A hierarchical z-scheme CdS–WO₃ photocatalyst with enhanced CO₂ reduction activity

Jian JIN, Jiaguo YU, Daipeng GUO, Can CUI, Wing Kei HO

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Abstract

The development of an artificial photosynthetic system is a promising strategy to convert solar energy into chemical fuels. Here, a direct Z-scheme CdS–WO₃ photocatalyst without an electron mediator is fabricated by imitating natural photosynthesis of green plants. Photocatalytic activities of as-prepared samples are evaluated on the basis of photocatalytic CO₂ reduction to form CH₄ under visible light irradiation. These Z-scheme-heterostructured samples show a higher photocatalytic CO₂ reduction than single-phase photocatalysts. An optimized CdS–WO₃ heterostructure sample exhibits the highest CH₄ production rate of 1.02 μmol h⁻¹ g⁻¹ with 5 mol% CdS content, which exceeds the rates observed in single-phase WO₃ and CdS samples for approximately 100 and ten times under the same reaction condition, respectively. The enhanced photocatalytic activity could be attributed to the formation of a hierarchical direct Z-scheme CdS–WO₃ photocatalyst, resulting in an efficient spatial separation of photo-induced electron–hole pairs. Reduction and oxidation catalytic centers are maintained in two different regions to minimize undesirable back reactions of the photocatalytic products. The introduction of CdS can enhance CO₂ molecule adsorption, thereby accelerating photocatalytic CO₂ reduction to CH₄. This study provides novel insights into the design and fabrication of high-performance artificial Z-scheme photocatalysts to perform photocatalytic CO₂ reduction. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Original languageEnglish
Pages (from-to)5262-5271
JournalSmall
Volume11
Issue number39
Early online dateAug 2015
DOIs
Publication statusPublished - 2015

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Citation

Jin, J., Yu, J., Guo, D., Cui, C., & Ho, W. (2015). A hierarchical z-scheme CdS–WO₃ photocatalyst with enhanced CO₂ reduction activity. Small, 11(39), 5262-5271.

Keywords

  • CdS
  • Hierarchical
  • Photocatalytic CO₂ reduction
  • WO₃ hollow spheres
  • Z-scheme photocatalysts