UC Spark

Dr Aaron T Marshall

Chemical and Process Engineering

Phone: +64 3 364 2987 ext. 4292
Office: Civil/Mechanical Engineering E546

Fields of Research

  • Electrochemical wastewater treatment
  • Production of Hydrogen via water electrolysis
  • Hydrogen production from biomass
  • Reforming hydrocarbons to hydrogen in membrane reactors
  • Low temperature fuel cell development
  • Catalyst development and characterisation
  • Nanoparticle characterisation using synchrotron based x-ray techniques

Researcher Summary

The majority of my research interests are based around energy and hydrogen technologies. This includes activities on fuel cells, water electrolysis and recently conversion of biofuels in electrochemical reactors. I have an interest in surface chemistry, particularly using x-ray based methods to understand how and why reactions proceed on various surfaces. I have experience utilising synchrotron radiation to determine structure of materials and the binding of species to surfaces at the atomic scale under industrially relevant reaction conditions.

Another interest is the structure and formation of the electrode-electrolyte interface or electric double layer. This layer is of fundamental importance to all interfacial processes but in many cases the structure of this layer is un-resolved. I am particularly interested in the role that electron accumulation, space-layer charging and proton injection has on the structure of the electric double layer and electrode surface of conductive metal oxides, as this is most likely correlated to electrocatalytic activity.

Subject Area: Disciplines


Research Groups


Future Research

  • Electrochemical wastewater treatment
  • Water-gas shift reaction in novel membrane reactors

Key Methodologies

  • Cyclic voltammetry and electrochemical impedance spectroscopy
  • X-ray diffraction
  • X-ray absorption spectroscopy (synchrotron)
  • X-ray photoelectron spectroscopy
  • Electrochemistry, potentiostats
  • Scanning probe microscopy (AFM, STM)

