Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Quantum-sensing-enabled in situ imaging of free radicals in chemical reactions

Nature Catalysis volume 9, pages 319–327 (2026) Cite this article

Subjects

Abstract

In situ observation of chemical reactions with high sensitivity and high spatiotemporal resolution is a long-standing goal in chemistry. Up to now, only a few, very specific systems can be studied. High-resolution operando imaging of chemical reactions typically requires a fluorescent probe to be included in the reaction. Here we introduce an operando microscopy methodology, namely quantum-sensing-enabled chemical operando microscopy (QCOM), in which reaction-induced local physical field changes are intrinsically transformed into dynamic imaging contrast using nitrogen vacancy centres in diamond. QCOM simultaneously satisfies the criteria of detection sensitivity (around four free radicals per pixel), spatial resolution (full-width-at-half-maximum resolution of around 312 nm) and temporal resolution (~10–240 ms). This has enabled the direct, quantitative, operando imaging of free-radical generation in the photocatalytic hydrolysis of TiO2, revealing an unexpected spatiotemporal sequential activation effect. Our work combines quantum sensing with chemical reaction imaging, offering a comprehensive in situ methodology to explore spatiotemporal phenomena in chemistry.

The alternative text for this image may have been generated using AI.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on SpringerLink
  • Instant access to the full article PDF.

USD 39.95

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Quantum sensing of free radicals in photocatalytic reactions.
The alternative text for this image may have been generated using AI.
Fig. 2: Quantitative imaging of free radicals in the photocatalytic hydrolysis of TiO2.
The alternative text for this image may have been generated using AI.
Fig. 3: Observation of the spatiotemporal sequential activation effect.
The alternative text for this image may have been generated using AI.
Fig. 4: Direct operando electron spin spectroscopy of free radicals.
The alternative text for this image may have been generated using AI.

Similar content being viewed by others

Data availability

Raw data comprising a large number of movie files supporting the findings of this study are available from the authors upon reasonable request. Source data are provided with this paper.

Code availability

MATLAB codes for processing the raw data are provided in Supplementary Code 1.

References

  1. Halliwell, B. & Gutteridge, J.M.C. Free Radicals in Biology and Medicine (Oxford Univ. Press, 2015).

  2. Bonke, S. A., Risse, T., Schnegg, A. & Brückner, A. In situ electron paramagnetic resonance spectroscopy for catalysis. Nat. Rev. Methods Primers 1, 33 (2021).

    Article  CAS  Google Scholar 

  3. Van Schrojenstein Lantman, E. M., Deckert-Gaudig, T., Mank, A. J. G., Deckert, V. & Weckhuysen, B. M. Catalytic processes monitored at the nanoscale with tip-enhanced Raman spectroscopy. Nat. Nanotechnol. 7, 583–586 (2012).

    Article  PubMed  Google Scholar 

  4. Roeffaers, M. B. J. et al. Spatially resolved observation of crystal-face-dependent catalysis by single turnover counting. Nature 439, 572–575 (2006).

    Article  CAS  PubMed  Google Scholar 

  5. Sambur, J. B. et al. Sub-particle reaction and photocurrent mapping to optimize catalyst-modified photoanodes. Nature 530, 77–80 (2016).

    Article  CAS  PubMed  Google Scholar 

  6. Monai, M. et al. Restructuring of titanium oxide overlayers over nickel nanoparticles during catalysis. Science 380, 644–651 (2023).

    Article  CAS  PubMed  Google Scholar 

  7. Barroo, C., Wang, Z. J., Schloegl, R. & Willinger, M. G. Imaging the dynamics of catalysed surface reactions by in situ scanning electron microscopy. Nat. Catal. 3, 30–39 (2020).

    Article  CAS  Google Scholar 

  8. Yuan, W. T. et al. Visualizing H2O molecules reacting at TiO2 active sites with transmission electron microscopy. Science 367, 428–430 (2020).

    Article  CAS  PubMed  Google Scholar 

  9. Tao, F. & Salmeron, M. In situ studies of chemistry and structure of materials in reactive environments. Science 331, 171–174 (2011).

    Article  CAS  PubMed  Google Scholar 

  10. Dong, J. R. et al. Direct imaging of single-molecule electrochemical reactions in solution. Nature 596, 244–249 (2021).

