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Visualizing pore architecture and molecular transport boundaries in catalyst bodies with fluorescent nanoprobes


The performances of porous materials are closely related to the accessibility and interconnectivity of their porous domains. Visualizing pore architecture and its role on functionality—for example, mass transport—has been a challenge so far, and traditional bulk and often non-visual pore measurements have to suffice in most cases. Here, we present an integrated, facile fluorescence microscopy approach to visualize the pore accessibility and interconnectivity of industrial-grade catalyst bodies, and link it unequivocally with their catalytic performance. Fluorescent nanoprobes of various sizes were imaged and correlated with the molecular transport of fluorescent molecules formed during a separate catalytic reaction. A direct visual relationship between the pore architecture—which depends on the pore sizes and interconnectivity of the material selected—and molecular transport was established. This approach can be applied to other porous materials, and the insight gained may prove useful in the design of more efficient heterogeneous catalysts.

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The authors thank M. Rivera Torrente (Utrecht University, UU), I. Beurroies and M. V. Coulet (Aix-Marseille University) for Hg porosimetry data analysis, as well as R. Dalebout (UU) for Ar physisorption measurements. M. de Winter (UU) is thanked for his contribution to FIB–SEM measurements. F. Meirer (UU) and M. Vesely (UU) are also thanked for valuable discussions. This work was funded by a Netherlands Organisation for Scientific Research (NWO) Veni grant, awarded to G.T.W. (no. 722.015.003), a Marie Skłodowska-Curie grant agreement (no. 704544) (to A.D.C.) and a NWO Gravitation program (Netherlands Center for Multiscale Catalytic Energy Conversion, MCEC; to B.M.W.).

Author information

G.T.W., N.N., I.N. and A.D.C. contributed to the preparation, characterization and testing of samples. G.T.W. and B.M.W. designed and directed the project. All authors discussed the results and commented on the manuscript.

Competing interests

The authors declare no competing interests.

Correspondence to Gareth T. Whiting or Bert M. Weckhuysen.

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Further reading

Fig. 1: Visualizing accessibility and deactivation in zeolite-based catalyst bodies.
Fig. 2: Associating molecule size, type and location with accessibility.
Fig. 3: Visualizing molecular transport phenomena at different stages of a MTH reaction.
Fig. 4: Visualizing the effect of changing accessibility on catalyst performance.