A multicomponent equimolar proton-conducting quadruple hexagonal perovskite-related oxide system.

Since the high configurational entropy-driven structural stability of multicomponent oxide system was proposed Rost et al. in 2015, many experiments and simulations have been done to develop new multicomponent oxides. Although many notable findings have shown unique physical and chemical properties, high configurational entropy oxide systems that have more than 3 distinct cation sites are yet to be developed. By utilizing atomic-scale direct imaging with scanning transmission electron microscopy and AC-impedance spectroscopy analysis, we demonstrated for the first time that a multicomponent equimolar proton-conducting quadruple hexagonal perovskite-related Ba5RE2Al2ZrO13 (RE = rare earth elements) oxide system can be synthesized even when adding eight different rare earth elements. In particular, as the number of added elements was increased, i.e., as the configurational entropy was increased, we confirmed that the chemical stability toward CO2 was improved without a significant decrement of the proton conductivity. The findings in this work broaden the use of the crystal structure to which the multicomponent model can be applied, and a systematic study on the correlation between the configurational entropy and proton conductivity and/or chemical stability is noteworthy.

Functionally Graded Bismuth Oxide/Zirconia Bilayer Electrolytes for High-Performance Intermediate-Temperature Solid Oxide Fuel Cells (IT-SOFCs).

A functionally graded Bi1.6Er0.4O3 (ESB)/Y0.16Zr0.84O1.92 (YSZ) bilayer electrolyte is successfully developed via a cost-effective screen printing process using nanoscale ESB powders on the tape-cast NiO-YSZ anode support. Because of the highly enhanced oxygen incorporation process at the cathode/electrolyte interface, a novel bilayer solid oxide fuel cell (SOFC) yields extremely high power density of ∼2.1 W cm-2 at 700 °C, which is a 2.4 times increase compared to that of the YSZ single electrolyte SOFC.

Synthesis of nanoparticles using electrical explosion of Ni wire in Pt solution.

The structure, size and morphology of nanoparticles produced by electrical explosion of Ni wire in Pt(NH3)2(NO2)2 solution were investigated. TEM results showed the formation of Ni and Pt nanoparticles as a result of the procedure. Ni nanoparticles were formed by the explosion of the Ni wire due to the passage of high current, evaporation, ionization, and cooling in the liquid medium. Ni nanoparticles were near spherical and showed particle sizes ranging from a few nanometers up to 50 nm. Pt nanoparticles were possible formed by the dissolution of OH- in Pt(NH3)2(NO2)2 solution during the electrical explosion of the Ni wire resulting in a plasma reaction. The formed Pt nanoparticles were ellipsoidal and showed particle sizes ranging to less than 5 nm. The lattice parameter of the Pt nanoparticles almost corresponded to the standard values reported. The obtained results indicate that Pt nanoparticles can be formed from a Pt solution without a reducing agent by electrical explosion of a metallic wire resulting in a plasma reaction.