An in situ X-ray spectroscopic study of Mo6+ speciation in supercritical aqueous solutions

In situ XRF and Mo K-edge XAS measurements were made on the ID20-B beam line at the APS on MoO3 in 1 M H2O2 aqueous solution, at temperatures between 400 and 600 °C. The samples were analyzed using a modified Bassett-type hydrothermal diamond anvil cell. Our XRF measurements show that MoO3 is highly soluble in the supercritical H2O2 aqueous fluid. Analysis of XAS spectra shows that the Mo6+ ion exhibits consistent speciation in the H2O2 aqueous solution at temperatures ranging from 400 to 600 °C.