Enhanced photocatalytic properties of band structure engineered Pd/TiO2 via sequential doping

This paper reports on the sequential doping process of TiO 2 with hydrogen and fluorine for the enhancement of photocatalytic properties. The fluorinated Pd decorated TiO 2 showed 9.5-fold faster photo dye-degradation and 4-fold higher photoelectrochemical current. • The F ion occupies the O vacancy, inducing the F-Ti 3+ intermediate gap state in TiO 2 . • The sequential doped TiO 2 shows a 9.5-fold faster photocatalytic dye degradation. • The sequential doped TiO 2 shows a 4.5-fold higher photoelectrochemical property. Band structure engineering is an essential and promising approach for altering photocatalytic properties of TiO 2 for enhanced H 2 production and dye degradation reactions. Given this, we propose the fluorine incorporation strategy to the Pd decorated TiO 2, via the sequential doping process, using hydrogen and fluorine exhibiting a record photocurrent of ∼2 mA cm −2 (at 1.23 V vs RHE under 1 sun condition), and enhanced rhodamine B degradation. The physicochemical origin of increased photocatalytic activity is ascribed to the effective fluorine doping into the TiO 2 lattice via O-vacancies, and to the resulting modified band electronic structure that generates high energy carriers. Furthermore, an insight into the properties of sequential doped Pd loaded TiO 2 nanorod (Pd/F:TiO 2-x NR), under the scheme of F-Ti 3+ gap, states that mediated photocatalysis is provided with Ti-F bonding. Importantly, nanoscale imaging is used to monitor the direct charge at the surface of doped TiO 2 , which revealed valuable insights for the enhanced photocatalytic activity of TiO 2 .