High-performance TiO2/Ti photoanode using dielectric barrier discharge plasma for efficient solar water-splitting

TiO2 is one of the most promising photoanodes in photoelectrochemical (PEC) water-splitting due to its chemical stability, corrosion resistance, and cost-effectiveness. However, the TiO2 nanoparticles with high surface area and fast electron transfer have been grown on a Ti foil substrate through dielectric barrier discharge (DBD) plasma using Ar/O2 mixture gas. Optical emission spectroscopy (OES) was utilized to detect the reactive species existing in DBD plasma discharge during the process of treating titanium foil. The field emission scanning electron microscopy (FE-SEM) images revealed the morphology of TiO2 nanoparticles aggregated to form a microwire structure on a Ti foil substrate. The X-ray diffraction (XRD) patterns agreed with the anatase phase of the monoclinic TiO2 nanoparticles. PEC measurement showed that the synthesis of TiO2 nanoparticles using Ar/ O2 DBD plasma for a duration of 3-min resulted in the highest photocurrent response. This response reached the highest photocurrent density of 1.92 mA/cm2 at 1.23 V vs. RHE (versus a reversible hydrogen electrode). The photoconversion efficiency (& eng;) improved from 1.31 to 1.85 as the plasma treatment time increased from 1 min to 3 min. The remarkable performance can be attributed to the large surface area of the nanoparticles and their low charge resistance. Transient photocurrent-time curves are utilized to demonstrate the stability and repeatability of TiO2 nanoparticles. Ar/O2 DBD plasma treatment is a promising superior method to enhance the functionality of TiO2 in PEC water-splitting applications, as demonstrated in the literature comparison.