In@CdS sensitized TiO2 nano-rod for enhanced photocatalytic and photoelectrochemical performance under visible light

Abstract

Titanium dioxide (TiO2) nano-rod are synthesized by one step hydrothermal method while cadmium sulphide (CdS) and Indium (In) doped CdS quantum dots (QDs) are sensitized on the surface of TiO2 nano-rod by using successive ionic layer adsorption and reaction (SILAR) approach. Characterization of this material was done using XRD, XPS, FE-SEM, EDX, HR-TEM, Raman, UV-DRS, PL, EPR. XRD pattern attributed that the preferential orientation of TiO2 grains is along the (101) plane perpendicular to the FTO substrate. XRD pattern also reveals the sensitization of CdS QDs in form of hexagonal CdS QDs and doping of In into CdS QDs. FE-SEM analysis suggests that the TiO2 nano-rod are uniform, thick and grown vertically on the FTO plate. Detailed investigations of the ‘In’ sensitization in 2%In-CdS/TiO2 were carried out by HR-TEM studies. UV-DRS analysis shows decrease in the band gap energy as doping of In in CdS/TiO2 nano-rod increases. EPR analysis reveals the presence of oxygen vacancies due to sensitization of ‘In’ on CdS/TiO2 matrix. The photoelectrochemical and photocatalytic performance of In doped CdS QDs embellished on the surface of TiO2 nano-rod photoanode was investigated by varying the concentration of In. The photo electrochemical (PEC) and photocatalytic H2 generation performance under natural sunlight of as prepared photoanode are explored in terms of photocurrent density and amount of H2 generation. 2% In-CdS/TiO2/Pt/FTO nano-rod shows highest 22.12 ml/h/g of hydrogen generation and photocurrent density of 4.78 (mA/cm2).