High-Throughput Physical Vapour Deposition (HT-PVD) based on Molecular Beam Epitaxy methods1 has been used to synthesize libraries of catalysts which have subsequently been screened for their electrochemical activity and stability. A screening method is briefly described2 which has been applied to measurements on model supported metal nano-particle HT-PVD catalyst libraries.

 

Considerable effort has been made to find alternative supports for platinum based catalysts in order to improve the particle stability and improve the three-phase boundary in fuel cell applications. HT-PVD model catalyst methodology has been applied to the study of support and particle size effects in electrocatalysis.3 Experiments have demonstrated the potential for using a support such as titania to induce CO oxidation electro-catalytic activity in gold particles,4 with an optimum particle size observed at ca. 3nm (Figure). No induced activity is observed for carbon supports. The similarities with the low temperature oxidations exhibited by supported Au in heterogeneous catalytic are highlighted. Extending this methodology to supported platinum based catalysts, the effect of particle size is demonstrated in the reduction of oxygen for the model carbon supported platinum catalysts, highlighting the limitations of catalyst dispersion. Supporting platinum on titania can result is a strong poisoning of the oxygen reduction catalysis.5

 

The combination of ab-initio theory and electrocatalyst screening also provides a powerful combination in the search for precious metal alloy and non noble metal alloy catalysts. Examples are given for anode hydrogen oxidation (HOR) catalysts such as Pd based,6 and tungsten copper7 alloys.

 

References

1. S. Guerin and B. E. Hayden; J. Comb. Chem. 8 (2006) 66-73.

2. S. Guerin, B.E. Hayden, et.al.; J. Comb. Chem. 6 (2004) 149 - 158.

3. S. Guerin, B.E. Hayden, D. Pletcher, et.al.; J. Comb. Chem. 8 (2006) 791-798.

4. B.E. Hayden, D. Pletcher and J.-P. Suchsland; Angewandte Chemie Int. Ed. 46 (2007) 3530-3532.

5. B.E. Hayden, D. Pletcher, J.-P. Suchsland et.al.; Phys. Chem. Chem. Phys. 11 (2009) 1564-1570. ibid: Phys. Chem. Chem. Phys., 2009, 11, 9141–9148.

6. F. A. Al-Odail, A. Anastasopoulos, and B. E. Hayden; Phys. Chem. Chem. Phys. 12 (2010) 11398-11406. Ibid; Topics in Catalysis 54 (2011) 77-82.

7. A. Anastasopoulos, J. Blake, John and B.E. Hayden; J. Phys. Chem. C, 115 (2011) 19226-19230.