Sol-gel synthesis and characterization of molybdenum oxide gels

Monolithic molybdenum oxide aerogels and xerogels were synthesized by sol-gel methods using a variety of sol compositions from the system Mo(OC3H7)(5)/MoCl3(OC3H7)(2)/acetonitrile/nitric acid/H2O. The aerogels were found to be of density 0.1-0.2 g/cm(3) with surface areas between 150-180 m(2)/g. The xerogels had densities between 1.5-2.0 g/cm(3) and surface areas less than 10 m(2)/g. The as-prepared gels are amorphous materials with compositions corresponding to MoO3-x. 1.0H(2)O . 0.3CH(3)NH(2). Crystallization to the orthorhombic phase occurs at 350 degrees C. Electrochemical measurements demonstrate that lithium can be intercalated reversibly into the aerogel structure. An ambient pressure drying method based on the use of low surface tension solvents produced monolithic gels with high surface areas (250-270 m(2)/g) and densities between 0.7-0.9 g/cm(3). (C) 1998 Elsevier Science B.V. All rights reserved.