Julia Melisande T. A. Fischer1*, Marlies Hankel1, Debra J. Searles1,2Author, Author, Author 

 

1Centre for Theoretical and Computational Molecular Science, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland 4072, Australia.
2
School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia.

 

A single-atom catalyst (SAC) refers to an isolated single metal atom, stabilized in a solid substrate, which functions as an active centre for heterogeneous catalysis.  The main advantage of using these catalysts is that they reduce the amount of expensive, rare metals required. Paired SAC refers to the combined effect of two single atoms adjacent to each other.

It is widely known that the best electrochemical catalyst for the oxygen reduction reaction (ORR) is Pt. In collaboration with Yao’s experimental group,2 we have shown that the Co and Pt paired SAC outperforms the Pt metal catalyst for the ORR. In experimental studies, the distribution of metal distances and the chemical environment were determined for high performance paired SACs. Based on this information, model structures were constructed and density functional theory (DFT) calculations carried out on these systems. Nitrogen doped graphene with different sized vacancies were used to vary the metal-metal distances of the Co and Pt atoms. The free energies of intermediate species of the OOR were calculated to determine the likely mechanism of the reaction on these systems. Further, to compare the results to the experiments, the overpotentials were determined from the difference in voltage for the reaction to occur experientially and the thermodynamically expected value. Both calculations and experiments show that enhancement of the ORR can be obtained with a lower overpotential using a combined CoPt system rather than a Pt paired SAC.

 

1 Yang, X. F., Wang, A., Qiao, B., Li, J. , Liu, J. and Zhang, T. Acc. Chem. Res. 2013, 46 (8), 1740-1748. Single-atom catalysts: a new frontier in heterogeneous catalysis.

2 Zhang, L., Fischer, J. M. T. A., Jia, Y., Yan, X., Xu, W., Wang, X., Chen, J., Hankel, M., Searles, D. J., Feng S. and Yao X. manuscript in preparation.

Biographic Details

Name: Julia Melisande Fischer

Affiliation: Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland 4072, Australia.

E-mail: jmta.fischer@uq.net.au

Research interests: Surface catalysis, density functional theory, nanomaterials, carbon dioxide reduction, hydrogen evolution reaction, two dimensional material, graphene

 

Julia Melisande Fischer received both her Bachelor and Master degree in chemistry at the University of Ulm in Germany. Currently she is completing her PhD in the Australian Institute for Bioengineering and Nanotechnology at the University of Queensland and holds an International Postgraduate Research Scholarship.