Pt-Chitosan-TiO2 for Efficient Photocatalytic Hydrogen Evolution via Ligand-to-Metal Charge Transfer Mechanism under Visible Light

The Pt-chitosan-TiO2charge transfer (CT) complex was synthesized via the sol-gel and impregnation method. The synthesized photocatalysts were thoroughly characterized, and their photocatalytic activity were evaluated toward H2production through water reduction under visible-light irradiation. The effect of the preparation conditions of the photocatalysts (the degree of deacetylation of chitosan, addition amount of chitosan, and calcination temperature) on the photocatalytic activity was discussed. The optimal Pt-10%DD75-T200 showed a H2generation rate of 280.4 μmol within 3 h. The remarkable visible-light photocatalytic activity of Pt-chitosan-TiO2was due to the CT complex formation between chitosan and TiO2, which extended the visible-light absorption and induced the ligand-to-metal charge transfer (LMCT). The photocatalytic mechanism of Pt-chitosan-TiO2was also investigated. This paper outlines a new and facile pathway for designing novel visible-light-driven photocatalysts that are based on TiO2modified by polysaccharide biomass wastes that are widely found in nature.Keywords:photocatalyst;TiO2;chitosan;H2evolution;LMCT;visible light