Uranium hydroxide/oxide deposits on uranyl reduction.

We clarified the chemical reaction of deposits following the reduction of uranyl ions (UO) from the results of electrochemical quartz crystal microbalance, impedance spectra, and X-ray absorption fine structure measurements. We propose the following deposition mechanism: (1) U is formed by the disproportionation of U, (2) U forms U hydroxide deposits, and (3) finally, the hydroxide deposits change to U oxide, which generally have a larger electrical resistance than the hydroxide form.