    Article  CAS  PubMed  Google Scholar 

  11. Zhang, Z. Q. et al. Direct probing of single-molecule chemiluminescent reaction dynamics under catalytic conditions in solution. Nat. Commun. 14, 7993 (2023).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  12. Degen, C. L., Reinhard, F. & Cappellaro, P. Quantum sensing. Rev. Mod. Phys. 89, 035002 (2017).

    Article  Google Scholar 

  13. Schirhagl, R., Chang, K., Loretz, M. & Degen, C. L. Nitrogen-vacancy centers in diamond: nanoscale sensors for physics and biology. Annu. Rev. Phys. Chem. 65, 83–105 (2014).

    Article  CAS  PubMed  Google Scholar 

  14. Simpson, D. A. et al. Electron paramagnetic resonance microscopy using spins in diamond under ambient conditions. Nat. Commun. 8, 458 (2017).

    Article  PubMed  PubMed Central  Google Scholar 

  15. Steinert, S. et al. Magnetic spin imaging under ambient conditions with sub-cellular resolution. Nat. Commun. 4, 1607 (2013).

    Article  CAS  PubMed  Google Scholar 

  16. Barton, J. et al. Nanoscale dynamic readout of a chemical redox process using radicals coupled with nitrogen-vacancy centers in nanodiamonds. ACS Nano 14, 12938–12950 (2020).

    Article  CAS  PubMed  Google Scholar 

  17. Radu, V. et al. Dynamic quantum sensing of paramagnetic species using nitrogen-vacancy centers in diamond. ACS Sens. 5, 703–710 (2020).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  18. Kucsko, G. et al. Nanometre-scale thermometry in a living cell. Nature 500, 54–58 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  19. Bhattacharyya, P. et al. Imaging the Meissner effect in hydride superconductors using quantum sensors. Nature 627, 73–79 (2024).

    Article  CAS  PubMed  Google Scholar 

  20. Dolde, F. et al. Electric-field sensing using single diamond spins. Nat. Phys. 7, 459–463 (2011).

    Article  CAS  Google Scholar 

  21. Maze, J. R. et al. Nanoscale magnetic sensing with an individual electronic spin in diamond. Nature 455, 644–647 (2008).

    Article  CAS  PubMed  Google Scholar 

  22. Le Sage, D. et al. Optical magnetic imaging of living cells. Nature 496, 486–489 (2013).

    Article  PubMed  PubMed Central  Google Scholar 

  23. Balasubramanian, G. et al. Nanoscale imaging magnetometry with diamond spins under ambient conditions. Nature 455, 648–651 (2008).

    Article  CAS  PubMed  Google Scholar 

  24. Taylor, J. M. et al. High-sensitivity diamond magnetometer with nanoscale resolution. Nat. Phys. 4, 810–816 (2008).

    Article  CAS  Google Scholar 

  25. Du, J. F., Shi, F. Z., Kong, X., Jelezko, F. & Wrachtrup, J. Single-molecule scale magnetic resonance spectroscopy using quantum diamond sensors. Rev. Mod. Phys. 96, 025001 (2024).

    Article  CAS  Google Scholar 

  26. Lovchinsky, I. et al. Nuclear magnetic resonance detection and spectroscopy of single proteins using quantum logic. Science 351, 836–841 (2016).

    Article  CAS  PubMed  Google Scholar 

  27. Schneider, J. et al. Understanding TiO2 photocatalysis: mechanisms and materials. Chem. Rev. 114, 9919–9986 (2014).

    Article  CAS  PubMed  Google Scholar 

  28. Mzyk, A., Sigaeva, A. & Schirhagl, R. Relaxometry with nitrogen vacancy (NV) centers in diamond. Acc. Chem. Res. 55, 3572–3580 (2022).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  29. Tetienne, J. P. et al. Spin relaxometry of single nitrogen-vacancy defects in diamond nanocrystals for magnetic noise sensing. Phys. Rev. B 87, 235436 (2013).

    Article  Google Scholar 

  30. Nasikhudin et al. Study on photocatalytic properties of TiO2 nanoparticle in various pH condition. J. Phys. Conf. Ser. 1011, 012069 (2018).

