Nanoparticle

The workhorse in both environmental and industrial heterogeneous catalysis is supported nanoparticles. Moreover, nanoparticles also play a central role in electrocatalytic applications such as fuels cells. Many catalytic materials are scarce and expensive, which makes it very important to utilize them as efficiently as possible. Nanoparticles are perfectly suited for this job, since they have extremely high catalytic surface areas per mass. Furthermore, the catalytic properties of a material often changes drastically when it is produces in the form of nanoparticles.

In our group, we work to understand catalytic nanoparticles on a fundamental level by producing model systems of size-selected nanoparticles, characterizing them, and testing them for catalytic reactions.

Although our research is fundamental in nature, our goals is to solve real problems in real applications, leading us to frequent collaboration with industrial partners such as Haldor Topsøe. We also collaborate internally with DTU partners, especially DTU Center for Electron Nanoscopy, which is equipped with world-class electron microscopy facilities. Below is a high-resolution STEM image of Ni-Mo-S nanoparticles where the atomic structure is clearly visible.

Going smaller

Even though traditional nanoparticle catalyst design has been incredible successful in many environmental and industrial applications, it is subject to fundamental limitations and for a number of ‘Dream Reactions’ we have no viable catalyst today.

By going smaller to nanoparticles smaller than 2 nm and all the way down to clusters with a countable number of atoms, e.g. trimers, dimers and single atoms, the catalytic properties will significantly change as compared to their nanoparticle counterparts.


At SurfCat we are using cluster sources to create model system catalysts of single atoms, dimers and slightly larger entities in the transition regime between clusters with countable atoms and large nanoparticles >2nm, to explore their catalytic properties.

 

Cluster sources

At SurfCat we have two magnetron-based cluster sources capable to producing mass-selected entities ranging from nanoparticles all the way down to single atoms. An illustration of one of the cluster sources is displayed below.

 

The mass filter is based on time-of-flight (TOF) orthogonal to the direction of flight, which easily allows us to select entities with a countable number of atoms. An example of a mass spectrum is displayed below where platinum entities with 1-10 atoms can clearly be resolved and selected for deposition.

 

Current projects

We are developing catalytic model systems for a wide range of different reactions including:

  • Oxygen Evolution Reaction

  • Oxygen Reduction Reaction

  • Hydrogenperoxide formation

  • CO2 reduction

  • Electrochemical ammonia production

  • Thermocatalytic methanol synthesis

Selected papers

  1. Impact of Size and Lattice Oxygen on Water Oxidation on NiFeOxHy
    C. Roy, B. Sebök, S. B. Scott, E. M. Fiordaliso, J. E. Sørensen, A. Bodin, D. B. Trimarco, C. D. Damsgaard,  P. C. K. Vesborg, O. Hansen, I. E. L. Stephens, J. Kibsgaard, and I. Chorkendorff
    Nature Catalysis (2018), Accepted.


  2. Engineering Ni–Mo–S Nanoparticles for Hydrodesulfurization
    A. Bodin, A.-L. N. Christoffersen, C. F. Elkjær, M. Brorson, J. Kibsgaard, S. Helveg, I. Chorkendorff
    Nano Lett.  18, 3454-3460, (2018)

  3. Operando XAS Study of the Surface Oxidation State on a Monolayer IrOx on RuOx and Ru Oxide Based Nanoparticles for Oxygen Evolution in Acidic Media
    A. F. PedersenM. Escudero-EscribanoB. SebökA. BodinE. PaoliR. FrydendalD. FriebelI. E. L. StephensJ. RossmeislI. Chorkendorff, and A. Nilsson
    J. Phys. Chem. B, 122 (2), pp 878–887 (2018)

  4. Scalability and feasibility of photoelectrochemical H2 evolution: the ultimate limit of Pt nanoparticle as an HER catalyst
    E. Kemppainen, A. Bodin, B. Sebök, T. Pedersen, B. Seger, B. Mei, D. Bae, P. C. K. Vesborg, J. Halme, O. Hansen, P. D. Lund, and I. Chorkendorff 
    Energy Environ. Sci., 8, 2991-2999, (2015)

  5. Mass-selected nanoparticles of PtxY as model catalysts for oxygen electroreduction
    P. Hernandez-FernandezF. MasiniD. N. McCarthyC. E. StrebelD. FriebelD. DeianaP. MalacridaA. NierhoffA. BodinA. M. WiseJ. H. NielsenT. W. HansenA. NilssonI. E. L. Stephens, and I. Chorkendorff
    Nature Chemistry, 6, 732–738, (2014)

Contact

Ib Chorkendorff
Professor
DTU Physics
+45 45 25 31 70

Contact

Jakob Kibsgaard
Associate Professor
DTU Physics
+45 45 25 32 90
http://www.fysik.dtu.dk/english/Research/SURFCAT/SurfCat-research/Nanoparticle
23 OCTOBER 2018