Nanoporous carbon materials are a versatile source of carbons that would be useful in applications ranging from electronics to electrochemical energy storage. Here, we focus on nanoporous carbon materials prepared by direct carbonization of zeolitic imidazolate frameworks (ZIF-8) towards supercapacitor applications. Several types of nanoporous carbons have been prepared by varying the applied carbonization temperature. The symmetric devices assembled using nanoporous carbon electrodes were tested for their optimal performance in the electrolyte of sulfuric acid solution. We demonstrate the effects of various factors (e.g., surface area, nitrogen content, degree of graphitization, and relative percentage of micropores) on the performance.

High density ex situ magnesium diboride bulks were synthesized from commercial MgB 2 powder using spark plasma sintering under a range of applied uniaxial pressures between 16 and 80 MPa. The microstructure was characterized using x-ray diffraction, scanning electron microscopy, polarized optical microscopy, Vickers hardness measurements, and density measurements using the Archimedes method. By combining these data with those for other bulk samples we have developed a correlation curve for the hardness and density for magnesium diboride for relative densities of 60-100%. The superconducting properties were determined using magnetization measurements. Comparison to samples of significantly higher porosity indicates a positive correlation between magnetization critical current density and bulk density for magnesium diboride bulks up to around 90% density. Above this level other microstructural processes such as grain growth begin to influence the critical current density, suggesting that full elimination of porosity is not necessary to obtain high critical current density. We conclude that the best superconducting properties are likely to be obtained with a combination of small grain size and minimal porosity.

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Cobalt sulfide/sulfur dopedc arbon composites (Co 9 S 8 /S-C) were synthesized by calcining ar ationally designed sulfur-containing cobalt coordinationc omplexi na n inert atmosphere.F rom the detailed transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analyses,t he electrocatalytically active Co 9 S 8 nanoparticles were clearly obtained and combined with the thin sulfur doped carbon layers. Electrochemical data showed that Co 9 S 8 /S-C had ag ood activity and long-term stability in catalyzing oxygen evolution reactioni na lkaline electrolyte, even better than the traditional RuO 2 electrocatalyst. The excellente lectrocatalytic activity of Co 9 S 8 /S-C was mainly attributed to the synergistic effect between the Co 9 S 8 catalyst which contributed to the oxygen evolutionr eactiona nd the sulfurd oped carbon layer whichf acilitated the adsorption of reactants, prevented the Co 9 S 8 particles from aggregating and served as the electrically conductivebinder between each component.

In this work, Cu 2 ZnSnS 4 (CZTS) absorber layers were fabricated using a two-stage process. Sequentially deposited Cu-Zn-Sn thin film layers on metallic foils were annealed in an Ar + S 2(g) atmosphere. We aimed to investigate the role of flexible titanium and molybdenum foil substrates in the growth mechanism of CZTS thin films. The Raman spectra and X-ray photoelectron spectroscopy analyses of the sulfurized thin films revealed that, except for the presence of Sn-based secondary phases, nearly pure CZTS thin films were obtained. Additionally, the intense and sharp X-ray diffraction peak from the (112) plane provided evidence of good crystallinity. Electron dispersive spectroscopy analysis indicated sufficient sulfur content but poor Zn atomic weight percentage in the films. Absorption and band-gap energy analyses were carried out to confirm the suitability of CZTS thin films as the absorber layer in solar cell applications. Hall effect measurements showed the p-type semiconductor behavior of the CZTS samples. Moreover, the back contact behavior of these metallic flexible substrates was investigated and compared. We detected formation of cracks in the CZTS layer on the molybdenum foils, which indicates the incompatibility of molybdenum's thermal expansion coefficient with the CZTS structure. We demonstrated the application of the magnetron sputtering technique for the fabrication of CZTS thin films on titanium foils having lightweight, flexible properties and suitable for roll-to-roll manufacturing for high throughput fabrication. Titanium foils are also cost competitive compared to molybdenum foils.