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A Hierarchical Z-Scheme α-Fe<sub>2</sub> O<sub>3</sub> /g-C<sub>3</sub> N<sub>4</sub> Hybrid for Enhanced Photocatalytic CO<sub>2</sub> Reduction.

Author
Abstract
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The challenge in the artificial photosynthesis of fossil resources from CO2 by utilizing solar energy is to achieve stable photocatalysts with effective CO2 adsorption capacity and high charge-separation efficiency. A hierarchical direct Z-scheme system consisting of urchin-like hematite and carbon nitride provides an enhanced photocatalytic activity of reduction of CO2 to CO, yielding a CO evolution rate of 27.2 µmol g-1 h-1 without cocatalyst and sacrifice reagent, which is >2.2 times higher than that produced by g-C3 N4 alone (10.3 µmol g-1 h-1 ). The enhanced photocatalytic activity of the Z-scheme hybrid material can be ascribed to its unique characteristics to accelerate the reduction process, including: (i) 3D hierarchical structure of urchin-like hematite and preferable basic sites which promotes the CO2 adsorption, and (ii) the unique Z-scheme feature efficiently promotes the separation of the electron-hole pairs and enhances the reducibility of electrons in the conduction band of the g-C3 N4 . The origin of such an obvious advantage of the hierarchical Z-scheme is not only explained based on the experimental data but also investigated by modeling CO2 adsorption and CO adsorption on the three different atomic-scale surfaces via density functional theory calculation. The study creates new opportunities for hierarchical hematite and other metal-oxide-based Z-scheme system for solar fuel generation.

Year of Publication
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2018
Journal
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Advanced materials (Deerfield Beach, Fla.)
Date Published
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2018
ISSN Number
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0935-9648
URL
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http://dx.doi.org/10.1002/adma.201706108
DOI
:
10.1002/adma.201706108
Short Title
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Adv Mater
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