Enhanced Gas Sensing Performance of rGO Wrapped Crystal Facet-Controlled Co₃O₄ Nanocomposite Heterostructures

Abstract

Crystal facet engineering and graphene modification are both effective means to improve the gas sensing performance of metal oxide semiconductors (MOSs) currently. However, research on the crystal facet effect and synergistic effect of graphene modification of p-type MOS sensors is relatively lacking. Here, ptype Co 3 O 4 nanocrystals with controlled crystal facets ({112} and {100}) were in situ wrapped in the two-dimensional (2D) nanosheet network of graphene. It was found that bare {112} facets showed a significantly higher triethylamine sensing performance than {100} facets, implying a strong crystal facet effect. Interestingly, the triethylamine sensing performance of {112} facets was significantly improved after rGO modification, while the performance improvement of Co 3 O 4 {100} was limited after rGO modification. Further study suggested that {112} facets contained more active Co 3+ species and chemically adsorbed oxygen species than {100} facets, which promoted the adsorption of triethylamine and the subsequent sensing reaction. In addition, the strong electronic interaction between Co 3 O 4 {112} crystal facets and rGO promoted efficient charge exchange through the heterogeneous interface. This work provides a new way to improve the gas sensing performance of Co 3 O 4 through the synergistic effect of crystal facet engineering and graphene modification.

Metal Oxide Semiconductor Sensors for Triethylamine Detection: Sensing Performance and Improvements

“…Responses of RGO/α-Fe2O3 nanocom sites display better linearity and superior sensing performance. Yu et al [124] modified Co3O4 nanoparticles by wrapping RGO via a simple hy thermal method. In their experiments, they found that Co3O4 with {100} crystal plane…”

Room-Temperature Triethylamine Sensor Based on Reduced Graphene Oxide/CeO2 Nanocomposites

“…Incorporating reduced graphene oxide (RGO) into SMOx nanostructures not only enables the sensor operation at RT due to the good electrical conductivity , but also leads to general improvements in the TEA-sensing performance. Nanocomposites based on RGO/SMOx have a lower operating temperature, improved selectivity, and a higher sensor signal to TEA than bare SMOx. − …”

In situ construction of AFe2O4/Fe2O3 (A = Cd, Ca, Zn) array structures for selective detection of VOCs

“…In order to realize the detection of mixed VOC gases, it becomes extremely important to prepare sensing materials with high selectivity and response. In the past few decades, many strategies have been used to improve the sensitivity and selectivity of materials, 12–14 such as tuning different crystalline planes of materials, 15,16 constructing heterogeneous interfaces, 17,18 doping single atoms, 19–21 and growing arrays in situ . 22,23 As an effective means to control surface properties, crystal plane engineering has become a research hotspot in the field of MOS gas sensors in recent years.…”

“…Due to the exposure of the {112} crystal plane of Co 3 O 4 , it has good selectivity for triethylamine. 15 Gui et al prepared WO 3 with highly active {−112} crystal planes by a microwave hydrothermal method, which was highly selective for triethylamine at room temperature. 16 Meanwhile, interface engineering has become an effective strategy for designing high-performance sensing materials because at interfaces the most critical sensing processes for gas adsorption and diffusion occur.…”