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Manganese oxide octahedral molecular sieves (OMS) are important materials in environmental chemistry, electrochemistry, and heterogeneous catalysis. Here, a rapid process to prepare cryptomelane-type octahedral molecular sieve (OMS-2) nanomaterials using a microwave assisted hydrothermal technique (MW-HT) is presented. With the assistance of microwaves in the hydrothermal reaction, the preparation time of OMS-2 can be as short as 10 s; up to 4 days are required in a conventional hydrothermal reaction. Direct observation of reaction temperature and pressure in the hydrothermal reaction can be achieved in real time in the reaction process. Reaction time and temperature are two parameters chosen to examine the formation conditions of OMS-2 materials. A reaction temperature below 80 °C resulted in the formation of amorphous manganese oxide material, whereas crystalline phase OMS-2 materials were formed at increased reaction temperatures to 100 °C or above. Studies by field emission scanning electron microscop...

CuO is an important transition metal oxide with a narrow bandgap (Eg = 1.2 eV). CuO has been used as a catalyst, a gas sensor, in anode materials for Li ion batteries. CuO has also been used to prepare high temperature superconductors and magnetoresistance materials. In this paper, CuO with urchin-like morphologies has been synthesized via a simple reflux method. The reflux method has advantages over other solution-based techniques, such as ease of operation, safety, and high yield (95%). XRD results showed pure tenorite CuO was produced. FE-SEM exhibited an urchin-like morphology of CuO, which is composed of aggregates of nanosized strips. HR-TEM showed that the strips were single crystals with the lattice fringe of 2.3 A, which corresponds to (111). DSC and TGA results suggested that as-synthesized CuO had high thermal stability. Time-dependent experiments were conducted to illustrate the evolution of the urchin-like morphology and crystal phase formation of CuO. The effects of copper sources and precip...

The first example of a highly water-tolerant, hydrophobic polymer coated metal oxide catalyst systems is reported for CO oxidation. Studies show that protected catalysts have 5.3 times longer lifetimes than unprotected catalysts under highly humid conditions. This idea is simple and general for many different metal oxide catalyst systems.

Indium-doped manganese oxide materials have been hydrothermally synthesized. Doped indium was found to be in framework sites in synthetic cryptomelane. Cyclic voltammetry (CV) results show that man...