    Article  Google Scholar 

  31. Chen, R. T. et al. Spatiotemporal imaging of charge transfer in photocatalyst particles. Nature 610, 296–301 (2022).

    Article  CAS  PubMed  Google Scholar 

  32. Chen, R. T. et al. Charge separation via asymmetric illumination in photocatalytic CuO particles. Nat. Energy 3, 655–663 (2018).

    Article  CAS  Google Scholar 

  33. Plazinski, W. & Rudzinski, W. Kinetics of adsorption at solid/solution interfaces controlled by intraparticle diffusion: a theoretical analysis. J. Phys. Chem. C 113, 12495–12501 (2009).

    Article  CAS  Google Scholar 

  34. Chen, X. H. et al. The formation time of Ti–O and Ti–O–Ti radicals at the n-SrTiO/aqueous interface during photocatalytic water oxidation. J. Am. Chem. Soc. 139, 1830–1841 (2017).

    Article  CAS  PubMed  Google Scholar 

  35. Karim, W. et al. Catalyst support effects on hydrogen spillover. Nature 541, 68–71 (2017).

    Article  CAS  PubMed  Google Scholar 

  36. Zou, N. M. et al. Cooperative communication within and between single nanocatalysts. Nat. Chem. 10, 607–614 (2018).

    Article  CAS  PubMed  Google Scholar 

  37. Vogt, C. & Weckhuysen, B. M. The concept of active site in heterogeneous catalysis. Nat. Rev. Chem. 6, 89–111 (2022).

    Article  PubMed  Google Scholar 

  38. Mamin, H. J., Sherwood, M. H. & Rugar, D. Detecting external electron spins using nitrogen-vacancy centers. Phys. Rev. B 86, 195422 (2012).

    Article  Google Scholar 

  39. Barry, J. F. et al. Sensitivity optimization for NV-diamond magnetometry. Rev. Mod. Phys. 92, 015004 (2020).

    Article  CAS  Google Scholar 

  40. Buettner, G. R. The spin trapping of superoxide and hydroxyl free radicals with DMPO (5,5-dimethylpyrroline-N-oxide): more about iron. Free Radic. Res. Commun. 19, S79–S87 (1993).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  41. Rubinas, O. R. et al. Optimization of the double electron–electron resonance for C-centers in diamond. Phys. Status Solidi Rapid Res. Lett. 16, 2100561 (2022).

    Article  CAS  Google Scholar 

  42. Seif-Eddine, M. et al. Operando film-electrochemical EPR spectroscopy tracks radical intermediates in surface-immobilized catalysts. Nat. Chem. 16, 1015–1023 (2024).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  43. Xu, W. L., Kong, J. S., Yeh, Y. T. E. & Chen, P. Single-molecule nanocatalysis reveals heterogeneous reaction pathways and catalytic dynamics. Nat. Mater. 7, 992–996 (2008).

    Article  CAS  PubMed  Google Scholar 

  44. Hansen, P. L. et al. Atom-resolved imaging of dynamic shape changes in supported copper nanocrystals. Science 295, 2053–2055 (2002).

    Article  CAS  PubMed  Google Scholar 

  45. Tao, F. K. & Salmeron, M. Surface restructuring and predictive design of heterogeneous catalysts. Science 386, eadq0102 (2024).

    Article  CAS  PubMed  Google Scholar 

  46. Kazuma, E., Jung, J., Ueba, H., Trenary, M. & Kim, Y. Real-space and real-time observation of a plasmon-induced chemical reaction of a single molecule. Science 360, 521–525 (2018).

    Article  CAS  PubMed  Google Scholar 

  47. Zhang, R. et al. Chemical mapping of a single molecule by plasmon-enhanced Raman scattering. Nature 498, 82–86 (2013).

    Article  CAS  PubMed  Google Scholar 

  48. Hartman, T., Geitenbeek, R. G., Whiting, G. T. & Weckhuysen, B. M. Operando monitoring of temperature and active species at the single catalyst particle level. Nat. Catal. 2, 986–996 (2019).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

We thank X. Yang, D. Wang and B. Shan for their careful reading of this paper. This study was funded by the National Natural Science Foundation of China (21974123, J.F.), the National Key R&D Program of China (2020YFA0211200, J.F.), the Fundamental Research Funds for the Zhejiang Provincial Universities (226202500087, J.F.) and the Fundamental Research Funds for the Central Universities (K20220088, J.F.). J.F. acknowledges the support of the New Cornerstone Science Foundation through the XPLORER PRIZE. We thank the Micro and Nano Fabrication Center (Y. Sun and J. Sun), the Analysis Center of Agrobiology and Environmental Sciences, and the Chemistry Instrumentation Center (X. Ding) at Zhejiang University for technical assistance.

