Selective oxidation of benzyl alcohol over TiO2 nanosheets with exposed {0 0 1} facets: Catalyst deactivation and regeneration

Increasing interest has been devoted to synthesizing TiO2 nanocrystals with reactive {0 0 1} facets (TiO2-001) as photocatalysts for potential applications, but relative research works on the photocatalytic stability of TiO2-001 nanocrystals are rarely reported. Here, we have prepared TiO2-001 using a facile hydrothermal method and studied its photocatalytic activity and stability toward selective oxidation of benzyl alcohol. The results show that TiO2-001 suffers from a serious deactivation. By a series of joint techniques, we find that lots of oxygen vacancies have been formed on the surface of the used TiO2-001, which is responsible for the loss in photoactivity of TiO2-001. A possible formation mechanism of the oxygen vacancies on the TiO2-001 surface is proposed. The regeneration of the catalyst can be realized by simply refluxing the used TiO2-001 in water at 100 °C.

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► The stability of TiO2-001 photocatalyst is investigated.
► The TiO2-001 photocatalyst suffers from a serious deactivation.
► The oxygen vacancies formation is responsible for the deactivation.
► A water refluxing method is able to regenerate the deactivated TiO2-001.