High-throughput synthesis and screening of titania-based photocatalysts

Titanium dioxide is widely known as a prominent photocatalyst material and research in this area has increased substantially over the last decades. However, the photoactivity of TiO2 is hindered by several factors, such as a relatively high photogenerated electron-hole recombination rate and a wide bandgap of ∼3.2 eV, rendering it inactive under visible light. Approaches to optimize the TiO2 photocatalyst, either by altering its morphological or chemical properties, have been conducted for many years, yet further modification of this semiconductor has the potential to yield photocatalysts with excellent properties and higher photocatalytic activity. This could be effectively explored using combinatorial synthesis coupled with high-throughput characterization approaches. Such an approach has been widely applied for the discovery of new functional materials, including photocatalysts. By using high-throughput synthesis and characterization technology, preparation and screening of materials on small sample scales can be accelerated; hence, new TiO2-based photocatalysts with enhanced photocatalytic activity can be acquired more rapidly. Additionally, the large database of materials being systematically examined will greatly build our fundamental understanding of the relation between materials structure/composition and photocatalytic activity. This review details various high-throughput syntheses and characterization techniques applied to improve the photocatalytic properties of TiO2 materials and discuss several challenges that have been raised or may be encountered in the future when using this approach.