High performance carbon/silica co-decorated TiO₂ nanotubes for visible-light driven water splitting

Graphical abstract: Using amino-propyl-triethoxy silane (KH570) as silane couplers, a novel carbon/silica dots co-decorated TiO₂ nanotube (CS@TNT) is prepared through silane modification and thermal calcination approach. The CS@TNT retains its tubular morphology at as high as 500 °C, and presents a high activity (0.096 mmol/h) towards photocatalytic water splitting. - Highlights: • A novel route of silane-modification then H₂ calcination is developed. • Carbon and silica dots are highly dispersed on the TNT. • The CS@TNT retains its tubular morphology at as high as 500 °C. • A high activity (0.096 mmol/h) is achieved towards photocatalytic water splitting. • Effect of carbon/silica modification is investigated in detail. - Abstract: A novel carbon/silica co-decorated TiO₂ nanotubes (TNT) photocatalyst (CS@TNT) was prepared for visible light driven water splitting by a facile two-steps process of amino-propyl-triethoxy silane modification and calcination. Structure characterizations (XRD, STEM, XPS, UV–vis spectra and PL spectra) revealed that the silica and carbon dots were homogeneously dispersed on the surfaces of TNT. The introduced silica resists crystallization of TNT, and keeps the tubular morphology intact and high surface area; the co-existence of carbon dots increases the visible light absorbance capacity and promotes the electron-hole separation efficiency. The CS@TNT preserves intact tubular morphology during calcination (500 °C), and a high activity of 0.096 mmol/h is achieved, which was 1.7 times higher than that of actual catalyst made of gold nanoparticles loading on TNT.