Na-deposited TiO2 nanotubes for photo electrochemical water splitting with enhanced activity – A novel approach

Abstract

Hydrogen generation using sunlight as an energy source in a photoelectrochemical (PEC) cell is one of the most challenging tasks, and it is an environmentally friendly method for sustainable energy generation. In this work, Na-doped TiO2 nanotubes (Na-TNT) are used as the photoanode and platinum as a cathode for photoelectrochemical hydrogen generation under AM 1.5 G light illumination, generating a photocurrent of up to 0.12 mA cm−2 at 1.23 V (vs. reversible hydrogen electrode (RHE)), which is six times greater than pristine TiO2 nanotubes (TNT), which is found to be 0.02 mA cm−2. The Na-TNTs were prepared via the effortless thermal treatment of anodized TNT sheets over sodium chloride (NaCl) in a furnace at 450 °C, improving the light absorption and decreasing the recombination rate. The reason for enhanced activity upon introducing Na was investigated with structural, optical, and electrochemical studies.