The investigation of CdS-quantum-dot-sensitized Ag-deposited TiO2 NRAs in photoelectrochemical hydrogen production


Tezcan F., Ahmad A., Yerlikaya G., Zia-ur-Rehman Z., PAKSOY H. Ö. , KARDAŞ G.

NEW JOURNAL OF CHEMISTRY, 2022 (Journal Indexed in SCI) identifier

  • Publication Type: Article / Article
  • Publication Date: 2022
  • Doi Number: 10.1039/d2nj00678b
  • Title of Journal : NEW JOURNAL OF CHEMISTRY

Abstract

Photoelectrochemical hydrogen production using photoelectrodes with sophisticated hierarchical architecture designs combined with effective photoactive materials, has been found to be an impressive route for achieving high photoelectrocatalytic efficiency. Here, we investigated the photoelectrocatalytic hydrogen production of CdS quantum dot (QD)-sensitized TiO2 nanorod arrays (NRAs) decorated with Ag nanoparticles synthesized using simple and cost-effective routes. TiO2 NRAs were grown on a fluorine-doped tin oxide (FTO) substrate via a hydrothermal method, followed by loading with Ag nanoparticles and deposition of CdS QDs using electrochemical and successive ionic layer adsorption and reaction (SILAR) approaches. In this arrangement, the Ag nanoparticles were found to be sandwiched between the photo-electron collector TiO2 and the photosensitizer CdS QDs that act as an electron relay, thus speeding the electron transport and improving photogenerated charge separation. CdS QDs significantly enhance the solar light absorption capability of the photoelectrode from the ultraviolet to the visible portion of the solar spectrum, improving the photoconversion efficiency. The surface morphology and optical properties of the as-prepared photoanodes were investigated using scanning electron microscopy and a UV-vis spectrometer. Scanning electron microscopy (SEM) images confirm that increasing the number of SILAR cycles caused agglomeration of the CdS QDs on the TiO2 NRAs surface. Photoelectrochemical hydrogen production performance was investigated with linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) under simulated solar light of 100 mW cm(-2). The LSV results confirm that the bare TiO2 NRAs exhibit a maximum photocurrent density of 0.17 mA cm(-2) at 1.23 V-RHE. However, upon the deposition of CdS QDs, an optimum photocurrent density of 0.623 mA cm(-2) at 1.23 V-RHE was observed for the 10 SILAR cycle samples, which was further improved to 0.931 mA cm(-2) at 1.23 V-RHE upon the introduction of Ag nanoparticles.