to improve its removal potential is of much interest. In this work, therefore, TiO₂ nanoparticles were deposited on fine particles of zeolite. Zeolite/TiO₂ composites were evaluated by X-ray diffractometer, scanning electron microscope, Brunauer–Emmett–Teller, diffuse reflectance spectroscopy analyses. The results indicate that the presence of TiO₂ nanoparticles reduces the specific surface area. However, it causes the ability to absorb UV light. Increasing the amount of TiO₂ any further will bring about a redshift in absorption edge. Photocatalytic properties of the composites were assessed by methyl orange and cyanide ion removal examination. The 10%TiO₂ composite with the specific surface area of 34 m²/g and bandgap energy of 3.3 eV showed to be the most efficient. The superior photocatalytic performance of 10%TiO₂ sample was confirmed by the examination of producing hydrogen from water/methanol.

This work has developed a facile strategy to create magnetically separable, core-shell structured composites consisting of a magnetic Ag nanowires (NWs)/Fe₃O₄ cores and an outer mesoporous TiO₂ (mTiO₂) shell using a sol–gel process and subsequent hydrothermal treatment. Benefiting from the mesoporous anatase TiO₂ as well as the unique structures of the composite, the resulting Ag NWs/Fe₃O₄@mTiO₂ composite was employed as a catalyst for removal of the organic contaminants through a colorimetric photocatalytic degradation assay using methylene blue (MB) as a model contaminant. Moreover, the photocatalysts can be easily separated and recycled with an external magnetic field and possess prominent recoverability.

Exploring efficient and inexpensive oxygen evolution reaction (OER) electrocatalysts is essential for clean renewable energy systems. Ni-based nanomaterials have been intensively pursued for NiOOH can play a key role in OER processes in alkaline electrolytes. In this work, Ni nanoparticles (NPs) absorbed onto commercial carbon black and nitrogen-doped reduced graphene oxide as electrochemical catalysts activities in OER have been explored. The study found that the current density and Tafel slope of Ni/C nanocomposite in OER were affected obviously by different carbon supporter and the surface properties of Ni NPs. The work revealed that the Ni NPs electrical contact with supporter and surface hydrophilism of catalytically active species is more important than the size and loaded amount. The awareness of the catalytic kinetics difference deepened their comprehension of the structure–property relationship of the electrocatalyst, which would contribute to the rational design of excellent OER catalysts.

A facile morphological specific precipitation method by volumetric control of the precursors has been demonstrated to achieve tetrapod-like and dodecahedron-like Ag₃PO₄ microparticles, which show superior visible-light responsive of photocatalytic activity when comparing to TiO₂ (P25). This study also reveals that the tetrapod-like Ag₃PO₄ microparticles exhibit significantly higher photocatalytic activity (95.6% degradation within 20 min, k: 0.1937 min⁻¹) than the dodecahedrons (78.9% degradation within 30 min, k: 0.0593 min⁻¹) for the degradation of rhodamine B (RhB, 10 ppm) under low-power white light-emitting diode irradiation (300 mW cm⁻²), which may be attributed to the high reactivity of {110} facets. Moreover, holes and superoxide radicals were the main reactive species involved in RhB degradation.