University of Oulu

Chem. Mater. 2023, 35, 20, 8607–8620

Cs₃Bi₂Br₉/g-C₃N₄ direct Z-scheme heterojunction for enhanced photocatalytic reduction of CO₂ to CO

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Author: Baghdadi, Yasmine1; Temerov, Filipp1,2; Cui, Junyi1;
Organizations: 1Department of Chemical Engineering and Centre for Processable Electronics, Imperial College London, London SW7 2AZ, United Kingdom
2Nano and molecular system (NANOMO) research unit, University of Oulu, Oulu 90570, Finland
3Department of Graduation in Chemical Engineering, Universidade Federal do Rio Grande do Norte/UFRN, 59.078-970 Rio Grande do Norte, Brazil;
4Barrer Centre, Department of Chemical Engineering, Imperial College London, London SW7 2AZ, United Kingdom
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 11.2 MB)
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Language: English
Published: American Chemical Society, 2023
Publish Date: 2023-11-03


Lead-free halide perovskite derivative Cs₃Bi₂Br₉ has recently been found to possess optoelectronic properties suitable for photocatalytic CO₂ reduction reactions to CO. However, further work needs to be performed to boost charge separation for improving the overall efficiency of the photocatalyst. This report demonstrates the synthesis of a hybrid inorganic/organic heterojunction between Cs₃Bi₂Br₉ and g-C₃N₄ at different ratios, achieved by growing Cs₃Bi₂Br₉ crystals on the surface of g-C₃N₄ using a straightforward antisolvent crystallization method. The synthesized powders showed enhanced gas-phase photocatalytic CO₂ reduction in the absence of hole scavengers of 14.22 (±1.24) μmol CO g–1 h–1 with 40 wt % Cs₃Bi₂Br₉ compared with 1.89 (±0.72) and 5.58 (±0.14) μmol CO g–1 h–1 for pure g-C₃N₄ and Cs₃Bi₂Br₉, respectively. Photoelectrochemical measurements also showed enhanced photocurrent in the 40 wt % Cs₃Bi₂Br₉ composite, demonstrating enhanced charge separation. In addition, stability tests demonstrated structural stability upon the formation of a heterojunction, even after 15 h of illumination. Band structure alignment and selective metal deposition studies indicated the formation of a direct Z-scheme heterojunction between the two semiconductors, which boosted charge separation. These findings support the potential of hybrid organic/inorganic g-C₃N₄/Cs₃Bi₂Br₉ Z-scheme photocatalyst for enhanced CO₂ photocatalytic activity and improved stability.

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Series: Chemistry of materials
ISSN: 0897-4756
ISSN-E: 1520-5002
ISSN-L: 0897-4756
Volume: 35
Issue: 20
Pages: 8607 - 8620
DOI: 10.1021/acs.chemmater.3c01635
Type of Publication: A1 Journal article – refereed
Field of Science: 114 Physical sciences
Funding: M.D. and S.E. acknowledge the funding of UK Engineering and Physical Sciences Research Council (EPSRC) provided via Grant EP/S030727/1. F.T. acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programs (Grant Agreement No. 101002219). Y.B. and I.I. want to acknowledge Imperial College London for the Chemical Engineering Departmental Scholarship.
EU Grant Number: (101002219) CATCH - Cross-dimensional Activation of Two-Dimensional Semiconductors for Photocatalytic Heterojunctions
Dataset Reference: The data that support the findings of this study are openly available in a research data repository at:
Copyright information: © 2023 The Authors. Published by American Chemical Society. This publication is licensed under CC-BY 4.0.