Plant-Mediated Green Synthesis of Iron Nanoparticles

In the recent years, nanotechnology has emerged as a state-of-the-art and cutting edge technology with multifarious applications in a wide array of fields. It is a very broad area comprising of nanomaterials, nanotools, and nanodevices. Amongst nanomaterials, majority of the research has mainly focused on nanoparticles as they can be easily prepared and manipulated. Physical and chemical methods are conventionally used for the synthesis of nanoparticles; however, due to several limitations of these methods, research focus has recently shifted towards the development of clean and eco-friendly synthesis protocols. Magnetic nanoparticles constitute an important class of inorganic nanoparticles, which find applications in different areas by virtue of their several unique properties. Nevertheless, in comparison with biological synthesis protocols for noble metal nanoparticles, limited study has been carried out with respect to biological synthesis of magnetic nanoparticles. This review focuses on various studies outlining the novel routes for biosynthesis of these nanoparticles by plant resources along with outlining the future scope of work in this area

Angular Distribution of Damping Coefficient of Ablated Particle in Pure He, Ne, and Ar Gases

To investigate the angular distribution of damping coefficient of ablated particle under various ambient gases, nanocrystalline silicon films are systemically deposited on a circular substrate by pulse laser ablation in pure He, Ne, and Ar gases, respectively. Scanning electron microscopy images and Raman and X-ray diffraction spectra indicate that the average size of Si nanoparticles decreases with the increase of the departure angle between the film and the plume, and Ne gas induces the smallest and most uniform Si nanoparticles in size among all the three gases. Further theoretical simulation demonstrates the bigger the departure angle, the smaller the damping coefficient of ablated particle, and the damping coefficient in Ne gas is largest for the same angle, implying the most effective energy transfer between Si and ambient atoms

First-principle study on optical properties of spherical and cylindrical hydrogen-passivated Si nanoparticles with different sizes

To investigate the size dependence of the optical properties of the hydrogen-passivated Si nanoparticles (Hp-SiNPs), the energy bands and optical dielectric functions for two types of nanostructures, that is, the spherical Hp-SiNPs (SHp-SiNPs) with various diameters and the cylindrical Hp-SiNPs (CHp-SiNPs) with the same cross-section and various heights are calculated by using CASTEP software package based on density functional theory under generalised gradient approximation. The results show that for both SHp-SiNPs and CHp-SiNPs, the bandgaps increase, and the optical absorption edges of imaginary part of dielectric functions demonstrate blue-shifts as the sizes of Hp-SiNPs are reduced, which are consistent with the previous experimental data and theoretical conclusions. For CHp-SiNPs, the optics dielectric function behaves anisotropically owing to the geometrical anisotropy

Oxygen Vacancy Engineering of Fe-Doped NiMoO₄ for Electrocatalytic N₂ Fixation to NH₃

Electrochemical nitrogen reduction reaction (NRR) is a promising method for ammonia synthesis under ambient conditions. However, the NRR performance is limited to an extremely strong NN bond in N2 and the competing hydrogen evolution reaction. Introducing oxygen vacancies (OVs) has been considered as a forceful means to accelerate the sluggish NRR reaction kinetics. Herein, we reported the design of Fe-doped NiMoO4 catalysts for NRR. Fe doping can increase the amount of OVs in the catalyst and contribute to lattice strain enhancement, thereby leading to the improvement of the electron transport rate and catalytic active for NRR. In 0.1 M Na2SO4 solution, the 5% Fe-NiMoO4 catalyst achieves a NH3 yield rate of 15.36 μg h–1 mgcat.–1 and a Faradaic efficiency of 26.85% under −0.5 V versus RHE. Furthermore, the 5% Fe-NiMoO4 catalyst exhibits excellent stability (up to 13 h) during the reaction

Chiral Surfactant-Type Catalyst: Enantioselective Reduction of Long-Chain Aliphatic Ketoesters in Water

A series of amphiphilic ligands were designed and synthesized. The rhodium complexes with the ligands were applied to the asymmetric transfer hydrogenation of broad range of long-chained aliphatic ketoesters in neat water. Quantitative conversion and excellent enantioselectivity (up to 99% ee) was observed for α-, β-, γ-, δ- and ε-ketoesters as well as for α- and β-acyloxyketone using chiral surfactant-type catalyst <b>2</b>. The CH/π interaction and the strong hydrophobic interaction of long aliphatic chains between the catalyst and the substrate in the metallomicelle core played a key role in the catalytic transition state. Synergistic effects between the metal-catalyzed site and the hydrophobic microenvironment of the core in the micelle contributed to high stereoselectivity