Galvanic replacement reactions(GRRs) have been established as one of the most powerful and versatile methods for fabricating hollow-structured nanomaterials with tunable and well-defined structures and properties. In this report, we show that the scope of GRRs is significantly broadened by establishing Ag+[NO3-@Ag6O8] as the most potent crystalline oxidant viable in aqueous phase known to date. We determined the standard reduction potential of the heterogeneous redox-couple Ag+[NO3-@Ag6O8](s)/Ag+(aq) to be at +1.98 ±0.03V (vs. SHE) and at + 1.32 V at pH 7 which is higher than that of Mn3O4(s)/Mn2+(aq) redox-couple by ca. + 1.16 V. We showed that monodisperse Ag+[NO3-@Ag6O8] mesocrystals in well-defined structures were readily synthesized electrochemically without using any organic additives. We further demonstrated that, by employing Ag+[NO3-@Ag6O8] mesocrystals as oxidative(sacrificial) templates, the thermodynamic range of GRRs was significantly expanded, the kinetically-controlled products of oxide catalysts in mesobox-structures were produced, and especially meso-capsules of conducting polymer were fabricated via inorganic-to-organic hetero-GRRs, which was shown to drastically improve the stability of oxide catalysts under reactive conditions.
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