Recent progress in development of photocatalysts for visible-light-driven water splitting

Abstract

Water splitting using semiconductor photocatalysts under solar light has attracted much attention as one of the promising methods for clean hydrogen production by harvesting solar light energy. The effective utilization of visible light is one of the most important challenges to achieve the desired efficiency in practical application. In this review, we overview recent progress in development of semiconductor photocatalysts for water splitting under visible light. We firstly introduce early studies on photocatalytic water splitting using oxide semiconductors under UV light, along with the importance and difficulty of achieving visible-light-driven water splitting. Then, we introduce some successful examples of visible-light-driven water splitting using a single photocatalyst (i.e. a one-step photoexcitation system). Finally, some examples of visible-light-driven water splitting via two-step photoexcitation systems, so-called Z-scheme systems inspired by natural photosynthesis, will be introduced, especially focusing on such systems with visible-light-responsive non-oxide and mixed-anion photocatalysts.