Solar-driven hydrogen production from a water-splitting cycle based on carbon-TiO2 nano-tubes

Abstract

This study illustrates the structuring of the TiO2 within carbon nano-tubes to enhance the solar-driven production of hydrogen (S-DPOH) via water splitting. The newly developed Carbon-TiO2 nano-tubes (C-Ti-NTs) aimed at improving the practical applications of TiO2 composites under natural solar irradiation conditions, enhancing the absorption of UV and VIS-light, reduces the required bandgap energy and decreases the chance for photo-induced-charges recombination. The C-Ti-NTs were prepared using an alkaline hydrothermal method, characterized using different state of art techniques and tested for the S-DPOH via water splitting. Adding a carbon layer on the surface of TiO2 nano-tube with a thickness of ~1 nm reduced the bandgap of the C-Ti-NTs 0.88 eV, improved the quantum efficiency under UV light to 100%, enhanced the absorption capacity under VIS-light and extremely suppressed the charge recombination. The S-DPOH achieved a cumulative production of hydrogen (CPOH) during 50 h of solar irradiation of 43.75 mmol at a rate RPOH?of H2 production of 38.66 0.655 mmol/h.g, which is 1.5 folds higher than the maxim rate reported for pure TiO2-based photocatalyst. The obtained results confirmed the contribution of TiO2 for the production of hydrogen, which is expected to open a new insight towards the importance of architectural design and band engineering in the practical development of sustainable solar energy harvesting applications.