Clear experimental evidence from X-ray photoelectron spectroscopy and (31)P NMR spectroscopy has been obtained for the first time to confirm that the combination of Ag(+) cation with [L-Au](+) results in the formation of different complexes in solution. Re-evaluation of literature-reported gold-catalyzed reactions revealed a significant difference in the reactivities with and without silver. In extreme cases (more than "rare"), the conventional [L-Au](+) catalysts could not promote the reaction without the presence of silver. This investigation has therefore revealed a long-overlooked "silver effect" in gold catalysis and should lead to revision of the actual mechanism.

Nitrogenases are the only enzymes known to reduce molecular nitrogen (N ) to ammonia (NH ). By using methyl viologen (N,N'-dimethyl-4,4'-bipyridinium) to shuttle electrons to nitrogenase, N reduction to NH can be mediated at an electrode surface. The coupling of this nitrogenase cathode with a bioanode that utilizes the enzyme hydrogenase to oxidize molecular hydrogen (H ) results in an enzymatic fuel cell (EFC) that is able to produce NH from H and N while simultaneously producing an electrical current. To demonstrate this, a charge of 60 mC was passed across H /N EFCs, which resulted in the formation of 286 nmol NH mg MoFe protein, corresponding to a Faradaic efficiency of 26.4 %.

A thermally reduced graphene oxide film (r-GOF), with tailorable micro-structures and macro-properties, is fabricated by annealing a filtrated graphene oxide film (GOF) in a confined space. The structural evolution of the film at different annealing temperatures is systematically investigated, and further correlated to the thermal conductivity and mechanical performances. With the increase of temperature, more oxygencontaining functional groups are removed from the film by a simultaneous conversion from sp 3 to sp 2 carbon in the graphitic lattice. As the temperature reached 1200 C, the r-GOF achieves an ultrahigh thermal conductivity of ca. 1043.5 W m À1 K À1 , while 1000 C is a critical temperature in enhancing the thermal conductivity. Moreover, G1200 exhibits excellent mechanical stiffness and flexibility with a high tensile strength (13.62 MPa) and Young's modulus (2.31 GPa). The combined conductivity and mechanical performances render the r-GOFs promising materials as flexible lateral heat spreaders for electronics.

The general chemical formula of metal halide perovskite is ABX 3 , where A is a monovalent cation (such as FA + [ formamidinium], MA + [methylammonium], or Cs + ), B is a divalent metal cation (such as Pb 2+ , Sn 2+ , or Ge 2+ ), and X is a monovalent halogen anion (such as I − , Br − , or Cl − ). [9] Photovoltaic devices based on perovskite absorbers have achieved a certified power conversion efficiency (PCE) of 25.5% [10] in single-junction devices and obtained a PCE above 26.7% [11] in tandem devices, in which the best PCE is comparable to those of some commercially available products on the photovoltaic market, such as crystalline silicon (HIT, champion PCE of 26.7%), cadmium telluride (CdTe, champion PCE of 22.1%), gallium arsenide (GaAs, champion PCE of 27.8%), and copper indium gallium selenide (CIGS, champion PCE of 23.4%) solar cells. In particular, only sub-micron-thick absorber is needed in perovskite solar cells because of perovskite's high optical absorption coefficient of about 10 4 cm −1 , [12] therefore high specific power is expected. Combined with the low-temperature solution processability and radiation resistance, [13] these features render PSCs as a Metal halide perovskites have aroused burgeoning interest in the field of photovoltaics owing to their versatile optoelectronic properties. The outstanding power conversion efficiency, high specific power (i.e., power to weight ratio), compatibility with flexible substrates, and excellent radiation resistance of perovskite solar cells (PSCs) enable them to be a promising candidate for next-generation space photovoltaic technology. Nevertheless, compared with other practical space photovoltaics, such as silicon and III-V multi-junction compound solar cells, the research on PSCs for space applications is just in the infancy stage. Therefore, there are considerable interests in further strengthening relevant research from the perspective of both mechanism and technology. Consequently, the approaches used for and the consequences of PSCs for space applications are reviewed. This review provides an overview of recent progress in PSCs for space applications in terms of performance evolution and mechanism exploration of perovskite films and devices under space extreme environments.

