Table 1 Gas sensors with potential for analysis of VOCs in exhaled gases.
Target gas | Sensing material | Synthesis method | Sensing performance | Ref. |
|---|---|---|---|---|
Acetone | WO3 NFs | electrospinning | LOD>1 ppm | |
Si:WO3 | flame spray pyrolysis, anneal | DR: 4-70 ppm | ||
ZnO-PANI | self-assembly, coating | DR: 260−1300 ppm | ||
HAT7 and P3HT | Anneal, thermally deposited and oxygen-plasma etching | LOD >100ppb | ||
CS@rGO | chemical methods | LOD >20 ppb | ||
Pt/Al2O3 + Si/WO3 | flame spray pyrolysis, anneal | LOD>50 ppb | ||
ethanol | Ti3C2Tx-M2 | Chemical substitution | DR: 20-500 ppm | |
TiO2@2D-TiC | Etch, single-stept hermalde composition | DR: 0.01−60 ppm | ||
PVA/MWCNTs | spray layer by layer | LOD >9.17 ppm | ||
WS2/GONRs | chemical vapor transport, drop-casting method | DR: 1-21 ppm | ||
PVP-CB-EG | gravure printing, coating | LOD >40 ppm | ||
In2O3-PtNP NPs | oxygen reactive ion etching, etch and coat | LOD >3.9 ppb | ||
Bi2WO6/TiO2 | Electrospun, calcined | DR: 1-800 ppm | ||
isoprene | Pt-doped SnO2 | flame spray pyrolysis, directly deposited and situ annealed | LOD>5 ppb | |
rGO@ITO-PET | electrochemical-assisted deposition | LOD>237 ppb | ||
In2O3 NPs | co-precipitation method, anneal | LOD>1 ppb, R=143ppm-1 | ||
Au-loaded ZnO | solvothermal method, Sputter and anneal | LOD>6ppb | ||
flower-like In2O3 | hydrothermal method | LOD>5ppb | ||
methane | PI/SnSe2 | Single source co-evaporation, polycondensation, imidization | LOD >0.02% | |
PVP-CB-EG | gravure printing and coating | LOD >36 ppm | ||
Pt-doped SnO2 nanoflowers | hydrothermal process, thermal reduction method | DR: 5-5000ppm | ||
Co-doped ZnO | sol-gel method, in situ growth | DR: 100-5000ppm | ||
formaldehyde | ZnO/MXene NW | Etch, hydrothermal method | DR: 0.01-10 ppm, R=1.7128+1.0008X | |
SnO2/CMF | in situ growth | LOD>1 ppm | ||
acetaldehyde | Ni-doped ZnO | chemical spray pyrolysis technique | LOD >10 ppm | |
NiO+WO3 | hydrothermal chemical route, anneal | DR: 20-100ppm |
