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The room temperature synthesis of an all-solid-state Z-scheme CuO-doped BiOBr (CuO-Bi-BiOBr) photocatalyst has been described. These CuO-Bi-BiOBr ternary heterojunctions exhibit efficient photocatalytic activities for selective alcohol oxidation. The structures, morphologies, and compositions of the nanostructures were well characterized using field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and atomic absorption spectroscopy (AAS). The X-ray diffraction (XRD) pattern of the as-synthesized nanostructures confirms the formation of phase-segregated CuO and BiOBr nanocrystals, whereas X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM) analyses clearly indicate the formation of metallic bismuth nanoparticles (NPs). Next, the developed CuO-Bi-BiOBr ternary heterojunctions were applied as an efficient photocatalyst for the oxidation of alcohols into their corresponding aldehydes/ketones with high selectivity (>99%) and high conversion ratios (>99%). Herein, Bi metal NPs act as an electron mediator and bridge the connectivity between the two semiconductors, BiOBr and CuO, and, thus, a Z-scheme heterojunction is established. As expected, CuO-Bi-BiOBr has shown significantly superior activities compared to those of pure BiOBr. A possible mechanism for the photocatalytic oxidation process has been proposed. Radical scavenging experiments suggest that the active species, h+, ˙OH, e−, and ˙O2−, are dominant in the alcohol oxidation process. The as-synthesized CuO-Bi-BiOBr was reused several times without any significant deterioration in the original activities and it thus possesses relatively high stability for practical applications.

The experimental realization and computational validation for graphene oxide (GO) supported palladium (Pd)-iron (Fe) nanohybrids as a new generation electrocatalyst for proton-exchange membrane fuel cells (PEMFCs) has been reported. The experimental apprehension of the present catalyst system has been initiated with the graphene oxide, followed by the doping of Pd and Fe via thermal inter calation of palladium chloride and iron chloride with the in-situ downstream reduction to get nanohybrids of the GO-Pd-Fe. These nanohybrids are subsequently characterized by RAMAN, FT-IR, UV–Vis, XRD, SEM, EDS, TEM and HRTEM analysis. Furthermore, the first principle calculations based on Density Functional Theory (DFT) with semi-empirical Grimme DFT-D2 correction has been performed to support the experimental findings. Computational results revealed the alteration of graphene electronic nature from zero-band gaped to metallic/semi-metallic on adsorption of transition metal clusters. Moreover, the defect sites of the graphene surface are more favorable than the pristine sites for transition metal adsorption owing to the strong binding energies of the former. Electrochemical studies show that GO-Pd-Fe nanohybrids catalyst (Pd: Fe = 2:1) demonstrates excellent catalytic activity as well as the higher electrochemical surface area of (58.08 m2/g Pd–Fe)−1 which is higher than the commercially available Pt/C catalyst with electrochemical surface area 37.87 m2/(g Pt)−1.

Metal (mono-, bi-, and tri-) doped BiOBr nanostructures were developed as sunlight driven reusable catalysts for the selective photocatalytic oxidation of alcohols. We describe a room temperature synthesis procedure for a series of different metal-doped BiOBr nanostructures, followed by the characterization of their compositions, crystallinity, and morphology by XPS, XRD, and SEM-EDAX. The materials were then applied as a photocatalyst for the selective oxidation of alcohols into corresponding aldehydes or ketones under sunlight. Initially, the activities of the materials were optimized by the photocatalytic oxidation of benzyl alcohols into benzaldehyde. The Ag–Fe–Cu tri-metal loaded BiOBr demonstrated an exceptional activity, which was much higher than those of mono- and bi-metal doped BiOBr. The reaction was carried out in the absence of any external oxygen source and completed within 1.5 h with a very high conversion efficiency (>99%) and selectivity (>99%). For generalization, the activity of the Ag–Fe–Cu tri-metal loaded BiOBr was extended to other alcohols (viz., substituted benzyl alcohols, phenyl ethyl alcohol, and 2-propanol), and found to maintain the activity with a similar selectivity and yield. However, the time for completion of the reaction differed slightly depending on the precursor alcohol. Next, scavenging experiments were carried out to establish a plausible mechanism for the reaction. Photogenerated holes and superoxide radicals were found to be mainly responsible for maintaining such a high selectivity. In addition, the as-synthesized metal-doped catalysts remained stable during the photocatalytic conversion process and could be repeatedly utilized, suggesting its potential in practical applications.

Carbon nanomaterials such as graphene, carbon nanotubes, and fullerenes are superior materials over the other materials in the field of nanoscience and material science, due to their potential applications in various fields of science and technology. These materials are used as nanofiller for the preparation of polymer nanocomposites and are useful to enhance their properties exceptionally. However, their problem is associated with their poor solubility in aqueous and organic solvents which restricts their compatibility with polymer matrices, stopping these materials rfom achieving their full potential. To overcome this issue, surface modification of carbon nanomaterials via covalent and noncovalent functionalization with different polymers has previously been studied. This chapter highlights the noncovalent and covalent functionalization of carbon nanomaterials (graphene and CNT) through various types of interactions between polymers and carbon nanomaterials.

The composition of the essential oil from a new chemotype of Elsholtzia strobilifera Benth. collected from sub-alpine region of central Himalaya, India, has been investigated by Gas Chromatography and Gas Chromatography–Mass Spectrometry. The GC of the oil revealed the presence of more than 50 constituents, of which neral (18.3%) and geranial (29.9%) were found to be the major compounds and an absence of monoterpene hydrocarbons. Acylfuran derivatives, the specific chemical markers of the essential oils from the genus Elsholtzia were not detected.