Coating of nickel-aluminum -LDH on titanium oxide nanotubes for pure hydrogen production by photoelectrochemical method

Photoelectrochemical Electrochemical Water Splitting (PEC-WS) process, utilizing solar irradiation energy, encompasses its own specific procedure. Due to the reduction of fossil energy sources and the necessity for clean fuels, this process has long been under scrutiny by researchers. In this regard, the utilization of semiconductor metal oxides with a nanometric structure as photocatalysts holds significance due to their ease of fabrication, capability to convert solar energy into charge carriers, and stability in chemical environments.In this project, arrays of titanium dioxide (TiO2) nanotubes were investigated for their use as photocatalysts in the water splitting process. Initially, an array of well-ordered titanium dioxide nanotubes (TNT) with fully open ends was synthesized through a two-step electrochemical anodic oxidation method on a titanium substrate. Subsequently, in order to enhance the photocatalytic activity, layer-by-layer nickel-aluminum layerd double hydroxide (LDH) nanoparticles were synthesized through a co-precipitation method and deposited onto the TiO2 nanotube arrays using electrostatic self-assembly at various voltages through an electrochemical deposition method. LDH nanostructures have gained considerable importance in recent years due to features such as their layered structure and high specific surface area.Apart from evaluating structural and optical characteristics like XRD, FE-SEM, and DRS, the performance of TNT samples in the Photocatalytic Electrochemical (PEC) water splitting process was examined using tests such as LSV, EIS, and Mott-Schottky, employing a solar simulator with AM1.5 lamp in the wavelength range of 380-1000 nm. The FE-SEM and XRD results indicated the successful formation of the anatase phase, and the successful deposition of LDH onto the openings of the TiO2 nanotubes. Additionally, the results from DRS demonstrated that with an increase in the band gap voltage by 0.3 eV compared to TNT, the band gap of LDH decreased. Nevertheless, the bandgap of titanium dioxide nanotubes is relatively wide, leading to issues such as limited utilization of light energy and facile recombination. Several approaches have been put forth to tackle this quandary, among which is the technique of doping novel materials to enhance surface activity, thereby ameliorating light absorption capacity. In this study, the initial synthesis of titanium dioxide nanotubes was achieved through anodic oxidation, followed by the electrodeposition of nickel-aluminum LDH onto them using the electrochemical method. Subsequently, characterization and photoelectrochemical investigations were carried out on the photoanodes for hydrogen production. In order to investigate the photoelectrochemical behavior of these electrodes, a linear scan voltammetry test was used. So, synthesis of TiO2/NiAl-LDH can improved the photoelectrochemical hydrogen generation