Nanoporous Gold

About 30 years ago, the observation of high catalytic activity of gold nanoparticles on titania for low-temperature CO oxidation came as a surprise and brought gold catalysis into the limelight of scientific interest. Since then research on gold surface chemistry has fueled prospects of sustainable “green” catalysts with combined high selectivity and activity at moderate temperatures, as nanostructured gold has demonstrated on laboratory scale for several partial oxidation reactions.

Applications came more into reach when it turned out that nanoporous gold (npAu), a sponge-like, skeletal material comprised of pores and ligaments on the order of a few tens of nanometers shows comparable activity for low-temperature CO oxidation, too. Prepared by wet chemical corrosion of gold silver alloy, one key to its chemical activity is the surface composition, involving residual traces of the less noble metal Ag. At variance to Raney Nickel or Copper catalysts, npAu can be prepared as monolithic material.

Having conducted research on heterogeneous catalysis at nanoporous gold from the beginning, we have a continuing strong interest in identifying the underlying mechanisms of surface chemistry on the molecular scale as well as developing applications of this exciting catalytic material. Here, the high thermal and electrical conductivity as well as mechanical stability open up a wide range, ranging from catalysis to sensors to actuators.

Current projects

Applications of Nanoporous Gold in Heterogeneous Catalysis

Heterogeneous Catalysis with Gold from a Theoretical Perspective

Selection of Publications:

¹ A. Wittstock, V. Zielasek, J. Biener, C. M. Friend, M. Bäumer, Nanoporous Gold Catalysts for Selective Gas-Phase Oxidative Coupling of Methanol at Low Temperature, Science 327 (2010) 319. DOI: 10.1126/science.1183591

² V. Zielasek, B. Jürgens, C. Schulz, J. Biener, M. M. Biener, A. V. Hamza, M. Bäumer, Gold Catalysts: Nanoporous Gold Foams, Angew.Chem. Int. Ed. 45 (2006) 8241. DOI: 10.1002/anie.200602484

³ J. Biener, A. Wittstock, L. A. Zepeda-Ruiz, M. M. Biener, V. Zielasek, D. Kramer, R. N. Viswanath, J. Weissmüller, M. Bäumer, A. V. Hamza, Surface-chemistry-driven actuation in nanoporous gold, Nature Mater. 8 (2009) 47. DOI: 10.1038/nmat2335

⁴ A. Wittstock, B. Neumann, A. Schaefer, K. Dumbuya, C. Kübel, M. M. Biener, V. Zielasek, H.-P. Steinrück, J. M. Gottfried, J. Biener, A. V. Hamza, M. Bäumer, Nanoporous Au: An unsupported pure gold catalyst?, J. Phys. Chem. C 113 (2009) 5593. DOI: 10.1021/jp808185v

⁵ A. Wittstock, J. Biener, M. Bäumer, Nanoporous gold: a new material for catalytic and sensor applications, Phys. Chem. Chem. Phys. 12 (2010) 12919. DOI: 10.1039/c0cp00757a

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