Table 1.
Figure of merits of ammonia sensing by different methods.
| Material | Synthesis method | NH3 sensing method | Sensitivity | Reference |
|---|---|---|---|---|
| Colloidal silica beads modified with quantum dots and zinc (II) tetraphenylporphyrin | Assembling monodisperse silica nanoparticles via a microfluidic device | Colorimetric sensing | 7 ppm | 19 |
| Mesoporous TiO2 beads functionalized with gold nanoparticles (AuNPs-TiO2) | Structure-directing template assisted growth | Conductometric sensing |
5.56 over 600 ppm (Ethanol) |
20 |
| Silver oxide nanoparticle decorated carbon nanotubes (Ag2O/CNT NCs) | Wet chemical method | Electrochemical sensing | 32.856 μAμM-1 cm−2 | 21 |
| TiO2/GO/PANI | In-situ oxidative chemical polymerization | Conductivity mode | 5 ppm | 11 |
| Polyaniline ultrathin layers on reduced graphene oxide sheets | In-situ polymerization method | Chemiresistive Sensing | 3.0 × 10−4/ppm for 100 ppm | 17 |
| TiO2:Ce nanoparticles | Sol–gel method | Impedance Analysis | 2.5 for 500 ppm at 175 °C | 26 |
| TiO2/SnO2/WO3 hybrid nanostructures | Ultra-sonic assisted Sol–gel wet impregnation method | Keithley Electrometer | 59.90% | 27 |
| PPy/NDSA and PPy/DBSA layers | In-situ chemical deposition | Quartz Crystal Microbalance | 4 ppm | 9 |
| CeO2-rGO composite paper | Self-assembly method | Impedance Analysis | 51.70 ± 1.2% | Present work |