Issue

Vol. 17 (2025)

BiOCl Atomic Layers with Electrons Enriched Active Sites Exposed for Efficient Photocatalytic CO2 Overall Splitting

https://doi.org/10.1007/s40820-025-01723-2
Ting Peng
International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, People’s Republic of China
Yiqing Wang
International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, People’s Republic of China
Chung‑Li Dong
Department of Physics, Tamkang University, New Taipei City 25137, Taiwan, People’s Republic of China
Ta Thi Thuy Nga
Department of Physics, Tamkang University, New Taipei City 25137, Taiwan, People’s Republic of China
Binglan Wu
International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, People’s Republic of China
Yiduo Wang
International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, People’s Republic of China
Qingqing Guan
International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, People’s Republic of China
Wenjie Zhang
International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, People’s Republic of China
Shaohua Shen
International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, People’s Republic of China

Corresponding Author: Shaohua Shen

shshen_xjtu@mail.xjtu.edu.cn

Nano-Micro Letters, Vol. 17 (2025), Article Number: 223

Abstract

Given the limited exposure of active sites and the retarded separation of photogenerated charge carriers in those developed photocatalysts, photocatalytic CO2 splitting into value-added chemicals has suffered from the poor activity and remained in great challenge for real application. Herein, hydrothermally synthesized BiOCl with layered structure (BOCNSs) was exfoliated into thickness reduced nanosheets (BOCNSs-w) and even atomic layers (BOCNSs-i) via ultrasonication in water and isopropanol, respectively. In comparison with the pristine BOCNSs, the exfoliated BiOCl, especially BOCNSs-i with atomically layered structure, exhibits much improved photocatalytic activity for CO2 overall splitting to produce CO and O2 at a stoichiometric ratio of 2:1, with CO evolution rate reaching 134.8 µmol g−1 h−1 under simulated solar light (1.7 suns). By surpassing the photocatalytic performances of the state-of-the-art BilOmXn (X: Cl, Br, I) based photocatalysts, the CO evolution rate is further increased by 99 times, reaching 13.3 mmol g−1 h−1 under concentrated solar irradiation (34 suns). This excellent photocatalytic performance achieved over BOCNSs-i should be benefited from the shortened transfer distance and the increased built-in electric field intensity, which accelerates the migration of photogenerated charge carriers to surface. Moreover, with oxygen vacancies (VO) introduced into the atomic layers, BOCNSs-i is exposed with the electrons enriched Bi active sites that could transfer electrons to activate CO2 molecules for highly efficient and selective CO production, by lowering the energy barrier of rate-determining step (RDS), *OH + *CO2− → HCO3−. It is also realized that the H2O vapor supplied during photocatalytic reaction would exchange oxygen atoms with CO2, which could alter the reaction pathways and further reduce the energy barrier of RDS, contributing to the dramatically improved photocatalytic performance for CO2 overall splitting to CO and O2.


Highlights:
1 BiOCl atomic layers (BOCNSs-i) were prepared by exfoliating hydrothermally synthesized BiOCl (BOCNSs) via ultrasonication in isopropanol for efficient photocatalytic CO2 overall splitting to CO and O2.
2 The obtained BOCNSs-i photocatalyst exhibits a distinctly improved photocatalytic performance to stoichiometrically produce CO and O2 at the ratio of 2:1, with the CO evolution rate reaching 134.8 µmol g−1 h−1 under simulated solar light (1.7 suns) and reaching 13.3 mmol g−1 h−1 under concentrated solar irradiation (34 suns).
3 With the thickness of BiOCl photocatalyst reducing to atomic layers, the charge carrier transfer and separation were enhanced by shortened transfer distance and the increased built-in electric field intensity, and electrons enriched Bi sites were exposed for activating CO2 molecules.

Keywords

Photocatalysis CO2 overall splitting BiOCl atomic layers Charge separation
Peng, Ting, Yiqing Wang, Chung‑Li Dong, Ta Thi Thuy Nga, Binglan Wu, Yiduo Wang, Qingqing Guan, Wenjie Zhang, and Shaohua Shen. 2025. “BiOCl Atomic Layers With Electrons Enriched Active Sites Exposed for Efficient Photocatalytic CO2 Overall Splitting”. Nano-Micro Letters 17 (April):223. https://doi.org/10.1007/s40820-025-01723-2.
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