Flame-synthesis of copper-ceria catalysts
The widespread adoption of polymer electrolyte membrane fuels cells is reliant on the production of high-purity hydrogen with a carbon monoxide contaminant concentration of less than 50 ppm. To achieve this purity, copper ceria nanopowders have been proposed as a potential catalyst for the preferential oxidation of carbon monoxide from the hydrogen feed stream. Further to the high levels of activity and selectivity, copper-based catalysts are significantly cheaper than traditional precious metal catalysts (e.g. Pt, Au, Pd and Rh).
While conventional aqueous preparation methods rely upon successive adsorption, rinsing and calcination procedures, in this work attempts were made to synthesise copper-ceria nanoparticulate catalysts via the single-step Flame Spray Pyrolysis (FSP) process.
Major achievements and highlights
FSP-made copper-ceria catalysts were found to display high levels of CO oxidation at temperatures below 100°C and did not require high temperature oxidative pretreatments, unlike catalysts prepared by conventional methods.
The powders were also stable over extended periods of time, both under reaction conditions and in storage, unlike rival gold-based catalysts.
The prepared materials also exhibited high levels of selectivity over a broad temperature range with minimal hydrogen consumption.
Surface characterisation of the high activity catalysts revealed a unique dimeric structure for the copper component of the catalyst, which cannot be achieved via conventional preparation methods. This dimeric structure was found to enhance low temperature catalytic activity.
Future plans and directions
Given the novel dimeric structure and the high levels of carbon monoxide oxidation activity, other heterogeneous catalytic reactions, such as the removal of nitrogen oxides, will also be investigated.
A further theoretical description of the catalytic mechanism should also enable the targeted selection of promoters and the subsequent design of superior catalytic materials.
Collaborations
Collaborator |
Organisation |
Dr Yong Wang |
The University of Queensland |
Dr Keith Fisher |
University of Sydney |
