Particulate photocatalytic reactors with spectrum-splitting function for artificial photosynthesis.

Area of Science:

• Photocatalysis
• Solar Energy Conversion
• Chemical Engineering

Background:

• Efficient solar energy utilization is crucial for sustainable chemical production.
• Spectrum splitting offers a promising approach to maximize light absorption in photocatalytic systems.
• Particulate photocatalytic reactors are key for artificial photosynthesis.

Purpose of the Study:

• To apply spectrum splitting to particulate photocatalytic reactors for enhanced solar energy utilization.
• To investigate novel reactor configurations for improved solar-to-chemical conversion efficiencies.
• To model carrier supply processes and determine practical efficiency limits.

Main Methods:

• Implementing spectrum splitting using multiple cells with photocatalyst particles of varying bandgaps.
• Designing and comparing two spectrum-splitting reactor configurations: wide-gap/narrow-gap Z-scheme (WG/Z) and wide-gap/middle-gap/narrow-gap (WG/MG-NG).
• Developing a new model for carrier supply from semiconductor photocatalysts to active sites.

Main Results:

• Spectrum splitting is feasible with optically series-arranged cells containing different bandgap photocatalysts.
• Small photocatalyst particles (≤20 nm) enable efficient absorption of high-energy photons in wide-gap compartments and low-energy photons in narrow-gap compartments.
• Spectrum-splitting reactors achieved 1.5-1.6 times higher efficiencies for H2 and CO production compared to conventional Z-scheme reactors.
• The WG/MG-NG configuration demonstrated the highest efficiency and spectral robustness among the tested designs.

Conclusions:

• Spectrum-splitting reactors represent a promising advancement for artificial photosynthesis.
• The proposed WG/Z and WG/MG-NG configurations offer improved efficiency and robustness against solar spectrum variations.
• Further material development and reactor optimization can lead to highly efficient and practical solar-to-chemical conversion systems.