2 research outputs found
Chemically Reduced Graphene Oxide for Ammonia Detection at Room Temperature
Chemically reduced graphene oxide
(RGO) has recently attracted growing interest in the area of chemical
sensors because of its high electrical conductivity and chemically
active defect sites. This paper reports the synthesis of chemically
reduced GO using NaBH<sub>4</sub> and its performance for ammonia
detection at room temperature. The sensing layer was synthesized on
a ceramic substrate containing platinum electrodes. The effect of
the reduction time of graphene oxide (GO) was explored to optimize
the response, recovery, and response time. The RGO film was characterized
electrically and also with atomic force microscopy and X-ray photoelectron
spectroscopy. The sensor response was found to lie between 5.5% at
200 ppm (parts per million) and 23% at 2800 ppm of ammonia, and also
resistance recovered quickly without any application of heat (for
lower concentrations of ammonia). The sensor was exposed to different
vapors and found to be selective toward ammonia. We believe such chemically
reduced GO could potentially be used to manufacture a new generation
of low-power portable ammonia sensors
Cerium-Doped Copper(II) Oxide Hollow Nanostructures as Efficient and Tunable Sensors for Volatile Organic Compounds
Tuning
sensing capabilities of simple to complex oxides for achieving
enhanced sensitivity and selectivity toward the detection of toxic
volatile organic compounds (VOCs) is extremely important and remains
a challenge. In the present work, we report the synthesis of pristine
and Ce-doped CuO hollow nanostructures, which have much higher VOC
sensing and response characteristics than their solid analogues. Undoped
CuO hollow nanostructures exhibit high response for sensing of acetone
as compared to commercial CuO nanoparticles. As a result of doping
with cerium, the material starts showing selectivity. CuO hollow structures
doped with 5 at. % of Ce return highest response toward methanol sensing,
whereas increasing the Ce doping concentration to 10%, the material
shows high response for bothacetone and methanol. The observed
tunability in selectivity is directly linked to the varying concentration
of the oxygen defects on the surface of the nanostructures. The work
also shows that the use of hollow nanostructures could be the way
forward for obtaining high-performance sensors even by using conventional
and simple metal or semiconductor oxides