Tuning the Oxygen Release Temperature of Metal Peroxides over a Wide Range by Formation of Solid Solutions

Metal peroxides, with a labile peroxy bond, constitute a distinct class of inorganic compounds that can generate singlet oxygen species and works as versatile reagents in many important industrial processes such as in polymer initiation reactions. Even after several decades after their discovery, the number of metal peroxides yet is few and their utility is severely limited by the corresponding decomposition temperatures (T-dec), which cannot be tuned to suit the most desirable condition for a particular reaction. One way of overcoming this would have been to obtain solid solutions of two peroxides with different decomposition temperatures. Surprisingly, in contrast to the vast majority of extended solids such as the oxide, hydroxide, and perovskite families, solid solutions of metal peroxides have remained so far nonexistent. Here, we explore and demonstrate that peroxides of Zn and Mg, ZnO2 (T-dec similar to 200 degrees C), and MgO2 (T-dec = 300 degrees C) can form solid solutions in the entire solubility range. Importantly, the decomposition temperatures of the solid solutions lie between that for the constituent phases and changes the composition systematically. These findings provide the first genuine chemical system that can potentially be tuned to decompose at different predesigned temperatures to generate reactive oxygen species.