Letter

Nature 456, 222-225 (13 November 2008) | doi:10.1038/nature07516; Received 29 June 2008; Accepted 24 September 2008

Nanoscale chemical imaging of a working catalyst by scanning transmission X-ray microscopy

Emiel de Smit1, Ingmar Swart1, J. Fredrik Creemer2, Gerard H. Hoveling3, Mary K. Gilles4, Tolek Tyliszczak4, Patricia J. Kooyman5, Henny W. Zandbergen6, Cynthia Morin1, Bert M. Weckhuysen1 & Frank M. F. de Groot1

  1. Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht, The Netherlands
  2. DIMES-ECTM, Delft University of Technology, PO Box 5053, 2600 GB Delft, The Netherlands
  3. DEMO, Delft University of Technology, PO Box 5031, 2600 GA Delft, The Netherlands
  4. Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
  5. DelftChemTech and National Centre for High Resolution Electron Microscopy, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands
  6. Kavli Institute of NanoScience, National Centre for High Resolution Electron Microscopy, Delft University of Technology, PO Box 5046, 2600 GA Delft, The Netherlands

Correspondence to: Bert M. Weckhuysen1Frank M. F. de Groot1 Correspondence and requests for materials should be addressed to F.M.F.d.G. (Email: f.m.f.degroot@uu.nl) or B.M.W. (Email: b.m.weckhuysen@uu.nl).

The modern chemical industry uses heterogeneous catalysts in almost every production process1. They commonly consist of nanometre-size active components (typically metals or metal oxides) dispersed on a high-surface-area solid support, with performance depending on the catalysts' nanometre-size features and on interactions involving the active components, the support and the reactant and product molecules. To gain insight into the mechanisms of heterogeneous catalysts, which could guide the design of improved or novel catalysts, it is thus necessary to have a detailed characterization of the physicochemical composition of heterogeneous catalysts in their working state at the nanometre scale1, 2. Scanning probe microscopy methods have been used to study inorganic catalyst phases at subnanometre resolution3, 4, 5, 6, but detailed chemical information of the materials in their working state is often difficult to obtain5, 6, 7. By contrast, optical microspectroscopic approaches offer much flexibility for in situ chemical characterization; however, this comes at the expense of limited spatial resolution8, 9, 10, 11. A recent development promising high spatial resolution and chemical characterization capabilities is scanning transmission X-ray microscopy4, 12, 13, which has been used in a proof-of-principle study to characterize a solid catalyst14. Here we show that when adapting a nanoreactor specially designed for high-resolution electron microscopy7, scanning transmission X-ray microscopy can be used at atmospheric pressure and up to 350 °C to monitor in situ phase changes in a complex iron-based Fisher–Tropsch catalyst and the nature and location of carbon species produced. We expect that our system, which is capable of operating up to 500 °C, will open new opportunities for nanometre-resolution imaging of a range of important chemical processes taking place on solids in gaseous or liquid environments.

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