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) an d surface areas less than 10 m(2)/g. The as-prepared gels are amorphou s materials with compositions corresponding to MoO3-x. 1.0H(2)O . 0.3C H(3)NH(2). Crystallization to the orthorhombic phase occurs at 350 deg rees C. Electrochemical measurements demonstrate that lithium can be i ntercalated reversibly into the aerogel structure. An ambient pressure drying method based on the use of low surface tension solvents produc ed monolithic gels with high surface areas (250-270 m(2)/g) and densit ies between 0.7-0.9 g/cm(3). (C) 1998 Elsevier Science B.V. All rights reserved.