Hydrogen Generation by Photoelectrochemical Splitting of Water by Using CdS/TiO_2 Nanotube Photoanode

摘要

In this study, hydrogen is generated from water via photoelectrochemical (PEC) process by using CdS/TiO_2 photoanode, which is obtained in sequence chemical bath deposition (s-CBD) process. Experimentally, the CdS was deposited on TiO_2 NTAs in s-CBD process. First, the TiO_2 NTAs is immersed in Cd(NO_3)_2 and Na_2S solution subsequently several cycles followed by annealing to get CdS/TiO_2 photoanode. In this work, the factors were studied including immersion cycle, annealing temperature and UV illumination. The surface morphology, crystalline structure and CdS amount were characterized by SEM and XRD. The photoactivities of CdS/TiO_2 photoanodes and hydrogen generation rate were investigated by PEC splitting of water. The results showed that the photoanode annealing in air at 300℃ had the highest photoactivity and the crystalline structure of CdS was composed of zinc blende and a small amount of wurtzite. The saturated current density was 6.163 mA/cm and the maximum photoelectrochemical conversion was 4.45 % under Xenon lamp (I_0 = 100 mW/cm~2) illumination. Besides, the photoactivity of CdS(UV)/TiO_2 prepared under UV (λ_(max)=253.7 nm) illumination was reduced. This was probably due to the aggregation of CdS. To sum up, the CdS/TiO_2 photoanodes for photoelectrochemical splitting water could be a high prospective process of the energy source.