The ability of Nb2O5 and Ta2O5 to generate active oxygen in contact with hydrogen peroxide

• Ability of amorphous Nb2O5 and Ta2O5 in radical generation after H2O2 treatment
• Dependence of the radical types on the nature of metal oxide
• Peroxo radicals formed on amorphous Nb2O5 active in the oxidation of glycerol
• Differences between crystalline and amorphous oxides in the interaction with H2O2

Amorphous and crystalline niobium(V) and tantalum(V) oxides were treated with hydrogen peroxide and studied by XRD, UV–vis, FTIR and ESR techniques to identify changes on their surface upon interaction with hydrogen peroxide. Differences between amorphous and crystalline materials in the interaction with H2O2 depending on the hydroxylation of the surface and the nature of OH groups were evident. The type of radical species formed on hydroxylated amorphous materials treated with H2O2 depended on the nature of metal oxide. It was proved that peroxo radical species formed in the interaction of H2O2 with amorphous Nb2O5 were the active intermediates in the oxidation of glycerol to glycolic acid with hydrogen peroxide. The radicals formed on amorphous Ta2O5 surface treated with hydrogen peroxide were poorly active in the oxidation of glycerol. Detailed study of the above mentioned radicals is in progress and will be a subject of a separate paper.

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