Enhancement of Photoelectrocatalysis Efficiency by Using Nanostructured Electrodes

Hydrogen production and simultaneous photoelectrocatalytic pollutant oxidation using a TiO2/WO3 nanostructured photoanode under visible light irradiation

“…Advantages of template synthesis include the ability to increase catalyst surface area, improve reaction/interaction between the semiconductor and the electrolyte, consequently enhancing charge transfer efficiency and reducing electronhole recombination, and extend the absorption spectrum of the catalyst. 3 The cost of wastewater treatment is a major concern in industry, and there is a continual search for effective and inexpensive solutions. One attractive option is to employ photoelectrocatalytic techniques in order to explore a useful strategy by recovering the hydrogen generated at the counter electrode.…”

“…[4][5][6][7][8][9] There are considerable benefits derived from the coupling of oxide materials containing close band gap energies, such as TiO 2 (3.2 eV) and WO 3 (2.8 eV). The valence and conduction band energy diagrams for WO 3 and TiO 2 bicomponent materials indicate electron injection from the TiO 2 conduction band to WO 3 is favored, while hole transfer between valence bands occurs in the opposite direction. 4 This can increase the number of holes across the TiO 2 surface and enhance the flow of electrons towards the counter electrode, kept under bias potential, hence improving photoelectrocatalysis efficiency.…”

“…1,2 The coupling of two semiconductors presenting complementary optical properties can enhance electrode performance by improving charge separation (e -/h + ), minimizing charge recombination, and increasing photoactivity. 3 The coupling of WO 3 and TiO 2 can be especially useful for the photoelectrocatalytic oxidation of organic species. [4][5][6][7][8][9] There are considerable benefits derived from the coupling of oxide materials containing close band gap energies, such as TiO 2 (3.2 eV) and WO 3 (2.8 eV).…”

“…3 The coupling of WO 3 and TiO 2 can be especially useful for the photoelectrocatalytic oxidation of organic species. [4][5][6][7][8][9] There are considerable benefits derived from the coupling of oxide materials containing close band gap energies, such as TiO 2 (3.2 eV) and WO 3 (2.8 eV). The valence and conduction band energy diagrams for WO 3 and TiO 2 bicomponent materials indicate electron injection from the TiO 2 conduction band to WO 3 is favored, while hole transfer between valence bands occurs in the opposite direction.…”

“…Electrons and holes can be transferred from one to another semiconductor based on their conduction and valence band edge positions (E CB and E VB ) 17. The E CB and E VB values reported for WO3 are +0.25 V and +3.05 V, respectively, while the corresponding values for TiO 2 are -0.2 V and +3.2 V. 17 Recombination is decreased with increased low band gap energy material. Upon irradiation, electrons of the composite material are excited from the valence band of both layers to the conduction band, leaving holes in the valence band.…”