Photocatalytic water splitting on Au/TiO2 nanocomposites synthesized through various routes: Enhancement in photocatalytic activity due to SPR effect

摘要

In the present investigation, Au/TiO2 nanocomposites were prepared by in situ, photodeposition (PD) and SMAD method. The synthesized photocatalysts were evaluated for their photocatalytic activity in hydrogen generation. The hydrogen evolution rate was observed to be 1200μmolsh~(-1), 920μmols h~(-1) and 1600μmols h~(-1) for in situ, photodeposition (PD) and SMAD, respectively under UV-vis light illumination. However, under purely visible light illumination the highest hydrogen evolution of 32.4 μmols h~(-1) was observed in case of Au/TiO2 prepared by PD followed by SMAD (6.9μmols h~(-1)). The significantly high photocatalytic activity as demonstrated by AU/TiO2 synthesized by photodeposition method under purely visible light irradiation proves the potential of photocatalyst in efficient solar energy conversion. The poly disperse particles of AuNPs on TiO2 by photodeposition method enhances plasmonic effects. The catalyst was thoroughly characterized by powdered X-ray diffraction, UV-vis DRS and TEM for understanding the plasmonic properties. TEM images further substantiated the deposition of gold on TiO2 matrix of heterogeneous particle size with an average size of 8-10 nm (smaller particles) and 53-70 nm (bigger particles). The photodeposition of AuNPs on different titania supports was also studied.