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The electronic structure of catalysts influences the electrocatalytic behavior. Herein, the electronic structure of NiO nanocrystals is modified by doping with a small amount of Li+. The Li+ doped NiO nanocrystals show much better OER activity than pristine NiO and LiNiO2, which is a result of tuned Fermi levels, stronger hybridization between Ni 3d and O 2p, and narrowed energy band gap. This work provides a facile strategy to regulate NiO electronic energy bands to promote OER performance. [ABSTRACT FROM AUTHOR]

How a heavily charged metal nanocrystal, and further a dual-nanocrystals system behavior with continuous electron charging? This refers to the electric dynamics in charged particles as well as the crystal growth for real metal particles, but it is still opening in experimental observations and interpretations. To this end, we performed an in-situ electron-beam irradiation study using transmission electron microscopy (TEM) on the Au nanocrystals that freely stand on the nitride boron nanotube (BNNT). Au nanocrystalline particles with sizes of 2–4 nm were prepared by a well-controlled sputtering method to stand on the BNNT surface without chemical bonding interactions. Au nanoparticles presented the surface atomic disorder, diffusion phenomena with continuous electron-beam irradiation, and further, the long-range motion that contains mainly the three stages: charging, activation, and adjacence, which are followed by final crystal growth. Firstly, the growth process undergoes the lattice diffusion and subsequently the surface-dominated diffusion mechanism. These abnormal phenomena and observations, which are fundamentally distinct from classic cases and previous reports, are mainly due to the overcharging of Au nanoparticle that produces a surface activation state in terms of high-energy plasma. This work therefore brings about new observations for both a single and dual-nanocrystals system, as well as new insights in understanding the resulting dynamics behaviors. [ABSTRACT FROM AUTHOR]

Abstract: Novel MnCO3/α-Fe2O3 nanocrystal heterostructures, with MnCO3 nanorods 5–10nm in diameter and 15–50nm in length, grown onto the surfaces of the α-Fe2O3 nanohexahedrons sized around 30–50nm, were fabricated via a two-step solvothermal route. The coalescent planes of the heterostructure for the MnCO3 nanorod and the α-Fe2O3 nanohexahedron were determined to be (01̅4) and (110), respectively. The formation of the MnCO3 nanorods from the Mn contained amorphous flakes was tracked by transmission electron microscopy observations at various reaction stages, which suggested a rolling–broken–growth process. Evidenced by the comparative experimental result, the α-Fe2O3 nanohexahedrons played an important role in inducing the nucleation and growth of the hexagonal MnCO3 nanorods on their surfaces. [Copyright &y& Elsevier]

Abstract: The sodium borosilicate glass doped with indium nanocrystals have been successfully prepared by sol–gel route. The thermal stability behavior of the stiff gel is investigated by thermogravimetric (TG) and differential thermal (DTA) analysis. The crystal structure of the glass is characterized by X-ray powder diffraction (XRD). Particle composition is determined by X-ray photoelectron spectroscopy (XPS). Size and distribution of the nanocrystals are characterized by transmission electron microscopy (TEM) as well as high-resolution transmission electron microscopy (HRTEM). Results show that the indium nanocrystals in tetragonal crystal structure have formed in glass, and the average diameter is about 30nm. Further, the glass is measured by Z-scan technique to investigate the nonlinear optical (NLO) properties. The third-order NLO coefficient χ (3) of the glass is determined to be 2.81×10−10 esu. The glass with large third-order NLO coefficient is promising materials for applications in optical devices. [Copyright &y& Elsevier]

Abstract: Nano-composite of Fe-doped anatase TiO2 nanocrystals loaded on the hollow glass microbeads was prepared by co-thermal hydrolysis deposition and calcining treatment. The adherence of TiO2 mesoporous layers to the surfaces of hollow glass microbeads prevented the aggregation of TiO2 nanoparticles and benefited to their catalytic activity. The doping of Fe ions makes the absorption edge of the TiO2 based nano-composite red-shifted into the visible region. An effective photodegradation of the methyl orange aqueous solution was achieved under visible light (λ>420nm) irradiation, revealing the potential applicability of such nano-composite in some industry fields, such as air and water purifications. [Copyright &y& Elsevier]