Lignosulfonate supported CeO2/Co3O4 nanocomposites with dual enzyme activity for colorimetric detection of catechol and smartphone-assisted visual ratiometric analysis

Aolin Bao; Bo Cao; Ruizhe Zhang; Yanan Ding; Haifeng Zhou; Guijiang Li; Gao-Chao Fan; Qingyun Liu

doi:10.1016/j.saa.2025.127125

Lignosulfonate supported CeO₂/Co₃O₄ nanocomposites with dual enzyme activity for colorimetric detection of catechol and smartphone-assisted visual ratiometric analysis

Spectrochim Acta A Mol Biomol Spectrosc. 2025 Nov 3;348(Pt 1):127125. doi: 10.1016/j.saa.2025.127125. Online ahead of print.

Authors

Aolin Bao¹, Bo Cao¹, Ruizhe Zhang¹, Yanan Ding², Haifeng Zhou¹, Guijiang Li¹, Gao-Chao Fan³, Qingyun Liu⁴

Affiliations

¹ College of Chemical and Biological Engineering, Shandong University of Science and Technology, Qingdao 266590, China.
² College of Electronic and Information Engineering, Shandong University of Science and Technology, 266590 Qingdao, China. Electronic address: dingyn@sdust.edu.cn.
³ Shandong Key Laboratory of Biochemical Analysis, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
⁴ College of Chemical and Biological Engineering, Shandong University of Science and Technology, Qingdao 266590, China. Electronic address: qyliu@sdust.edu.cn.

PMID: 41205429
DOI: 10.1016/j.saa.2025.127125

Abstract

Catechol poses significant environmental and health risks, colorimetric sensing is an effective method for catechol detection. Constructing nanozyme with enhanced activity is necessary in colorimetric sensing. In our work, sodium lignosulfonate (SL) supported CeO₂/Co₃O₄ heterojunctions (SL/CeO₂/Co₃O₄) have been prepared, compared to CeO₂/Co₃O₄, the catalytic performance of SL/CeO₂/Co₃O₄ is much enhanced. The improved nanozyme activity is ascribed to the increased specific surface area and more exposed active sites, which made the catalyst more effective in adsorption and activation of reactants. Besides, the oxygen vacancies induced by SL and the sulfur/carbon-containing groups due to the low-temperature calcination also exert a synergistic effect on the enhanced activity. Surprisingly, the SL/CeO₂/Co₃O₄ exhibit dual enzyme activities (peroxidase/oxidase), mechanistic studies revealed that the oxidase activity was derived from the oxygen vacancy and O₂^•-, while the peroxidase activity originated from ¹O₂ and O₂^•- generated during H₂O₂ catalysis. Leveraging the excellent peroxidase activity, a colorimetric detection platform for catechol was developed, demonstrating high selectivity, strong anti-interference capability, and a good linear relationship in the range of 0.05-1.0 μM, with a detection limit as low as 10 nM. In addition, a smartphone-assisted visual ratiometric biosensor was designed using Image J software, enabling portable and quantitative determination of catechol in water samples. This research not only developed a novel lignin-based nanozyme with high catalytic activity, but also established a smartphone-enabled ratiometric colorimetric sensor, providing a promising solution for the detection of hazardous substances.

Keywords: Catechol sensing; CeO(2)/Co(3)O(4) heterojunction; Colorimetric detection; Dual enzyme activity; Sodium lignosulfonate.