Spontaneous Ordering of Oxide Nanostructures

Abstract

We report the spontaneous formation of uniformly distributed arrays of "tips" (tall conical hillocks) upon oxidation of palladium (Pd) thin films. The formation of the palladium oxide tips depended on the thickness and granularity of the Pd film and on annealing and oxidation conditions. As the Pd film thickness increased from 40 to 200 nanometers, the average height of the tips increased from 0.5 to 1.2 micrometers, their height distribution became broader, and their density decreased from 55 x 10(6) to 12 x 10(6) per square centimeter. Enhanced photoelectron emission from locations corresponding to the tips suggests their possible use in field emission applications.

Growth and decomposition of aligned and ordered PdO nanoparticles

“…[37] In that study it was observed that after oxidation at 575 K, the Rh metal particle surface was surrounded by a 1 nm oxidic layer, as evident in high-resolution images, while oxidation at higher temperature (725 K) resulted in the formation of a shell of hexagonal α-Rh 2 O 3 epitaxially covering the remaining Rh metal core, i.e., just the opposite situation as in the case of PdO/Pd. In analogy, a kinetically stable O-Rh-O trilayer surface oxide was observed during oxidation of a Rh(111) surface, [38] while three-dimensional PdO island growth was observed by atomic force microscope (AFM) imaging of Pd films annealed in O 2 at 1173 K. [39] Hence, the growth of PdO and Rh 2 O 3 proceeds via different mechanisms and PdO growth involves the formation of distinct PdO islands and/or crystallites rather than the formation of a thin adhesive layer.…”

Palladium/Copper Alloy Composite Membranes for High Temperature Hydrogen Separation From Coal-Derived Gas Streams

“…There is evidence in the nanotechnology literature to support this hypothesis. Figure 9 shows conical palladium oxide structures formed by oxidizing a Pd film on a single crystal oxide support at 900 °C [11]. The height of these structures is approximately 1 µm, close to the thickness of our Pd-Cu films.…”

Modified Au-Based Nanomaterials Studied by Surface Plasmon Resonance Spectroscopy

“…11, 71 However, few works have explored the possibility to use it with other non-noble metals. [156][157][158] Moreover, to our best knowledge, this method has never been applied to obtain complex NPs with more than one phase.…”