Controllable Synthesis of Silver-Nanoparticle-Modified TiO2 Nanotube Arrays for Enhancing Photoelectrochemical Performance

One-dimensional TiO2 nanotube arrays have attracted tremendous interest due to their superior physical and chemical properties. However, one of the noteworthy drawbacks of them is the poor visible light utilization owing to their large energy gap. In order to effectively enhance their visible light absorption and boost up their photoelectrochennical performance, plasmonic Ag nanoparticles with specific size and uniform dispersion are selected and loaded on the surface of TiO2 nanotubes. Up to now, the rational design and effective control of the morphology of Ag nanoparticles have rarely been achieved due to the intrinsic limitation of the traditional method. Herein, we have successfully reached the modulation of the dimension of Ag nanoparticles through a modified solvothernnal method. It is found that the dimension and distribution of Ag nanoparticles play an important role on the photoelectrochemical performance of TiO2 nanotube arrays. In particular, it has been proposed that only the Ag nanoparticles with suitable dimension and uniform distribution can greatly improve the photoelectric activities of TiO2 due to its superior surface plasmon resonance under visible light. Additionally, the influence factors of Ag nanoparticles during the solvothermal process have also been discussed detailedly.