The electrochemical reduction of hydrogen peroxide on uranium dioxide electrodes in alkaline solution

The electrochemical reduction of hydrogen peroxide on uranium dioxide under intermediate pH to acidic conditions

“…3 shows a series of voltammograms recorded, with and without H 2 O 2 , in solutions of various pH values in the range 4-9. The general features of the CVs are the same, and consistent with previous observations [21]. At the beginning of the scan near the negative limit, a diffusion-controlled limiting current is observed.…”

“…6 for m = 1. The slopes obtained in this manner are shown for the pH range 3-9 in Table 1 and are consistently very large, as previously observed at the higher pH of 9.8 [21] (and also shown in Table 1). Although not shown in Table 1, similar slopes have been observed up to pH 12 [21].…”

“…The slopes obtained in this manner are shown for the pH range 3-9 in Table 1 and are consistently very large, as previously observed at the higher pH of 9.8 [21] (and also shown in Table 1). Although not shown in Table 1, similar slopes have been observed up to pH 12 [21]. These values are consistent with the mechanism proposed previously [21,23] involving reaction steps (1) and (2), and confirm that, provided the UO 2+x layer is stable on the electrode surface, the mechanism of H 2 O 2 reduction is the same and independent of pH.…”

“…A problem with the use of this equation is its insensitivity to the choice of reaction order [48] and our previous evidence that demonstrates that reaction orders can be fractional [21] and change with potential and [H 2 O 2 ] [23]. Taking m = 1, the measured currents at various pH values over the range 3-9 have been corrected for diffusion using Eq.…”

“…The influence of H 2 O 2 on fuel corrosion has been extensively studied [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] and much of the early literature has been reviewed [5,24]. The cathodic reduction of H 2 O 2 on UO 2 surfaces was found to proceed via a coupled chemical-electrochemical process in which H 2 O 2 chemically creates U IV -U V donor-acceptor sites on the UO 2 surface…”