Enhanced Gas Sensing by Individual SnO₂ Nanowires and Nanobelts Functionalized with Pd Catalyst Particles

Abstract

The sensing ability of individual SnO(2) nanowires and nanobelts configured as gas sensors was measured before and after functionalization with Pd catalyst particles. In situ deposition of Pd in the same reaction chamber in which the sensing measurements were carried out ensured that the observed modification in behavior was due to the Pd functionalization rather than the variation in properties from one nanowire to another. Changes in the conductance in the early stages of metal deposition (i.e., before metal percolation) indicated that the Pd nanoparticles on the nanowire surface created Schottky barrier-type junctions resulting in the formation of electron depletion regions within the nanowire, constricting the effective conduction channel and reducing the conductance. Pd-functionalized nanostructures exhibited a dramatic improvement in sensitivity toward oxygen and hydrogen due to the enhanced catalytic dissociation of the molecular adsorbate on the Pd nanoparticle surfaces and the subsequent diffusion of the resultant atomic species to the oxide surface.

Surface plasmon-enhanced gas sensing in single gold-peapodded silica nanowires

“…Because of their large surface areas, nanostructures such as nanowires (NWs), 3 nanotubes, 4,5 nanorods 6 and nanoparticles (NPs) 7 offer large reaction cross sections for signal generation. To further enhance the sensing performance of these nanostructures, surface modification, [8][9][10] applications of high electrical bias 11 and high operational temperatures (T4100 1C) 12 have been used.…”

“…Because of their large surface areas, nanostructures such as nanowires (NWs), 3 nanotubes, 4,5 nanorods 6 and nanoparticles (NPs) 7 offer large reaction cross sections for signal generation. To further enhance the sensing performance of these nanostructures, surface modification, [8][9][10] applications of high electrical bias 11 and high operational temperatures (T4100 1C) 12 have been used.Improving the sensing performance with light has also been demonstrated using ZnO-based nanostructures under UV illumination. 13 However, most of these approaches have required high operational temperatures, high biases and light outside the visible range (400-800 nm), which has somewhat limited their general applicability.…”

Electrochemical Sensors

“…Kolmakov and coworkers enhanced the oxygen and hydrogen gas sensitivity of SnO2 nanowires, when used as chemiresistor, by plating them with Pd catalyst particles. 114 The enhancement was explained by the catalytic action of Pd, which was argued predissociate the adsorbing species before the actual chemisorption process. The selectivity of the device was not discussed in this paper.…”

Assembling SnO Nanosheets into Microhydrangeas: Gas Phase Synthesis and Their Optical Property

“…SnO and SnO 2 are two important wide band gap semiconductors. Tin dioxide (SnO 2 , E g = 3.62 eV, at 300 K) has been widely studied due to its promising applications in gas sensors [1][2][3], solar cells [4], optical devices [5][6], lithium ion batteries [7][8], and photocatalysts [9][10][11]. In contrast, the investigation of SnO materials has fallen behind, perhaps because it decomposes easily at elevated temperature and the divalent tin ion can be oxidized to the tetravalent one.…”