Proton conducting SmNiO₃ (SNO) thin films were grown on (001) LaAlO₃ substrates for systematically investigating the proton transport properties. X-ray Diffraction and Atomic Force Microscopy studies reveal that the as-grown SNO thin films have good single crystallinity and smooth surface morphology. The electrical conductivity measurements in air indicate a peak at 473 K in the temperature dependence of the resistance of the SNO films, probably due to oxygen loss on heating. A Metal-Insulator-Transition occurs at 373 K for the films after annealing at 873 K in air. In a hydrogen atmosphere (3% H₂/97% N₂), an anomalous peak in the resistance is found at 685 K on the first heating cycle. Electrochemical Impedance Spectroscopy studies as a function of temperature indicate that the SNO films have a high ionic conductivity (0.030 S/cm at 773 K) in a hydrogen atmosphere. The activation energy for proton conductivity was determined to be 0.23 eV at 473–773 K and 0.37 eV at 773–973 K respectively. These findings demonstrate that SNO thin films have good proton conductivity and are good candidate electrolytes for low temperature proton-conducting Solid Oxide Fuel Cells.

A high yield of silver nanotubes with large aspect ratio were conveniently synthesized via an organic-assist solvothermal preparation technique using polyvinyl pyrrolidone (PVP) as a capping reagent and architecture soft-template. The molecular ratio between the repeating unit of PVP and AgNO₃ plays a crucial role in determining the geometric shape of the product. Such novel-type Ag nanotubes were self-assembled by Ag nanoparticles, which had largely similar crystallographic orientation, forming a texture. The fact that nanoparticles without anisotropic crystal structures can form such superstructures by self-assembly may open a window for understanding a range of nanotube formation processes.