A new synthetic route to in-chain metallopolymers via copper( i ) catalyzed azide–platinum–acetylide iClick
The first example of an in-chain metallo-poly(triazolate) synthesized by CuAAC is reported.
Chemistry↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Comparison of nucleophilic- and radical-based routes to the formation of manganese-main group element single bonds
One-electron activation of main-group substrates by a stable manganese metalloradical provides a facile pathway to Mn-element single bonds.
Chemistry↗
A simple, highly efficient route to electroless gold plating on complex 3D printed polyacrylate plastics
Here, compared to tedious, multi-step treatments for electroless gold plating of traditional thermoplastics, this communication describes a simpler three-step procedure for 3D printed crosslinked polyacrylate substrates. This allows for the synthesis of ultralight gold foam microlattice materials with great potential for architecture-sensitive applications in future energy, catalysis, and sensing.
36 MATERIALS SCIENCE↗
Rapid route to efficient, scalable, and robust perovskite photovoltaics in air
RSPP is a unique up-scalable method to produce high quality photoactive perovskite in seconds in open-air.
14 SOLAR ENERGY↗
Flexible GaAs solar cells on roll-to-roll processed epitaxial Ge films on metal foils: a route towards low-cost and high-performance III–V photovoltaics
In this work, we describe a unique roll-to-roll plasma-enhanced chemical vapor deposition (R2R-PECVD) technique to grow high-quality single-crystalline-like Ge films on flexible metal foils, an important advancement towards scalable processing of epitaxial Ge films at low-cost. Ion-beam assisted deposition was used to create single-crystalline-like substrate templates to enable epitaxial growth of Ge films. The Ge films were highly (004) oriented, biaxially-textured and showed remarkable crystalline quality, equivalent to single-crystal Ge wafers. Subsequently, the Ge films on metal foils were used as substrates to fabricate flexible GaAs single-junction solar cell by metal-oxide chemical vapor deposition (MOCVD). The champion device showed efficiency of 11.5%, and the average efficiency of four devices was 8% at 1 sun, the highest reported on GaAs PV directly deposited on alternative flexible substrates. Devices made on CVD-Ge film exhibited significantly improved performance compared to the ones grown on sputtered Ge films. Scalable production of inexpensive and flexible epi-Ge films will not only be useful for developing low-cost and high-performance III–V solar cells, but also for emerging flexible electronic devices applications.
14 SOLAR ENERGY↗
Low temperature synthesis route and structural characterization of (Bi 0.5 A 0.5 )(Sc 0.5 Nb 0.5 )O 3 ( A = K + and Na + ) perovskites
We report two new perovskites, (Bi 0.5 A 0.5 )(Sc 0.5 Nb 0.5 )O 3 where A = K + and Na + , have been made phase pure for the first time. The synthesis procedure that prevented the formation of pyrochlore impurities is described. B -site ordering in A = K + is successfully achieved by prolonged heating. Combined Rietveld refinement on synchrotron X-ray diffraction and neutron diffraction data is used to determine the complex average structure of these materials. A = Na + crystallizes in the tetragonal P 4/ mbm space group and has disordered a 0 a 0 c + rotations of B O 6 octahedra. A = K + crystallizes in the cubic Pm m space group, but shows local A -site displacements in the [100] direction. Both materials are highly disordered but illustrate the potential of ( A )NbO 3 -BiScO 3 solid solutions as useful piezoelectrics or relaxors.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Click chemistry as a route to the synthesis of structurally new and magnetically interesting coordination clusters: a {NiII8} complex with a trapezoidal prismatic topology
A {Ni 8 } cluster with trapezoidal prismatic topology was prepared via the click reaction between MeCN and N 3 − ions.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Deep eutectic solvent route synthesis of zinc and copper vanadate n-type semiconductors – mapping oxygen vacancies and their effect on photovoltage
