Room temperature conversion of metal oxides (MO, M = Zn, Cd and Mg) to peroxides: insight into a novel, scalable and recyclable synthesis leading to their lowest decomposition temperatures

Metal peroxides (MO sub(2)) have long been used as preferred reagents in organic and inorganic reactions as well as in plastic processing and concrete industries due to the characteristic O-O peroxo linkage that is easily cleaved at moderate temperatures to produce activated oxygen and metal oxide. While these compounds are usually obtained by reacting metal ions with H sub(2)O sub(2) under basic conditions at elevated temperatures, we demonstrate that the nanoparticles of MgO sub(2), ZnO sub(2) and CdO sub(2) can be accomplished by reacting the corresponding metal oxides with H sub(2)O sub(2) under ambient conditions. These peroxide nanocrystals exhibit the lowest decomposition temperatures (T sub(d)), 25-80 degree C lower than the reported values, making them suitable for solution based reactions. It is found that the lowering of T sub(d) can be controlled by tailoring the metal-oxide defects induced by the synthesis procedure. Based on a similar reaction mechanism, we now demonstrate that ZnS as well as Zn can also be converted to ZnO sub(2) nanocrystals under ambient conditions. The possibility of converting metal oxides to metal peroxides and vice versamakes it a recyclable process and the lower T sub(d) is expected to expand their usage in solution processes.