Titania morphologies modified gold nanoparticles for highly catalytic photoelectrochemical water splitting

Different morphologies of titania with different dimensions (0, 1 and 2 D) were prepared using hydrothermal technique and Au nanoparticles were deposited on its surface using photoreduction method. The obtained materials were characterized using X-ray diffraction, HRTEM and FESEM. The optical properties were studied for all morphologies before and after depositing of Au nanoparticles, a clear shift toward visible light absorption was confirmed after Au loading. Moreover, the surface area, pore size and pore volume were discussed and revealed that BET surface area was decreased after Au nanoparticles deposition on all morphologies. The prepared materials were applied as a photoanode for water splitting in alkaline media and the effect of titania dimension and Au deposition on the photocurrent were investigated. Au deposition on the surface of titania dramatically improves the performance of photocurrent generation during photoelectochemical electrolysis of water under simulated solar light irradiation. The titania dimension played a significant role on the value of photocurrent. Au modified nanotubes (1D) exhibit the highest photocurrent with high stability. The maximum photocurrent densities were 1.16, 0.63, 1.45, 2.97, 3.28, and 5.23 mA cm(-2) at an applied potential of 1 V with 4.98, 2.01, 2.50, 3.47, 4.05, and 5.19 times increment for particles (0D), sheets (2D), tubes (1D), particles@Au, sheets@Au, and tubes@Au compared to its corresponding current density in dark respectively. Depositing of Au nano particles on titania, decreases the charge transfer resistance due to the surface plasmon resonance effect of Au nanoparticles leading to enhancement in the photoelectrochemical activity. TNT@Au photoanode had the longest electron pass due to the tubular form (1D) which help in charge separation.