Controlled Variable Oxidative Doping of Individual Organometallic Nanoparticles

The charging and controlled oxidative doping of single organometallic ferrocene nanoparticles is reported in aqueous sodium tetrafluoroborate using the nano‐impacts method. It is shown that ferrocene nanoparticles of approximately 105 nm diameter are essentially quantitatively oxidatively doped with the uptake of one tetrafluoroborate anion per ferrocene molecule at suitably high overpotentials. By using lower potentials, it is possible to achieve low doping levels of single nanoparticles in a controlled manner.     

Lanthanide‐Doped Nanocrystals: Strategies for Improving the Efficiency of Upconversion Emission and Their Physical Understanding

The fundamental understanding of lanthanide‐doped upconverted nanocrystals remains a frontier area of research because of potential applications in photonics and biophotonics. Recent studies have revealed that upconversion luminescence dynamics depend on host crystal structure, size of the nanocrystals, dopant concentration, and core–shell structures, which influence site symmetry and the distribution and energy migration of the dopant ions. In this review, we bring to light the influences of doping/co‐doping concentration, crystal phase, crystal size of the host, and core–shell structure on the efficiency of upconversion emission. Furthermore, the lattice strain, due to a change in the crystal phase and by the core–shell structure, strongly influences the upconversion emission intensity. Analysis suggests that the local environment of the ion plays the most significant role in modification of radiative and nonradiative relaxation mechanisms of overall upconversion emission properties. Finally, an outlook on the prospects of this research field is given.     

Controlled Synthesis of N‐Doped Carbon Nanospheres with Tailored Mesopores through Self‐Assembly of Colloidal Silica

Limited strategies have been established to prepare monodisperse mesoporous carbon nanospheres (MCNs) with tailored pore sizes. In this work, a method is reported to synthesize MCNs by combining polymerization of aniline with co‐assembly of colloidal silica nanoparticles. The controlled self‐assembly behavior of colloidal silica enables the formation of uniform composite nanospheres and convenient modulation over mesopores. After carbonization and removal of sacrificial templates, the resultant MCNs possess tunable mesopores (7–42 nm) and spherical diameters (90–300 nm), as well as high surface area (785–1117 m² g^?1), large pore volume (1.46–2.01 cm³ g^?1) and abundant nitrogen moieties (5.54–8.73 at %). When serving as metal‐free electrocatalysts for the oxygen reduction reaction (ORR), MCNs with an optimum pore size of 22 nm, compared to those with 7 and 42 nm, exhibit the best ORR performance in alkaline medium.     

Iridium‐ and Osmium‐decorated Reduced Graphenes as Promising Catalysts for Hydrogen Evolution

Renewable energy sources are highly sought after as a result of numerous worldwide problems concerning the environment and the shortage of energy. Currently, the focus in the field is on the development of catalysts that are able to provide water splitting catalysis and energy storage for the hydrogen evolution reaction (HER). While platinum is an excellent material for HER catalysis, it is costly and rare. In this work, we investigated the electrocatalytic abilities of various graphene–metal hybrids to replace platinum for the HER. The graphene materials were doped with 4f metals, namely, iridium, osmium, platinum and rhenium, as well as 3d metals, namely, cobalt, iron and manganese. We discovered that a few hybrids, in particular iridium‐ and osmium‐doped graphenes, have the potential to become competent electrocatalysts owing to their low costs and—more importantly—to their promising electrochemical performances towards the HER. One of the more noteworthy observations of this work is the superiority of these two hybrids over MoS₂, a well‐known electrocatalyst for the HER.     

The Quest for Polysulfides in Lithium–Sulfur Battery Electrolytes: An Operando Confocal Raman Spectroscopy Study

Confocal Raman spectra of a lithium–sulfur battery electrolyte are recorded operando in a depth‐of‐discharge resolved manner for an electrochemical cell with a realistic electrolyte/sulfur loading ratio. The evolution of various possible polysulfides is unambiguously identified by combining Raman spectroscopy data with DFT simulations.     

A Ratiometric Luminescent Thermometer Co‐doped with Lanthanide and Transition Metals

Herein, we report the fabrication of a sensitive ratiometric and colorimetric luminescent thermometer with a wide operating‐temperature range, from cryogenic temperatures up to high temperatures, through the combination of lanthanide and transition metal complexes. Benefiting from the transition metal complex as a self‐reference, the lanthanide content in the mixed‐coordination complex, Eu_0.05(Mebip‐mim bromine)_0.15Zn_0.95(Mebip‐mim bromine)_1.9, was lowered to 5 %.     

火试金法测定铜硫矿中的金和银量的研究

本文针对铜硫矿中铜含量较高的特性,建立了适合该试样的配料比、高温熔融,金、银与铅形成合金,利用其比重悬殊与熔渣分离,将铅扣灰吹得金、银合粒,用硝酸分金,用重量法测定金量,用容量法测定银量。方法的相对标准偏差0.66%到4.78%,加标回收率96.5%到100.6%。