MICROWAVE-ASSISTED SELECTIVE DEOXYGENATION OF LAYER-CONTAINING AND CHAIN-CONTAINING OXIDES

Very rapid (within 5 min), selective, single-step deoxygenation of lay er- and chain-containing oxides, MoO3, CrO3, V2O5, alpha-VOPO4 . 2H(2) O and Ag6Mo10O33 has been accomplished using graphitic carbon in a mic rowave-assisted reaction. The products were found to be MoO2, Cr2O3, V O2, VPO4 and a mixture of (Ag + MoO2), respectively. Products were cha racterised by X-ray diffraction (XRD), differential scanning calorimet ry (DSC), IR and electron paramagnetic resonance (EPR) spectroscopies. Although conventional methods of preparing these materials are tediou s, the present method is simple, fast and yields very homogeneous prod ucts of good crystallinity. Our results reveal that while layer- and c hain-containing oxides undergo rapid microwave-assisted carbothermal r eduction, the non-layered materials do not. The high structural select ivity of these reactions is suggestive of the topochemical nature of t he fast reduction process.