Iron dopant in zinc oxide nanorods-based photoanode using chemical bath deposition method for photoelectrochemical water-splitting

Abstract

Utilization of zinc oxide as a photoanode in photoelectrochemical (PEC) water splitting is cost-effective and environmentally friendly choices compared to noble metals, although some enhancements are required to address the limited light absorption and significant charge recombination. Iron as metal doping and nanorod structure, on the other hand, offers solutions to overcome these limitations. An in-depth study employing iron-doped zinc oxide nanorods using various concentrations of iron fabricated through a chemical bath deposition (CBD) method due to its high-quality results and scale-up feasibility, shows enhanced structures, electrical characteristics, optical properties, charge transfer speed, and overall effectiveness in converting solar energy to hydrogen. This dopant was effectively integrated into the photoanode, resulting in a reduction of the bandgap to 3.19 eV and the creation of nanorods that are both thinner and longer. The photocurrent density for the oxygen evolution reaction (OER) is 6 mA/cm2, and for the hydrogen evolution reaction (HER), it is 1.3 mA/cm2. Electrochemical Impedance Spectroscopy shows lower resistance and an improved diffusion coefficient, resulting in reduced energy requirements for hydrogen production. The solar-to-hydrogen efficiency is also reported at 4.7%. This method shows potential for future progress and possible performance improvements.