Microwave-Induced Nanoscale Convection, Polarisation, and Thermal Effects Leading to Innovative Analytical Technology

Lead Research Organisation: University of Bath
Department Name: Chemistry


Our project hypothesis is that extremely energetic microwave-driven convection and heating are possible for both inlaid-disk nanoelectrodes and nanoparticles immersed in solution and that massive improvements in electroanalytical processes can be achieved with these microwave effects. These phenomena (temperature, mass transport) can be directly measured and quantified in electrochemical experiments employing nanoelectrodes. At very small electrodes turbulence can be suppressed and unusually fast convective flow can be achieved (driven by microwave induced thermal gradients) giving high currents and beneficial effects e.g. kinetic resolution in analytical applications (sulphide, thiol, arsenite, oxygen, carbon dioxide, etc.). More importantly, the adsorption of microwaves into the double layer of interfaces with sufficiently fast RC time constant (e.g. at nanoelectrodes) has never been reported and may again lead to novel chemical phenomena (e.g. for processes involving H2, CO2, or CO adsorbates on Pt, Pd, or Au). These kinds of processes (which occur only at nanoelectrodes or nanoparticles) could be important for sensor and fuel cell processes.


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Description We were able to focus microwave energy into a very small spot adjacent to the electrode into the solution phase. This provides a completely new mechanism of microwave enhancement where extreme conditions are generated not at the electrode surface, but just a small distance away in the solution.

We discovered that for very small "nano-electodes" the extreme conditions reached levels that plasma, arching, and discharge occurred, which ultimately damaged the sensor electrodes. For micro-electrodes the extreme conditions created super-heating and extreme mass transport. These are unusual conditions and we still explore potential applications, for example in "flash-synthesis" of metal nanoparticles at micro-steel electrodes.
Exploitation Route Creating extreme conditions in a small volume does not directly link to traditional microwave technology fields, but in analysis and in micro-fluidics, this should trigger new technologies (e.g. in fast digestion or heat shock conversion). The type of measurements we started during this project are now performed also by researchers in China and further developments may be possible.
Sectors Environment,Healthcare

Description Researchers in China have continued using our methodology. Collaborators in Brazil have recently started exploring microwave activation in corrosion and other electrochemical processes. Discussion with industry has so far not developed into follow-up non-academic developments.
First Year Of Impact 2010
Sector Environment,Healthcare
Impact Types Societal