Atmosphere-dependent hydrogenation of TiO2 nanotubes synthesized via one- and two-step anodization for enhanced photoelectrochemical performance

• TSA-H shows only 4% photocurrent decay after prolonged UV illumination. • Two-step anodized TiO 2 nanotubes exhibit superior photocurrent stability. • Defect engineering in pure H 2 boosts donor density to 3.51 × 10 22 cm −3 . • PEC performance is more sensitive to H 2 atmosphere than anodization method. • XPS confirms highest oxygen vacancies in TSA-H, enhancing charge transport. This study investigates the influence of hydrogenation atmosphere on the physicochemical and photoelectrochemical