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One foundational motivation for chemical sensing is that knowledge of the presence and level of a chemical agent
informs decisions about treatment of the agent, for example by sequestration, separation or chemical conversion to a less
harmful substance. Commonly the sensing and treatment steps are separate. However, the disjoint detection/treatment
approach is neither optimal, nor required. Thus, we are investigating how nanostructured architectures can be
constructed so that molecular transport (analyte/reagent delivery), chemical sensing (optical or electrochemical) and
subsequent treatment can all be coupled in the same physical space during the same translocation event. Chemical
sensors that are uniquely well-poised for integration into 3-D micro-/nanofluidic architectures include those based on
plasmonics and impedance. Following detection, treatment can be substantially enhanced if mass transport limitations
can be overcome. In this context, in situ generation of reactive species within confined geometries, such as nanopores or
nanochannels, is of significant interest, because of its potential utility in overcoming mass transport limitations in
chemical reactivity. Solvent electrolysis in electrochemically coupled nanochannels supporting electrokinetic flow for
the generation of reactive species, can produce arbitrarily tunable quantities of reagents, such as O2 or H2, in situ in close proximity to the site of a hydrogenation catalyst, for example. Semi-quantitative estimates of the local H2 concentration are obtained by comparing the spatiotemporal fluorescence behavior and current measurements with finite element simulations accounting for electrolysis and subsequent convection and diffusion within the confined geometry. H2 saturation can easily be achieved at modest overpotentials.
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