Ternary metal oxides M 2 V 2 O 7–δ (M = Zn and Cu) were synthesized by dissolving binary metal oxide precursors in an environmentally benign deep eutectic solvent (DES), which is a eutectic mixture of a hydrogen bond donor and acceptor, followed by annealing in an open crucible. The unique reaction environment provided by the evolved ammonia allows for stabilization of oxygen vacancies and reduced oxidation states of metal ions within an oxide matrix without the need for any post-treatment with flammable reducing agents. According to comprehensive characterization, including X-ray photoelectron spectroscopy (XPS), neutron powder diffraction, and UV-vis spectroscopy, oxygen deficiency is accompanied by reduced oxidation states of metal centers (Cu + or V 4+ ), resulting in oxides with mixed-valence metal oxidation states. The amount of oxygen vacancies can be tuned by changing the annealing temperature providing control over band gaps of ternary metal oxides and mid-gap states from reduced metal centers. All synthesized vanadates are n-type semiconductors based on negative photovoltages obtained from surface photovoltage spectroscopy (SPS). A decay of the photovoltage with increasing annealing temperatures is attributed to electron trapping and electron/hole recombination at V 4+ and Cu + mid-gap states. This work shows for the first time the impact of oxygen vacancies on the electronic structure of DES synthesized oxides for solar energy conversion applications.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Facile synthetic routes to bridge-functionalised calix[4]arenes
Ring-opening of furans at the equatorial methylene bridge positions of a calix[4]arene gives access to a range of new molecules (in good yield) that have widespread potential impact in supramolecular chemistry amongst other areas.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Acetate intercalated Mg–Al layered double hydroxides (LDHs) through modified amide hydrolysis: a new route to synthesize novel mixed metal oxides (MMOs) for CO 2 capture
SEM images of MMOs derived from Mg–Al-acetate intercalated LDHs synthesized by acetamide hydrolysis with (a) Mg/Al = 3, (b) Mg/Al = 4 and their high temperature CO 2 capture capacity versus temperature (c) were obtained.
Manohara, G. V.↗
The sol–gel autocombustion as a route towards highly CO 2 -selective, active and long-term stable Cu/ZrO 2 methanol steam reforming catalysts
The adaption of the sol-gel autocombustion method to the Cu/ZrO 2 system opens new pathways for the specific optimisation of the activity, long-term stability and CO 2 selectivity of methanol steam reforming (MSR) catalysts. Calcination of the same post-combustion precursor at 400 °C, 600 °C or 800 °C allows accessing Cu/ZrO 2 interfaces of metallic Cu with either amorphous, tetragonal or monoclinic ZrO 2 , influencing the CO 2 selectivity and the MSR activity distinctly different. While the CO 2 selectivity is less affected, the impact of the post-combustion calcination temperature on the Cu and ZrO 2 catalyst morphology is more pronounced. A porous and largely amorphous ZrO 2 structure in the sample, characteristic for sol-gel autocombustion processes, is obtained at 400 °C. This directly translates into superior activity and long-term stability in MSR compared to Cu/tetragonal ZrO 2 and Cu/monoclinic ZrO 2 obtained by calcination at 600 °C and 800 °C. The morphology of the latter Cu/ZrO 2 catalysts consists of much larger, agglomerated and non-porous crystalline particles. Based on aberration-corrected electron microscopy, we attribute the beneficial catalytic properties of the Cu/amorphous ZrO 2 material partially to the enhanced sintering resistance of copper particles provided by the porous support morphology.
36 MATERIALS SCIENCE↗
Comproportionation of a dialuminyne with alane or dialane dihalides as a clean route to dialuminenes
Stoichiometric comproportionation of a dialuminyne and aluminum halides in hexane or ether cleanly yields a dialuminene which rapidly decomposes. In benzene a dialuminene/benzene cycloaddition product is generated.
