Multichannel Room-Temperature Gas Sensors Based on Magnetic-Field-Aligned 3D Fe₃O₄@SiO₂@Reduced Graphene Oxide Spheres

Abstract

Reduced graphene oxide (rGO) is considered as one of the ideal sensing materials for high-performance roomtemperature gas sensors owing to its large specific surface areas, numerous active sites, and high carrier mobility. However, the sensing performance cannot be maximized due to the inevitable sheet stacking and agglomeration. Herein, we firstdemonstrate multichannel room-temperature gas sensors using magnetic-fieldinduced alignment of three-dimensional (3D) Fe 3 O 4 @SiO 2 @rGO core−shell spheres. Moreover, the sensing channels composed of spheres can be tailored by changing the concentration of spheres and the magnetic field. Experimental results suggest that the multichannel 3D Fe 3 O 4 @SiO 2 @rGO sensor exhibits an ultrahigh sensitivity of 34.41 with a good response stability and high selectivity toward 5 ppm of NO 2 at room temperature, which is ca. 7.96 times higher than that of the random 3D rGO gas sensor. The high performance can be mainly ascribed to a full utilization of their large specific surface area and active sites of rGO nanosheets. We believe that our results not only contribute to the development of high-performance rGO-based sensing devices, but also provide a general approach to maximize the sensing performance of other nanomaterials.

Adsorption of gas molecules on buckled GaAs monolayer: a first-principles study

“…Magnetic gas sensors have gained popularity in recent times due to their safety and lack of electrical contacts. [71][72][73] Hence, the prospect of GaAs monolayer as a magnetic gas sensor has been explored. Spin-polarized DFT calculations were performed to analyze the magnetic moment of the gas adsorbed systems.…”

Highly Sensitive Ammonia Gas Detection at Room Temperature by Integratable Silicon Nanowire Field-Effect Sensors

“…So far, the most widely used NH 3 gas sensors are based on bulk or nanostructured metal oxide semiconductor materials that require a high working temperature of typically 200–450 °C. − This leads to a high-power consumption and limited application scenarios for wearable and portable electronics that are supposed to attach to or be in the close proximity of skin surfaces. Therefore, in recent years, intensive research efforts have been devoted to the development of advanced gas sensors that can operate at room temperature (RT), with nanostructured channel materials, such as silicon nanowires (SiNWs), − conductive polymer, , carbon nanotubes, , graphene, or their composite. , Particularly, the one-dimensional SiNW channels, with high surface-to-volume ratio and chemical activity on the sidewall, have been considered as the ideal choice for NH 3 gas sensing that can work at RT, thanks to an efficient adsorption of gas molecular species on the sidewall of tiny SiNW channels, typically with diameter <80 nm. , In addition, the high stability and biocompatibility of SiNWs are also beneficial for developing a new generation of wearable and portable chemical/biological sensors. − …”

“…Therefore, in recent years, intensive research efforts have been devoted to the development of advanced gas sensors that can operate at room temperature (RT), with nanostructured channel materials, such as silicon nanowires (SiNWs), 7−9 conductive polymer, 10,11 carbon nanotubes, 12,13 graphene, or their composite. 1,14 Particularly, the one-dimensional SiNW channels, with high surface-tovolume ratio and chemical activity on the sidewall, 15 have been considered as the ideal choice for NH 3 gas sensing that can work at RT, thanks to an efficient adsorption of gas molecular species on the sidewall of tiny SiNW channels, typically with diameter <80 nm. 7,16 In addition, the high stability and biocompatibility of SiNWs are also beneficial for developing a new generation of wearable and portable chemical/biological sensors.…”

Laser-patterned carbon coatings on flexible and optically transparent plastic substrates for advanced biomedical sensing and implant applications

“…It may also act as a barrier layer to protect the substrate from moisture absorption; in addition, it can be utilized for catalytic sensing via enzymatic and non-enzymatic mechanisms. [13][14][15][16][17] Currently, high quality reduced graphene oxide (rGO) can be produced by thermal or chemical reduction of graphene oxide (GO). The conventional furnace-based thermal reduction of GO approach is problematic as it exposes the entire device to high temperatures, leading to substrate degradation.…”