Integration of redox cocatalysts for artificial photosynthesis

Solar fuels and chemical production using photosynthetic devices by harnessing solar energy remains an attractive prospect owing to its being a potential alternative to fossil feedstocks, though such artificial photosynthetic systems for direct solar-to-chemical conversion are still far from industrial applications as a consequence of emergent challenges that may be well addressed by the exploration of integrated photocatalysis devices with enhanced activity, selectivity, and stability. Simultaneously embedding dual cocatalysts onto photocatalysts aims to tackle these limitations of artificial photosynthesis initiated by the bare photocatalyst while offering an opportunity to realize their synergistic operations. In this review, we summarize the essential design principles and emerging configurations of dual cocatalysts, and provide a side-by-side comparison to reveal their strengths and deficiencies. In parallel, we discuss how to choose a pair of redox cocatalysts for a specific photocatalytic redox reaction, and how some key lessons that have emerged from the relevant studies can be applied into further investigations for fuels and chemicals generation. Finally, we outline the remaining challenges and potential advances in the discovery of a robust and renewable artificial photosynthesis system. This review summarizes the design principle, emerging configurations, and photocatalytic applications of redox cocatalysts, and offers insights and perspectives on this topic.