Selective photocatalytic oxidation of 3-pyridinemethanol on platinized acid/base modified TiO2

Abstract

TiO₂ catalysts, modified with acidic or alkaline solutions and then platinized, were used for the partial photocatalytic oxidation of 3-pyridinemethanol to 3-pyridinemethanal and vitamin B₃ under environmentally friendly conditions. The reaction took place in water under UVA light and air oxygen. Catalysts were characterized by TEM, photoluminescence, DRIFT-IR, Raman, DRS, XPS, and photocurrent measurements. The photocatalytic activity results show that Pt loading of untreated samples leads to a significant activity improvement (hence product yield) as much as acid and alkaline treatments do. Moreover, the alkaline treated TiO₂ samples exhibit a further increase in activity after loading with Pt. Pt acts as an electron scavenger promoting electron transfer from the TiO₂ conduction band, consequently boosting the photogenerated pair numbers available for the reactive process. Photocurrent measurements show that the TiO₂ photocatalysts' active sites increase significantly after platinization and alkaline/acid treatment. The treated and/or Pt loaded catalysts showed good thermal stability (at least up to 400 °C).