الفهرس 
PrefaceOnly 14 pages are availabe for public view
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Abstract
Throughout this dissertation, the photocatalytic activity of doped TMC and TMC composites has been studied. In addition, the mechanchishm of photocatalytic activity was thoroughly studied using femtosecond time-resolved diffuse reflectance spectroscopy, single-particle confocal fluorescence microscopy and photoelectrochemical technique. In Chapter 1, N-TMC, F-TMC, and N,F-TMC were prepared by the simple post modification. N,F-TMC has high photocatalytic for the degradation of RHB and 4-NP under the visible light irradiation. The high activity of N, F-TMC is attributed to the synergetic effect of N and F doping. Femtosecond time-resolved diffuse reflectance (TDR) spectroscopy was used to clarify the charge-separation, trapping and recombination mechanism, indicating an important role of F for increasing the photocatalytic activity. In Chapter 2, broad band visible and even NIR light harvesting over TMC has been successfully achieved by loading Au NRs onto TMC. Using four Au NRs with different aspect ratios is beneficial for the preparation of Au NRs/TMC with adjustable light absorption from visible to NIR-region. All Au NRs/TMC exhibit photocatalytic activity for H2 production from aqueous methanol solution. However, with the increase of the aspect ratio, the LSPR peak shift toward longer wavelength region with lower photon energy. Au NRs/TMC-780 shows the highest photocatalytic activity (924 µmol h-1 g-1) compared to (65 µmol h-1 g-1) for Au NRs/P25-780 indicating efficient charge transfer on TMC. Hot electron injection from SPR excited AuNRs to TMC at the interface between Au NRs and TMC, followed by electron transfer in TMC, were verified using single-particle PL measurement and femtosecond time resolved diffuse reflectance spectroscopy. The strong PL quenching at LSPR peak of Au NRs loaded onto TMC compared to bare Au NRs confirmed the electron transfer from Au NRs to TMC. In Chapter 3, a series of g-C3N4 NS/TMC with different component of g-C3N4 NS were fabricated. The photocatalytic activity of g-C3N4 NS (31 wt%)/TMC for H2 evolution (3.6 µ mol h-1) under visible light irradiation (λ> 420 nm) under visible light irradiation (λ> 420 nm) is nearly 20 times and 7 times higher than that of g-C3N4 NS and g-C3N4 NS (31 wt%)/P25 composite, respectively, without any cocatalyst. Electrochemical and PL measurements indicate that this increase in photocatalytic activity is mainly ascribed to the improved separation of photogenerated charge carriers. The fs-TDR was performed to study charge carrier kinetic. The lifetime of electrons and holes increase and the recombination of photogenerated charge carriers is decreased due to the tight interface between g-C3N4 NS and plate TMC which facilitates the charge transfer. The fs-TDR confirms that TMC acts as electron transfer channel to promote the charge separation.