Mesoporous Carbon Supported Metal Catalysts for Sustainable Hydrogenation Reactions
Final Report Abstract
Within this project we chould shed some light on the role of the metal-support interactions in carbon-supported palladium nanoparticles. The focus of the project was here in particular on how this interaction and doping of the carbon support modifies the reactivity of hydrogen in hydrogenation reactions. As typical for theoretical studies in the context of heterogeneous catalysis, a major challenge has been the size and the complexity of the real catalytic system and that is has not a single well-defined atomistic structure. In this case we modelled the real system by two palladium clusters supported by polycyclic aromatic hydrocarbon. We investigated how the carbon-support influences the adsorption of molecular hydrogen on the supported palladium particles, its migration from the palladium particles to the carbon surface and the diffusion on the support. The doping of the carbon support with oxygen or nitrogen heteroatoms modifies electronic properties of the support. This as strong effects on the metal-support interactions. For example do pyridinic N atoms in the support serve as anchor points for Pd nanoparticles. The doping with heteroatoms also influences the so-called spill-over hydrogen on the carbon support which for example will accumulate in the vicinity of graphitic nitrogen dopant atoms. A particular highlight of the project was the unexpected finding of a strong metallsupport interaction between palladium nanocluster and pyridinic nitrogen heteratoms that lead to a local change of the oxidation states of the Pd atoms bonded to the pyridinic nitrogens. This turns the system into a bifunctional palladium catalyst which can simultaneously activate formic acid and stabilize H− as reducing agent as shown in a joint theoretical and experimental research paper published in Angew. Chemie.
Publications
- A quantum chemical study of hydrogen adsorption on carbon-supported palladium clusters, Phys. Chem. Chem. Phys., 21, 21577–21587 (2019)
L Warczinski and C. Hättig
(See online at https://doi.org/10.1039/C9CP04606B) - Anchoring of palladium nanoparticles on N-doped mesoporous carbon, Phys. Chem. Chem. Phys., 22, 21317–21325 (2020)
L. Warczinski, B. Hu, T. Eckhard, B. Peng, M. Muhler, C. Hättig
(See online at https://doi.org/10.1039/D0CP03234D) - Formic acid-assisted selective hydrogenolysis of 5-hydroxymethylfurfural to 2,5- dimethylfuran over bifunctional Pd nanoparticles supported on N-doped mesoporous carbon, Angew. Chem. Int. Ed., 60, 6807–6815 (2021)
B. Hu, L. Warczinski, X. Li, M. Lu, J. Bitzer, M. Heidelmann, T. Eckhard, Q. Fu, J. Schulwitz, M. Merko, M. Li, W. Kleist, C. Hättig, M. Muhler, B. Peng
(See online at https://doi.org/10.1002/anie.202012816) - How nitrogen doping affects hydrogen spillover on carbon-supported Pd nanopara ticles: new insights from DFT, J. Chem. Phys. C, 125, 9020–9031 (2021)
L. Warczinski and C. Hättig
(See online at https://doi.org/10.1021/acs.jpcc.0c11412)
