H2O2-Based Selective Oxidations Catalyzed by Supported Polyoxometalates: Recent Advances

Polyoxometalates (POMs) are transition metal oxygen anionic clusters that are oxidatively and thermally robust due to their inorganic, metal oxide-like nature. The versatility of their structures and compositions ensures tunable acid and redox properties, solubility, and functionality. The potential of POMs as homogeneous catalysts and building blocks for the construction of heterogeneous selective oxidations catalysts is being intensively investigated. POM catalysts immobilized on solid supports have the clear advantages of easy separation and reuse and, thus, better meet the requests of sustainable chemistry, provided that they are leaching-resistant under the reaction conditions. Here, we give a brief overview of recent advances in the field of liquid-phase selective oxidation of organic compounds using supported POMs and the green oxidant-hydrogen peroxide, with a focus on the critical issues of the catalyst stability and reusability. The scope and limitations of various approaches to POM immobilization are discussed.