Transition state and product diffusion control by polymer–nanocrystal hybrid catalysts


Effective catalysts stabilize specific transition states and control the transport of species to and from catalytically active sites. Enzymes show these traits thanks to their diverse amino acid functional groups encapsulating metal centres, but are limited in the reaction conditions in which they can operate. Realizing a catalyst with this kinetic and transport control that can be used under demanding industrial conditions is challenging. Here, we show a modular approach for the systematic synthesis of polymer–nanocrystal hybrids, where palladium nanocrystals are encapsulated within tunable microporous polymer layers. The polymer chemistry and morphology control the catalytic performance of the metal sites, affecting the transition state for CO oxidation and controlling the transport of CO2 away from the active site. This approach can be applied to other polymer–nanocrystal compositions and catalytic applications, and is therefore expected to have an impact in many areas of catalysis.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Modular synthesis of the Pd/polymer composites.
Fig. 2: Characterization of POF-encapsulated Pd NCs.
Fig. 3: Kinetic studies of the mechanism of CO oxidation on several Pd-based materials prepared in this study.
Fig. 4: Oscillations in activity.
Fig. 5: Diffusion limitations.

Data availability

All data are available from the authors upon reasonable request.


  1. 1.

    Oyama, S. T. & Somorjai, G. A. Homogeneous, heterogeneous and enzymatic catalysis. J. Chem. Educ. 65, 765 (1988).

  2. 2.

    Vojvodic, A. & Norskov, J. K. New design paradigm for heterogeneous catalysts. Natl Sci. Rev. 2, 140–143 (2015).

  3. 3.

    Breslow, R. & Overman, L. E. An ‘artificial enzyme’ combining a metal catalytic group and a hydrophobic binding cavity. J. Am. Chem. Soc. 92, 1075–1077 (1970).

  4. 4.

    Katz, A. & Davis, M. E. Molecular imprinting of bulk, microporous silica. Nature 403, 2–5 (2000).

  5. 5.

    Copéret, C., Chabanas, M., Saint-Arroman, R. P. & Basset, J.-M. Homogeneous and heterogeneous catalysis: bridging the gap through surface organometallic chemistry. Angew. Chem. Int. Ed. 42, 156–181 (2003).

  6. 6.

    Groothaert, M. H., Smeets, P. J., Sels, B. F., Jacobs, P. A. & Schoonheydt, R. A. Selective oxidation of methane by the bis(μ-oxo)dicopper core stabilized on ZSM-5 and mordenite zeolites. J. Am. Chem. Soc. 127, 1394–1395 (2005).

  7. 7.

    Marshall, S. T. et al. Controlled selectivity for palladium catalysts using self-assembled monolayers. Nat. Mater. 9, 853–858 (2010).

  8. 8.

    Schrader, I., Warneke, J., Backenköhler, J. & Kunz, S. Functionalization of platinum nanoparticles with l-proline: simultaneous enhancements of catalytic activity and selectivity. J. Am. Chem. Soc. 137, 905–912 (2015).

  9. 9.

    Ye, R., Zhukhovitskiy, A. V., Deraedt, C. V., Toste, F. D. & Somorjai, G. A. Supported dendrimer-encapsulated metal clusters: toward heterogenizing homogeneous catalysts. Acc. Chem. Res. 50, 1894–1901 (2017).

  10. 10.

    Zhao, M., Sun, L. & Crooks, R. M. Preparation of Cu nanoclusters within dendrimer templates. J. Am. Chem. Soc. 120, 4877–4878 (1998).

  11. 11.

    Lu, G. et al. Imparting functionality to a metal–organic framework material by controlled nanoparticle encapsulation. Nat. Chem. 4, 310–316 (2012).

  12. 12.

    Zhao, M. et al. Metal–organic frameworks as selectivity regulators for hydrogenation reactions. Nature 539, 76–80 (2016).

  13. 13.

    Rodríguez-San-Miguel, D. et al. Confining functional nanoparticles into colloidal imine-based COF spheres by a sequential encapsulation–crystallization method. Chemistry 23, 8623–8627 (2017).

  14. 14.

    Maligal-Ganesh, R. V. et al. A ship-in-a-bottle strategy to synthesize encapsulated intermetallic nanoparticle catalysts: exemplified for furfural hydrogenation. ACS Catal. 6, 1754–1763 (2016).

  15. 15.

    Cargnello, M. et al. Exceptional activity for methane combustion over modular Pd@CeO2 subunits on functionalized Al2O3. Science 337, 713–717 (2012).

  16. 16.

    Gounder, R. & Iglesia, E. The roles of entropy and enthalpy in stabilizing ion-pairs at transition states in zeolite acid catalysis. Acc. Chem. Res. 45, 229–238 (2012).

  17. 17.

    Katsoulidis, A. P. et al. Copolymerization of terephthalaldehyde with pyrrole, indole and carbazole gives microporous POFs functionalized with unpaired electrons. J. Mater. Chem. A 1, 10465 (2013).

  18. 18.

