Sustained, Photocatalytic CO₂ Reduction to CH₄ in a Continuous Flow Reactor by Earth-Abundant Materials: Reduced Titania-Cu₂O Z-Scheme Heterostructures
Photocatalytic conversion of CO₂ and water vapor to hydrocarbon fuels is a promising approach for storing solar energy while reducing greenhouse gas emissions. However, still certain issues including low product yields, limited photocatalyst stability and relatively high cost have hampered practical implementation of this technology. In the present work, a unique strategy is adopted to synthesize a stable, and inexpensive photocatalyst comprised of earth-abundant materials: a reduced titania-Cu₂O Z-scheme heterostructure. Under illumination for 6 h, the optimized reduced titania-Cu₂O photocatalyst enables 0.13 % photoreduction of highly diluted CO₂ with water vapors to 462nmol g⁻¹ of CH₄ while showing excellent stability over seven testing cycles (42 h). Our studies show the Z-scheme inhibits Cu₂O photocorrosion, while its synergistic effects with reduced titania result in sustained CH₄ formation in a continuous flow photoreactor. To the best of our knowledge stability exhibited by the reduced titania-Cu₂O Z-scheme is the highest for any Cu-based photocatalyst.
© 2020 Elsevier B.V. Received 19 May 2020, Revised 4 July 2020, Accepted 15 July 2020, Available online 16 July 2020. The authors thankfully acknowledge the support of the Ministry of Science and ICT (2017R1E1A1A01074890). This research was also supported by the Technology Development Program to Solve Climate Changes of the National Research Foundation (NRF) funded by the Ministry of Science and ICT (2015M1A2A2074670) and by Flux Photon Corporation. The authors declare that there are no conflicts of interest.
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