Queen, Joshua D.↗
Evaluating solvothermal and mechanochemical routes towards the metal–organic framework Mg 2 ( m -dobdc)
Metal–organic frameworks bearing coordinatively unsaturated Mg(II) sites are promising materials for gas storage, chemical separations, and drug delivery due to their low molecular weights and lack of toxicity. Furthermore, there remains a limited number of such MOFs reported in the literature. Herein, we investigate the gas sorption properties of the understudied framework Mg 2 (m-dobdc) (dobdc 4– = 4,6-dioxido-1,3-benzenedicarboxylate) synthesized under both solvothermal and mechanochemical conditions. Both materials are found to be permanently porous, as confirmed by 77 K N 2 adsorption measurements. In particular, Mg 2 (m-dobdc) synthesized under mechanochemical conditions using exogenous organic base displays one of the highest capacities reported to date (6.14 mmol g –1 ) for CO 2 capture in a porous solid under simulated coal flue gas conditions (150 mbar, 40 °C). As such, mechanochemically synthesized Mg 2 (m-dobdc) represents a promising new framework for applications requiring high gas adsorption capacities in a porous solid.
36 MATERIALS SCIENCE↗
Exploring mechanistic routes for light alkane oxidation with an iron–triazolate metal–organic framework
In this work, we computationally explore the formation and subsequent reactivity of various iron-oxo species in the iron–triazolate framework Fe 2 (m-OH) 2 (bbta) (H2bbta = 1H,5H-benzo(1,2-d:4,5- d0)bistriazole) for the catalytic activation of strong C–H bonds. With the direct conversion of methane to methanol as the probe reaction of interest, we use density functional theory (DFT) calculations to evaluate multiple mechanistic pathways in the presence of either N 2 O or H 2 O 2 oxidants. These calculations reveal that a wide range of transition metal-oxo sites – both terminal and bridging – are plausible in this family of metal–organic frameworks, making it a unique platform for comparing the electronic structure and reactivity of different proposed active site motifs. Based on the DFT calculations, we predict that Fe 2 (m-OH)2(bbta) would exhibit a relatively low barrier for N 2 O activation and energetically favorable formation of an [Fe(O)] 2+ species that is capable of oxidizing C–H bonds. In contrast, the use of H 2 O 2 as the oxidant is predicted to yield an assortment of bridging iron-oxo sites that are less reactive. We also find that abstracting oxo ligands can exhibit a complex mixture of both positive and negative spin density, which may have broader implications for relating the degree of radical character to catalytic activity. In general, we consider the coordinatively unsaturated iron sites to be promising for oxidation catalysis, and we provide several recommendations on how to further tune the catalytic properties of this family of metal–triazolate frameworks.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Enabling fine-grain free 2-micron thick CISe/CIGSe film fabrication via a non-hydrazine based solution processing route
Fine grain layer formation in solution processed CuInSe 2 /CuInGaSe 2 (CISe/CIGSe) photovoltaic devices is controlled through surface modifications and ink manipulations to achieve improved performance and fine grain free morphologies.
Deshmukh, Swapnil D.↗
Synthesis of SrTiO 3 and Al-doped SrTiO 3 via the deep eutectic solvent route
SrTiO 3 and aluminum-doped SrTiO 3 are synthesized by calcination of metal salts dissolved in a deep eutectic solvent (DES) without any post-synthesis treatment.
36 MATERIALS SCIENCE↗
On route to one-pot synthesis of delaminated Al-SSZ-70 zeolite via partial substitution of OSDA with CTAOH surfactant
Direct synthesis of delaminated layered zeolitic materials aims to synthesize confined catalysts for reactions involving sterically bulky reactants, which are too large to benefit from conventional three-dimensional confinement in micropores.
Chemistry↗
Catalytic ammonia reforming: alternative routes to net-zero-carbon hydrogen and fuel
Ammonia is a promising net-zero-carbon energy vector whose hydrogen content is accessible via multiple catalytic pathways. This perspective highlights advances in NH 3 reforming catalysis and opportunities for reaction engineering of reformer devices.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