Reducing action of persulfuric acid

Although H2S2O8 shows weak oxidizing property at room temperature, it works as a strong oxidizing agent at higher temperature via H2SO5 to H2O2 finally and therefore it had been used only as an oxidizing agent. However, H2O2 oxidizes compounds of lower valency, while it reduces that of higher valency, namely it reduces oxidizing compounds and so H2S2O8, which converted to H2O2 at higher temperature is considered. to react as a reducing agent towards oxidizing com pounds. While H2SO4 was added to heat with KMnO4, MnO2, Ce(SO4)2, CeO2, K2Cr2O7, CrO3, NH4VO3 and V2O5, and then (NH4)2S2O8 was added, they were recognized to be reduced. Therefore, if (NH4)2S2O8 is used as an oxidizing agent, it should be heated after it is added at room temperature, however, in order to use it as a reducing agent, it should be added after it is heated.