Equipment


Affiliations


Publications


Journal Article
  • Marshall, A.T. and Haverkamp, R.G. (2012) Nanoparticles of IrO2 or Sb-SnO2 increase the performance of Iridium oxide DSA electrodes. Journal of Materials Science 47(3): 1135-1141. http://dx.doi.org/10.1007/s10853-011-5958-x.
  • Haverkamp, R.G., Marshall, A.T. and Cowie, B.C.C. (2011) Energy resolved XPS depth profile of (IrO2, RuO2, Sb2O5, SnO2) electrocatalyst powder to reveal core-shell nanoparticle structure. Surface and Interface Analysis 43(5): 847-855. http://dx.doi.org/10.1002/sia.3644.
  • Haverkamp, R.G. and Marshall, A.T. (2009) The mechanism of metal nanoparticle formation in plants: limits on accumulation. Journal of Nanoparticle Research 11(6): 1453-1463. http://dx.doi.org/10.1007/s11051-008-9533-6.
  • Marshall, A.T. and Haverkamp, R.G. (2008) Production of hydrogen by the electrochemical reforming of glycerol-water solutions in a PEM electrolysis cell. International Journal of Hydrogen Energy 33(17): 4649-4654. http://dx.doi.org/10.1016/j.ijhydene.2008.05.029.
  • Williams, M.A.K., Marshall, A., Haverkamp, R.G. and Draget K.I. (2008) Stretching single polysaccharide molecules using AFM: A potential method for the investigation of the intermolecular uronate distribution of alginate? Food Hydrocolloids 22(1): 18-23. http://dx.doi.org/10.1016/j.foodhyd.2007.01.020.
  • Haverkamp, R.G., Marshall, A.T. and Williams, M.A.K. (2007) A Model for Stretching Elastic Biopolymers which Exhibit Conformational Transitions. Physical Review E: Statistical, Nonlinear, and Soft Matter Physics 75(2): 021907. http://dx.doi.org/10.1103/PhysRevE.75.021907.
  • Marshall, A.T., Haverkamp, R.G., Davies, C.E., Parsons, J.G., Gardea-Torresdey, J.L. and van Agterveld, D. (2007) Accumulation of Gold Nanoparticles in Brassic Juncea. International Journal of Phytoremediation 9(3): 197-206. http://dx.doi.org/10.1080/15226510701376026.
  • Haverkamp, R.G., Marshall, A.T. and Williams, M.A.K. (2007) Entropic and Enthalpic Contributions to the Chair-Boat Conformational Transformation in Dextran under Single Molecule Stretching. Journal of Physical Chemistry B 111(48): 13653–13657. http://dx.doi.org/10.1021/jp076052t.
  • Marshall, A., Børresen, B., Hagen, G., Tsypkin, M. and Tunold, R. (2007) Hydrogen production by advanced Proton Exchange Membrane (PEM) water electrolysers - Reduced energy consumption by improved electrocatalysis. Energy 32(4): 431-436. http://dx.doi.org/10.1016/j.energy.2006.07.014.
  • Williams, M.A.K., Marshall, A.T., Anjukandi, P. and Haverkamp, R.G. (2007) Investigation of the effects of fine structure on the nanomechanical properties of pectin. Physical Review E: Statistical, Nonlinear, and Soft Matter Physics 76(2): 021927. http://dx.doi.org/10.1103/PhysRevE.76.021927.
  • Marshall, A.T., Sunde, S., Tsypkin, M. and Tunold, R. (2007) Performance of a PEM water electrolysis cell using IrxRuyTazO2 electrocatalysts for the oxygen evolution electrode. International Journal of Hydrogen Energy 32(13): 2320-2324. http://dx.doi.org/10.1016/j.ijhydene.2007.02.013.
  • Haverkamp, R.G., Marshall, A.T. and van Agterveld, D. (2007) Pick your Carats: Nanoparticles of Gold-Silver-Copper Alloy Produced In Vivo. Journal of Nanoparticle Research 9(4): 697-700. http://dx.doi.org/10.1007/s11051-006-9198-y.
  • Marshall, A., Børresen, B., Hagen, G., Tsypkin, M. and Tunold, R. (2006) Electrochemical characterisation of IrxSn1-xO2 powders as oxygen evolution electrocatalysts. Electrochimica Acta 51(15): 3161-3167. http://dx.doi.org/10.1016/j.electacta.2005.09.004.
  • Marshall, A., Børresen, B., Hagen, G., Sunde, S., Tsypkin, M. and Tunold, R. (2006) Iridium oxide-based nanocrystalline particles as oxygen evolution electrocatalysts. Russian Journal of Electrochemisty 42(10): 1134-1140. http://dx.doi.org/10.1134/S1023193506100223.
  • Marshall, A., Børresen, B., Hagen, G., Tsypkin, M. and Tunold, R. (2005) Preparation and characterisation of nanocrystalline IrxSn1-xO2 electrocatalytic powders. Materials Chemistry and Physics 94(2-3): 226-232. http://dx.doi.org/10.1016/j.matchemphys.2005.04.039.
  • Marshall, A., Tsypkin, M., Børresen, B., Hagen, G. and Tunold, R. (2004) Nanocrystalline IrxSn1-xO2 electrocatalysts for oxygen evolution in water electrolysis with polymer electrolyte - Effect of heat treatment. Journal of New Materials for Electrochemical Systems 7: 197-204.
Conference Contribution - Full conference paper
  • Padayachee, D., Golovko, V. and Marshall, A.T. (2012) Development of electrocatalysts for glycerol fuel cells. Wellington, New Zealand: Chemeca2012, 23-26 Sep 2012.
  • Mellsop, S.R., Marshall, A.T. and Gardiner, A. (2012) Development of electrocatalysts for the oxygen evolution reaction in alkaline solution. Wellington, New Zealand: Chemeca2012, 23-26 Sep 2012.
  • Marshall, A.T. and MacDonald, M.J. (2012) Electrochemical oxidation of biodiesel wastewater using a dimensionally stablised anode. Wellington, New Zealand: Chemeca2012, 23-26 Sep 2012.
  • Evelyn, E., Marshall, A.T. and Gostomski, P. (2012) Ethanol oxidation in a microbial fuel cell (MFC) utilising various mediators and potential intergration of a MFC into an anaerobic biofiltration system. Wellington, New Zealand: Chemeca2012, 23-26 Sep 2012.
Conference Contribution - Paper in published proceedings
  • Penniall, C., Williamson, C. and Marshall, A.T. (2012) Comparison of the performance of washcoating variations for Fisher-Tropsch synthesis in a microchannel reactor. Wellington, New Zealand: Chemeca2012, 23-26 Sep 2012.
  • Tunold, R., Marshall, A., Rasten, E., Tsypkin, M., Owe, L. and Sunde, S. (2010) Materials for Electrocatalysis of Oxygen Evolution in PEM Water Electrolysis. Vienna, Austria: 216th Electrochemical Society Meeting, 4-9 Oct 2009. In ECS Transactions 25(23) 103-117. http://dx.doi.org/10.1149/1.3328515.
  • Marshall, A.T., Haverkamp, R.G. and Williams, M.A.K. (2006) Stretching single molecules of pectin and their force induced conformational transformations. Rotorua, New Zealand: NZIC Conference, 2-6 Dec 2006. 151-152.
Conference Contribution - Abstract
  • Marshall, A., Børresen, B., Hagen, G., Tsypkin, M. and Tunold, R. (2006) Nanocrystalline Oxides as Oxygen Evolution Electrocatalysts for PEM Water Electrolysis. Denver, CO, USA: 209th Electrochemical Society Meeting, 7-12 May 2006.
  • R.G. Haverkamp, A. T. Marshall. and M.A.K Williams. (2006) Single Molecule Polysaccharide Stretching - A Model for the Conformational Transitions. Rio de Janeiro, Brazil: 41st International Symposium on Macromolecules - IUPAC World Polymer Congress MACRO 2006, 16-21 Jul 2006.
Conference Contribution - Oral presentation
  • Tunold, R., Tsypkin, M.A., Marshall, A. and Rasten, E. (2011) Electrocatalysis of oxygen evolution in PEM water electrolysis cell. Chania, Greece: 9th European Symposium on Electrochemical Engineering (ESSE), 19-23 Jun 2011.
  • Marshall, A.T. and Haverkamp, R.G. (2009) Structural analysis of conductive metal oxide electrocatalysts. Wellington, New Zealand: New Zealand Synchrotron Users' Meeting 2009, 20-21 Apr 2009.
  • Haverkamp, R.G., Marshall, A. and Williams, M. (2007) The Thermodynamics of Single Molecule Stretching of Polysaccharides: Implications for Elastic Tissues. Salt Lake City, UT, USA: AIChE Annual Meeting, 4-9 Nov 2007.
  • Williams, M.A.K., Haverkamp, R.G., Marshall, A. and Draget, K.I. (2006) Stretching single polysaccharide molecules using AFM. Trondheim, Norway: 8th International Hydrocolloids Conference, 18-22 Jun 2006.