Pure and Au-decorated sub-micrometer ZnO spheres were successfully grown on glass substrates by simple chemical bath deposition and photoreduction methods. The analysis of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images, energy-dispersive X-ray spectroscopy (EDS), UV–vis absorption, and photoluminescence (PL) spectra results were used to verify the incorporation of plasmonic Au nanoparticles (NPs) on the ZnO film. Time-resolved photoluminescence (TRPL) spectra indicated that a surface plasmonic effect exists with a fast rate of charge transfer from Au nanoparticles to the sub-micrometer ZnO sphere, which suggested the strong possibility of the use of the material for the design of efficient catalytic devices. The NO2 sensing ability of as-deposited ZnO films was investigated with different gas concentrations at an optimized sensing temperature of 120 °C. Surface decoration of plasmonic Au nanoparticles provided an enhanced sensitivity (141 times) with improved response (τRes = 9 s) and recovery time (τRec = 39 s). The enhanced gas sensing performance and photocatalytic degradation processes are suggested to be attributed to not only the surface plasmon resonance effect, but also due to a Schottky barrier between plasmonic Au and ZnO structures.
In this paper, research on a CO catalytic gas sensor based on nano-crystalline perovskite oxide NdFeO
3 designed for exhaust gas measurement is presented. Nano-crystalline oxide NdFeO
3 was synthesized by a sol–gel citrate technique. The gas sensing characteristics of this sensor were investigated in the concentration range of CO between 0 and 5 vol.% in air. The influences of C
3
H
8, C
4
H
16 gases, relative humidity and air-flow rate on the cross-sensitivity of the CO sensor were also studied.
SummaryThe effect of palladium doping of zinc oxide nanoparticles on the photoluminescence (PL) properties and hydrogen sensing characteristics of gas sensors is investigated. The PL intensity shows that the carrier dynamics coincides with the buildup of the Pd-related green emission. The comparison between the deep level emission and the gas sensing response characteristics allows us to suggest that the dissociation of hydrogen takes place at PdZn-vacancies ([Pd 2+(4d9)]). The design of this sensor allows for a continuous monitoring in the range of 0–100% LEL H2 concentration with high sensitivity and selectivity.
We
reported the synthesis and full characterization of ultralong
Bi2S3 nanowires with diameters of 60–80
nm and lengths above 1 μm, showing growth in the [001] direction.
Combining the computed lattice dynamics of orthorhombic Bi2S3 with the experimental micro-Raman scattering study
provided comprehensive solutions. We demonstrate that 10 active modes
originated from Raman symmetry modes (4Ag + 2B1g + 3B2g + 1B3g), and the peak at 124 cm–1 is due to the IR-active B3u mode. The
use of the Bi2S3 catalyst for dewatering hexavalent
chromium-containing wastewater was also reported. This confirms it
to be a potential candidate for photocatalytic environmental remediation.
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