Materials GOx immobilization Km app / mM Ref. PVA-g-P(4-VP) films Physical entrapment 19 1 Nafion film Covalent attachment with GA, BSA and Nafion 14.91 2 Chitosan matrix Covalent attachment with GA in a 5% (v/v) glycerol solution 14.2 3 NiO modified glassy carbon electrodes Co-deposition with NiO nanoparticles at 0.8 V for 15 min in buffer solution 2.7 4 Gold nanoparticles Thiol-Cystamine modification of Au with IO4oxidized GOx 4.3

Luminescent thermometers working at the nanoscale with high spatial resolution, where the conventional methods are ineffective, have emerged over the last couple of years as a very active field of research. Lanthanide-based materials are among the most versatile thermal probes used in luminescent nanothermometers. Here, nanorods of metal organic framework Tb0.99Eu0.01(BDC)1.5(H2O)2 (BDC = 1-4-benzendicarboxylate) have been prepared by the reverse microemulsion technique and characterized and their photoluminescence properties studied from room temperature to 318 K. Aqueous suspensions of these nanoparticles display an excellent performance as ratiometric luminescent nanothermometers in the physiological temperature (300-320 K) range.

In this work, a simple lignin‐based laser lithography technique is developed and used to fabricate on‐chip microsupercapacitors (MSCs) using 3D graphene electrodes. Specifically, lignin films are transformed directly into 3D laser‐scribed graphene (LSG) electrodes by a simple one‐step CO2 laser irradiation. This step is followed by a water lift‐off process to remove unexposed lignin, resulting in 3D graphene with the designed electrode patterns. The resulting LSG electrodes are hierarchically porous, electrically conductive (conductivity is up to 66.2 S cm−1), and have a high specific surface area (338.3 m2 g−1). These characteristics mean that such electrodes can be used directly as MSC electrodes without the need for binders and current collectors. The MSCs fabricated using lignin laser lithography exhibit good electrochemical performances, namely, high areal capacitance (25.1 mF cm−2), high volumetric energy density (≈1 mWh cm−3), and high volumetric power density (≈2 W cm−3). The versatility of lignin laser lithography opens up the opportunity in applications such as on‐chip microsupercapacitors, sensors, and flexible electronics at large‐scale production.

The application of graphite anodes in potassium-ion batteries (KIB) is limited by the large variation in lattice volume and the low diffusion coefficient of potassium ions during (de)potassiation. This study demonstrates nitrogendoped, defect-rich graphitic nanocarbons (GNCs) as high-performance KIB anodes. The GNCs with controllable defect densities are synthesized by annealing an ethylenediaminetetraacetic acid nickel coordination compound. The GNCs show better performance than the previously reported thin-walled graphitic carbonaceous materials such as carbon nanocages and nanotubes. In particular, the GNC prepared at 600 °C shows a stabilized capacity of 280 mAh g −1 at 50 mA g −1 , robust rate capability, and long cycling life due to its high-nitrogen-doping, short-range-ordered, defect-rich graphitic structure. A high capacity of 189 mAh g −1 with a long cycle life over 200 cycles is demonstrated at a current density of 200 mA g −1 . Further, it is confirmed that the potassium ion storage mechanism of GNCs is different from that of graphite using multiple characterization methods. Specifically, the GNCs with numerous defects provide more active sites for the potassiation process, which results in a final discharge product with short-range order. This study opens a new pathway for designing graphitic carbonaceous materials for KIB anodes.

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Individual multiwalled boron nitride nanotubes of different diameters (40−100 nm) were bent inside a 300 kV high-resolution transmission electron microscope (TEM) using a new fully integrated TEM−atomic force microscope (AFM) piezodriven holder under continuous recording of force−piezodisplacement curves. The tubes were gently compressed in situ (i.e., inside the electron microscope) between a piezomovable aluminum wire and a silicon cantilever. Typically, bending stress values ranging from ∼100 to ∼260 MPa, and corresponding to elastic moduli of 0.5−0.6 TPa, were estimated. Tube gross failures were absent up to very large bending angles (in excess of 115°). Extending the bending angles beyond 30−40°resulted in the elastic deformation of BN nanotubes, which proceeded through the propagation of consecutive momentary kinks. These had the effect of accumulating a bending curvature rather then uniformly curl the tube under the compression load. These kinks were found to be entirely reversible on reloading with no (or marginal) traces of residual plastic deformation.

The limited potassium‐ion intercalation capacity of graphite hampers development of potassium‐ion batteries (PIB). Edge‐nitrogen doping is an effective approach to enhance K‐ion storage in carbonaceous materials. One shortcoming is the lack of precise control over producing the edge‐nitrogen configuration. Here, a molecular‐scale copolymer pyrolysis strategy is used to precisely control edge‐nitrogen doping in carbonaceous materials. This process results in defect‐rich, edge‐nitrogen doped carbons (ENDC) with a high nitrogen‐doping level (up to 10.5 at %) and a high edge‐nitrogen ratio (87.6 %). The optimized ENDC exhibits a high reversible capacity of 423 mAh g−1, a high initial Coulombic efficiency of 65 %, superior rate capability, and long cycle life (93.8 % retention after three months). This strategy can be extended to design other edge‐heteroatom‐rich carbons through pyrolysis of copolymers for efficient storage of various mobile ions.

Graphene oxide (GO) and reduced graphene oxide (rGO) have congregated much interest as promising active materials for a variety of applications such as electrodes for supercapacitors. Yet, partially given the absence of comparative studies in synthesis methodologies, a lack of understanding persists on how to best tailor these materials. In this work, the effect of using different graphene oxidation-reduction strategies in the structure and chemistry of rGOs is systematically discussed. Two of the most popular oxidation routes in the literature were used to obtain GO. Subsequently, two sets of rGO powders were synthesised employing three different reduction routes, totalling six separate products. It is shown that the extension of the structural rearrangement in rGOs is not just dependent on the reduction step but also on the approach followed for the initial graphite oxidation.