Interaction of hybrid nanowire-nanoparticle structures with carbon monoxide

A gas-phase sensor based on a GaN nanowire mat decorated with Au nanoparticles was studied both experimentally and theoretically. The sensor is responsive to CO and H2 and could be used to study the water-gas-shift reaction, which involves combining CO and H2O to produce H2. It was shown that for catalyzing this reaction using support Au nanoparticles, the sequence in which the reactants are exposed to the catalyst surface is critical. To quantitatively evaluate the sensor response to gas exposure a depletion model was developed that considered the Au nanoparticle-semiconductor interface as a nano-Schottky barrier where variation in the depletion region caused changes in the electrical conductivity of the nanowires.