Gas sensors based on metal oxide (MOx) nanowires are a promising area of research, as their high aspect ratio allow a high degree of sensitivity, while synthesis via thermal oxidation is possible at temperatures which are compatible with silicon technology. However, these sensors have issues with cross sensitivity, reacting to different gases in similar ways. One solution to differentiate the response is to develop an array of nanowires each functionalised with different nanoparticles.
Nanoparticles on MOx supports have been used as inorganic heterogeneous catalysts across a variety of gas-based applications for decades including chemical synthesis, industrial production processes and removing pollutants from car exhaust. Nanoclusters synthesised through cluster beam deposition techniques have been emerging over the past two decades as a new tool in undertanding of nanoparticle catalysts. This technique is advantageous for silicon technology as the nanoparticles produced are free from surfactants, solvents and ligands.
This presentation will detail the decoration of CuO nanowire sensing elements using physically deposited gas condensed clusters of catalytic nanoparticles, and the systems subsequent performance as a sensor to CO and acetone. Further work using aberration corrected HDAAF S/TEM and XPS to elcuidate the changes in the nanowire/nanocluster system with increasing temperature will also be shown.
Results from our work demonstrate that CuO nanowires functionalised with nanoclusters including Pt and Ru do exhibit changed sensor behaviour in response to test gases. In addition, as this synthesis method is free from additional ligands and other stabilises, we give some consideration and discussion to changes in the nanoparticles (i.e. possible oxidation state) and the interface between the nanoparticle and nanowire as a result of running these sensing elements at different temperatures.
 S. Steinhauer, A. Chapelle, P. Menini, and M. Sowwan,
ACS Sensors, 1(5), (2016), 503-507
 S. Steinhauer, V. Singh, C. Cassidy, C. Gspan, W. Grogger, M. Sowwan, and A. Köck,
Nanotechnology, 26, (2015), 175502
 S. Steinhauer, J. Zhao, V. Singh, T. Pavloudis, J. Kioseoglou, K. Nordlund, F. Djurabekova, P. Grammatikopoulos, and M. Sowwan,
Chemistry of Materials, 29(14), (2017), 6153-6160