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The intercalation pseudocapacitance which leads to the extraordinary charge storage properties has been confirmed as an intrinsic capactive property of orthorhombic Nb2O5 (T-Nb2O5) nanocrystals. However, the poor electronic conductivity of T-Nb2O5 nanocrystals may limit its electrochemical utilization and high-rate performance especially for thick electrodes with high mass loadings. To address this issue, we herein reported a hydrothermal-heat treatment method to anchor T-Nb2O5 nanocrystals on conductive graphene sheets, which forms a layer-by-layer integrated electrode with much shortened ion transport paths and results in excellent electrochemical capacitive properties, including high capacitance (626 C g -1 ), excellent rate handling and cyclic stability. Furthermore, asymmetric supercapacitors were constructed by using the high-rate response T-Nb2O5/graphene nanocomposite and mesoporous carbon as the negative and positive electrode, respectively. The asymmetric supercapacitor could deliver a high energy density of 16 Wh kg -1 at an unprecedented power density of 45 kW kg -1 (discharge time of 1.2 s). The outstanding power properties of the supercapacitors are mainly attributed to the improved high-rate Li-insertion/extraction capability of the T-Nb2O5/graphene electrode and appropriate pairing of mesoporous carbon electrode. Fig. 1 (a) Schematic diagram of the fabrication of the T-Nb2O5/graphene nanocomposites; (b) XRD patterns and (c) Raman spectra of GO, Nb2O5/rGO and T-Nb2O5/graphene.We report a simple hydrothermal and heat-treatment process to fabricate T-Nb2O5/graphene nanocomposite as a high-performance pseudocapactive materials. With the unique pairing of T-Nb2O5/graphene pseudocapactive material with mesoporous carbon electrodes, the asymmetrical supercapacitors show high energy and power densities, and excellent cycling performance.

Increasing greenhouse gas emissions have resulted in greater motivation to find novel carbon dioxide (CO ) reduction technologies, where the reduction of CO to valuable chemical commodities is desirable. Molybdenum-dependent formate dehydrogenase (Mo-FDH) from Escherichia coli is a metalloenzyme that is able to interconvert formate and CO . We describe a low-potential redox polymer, synthesized by a facile method, that contains cobaltocene (grafted to poly(allylamine), Cc-PAA) to simultaneously mediate electrons to Mo-FDH and immobilize Mo-FDH at the surface of a carbon electrode. The resulting bioelectrode reduces CO to formate with a high Faradaic efficiency of 99±5 % at a mild applied potential of -0.66 V vs. SHE.

Nitrogen-enriched mesoporous carbons (NMCs) were decorated with ultrafine La 2 O 3 nanoparticles via a simple wet impregnation method. The resulting composites with well developed mesoporous structures, high nitrogen content and uniform dispersions of La 2 O 3 nanoparticles served as scaffolds to house sulfur for high rate lithium-sulfur batteries. Apart from their on-site trapping of polysulfides, the La 2 O 3 nanoparticles decorated on the mesoporous carbon framework were also found to have a strong catalytic effect on sulfur reduction, offering high discharge voltages and fast electrochemical reaction kinetics. Combining the multiple effects of the well developed mesopores, nitrogen doping and La 2 O 3 nanoparticles, the resulting ternary NMC/La 2 O 3 /S nanocomposites can deliver an initial capacity of 1043 mA h g À1 at 1 C, which remains at 799 mA h g À1 after 100 cycles. Moreover, they still maintain ultrahigh rate capacities of 579 and 475 mA h g À1 at 3 C and 5 C, respectively, after 100 cycles. These encouraging results suggest that other metal oxides with suitable adsorption and catalytic abilities can be widely applied to decorate carbon frameworks for use in high rate lithium-sulfur systems.