Graphene‐Oriented Construction of 2D SnS for Methanol Gas‐Sensor Application

Abstract

Group‐IV monochalcogenides with unique 2D puckered honeycomb structure (MX, M = Ge, Sn/X = S, Se) have a great prospect in the gas‐sensor field. Herein, an exploratory study on 2D SnS is synthesized through a solvothermal method, is performed for promising methanol sensor. To break through the inhibition of the general agglomeration and poor conductivity of solvothermal synthesized SnS on gas‐sensing performance, a hybrid of SnS@rGO is designed and constructed based on poly(diallyl dimethyl ammonium chloride) (PDDA)‐assisted electrostatic self‐assembly. With directed growth of SnS on the PDDA‐modulated graphene oxide (GO), an expected architecture characterized by well‐dispersed loosely arranged SnS nanosheets attaching on the highly conductive rGO is achieved. The unique hybrid architecture and the conductivity modulation of rGO promotes sensing responses and dynamic characteristic of SnS‐based sensor toward methanol detection. The achieved SnS@rGO hybrid with less stacking architecture of SnS displays a ≈3.3‐fold enhancement in gas response to 15 ppm methanol in comparison to the flower‐like stacked SnS. The formation mechanism of SnS@rGO hybrid based on the oriented growth of SnS by PDDA‐modulated GO is clarified schematically and the response enhancement of the hybrid is demonstrated in terms of the unique architecture and the conductivity modulation.

Synergistic enhanced NH3-sensing of SnS via Ti3C2Tx-oriented vertical growth and oxygen-containing functional group regulation

“…In terms of morphology, the discrete SnS nanoflakes with vertical arrangement in the composite could expose a larger sensing area, i.e., more active sites available for gas Environmental Science: Nano Paper adsorption, than the flower-like SnS formed by compact selfassembly, which is beneficial for the enhancement of gas sensitivity. Next, due to the different work functions of SnS and Ti 3 C 2 T x (4.8 eV and 3.4 eV), 57,58 the contact between SnS and Ti 3 C 2 T x forms a heterojunction to generate strong electronic interactions. In air, oxygen molecules are easily adsorbed on the active surface of SnS: 19,59 O 2 (gas) ↔ O 2 (ads)…”

“…, more active sites available for gas adsorption, than the flower-like SnS formed by compact self-assembly, which is beneficial for the enhancement of gas sensitivity. Next, due to the different work functions of SnS and Ti 3 C 2 T x (4.8 eV and 3.4 eV), 57,58 the contact between SnS and Ti 3 C 2 T x forms a heterojunction to generate strong electronic interactions. In air, oxygen molecules are easily adsorbed on the active surface of SnS: 19,59 O 2 (gas) ↔ O 2 (ads)O 2 (ads) + e − ↔ O 2 − According to Wolkenstein's model, when the operating temperature is lower than 100 °C, the oxygen molecules pre-adsorbed on the surface of the material will act as a strong oxidant to capture free electrons from the conduction band and be ionized in the form of O 2 − .…”

Adsorption and Sensing Performance toward Methanol Vapor on SnS/SnS2In-Plane Heterostructures

“…17 Our previous investigation also revealed that, at room temperature, the hybrid of SnS/rGO displayed a 3.3-fold enhancement in gas response to 15 ppm methanol in comparison to pure SnS. 18 However, the vertical vdW heterojunctions formed from pristine 2D nanomaterials generally show weak interlayer interaction and non-direct bonding due to the intrinsic inertia of nanolayer surface. 19 Thus, in the sensors based on various vdW heterostructures like BP/MoSe 2 and SnS/rGO, the response enhancement is mainly ascribed to the conductivity improvement due to the introduction of a highly conductive component (graphene, BP, etc.…”

“…For instance, as reported by Feng et al, the chemical sensor based on vdW heterojunctions of 2D BP/MoSe 2 shows capability of operating at room temperature, with the sensor response enhanced by 4.4 times toward 0.25 ppm NO 2 gas in comparison to the pure MoSe 2. Our previous investigation also revealed that, at room temperature, the hybrid of SnS/rGO displayed a 3.3-fold enhancement in gas response to 15 ppm methanol in comparison to pure SnS . However, the vertical vdW heterojunctions formed from pristine 2D nanomaterials generally show weak interlayer interaction and non-direct bonding due to the intrinsic inertia of nanolayer surface .…”

Mg-doped InSnO nanofiber field-effect transistor for methanol gas detection at room temperature

“…Nowadays, with the rapid development of the chemical industry, toxic and harmful gases such as NO 2 , SO 2 , H 2 S, CO and volatile organic compounds (VOCs) such as methanol, ethanol and formaldehyde will inevitably be emitted [1][2][3][4][5][6], which makes environmental and human health issues are getting more and more attention [7]. As one of the basic organic raw materials, methanol has important applications in many fields, such as energy batteries, biodiesel, laboratories, and chemical industries [4,7,8]. When methanol volatilizes into the air, it will threaten people's health [9].…”