Enhancing the visible-light sensitive photocatalysis of anatase TiO2 through surface-modification

This study is focused on developing visible-light sensitive anatase TiO2 photocatalysts rather than the conventional UV-sensitive photocatalysts. We have adopted a surface modification technique using sodium borohydride (NaBH4) chemical treatment. Thermal treatment under remarkably, favourable ambient air conditions were employed in this work instead of the previously reported inert gas or vacuum conditions, making it noteworthy. The synthesized surface-modified anatase TiO2 is yellow in colour and has a crystalline core and disordered shell structure. The surface-modified sample was enriched with photocatalytically active shallow-traps due to the presence of Ti3+ ions and singly ionized oxygen vacancies (Vo+). This surface-modified TiO2 sample showed enhanced photodegradation of organic pollutants under visible light. The photocatalytic performances of the pristine and surface-modified samples were compared with the commercially available standard photocatalyst, Degussa P25. Notably, the surface-modified sample showed the highest degradation of Rhodamine B (RhB) dye, with a rate constant of 6.11 × 10–3 min−1. In contrast, the corresponding values for the pristine sample and Degussa P25 catalysts were only 4.15 × 10–3 and 1.92 × 10–3 min−1, respectively. Our study summarises that surface modification is an effective strategy for developing efficient visible-light-sensitive TiO2 photocatalysts.