Self-healing for nanolayered manganese oxides in the presence of cerium(iv) ammonium nitrate: new findings

Abstract

The self-healing reactions for metal oxides are among the most important reactions. For Mn oxides in the presence of cerium(IV) ammonium nitrate, Mn(II) and MnO 4 À combine and heal the Mn oxide. In the reaction, Mn(II) is formed from the reductive dissolution of the Mn oxide or by disproportionation of Mn(III) on the surface of the oxide. This Mn(II) is then oxidized by cerium(IV) ammonium nitrate to MnO 4 À . The MnO 4 À in the presence of Mn oxide oxidizes water or in a second pathway is reduced by Mn(II) to form Mn oxide. Here, we use the multivariate curve resolution-alternative least squares method for the first time to analyze spectroscopic data and obtain concentration profiles of cerium(IV) ammonium nitrate and MnO 4 À during the reaction under different conditions.

From manganese complexes to nano-sized manganese oxides as water-oxidizing catalysts for artificial photosynthetic systems: Insights from the Zanjan team

“…In high enough potential both water oxidation and MnO 4 À reactions take place. MnO 4 À ions and similar species cause a long-term stability problem, separate Mn ions from the catalysts and decrease the activity of these compounds toward water oxidation [41,52,68,69]. Our group reported a new self-healing process of Mn oxides in the presence of Ce(IV).…”

“…Our group reported a new self-healing process of Mn oxides in the presence of Ce(IV). We found that in the reaction of these Mn oxides with Ce(IV), MnO 4 À ions are produced that change their concentration with time [69]. At the end of this reaction, all MnO 4 À ions are consumed, (Fig.…”

“…Our group also introduced a new mechanism for selfhealing of the Mn oxide phase in the presence of Ce (IV) (Fig. 7a) [41,52,68,69]. From the Pourbaix diagram (Fig.…”

Manganese oxides supported on gold nanoparticles: new findings and current controversies for the role of gold

“…The Najafpour's group reported on a self-healing reaction in the presence of Ce(IV) that remakes the Mn oxide phase from MnO 4 -ions (Najafpour and Pashaei 2012; Najafpour et al 2012cNajafpour et al , 2015a.…”

“…In the reaction of these Mn oxides with Ce(IV), MnO 4 -ions are produced as the decomposition product of the catalyst (Najafpour and Pashaei 2012;Najafpour et al 2012cNajafpour et al , 2015a. The MnO 4 -ions concentration changes with time (Najafpour et al 2015a, b).…”