Charge carrier generation and control on plasmonic Au clusters functionalized TiO2 thin films for enhanced visible light water splitting activity

Abstract

We present the remarkable plasmon-enhanced photoelectrochemical (PEC) water splitting activity by swapping the gold (Au) clusters position at TiO2 interface. Specifically, we propose novel and strategic Au clusters functionalized TiO2 thin films (Au/TiO2 and TiO2/Au) as a potential photoelectrode to regulate the charge carrier generation-and transportation by creating progressive localized electric field and surface plasmon-resonance platforms. Firstly, XRD results suggests that significant structural changes in the preferred (101) plane of anatase TiO2 with respect to Au (111). Furthermore, we have carried out XPS spectra to confirm the presence of Ti, O and Au anchoring sites. Moreover, FESEM images revealed successful distribution of Au clusters on and under the TiO2 surface. Interestingly, optical transmittance was effectively varied by the Au clusters position. As a result, C-V, I-V and I-t studies accurately demonstrated the establishing of localized electric field at the Au cluster-TiO2 interface, which yielded remarkable charge carrier generation and long-term stability by the Au/TiO2 photo electrode than TiO2/Au. As evidenced from the above results, the tailored Au/TiO2 sequence exhibits superior PEC water splitting activity through establishing the trapping of incident light due to the confinement of Au clusters under the TiO2. Comprehensively, the optimization of the above findings represents an interesting route to develop the novel energy conversion devices for water splitting application.