Metal-catalysed reactions are often hypothesized to proceed on bifunctional active sites, whereby colocalized reactive species facilitate distinct elementary steps in a catalytic cycle1,2,3,4,5,6,7,8. Bifunctional active sites have been established on homogeneous binuclear organometallic catalysts9,10,11. Empirical evidence exists for bifunctional active sites on supported metal catalysts, for example, at metal–oxide support interfaces2,6,7,12. However, elucidating bifunctional reaction mechanisms on supported metal catalysts is challenging due to the distribution of potential active-site structures, their dynamic reconstruction and required non-mean-field kinetic descriptions7,12,13. We overcome these limitations by synthesizing supported, atomically dispersed rhodium–tungsten oxide (Rh-WOx) pair site catalysts. The relative simplicity of the pair site structure and sufficient description by mean-field modelling enable correlation of the experimental kinetics with first principles-based microkinetic simulations. The Rh-WOx pair sites catalyse ethylene hydroformylation through a bifunctional mechanism involving Rh-assisted WOx reduction, transfer of ethylene from WOx to Rh and H2 dissociation at the Rh-WOx interface. The pair sites exhibited >95% selectivity at a product formation rate of 0.1 gpropanal cm−3 h−1 in gas-phase ethylene hydroformylation. Our results demonstrate that oxide-supported pair sites can enable bifunctional reaction mechanisms with high activity and selectivity for reactions that are performed in industry using homogeneous catalysts.
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Source data associated with all theoretical and experimental analysis are provided with this paper. The data and code necessary to build the DFT-based microkinetic model that supports the plots in this paper are available on Zenodo at https://doi.org/10.5281/zenodo.6525676. Any other data in the supplementary information will be provided by the corresponding author upon request.
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I.R., J.Q., S.L., D.G.V., S.C. and P.C. acknowledge the Catalysis Center for Energy Innovation, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under award number DE-SC0001004. M.X., X.Y. and X.P. acknowledges the NSF awards under grant nos CBET-2031494 and CHE-1955786 for support for the microscopy. This research used 7-BM (QAS) beamline of the National Synchrotron Light Source II, a US DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-SC0012704. Beamline operations were supported in part by the Synchrotron Catalysis Consortium (US DOE, Office of Basic Energy Sciences, grant no. DE-SC0012335). I.R. acknowledges the National Research Foundation of Korea (NRF) grant funded by The Ministry of Science and ICT (MSIT) (NRF-2021R1F1A1054980). The authors acknowledge the use of facilities and instrumentation at the UC Irvine Materials Research Institute (IMRI) supported in part by the NSF through the MRSEC program (DMR-2011967). We acknowledge A. B. Getsoian for providing the 10% Rh/Al2O3 Rh nanoparticle control sample. J. Resasco is acknowledged for his comments on the paper.
The authors declare no competing interests.
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Ro, I., Qi, J., Lee, S. et al. Bifunctional hydroformylation on heterogeneous Rh-WOx pair site catalysts. Nature 609, 287–292 (2022). https://doi.org/10.1038/s41586-022-05075-4