Author information

Author notes

  1. These authors contributed equally: Yibo Yang, Zengrong Zhou.

Authors and Affiliations

  1. Laboratory of Experimental Physical Biology, Department of Chemistry, Zhejiang University, Hangzhou, China

    Yibo Yang, Zengrong Zhou, Yang Xu, Sijin Li, Zihan Mao, Chunxiao Zhao, Wenjing Duan, Shiyang Lyu, Yunze Zhou, Ziqing Zhang, Wenxin Zhu & Jiandong Feng

  2. Beijing Academy of Quantum Information Sciences, Beijing, China

    Feihao Zhang

  3. College of Optical Science and Engineering, Zhejiang University, Hangzhou, China

    Jiandong Feng

  4. Institute of Fundamental and Transdisciplinary Research, Zhejiang University, Hangzhou, China

    Jiandong Feng

Authors
  1. Yibo Yang
    View author publications

    Search author on:PubMed Google Scholar

  2. Zengrong Zhou
    View author publications

    Search author on:PubMed Google Scholar

  3. Yang Xu
    View author publications

    Search author on:PubMed Google Scholar

  4. Sijin Li
    View author publications

    Search author on:PubMed Google Scholar

  5. Feihao Zhang
    View author publications

    Search author on:PubMed Google Scholar

  6. Zihan Mao
    View author publications

    Search author on:PubMed Google Scholar

  7. Chunxiao Zhao
    View author publications

    Search author on:PubMed Google Scholar

  8. Wenjing Duan
    View author publications

    Search author on:PubMed Google Scholar

  9. Shiyang Lyu
    View author publications

    Search author on:PubMed Google Scholar

  10. Yunze Zhou
    View author publications

    Search author on:PubMed Google Scholar

  11. Ziqing Zhang
    View author publications

    Search author on:PubMed Google Scholar

  12. Wenxin Zhu
    View author publications

    Search author on:PubMed Google Scholar

  13. Jiandong Feng
    View author publications

    Search author on:PubMed Google Scholar

Contributions

J.F. conceptualized the project. J.F. and Y.Y. designed the set-up. Y.Y. built the set-up with help from Y.X and S.L. Z. Zhou wrote the sequence and quantitative model. Y.Y., Z. Zhou, F.Z., Z.M., C.Z., W.D., S.L., Y.Z., Z. Zhang and W.Z. conducted and analysed the experiments. J.F. supervised the work. J.F. and Y.Y. wrote the paper with feedback from other authors.

Corresponding author

Correspondence to Jiandong Feng.

Ethics declarations

Competing interests

J.F. and Y.Y. are listed as inventors in a filed patent (Publication number: CN120102536A) describing the quantum-enabled in-situ imaging technique. The other authors declare no competing interests.

Peer review

Peer review information

Nature Catalysis thanks Johan Hofkens and Ming Zhao for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information (download PDF )

Supplementary Discussions 1–12, Tables 1 and 2, and Figs. 1–28.

Supplementary Code 1

Matlab codes for processing raw image stacks acquired by QCOM.

Supplementary Video 1 (download MP4 )

Dynamic free-radical imaging of a single TiO2 nanowire during photocatalysis.

Source data

Source Data Fig. 1 (download XLSX )

Statistical source data.

Source Data Fig. 2 (download XLSX )

Statistical source data.

Source Data Fig. 3 (download XLSX )

Statistical source data.

Source Data Fig. 4 (download XLSX )

Statistical source data.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Yang, Y., Zhou, Z., Xu, Y. et al. Quantum-sensing-enabled in situ imaging of free radicals in chemical reactions. Nat Catal 9, 319–327 (2026). https://doi.org/10.1038/s41929-026-01499-7

Download citation

  • Received:

  • Accepted:

  • Published:

  • Version of record:

  • Issue date:

  • DOI: https://doi.org/10.1038/s41929-026-01499-7

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing