Graphitic carbon nitride (g-C3N4) and TiO2 nanotubes (TNT) have made significant breakthroughs in the field of photocatalysis because of their unique features, such as environmental friendliness, low cost and good stability. Herein, we present the improved photo-electrochemical performance under AM 1.5G irradiation of three different photoanodes based on TNT coated with g-C3N4 via the effortless thermal treatment of anodized TNT sheets over melamine (TNT-M), urea (TNT-U) and dicyanamide (TNT -D). A maximum photocurrent of up to 0.14 mA cm−2 at 1.23 V (vs. RHE) is obtained under illumination using AM 1.5 G light source for TNT-D, which is ten times greater than pristine TNT (0.014 mA cm−2). A good photoelectrochemical stability with efficient charge transfer is observed, and electrochemical impedance spectra reveal that better photoelectrochemical performance is due to the reduced electron-hole pair recombination via the development of heterojunction between TNT and g-C3N4 compared to the bare-TNT electrode. © 2024 Korean Physical Society

Keywords: graphitic carbon nitride, Photo electrocatalysis, TiO₂ nanotubes, Water splitting