Chemical Sensing and Catalysis by One-Dimensional Metal-Oxide Nanostructures

Abstract

Metal-oxide nanowires can function as sensitive and selective chemical or biological sensors, which could potentially be massively multiplexed in devices of small size. The active nanowire sensor element in such devices can be configured either as resistors whose conductance is altered by charge-transfer processes occurring at their surfaces or as field-effect transistors whose properties can be controlled by applying an appropriate potential onto its gate. Functionalizing the surface of these entities offers yet another avenue for expanding their sensing capability. In turn, because charge exchange between an adsorbate and the nanowire can change the electron density in the nanowire, modifying the nanowire's carrier density by external means, such as applying a potential to the gate, could modify its surface chemical properties and perhaps change the rate and selectivity of catalytic processes occurring at its surface. Although research on the use of metal-oxide nanowires as sensors is still in early stages, several encouraging experiments have been reported that are interesting in their own right and indicative of a promising future.

Comparative investigation of three types of ethanol sensor based on NiO-SnO2 composite nanofibers

“…Previous papers discussed that 1D nanomaterials showed fast response and recovery speeds, which were due to the high surface-to-volume ratios, while the web-like structures of these materials could easily absorb and desorb gas molecules [13]. Similar results are also found in our investigation.…”

“…Simultaneously, the high surface-to-volume ratios of 1D nanomaterials can provide more sites for analyte molecule adsorption, leading to high response values and short response/recovery times [12]. Moreover, their large length-to-diameter characteristic can also cause charge carriers to traverse the barriers introduced by molecular recognition [13]. Many scientists agree that these novel materials are expected to replace traditional nanoparticles and nanopowders, and be widely chosen to fabricate microsensors or nanosensors [14][15][16].…”

Depth-resolved cathodoluminescence study of zinc oxide nanorods catalytically grown on p-type 4H-SiC

“…All such nanostructures have been successfully synthesized and have attracted interest because they can be used as building blocks for future optoelectronic devices. These nanostructures have many advantages among which large surface to volume ratio, good crystal quality and unique photonic properties [8,9]. So far, among these structures, the NRs of ZnO are grown with relatively better crystalline quality with lower defect density compared to bulk and thin films due to their small footprint and the release of strain and stress due to the relaxing large surface area to volume ratio.…”

Sub-nA spatially resolved conductivity profiling of surface and interface defects in ceria films

“…C Coupling between electronic and ionic transport in solid oxides underpins an immense range of energy storage and conversion technologies. Such phenomena are further employed in macroscopic and nanoscale chemical sensors, [1][2][3] enabling the detection of a broad range of gaseous and liquid species and can be further utilized in electrochemical transducers. 4 Recently, a broad range of potential applications for ionic and mixed ionic electronic conductors (MIECs) 5,6 has emerged in information technologies for electroresistive memories and neuromorphic electronic devices.…”