Hydrogen from photo-catalytic water splitting process: A review

Recently, great attention has been focused on hydrogen as a potential energy vector and on the use of water-splitting technology as a clean and renewable means to generate hydrogen using solar energy. Numerous attempts have been made to develop photo-catalysts that work not only under UV light but also under visible-light illumination to efficiently utilize solar energy. One of the most well-known photo-catalysts used in the past forty years is TiO2. Despite having excellent characteristics as a photo-catalyst, TiO2 also has some limitations. This paper presents modification techniques that can be used to improve the drawbacks of TiO2, such as the addition of sacrificial agents into the solution. The role of sacrificial agents, such as methanol and several recent achievements by previous researchers have also been included.