High performance NaNbO3/CdS/Bi2S3 ternary heterostructured photoelectrocatalysts for efficient OER activity
Umar Farooq, Tokeer Ahmad
Abstract
CdS and Bi 2 S 3 decorated NaNbO 3 samples were prepared by hydrothermal and linker assisted combinatory approach using oleic acid and starch as surface capping agents. Successful deposition of small sized and high surface area CdS and Bi 2 S 3 over the smooth surface of large sized NaNbO 3 was carried out. To prepare heterostructures of NaNbO 3 different weight ratios of CdS and Bi 2 S 3 were employed. The as-prepared heterostructures were subsequently characterized by X-ray diffraction (XRD), UV–visible diffused reflectance spectroscopy (DRS), Field Emission Scanning Electron Microscopy (FESEM), Brauner-Emmette-Teller (BET) surface area studies, and X-ray Photoelectron spectroscopy (XPS) studies. As-developed heterostructures were investigated as photoelectrocatalysts (PEC) for oxygen evolution reaction (OER) from water splitting reaction. From PEC OER investigations, it was observed that heterostructured sample (HS-2) with 10 wt % CdS and 5 wt% Bi 2 S 3 show efficient and enhanced PEC OER activity as compared to the pristine parent compounds. The maximum current density of 11.9 mA/cm 2 with low onset potential of 0.89 V and low tafel slope of 107 mV/day was observed in HS-2 sample under white light illumination. The efficient and enhanced activity was attributed to red shift in the absorption of NaNbO 3 sample and efficient charge separation taking place due to deposition of CdS and Bi 2 S 3 over the surface of NaNbO 3 .