Doping rare earth cations with an additional chemical reduction synergistically weakened the photocatalytic performance of ceria

Junshan Zhang; Xisong Mao; Yuanpei Lan; Junqi Li; Chaoyi Chen; Jian Yang; Wei Zhang; Arun Murali; Li Liu; Qin Wang

doi:10.1007/s11356-023-25981-y

Doping rare earth cations with an additional chemical reduction synergistically weakened the photocatalytic performance of ceria

Environ Sci Pollut Res Int. 2023 Apr;30(17):51356-51367. doi: 10.1007/s11356-023-25981-y. Epub 2023 Feb 21.

Authors

Junshan Zhang^{1

2}, Xisong Mao^{1

2}, Yuanpei Lan^{3

4}, Junqi Li^{1

2}, Chaoyi Chen^{1

2}, Jian Yang⁵, Wei Zhang^{1

2}, Arun Murali⁶, Li Liu^{1

2}, Qin Wang^{1

2}

Affiliations

¹ Department of Metallurgical Engineering, College of Materials and Metallurgy, Guizhou University, Huaxi, Guiyang, 550025, Guizhou, China.
² Guizhou Province Key Laboratory of Metallurgical Engineering and Process Energy Saving, Guiyang, 550025, Guizhou, China.
³ Department of Metallurgical Engineering, College of Materials and Metallurgy, Guizhou University, Huaxi, Guiyang, 550025, Guizhou, China. yplan@gzu.edu.cn.
⁴ Guizhou Province Key Laboratory of Metallurgical Engineering and Process Energy Saving, Guiyang, 550025, Guizhou, China. yplan@gzu.edu.cn.
⁵ College of Materials Science and Engineering, Chongqing University, Shapingba, Chongqing, 400030, China.
⁶ Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT, 84112, USA.

PMID: 36809624
DOI: 10.1007/s11356-023-25981-y

Abstract

Chemical reducing or rare earth cations (RE) doping was normally employed to promote the photocatalytic performance of ceria, aimed to evaluate their cooperation influences, ceria was obtained by decomposing homogenously RE (RE = La, Sm, and Y)-doped CeCO₃OH in H₂. XPS and EPR results evidenced that the excess oxygen vacancies (OVs) were formed in RE-doped CeO₂ compared to the un-doped ceria. However, all the RE-doped ceria unexpectedly showed an impeded photocatalytic activity towards to methylene blue (MB) photodegradation. The 5% Sm-doped ceria had the best MB photodegradation ratio of 81.47% after 2-h reaction in all RE-doped samples, which was lower than that of 87.24% for the un-doped ceria. After doping RE cations and chemical reducing, the band gap of ceria were almost narrowed, while the PL spectra and photo-electro characterizations indicated that the separation efficiency of photo-excited e^-/h⁺ (electrons/holes) was reduced. The RE dopants and formed excess OVs including inner and surface OVs was proposed to promote the recombination of e^-/h⁺ which further hindered the generation of active species of ·O₂^- and ·OH, and finally weakened the photocatalytic activity of ceria.

Keywords: CeCO3OH; Ceria; Oxygen vacancies; Photocatalysis; Rare earths doping.

MeSH terms

Cations
Cecum*
Electrons
Metals, Rare Earth*
Methylene Blue
Oxygen

Substances

Cations
Metals, Rare Earth
Methylene Blue
Oxygen

Grants and funding

52164025/National Natural Science Foundation of China