Enhancing the solar hydrogen generation performance of nickel-oxide nanostructured thin films doped with molybdenum

Abstract

Using technology to store solar energy as hydrogen fuel (H2) on a scale corresponding to global energy use is a viable way to alleviate the energy crisis and environmental deterioration. This research deals with the manufacture of thin films prepared from nickel oxide (NiO) and their use in the photoelectrochemical (PEC) water-splitting process to produce green H2 as a clean energy fuel. Herein, pure and Mo-doped NiO thin films were successfully prepared using a straightforward sputtering method at different radio frequency (RF) power for the Mo target from 0 to 50 watt. x-ray diffraction (XRD), atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS), energy dispersive x-ray spectroscopy (EDX), and UV–vis spectroscopy techniques were used to analyze the structural, morphological, chemical composition, and optical characterization of the prepared films. The PEC behaviours for green H2 production and the impedance spectroscopy measurements were also investigated for all samples. In PEC measurements, the 50 W sample showed the highest PEC performance. At −0.4V versus RHE, the 50 W sample verified the highest value for the photocurrent density of about 1.7 mA cm−2 which was approximately four times more than the pure NiO sample. The applied biased photon-to-current conversion efficiency and incident photon-to-current conversion efficiency were also estimated. This research provided a fresh viewpoint on the design of highly active NiO-based photo-catalysts for the production of green H2 powered by solar light.