Graphene Oxide-Loaded SnO₂ Quantum Wires with Sub-4 Nanometer Diameters for Low-Temperature H₂S Gas Sensing

Abstract

Chemiresistive gas sensors with low power consumption, high sensitivity, and selectivity are of great significance for low-cost and efficient real-time gas detection. Herein, we present a highly sensitive and selective H 2 S gas sensor employing thin-layer graphene oxide (GO)-loaded sub-4 nm diameter SnO 2 quantum wires (QWs) through a simple mechanical mixing process. The SnO 2 QWs with the diameter smaller than 4 nm are decorated uniformly on the surface of the GO, which endows the heterostructure with high charge transport efficiency. The surface activity and adsorbed oxygen species of SnO 2 QWs, and the fast charge transfer channel of the GO nanosheet, are confirmed vital to the enhanced gas-sensing properties. As demonstrated, the asfabricated sensors exhibit an optimum gas-sensing performance for ppb-level H 2 S detection at 70 °C. In addition, our sensors are selectively sensitive to H 2 S and even show fast dynamic response and recovery kinetics toward ppb-level H 2 S at the high relative humidity of 85%. Moreover, GO-loaded SnO 2 QWs with solution processability enable the demonstration of a paper-based flexible H 2 S sensor for 500 ppb H 2 S detection with long-term stability. This result helps us to understand that the design and synthesis of 1D SnO 2 QWs/2D GO nanosheet nanocomposites will provide new paradigms for the future development of H 2 S-sensitive and selective materials.

High-Sensitive MEMS Hydrogen Sulfide Sensor made from PdRh Bimetal Hollow Nanoframe Decorated Metal Oxides and Sensitization Mechanism Study

“…Currently, various MOSs sensors have been employed to detect H 2 S due to its merits including low cost, fast response, and easy fabrication. − However, single MOSs gas sensors are difficult to match well with the actual requirement due to their rather high detection limit and low response . Therefore, the performance improvement of MOS-based sensors also has become the focus of people’s research. , Noble metals (such as Pd, Au, Rh, and Ru et al) in combination with MOSs always exhibit unique properties in the gas sensor fields owing to their specific chemical and electronic sensitization properties. − Moreover, some experiments have proved that noble metal/MOSs with high sensing performances could be easily designed by controlling the size, morphology, and dispersion of noble metals. ,− At present, the multielement system (includes two or more noble metals) is particularly attractive in the various fields (including biomedical diagnosis and therapy, energy storage and conversion, gas sensors and catalysis) because of material synergistic effects with unusual optical, electrical, chemical, and catalytic behaviors. ,− Among them, in the field of the gas sensor, bimetal can not only modulate the carrier concentration of the materials but also catalyze the reactions between detected gas molecules and surface-adsorbed oxygen species, which attracted more attention of the researchers.…”

Metastable Antimony‐Doped SnO2 Quantum Wires for Ultrasensitive Gas Sensors

“…In addition, the n-type doping effect is helpful for improving the conductivity. Noting that the gas-sensing reaction requires the activation energy for gas adsorption and chemical bond breaking, H 2 S should have the smaller bond energy of H-SH and the stronger reducing capability [49,50] compared with the interfering gas molecules. The favorable chemical interaction with the surface adsorbed oxygen species contributes to the H 2 S selectivity.…”

Recent Progress of Nanostructured Sensing Materials from 0D to 3D: Overview of Structure–Property‐Application Relationship for Gas Sensors

“…[ 287–290 ] Other flexible substrates such as polydimethylsiloxane (PDMS), hydrogel, and cellulose nanofibers are also exploited for the wearable sensor fabrication. [ 291–293 ] Whatever the kind of substrates to choose, favorable contact between substrates, electrodes, and sensing materials is also required for stable, reliable sensor operation. In particular, the sensing layer plays a pivotal role to realize gas sensing function, and meanwhile their mechanical properties are worth considering.…”