Although high temperature superconductors are promising for power applications, the production of low‐cost coated conductors with high current densities—at high magnetic fields—remains challenging. A superior superconducting YBa2Cu3O7–δ nanocomposite is fabricated via chemical solution deposition (CSD) using preformed nanocrystals (NCs). Preformed, colloidally stable ZrO2 NCs are added to the trifluoroacetic acid based precursor solution and the NCs' stability is confirmed up to 50 mol% for at least 2.5 months. These NCs tend to disrupt the epitaxial growth of YBa2Cu3O7–δ, unless a thin seed layer is applied. A 10 mol% ZrO2 NC addition proved to be optimal, yielding a critical current density JC of 5 MA cm−2 at 77 K in self‐field. Importantly, this new approach results in a smaller magnetic field decay of JC(H//c) for the nanocomposite compared to a pristine film. Furthermore, microstructural analysis of the YBa2Cu3O7–δ nanocomposite films reveals that different strain generation mechanisms may occur compared to the spontaneous segregation approach. Yet, the generated nanostrain in the YBa2Cu3O7–δ nanocomposite results in an improvement of the superconducting properties similar to the spontaneous segregation approach. This new approach, using preformed NCs in CSD coatings, can be of great potential for high magnetic field applications.

In this work, a ceramic composite of ZrW 2 O 8 and ZrO 2 was synthesized, in order to investigate the possibility of compensating the positive thermal expansion of ZrO 2 with the negative thermal expansion (NTE) compound ZrW 2 O 8 , tailoring the thermal expansion of these composites. The NTE material was mixed with varying amounts of ZrO 2 . The thermal expansion coefficients of this series of composites decrease with increasing amounts of ZrW 2 O 8 . Nevertheless, a negative deviation from the values expected by the rule of mixtures was found to be most pronounced in the middle of the compositional region.

Bismuth molybdate catalysts have been used for partial oxidation and ammoxidation of light hydrocarbons since the 1950s. In particular, there is the synergy effect (the enhancement of the catalytic activity in the catalysts mixed from different components) in different phases of bismuth molybdate catalysts which has been observed and studied since the 1980s; however, despite it being interpreted differently by different research groups, there is still no decisive conclusion on the origin of the synergy effect that has been obtained. The starting idea of this work is to find an answer for the question: does the electrical conductivity influence the catalytic activity (which has been previously proposed by some authors). In this work, highly conductive materials (SnO 2 , ZrO 2 ) and nonconductive materials (MgO) are added to beta bismuth molybdates (β-Bi 2 Mo 2 O 9 ) using mechanical mixing, impregnation, and sol−gel methods. The mixtures were characterized by XRD, BET, XPS, and EDX techniques to determine the phase composition and surface properties. The conductivities of these samples were recorded at the catalytic reaction temperature (300−450 °C). Comparison of the catalytic activities of these mixtures showed that the addition of 10% mol SnO 2 to beta bismuth molybdate resulted in the highest activity while the addition of nonconductive MgO could not increase the catalytic activity. This shows that there may be a connection between conductivity and catalytic activity in the mixtures of bismuth molybdate catalysts and other metal oxides.

The influence of using graphite (G) as a shaping agent for bismuth molybdate (BiMo) catalysts was analyzed. Shaping was done by tableting, with addition of different loadings of graphite (0, 0.5, 1, 3, 5, 7, and 10 wt %). The use of graphite during the pressing of bismuth molybdate powders eases tableting because of the lubricating properties of the former. Furthermore, the compressive strength of BiMo-G tablets is higher than that of pure BiMo. Concerning the physicochemical properties of BiMo-G, XRD and XPS showed that graphite changes neither the relative distribution of the crystallographic phases of bismuth molybdate nor the oxidation state of bismuth and molybdenum in the tableted powders. Consequently, the shaped BiMo-G catalysts displayed similar, or slightly better, performances in the selective oxidation of propylene to acrolein. TGA analysis of samples of BiMo-G confirmed the thermal stability of the catalysts under oxidative conditions. Graphite was observed to experience crystallization into the hexagonal 2H phase during the catalytic tests. The results reported herein demonstrate that graphite is an effective shaping agent for bismuth molybdate powders.

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A gallium 2,2′‐bipyridine‐5,5′‐dicarboxylate metal–organic framework (MOF), denoted as COMOC‐4, has been synthesized by solvothermal synthesis. This MOF exhibits the same topology as MOF‐253. CuCl2 was incorporated into COMOC‐4 by a post‐synthetic modification (PSM). The spectroscopic absorption properties of the MOF framework before and after PSM were compared with theoretical data obtained by employing molecular dynamics combined with time‐dependent DFT calculations on both the as‐synthesized and functionalized linker. The catalytic behavior of the resulting Cu2+@COMOC‐4 material was evaluated in the aerobic oxidation of cyclohexene with isobutyraldehyde as a co‐oxidant. In addition, the catalytic performance of Cu2+@COMOC‐4 was compared with that of the commercially available Cu‐BTC (BTC=benzene‐1,3,5‐tricarboxylate) MOF. Cu2+@COMOC‐4 exhibits a good cyclohexene conversion and an excellent selectivity towards cyclohexene oxide in comparison to the Cu‐based reference catalyst. Furthermore, no leaching of the active Cu sites was observed during at least four consecutive runs.

1,4,8,11-tetraazacyclotetradecane (cyclam) is widely known as an ideal ligand for chelating heavy metal ions such as Ni 2+ and Cu 2+ in aqueous media. In this work the consequences of chelation on the preference for high spin or low spin configuration were investigated for Fe 3+ , Ni 2+ , Cu 2+ and Cr 3+. Two methods were used to determine the number of unpaired electrons in the solid and dissolved complex. First the change of magnetic susceptibility of the crystalline powder as a function of temperature was measured. In the second case Evans NMR-based method was used to obtain information about the number of unpaired electrons in the dissolved complexes. In some cases, such as Fe 3+ and Ni 2+ , a discrepancy between the two methods was noticed. This behaviour is discussed in terms of the preference of the large high spin Ni 2+-ion to switch to the smaller low spin Ni 2+-ion in the aqueous environment, which better fits the cavity of the ligand in the square planar geometry. The results are influenced by the geometry of the complex, the aggregation state and the dimensions of the ions.

During the last decade the focus in superconductivity research has shifted towards the manufacturing of easy-to-handle superconductors, because of their high usability in electronic applications in comparison to bulky ceramics. This article reviews our recent progress made in the buffer-layer architecture of such a coated conductor, focusing on CeO 2 thin films prepared by an aqueous sol-gel method and deposited by dip-coating. Starting from water-soluble cerium(III) nitrate precursors, we were able to deposit films showing a very high degree of [002] orientation depending on the film characteristics and synthesis conditions. The formation and stability of the chemical complexes in the solu-