    Schwab, M. G. et al. Catalyst-free preparation of melamine-based microporous polymer networks through Schiff base chemistry. J. Am. Chem. Soc. 131, 7216–7217 (2009).

  19. 19.

    Hu, J. X. et al. Highly enhanced selectivity and easy regeneration for the separation of CO2 over N2 on melamine-based microporous organic polymers. Ind. Eng. Chem. Res. 53, 11828–11837 (2014).

  20. 20.

    Willis, J. J. et al. Systematic structure–property relationship studies in palladium-catalyzed methane complete combustion. ACS Catal. 7, 7810–7821 (2017).

  21. 21.

    Cargnello, M. et al. Efficient removal of organic ligands from supported nanocrystals by fast thermal annealing enables catalytic studies on well-defined active phases. J. Am. Chem. Soc. 137, 6906–6911 (2015).

  22. 22.

    Freund, H. J., Meijer, G., Scheffler, M., Schlögl, R. & Wolf, M. CO oxidation as a prototypical reaction for heterogeneous processes. Angew. Chem. Int. Ed. 50, 10064–10094 (2011).

  23. 23.

    Djéga-Mariadassou, G. & Boudart, M. Classical kinetics of catalytic reactions. J. Catal. 216, 89–97 (2003).

  24. 24.

    Allian, A. D. et al. Chemisorption of CO and mechanism of CO oxidation on supported platinum nanoclusters. J. Am. Chem. Soc. 133, 4498–4517 (2011).

  25. 25.

    Xu, X. & Goodman, D. W. An infrared and kinetic study of CO oxidation on model silica-supported palladium catalysts from 10–9 to 15 torr. J. Phys. Chem. 97, 7711–7718 (1993).

  26. 26.

    Falsig, H. et al. Trends in the catalytic CO oxidation activity of nanoparticles. Angew. Chem. Int. Ed. 47, 4835–4839 (2008).

  27. 27.

    Plath, P. J., Moller, K. & Jaeger, N. I. Cooperative effects in heterogeneous catalysis. J. Chem. Soc. Faraday Trans. I 84, 1751–1771 (1988).

  28. 28.

    Imbihl, R. & Ertl, G. Oscillatory kinetics in heterogeneous catalysis. Chem. Rev. 95, 697–733 (1995).

  29. 29.

    Vendelbo, S. B. et al. Visualization of oscillatory behaviour of Pt nanoparticles catalysing CO oxidation. Nat. Mater. 13, 884–890 (2014).

  30. 30.

    Stonkus, O. A. et al. Palladium nanoparticles supported on nitrogen-doped carbon nanofibers: synthesis, microstructure, catalytic properties and self-sustained oscillation phenomena in carbon monoxide oxidation. ChemCatChem 6, 2115–2128 (2014).

  31. 31.

    Ressler, T., Hagelstein, M., Hatje, U. & Metz, W. In situ XAS investigations of chemical oscillations in the oxidation of Co on supported Pd catalysts. J. Phys. IV France 7, 731–733 (1997).

  32. 32.

    Ogura, M. et al. Identification of the basic sites on nitrogen-substituted microporous and mesoporous silicate frameworks using CO2 as a probe molecule. Langmuir 34, 1376–1385 (2018).

  33. 33.

    Mason, C. R. et al. Enhancement of CO2 affinity in a polymer of intrinsic microporosity by amine modification. Macromolecules 47, 1021–1029 (2014).

  34. 34.

    Choi, J. G., Do, D. D. & Do, H. D. Surface diffusion of adsorbed molecules in porous media: monolayer, multilayer and capillary condensation regimes. Ind. Eng. Chem. Res. 40, 4005–4031 (2001).

  35. 35.

    Prasetyo, I., Do, H. D. & Do, D. D. Surface diffusion of strong adsorbing vapours on porous carbon. Chem. Eng. Sci. 57, 133–141 (2002).

  36. 36.

    Schneider, P. & Smith, J. M. Chromatographic study of surface diffusion. AIChE J. 14, 886–895 (1968).

  37. 37.

    Miyabe, K. Characteristics and mechanism of surface diffusion in reversed-phase liquid chromatography using various alkyl ligand bonded silica gels. Anal. Chem. 74, 2126–2132 (2002).

  38. 38.

    Gilliland, E. R. et al. Diffusion on surfaces. I. Effect of concentration on the diffusivity of physically adsorbed gases. Ind. Eng. Chem. Fund. 13, 95–100 (1974).

  39. 39.

    Roybal, L. A. & Sandler, S. I. Surface diffusion of adsorbable gases through porous media. AIChE J. 18, 39–42 (1972).

  40. 40.

    Turing, A. M. The chemical basis of morphogenesis. Philos. Trans. R. Soc. Lond. B 237, 37 (1952).

  41. 41.

    Lengyel, I. & Epstein, I. R. Diffusion-induced instability in chemically reacting systems: steady-state multiplicity, oscillation and chaos. Chaos 1, 69–76 (1991).

  42. 42.

    Higashi, K., Ito, H. & Oishi, J. Surface diffusion phenomena in gaseous diffusion. J. Nucl. Sci. Technol. 1, 198–204 (1962).

