Hydrothermal synthesis of transition metal oxides under mild conditions

A notable development in mild (less than or equal to 200 degrees C) hydrothermal synthesis in the past few years has been the extension of the synthesis technique from zeolites and metal phosphates to binary and ternary transition metal oxides. This low-temperature technique is critical to the formation of metastable phases not obtainable using traditional high-temperature methods. New phases, as well as known materials, of the oxides of tungsten, molybdenum, vanadium and manganese have been formed, often in highly crystalline form. One enhancement of the technique is microwave heating, which appears to accelerate nucleation, producing very uniform particles in a few hours.