  43. 43.

    Do, D. D. A model for surface diffusion of ethane and propane in activated carbon. Chem. Eng. Sci. 51, 4145 (1996).

  44. 44.

    Hites, R. A. Calculating the confidence and prediction limits of a rate constant at a given temperature from an Arrhenius equation using Excel. J. Chem. Educ. 94, 1402–1403 (2017).

  45. 45.

    van Aarle, W. et al. Fast and flexible X-ray tomography using the ASTRA toolbox. Opt. Express 24, 25129 (2016).

  46. 46.

    van Aarle, W. et al. The ASTRA Toolbox: a platform for advanced algorithm development in electron tomography. Ultramicroscopy 157, 35–47 (2015).

  47. 47.

    Otsu, N. A threshold selection method from gray level histograms. IEEE Trans. Syst. Man. Cybern. 9, 62–66 (1979).

  48. 48.

    van der Walt, S. et al. Scikit-image: image processing in Python. PeerJ 2, e453 (2014).

  49. 49.

    Seah, M. P. & Dench, W. A. Quantitative electron spectroscopy of surfaces. Surf. Interface Anal. 1, 2–11 (1979).

  50. 50.

    Yang, D. et al. Chemical analysis of graphene oxide films after heat and chemical treatments by X-ray photoelectron and micro-Raman spectroscopy. Carbon 47, 145–152 (2009).

  51. 51.

    Zhang, C., Hao, R., Liao, H. & Hou, Y. Synthesis of amino-functionalized graphene as metal-free catalyst and exploration of the roles of various nitrogen states in oxygen reduction reaction. Nano Energy 2, 88–97 (2013).

  52. 52.

    Hoffman, A. S. et al. Transmission and fluorescence X-ray absorption spectroscopy cell/flow reactor for powder samples under vacuum or in reactive atmospheres. Rev. Sci. Instrum. 87, 073108 (2016).

  53. 53.

    Ravel, B. & Newville, M. ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorption spectroscopy using IFEFFIT. J. Synchrotron Radiat. 12, 537–541 (2005).

  54. 54.

    Zabinsky, S. I., Rehr, J. J., Ankudinov, A., Albers, R. C. & Eller, M. J. Multiple-scattering calculations of X-ray-absorption spectra. Phys. Rev. B 52, 2995–3009 (1995).

  55. 55.

    Mehio, N., Dai, S. & Jiang, D. E. Quantum mechanical basis for kinetic diameters of small gaseous molecules. J. Phys. Chem. A 118, 1150–1154 (2014).

  56. 56.

    Kamrath, M. Z., Relph, R. A. & Johnson, M. A. Vibrational predissociation spectrum of the carbamate radical anion, C5H5N-CO2 , generated by reaction of pyridine with (CO2). J. Am. Chem. Soc. 132, 15508–15511 (2010).

Download references


Support for this work was provided by a seed grant through the Natural Gas Initiative at Stanford University. The authors thank E. Goodman (Stanford University) for help with microscopy, L. Kunz (Stanford University) for help with elemental analysis, A.-C. Yang and A. Aitbekova (Stanford University) for help with synthesis of the materials and O. Müller (SLAC National Laboratory) for help with X-ray absorption experiments. M.C. acknowledges further support from the School of Engineering at Stanford University and from a Terman Faculty Fellowship. A.R.R. acknowledges support from the National Science Foundation Graduate Research Fellowship Program. Characterization of the hybrid materials was performed at the Stanford Nano Shared Facilities (SNSF) at Stanford University supported by the National Science Foundation under award ECCS-1542152. XAS measurements were collected at SSRL beam lines 9-3 and 7-3. A.S.H., A.B. and S.R.B. acknowledge support from the Department of Energy, Basic Energy Sciences funded Consortium for Operando and Advanced Catalyst Characterization via Electronic Spectroscopy and Structure (Co-ACCESS) at SLAC.

Author information

A.R.R. and M.C. conceived the idea for the study. A.R.R. synthesized the materials and performed structural and catalytic characterization. C.J.W. contributed to structural characterization. A.A.H. performed tomography characterization. A.S.H. and A.B. contributed to XAS characterization supervised by S.R.B. A.M. and M.V. contributed to the synthesis of materials. M.C. supervised the entire project. A.R.R. and M.C. wrote the manuscript with contributions from all authors.

Correspondence to Matteo Cargnello.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

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

Supplementary information

Supplementary Information

Supplementary Figs. 1–11

Supplementary Video

HAADF–STEM tomography reconstruction of a POF/Pd/POF, initially shown as cross-sections of a single microparticle and later as a tilt series to create the 3D reconstruction followed by the surface generated after segmentation of the POF and the Pd particles. Finally, the same surface, but with 60% transparency of the POF material.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Riscoe, A.R., Wrasman, C.J., Herzing, A.A. et al. Transition state and product diffusion control by polymer–nanocrystal hybrid catalysts. Nat Catal 2, 852–863 (2019).

Download citation

Further reading