Table 2.
Gas sensing performance of TiO2 based porous and tubular structures at the optimal operating conditions.
| Shape/Composition | TiO2 Crystalline Structure | Synthesis Method | Operating Temperature (°C) | Target Gas, Concentration | Response | Response/Recovery Times | Ref. |
|---|---|---|---|---|---|---|---|
| Tubular Au-TiO2 |
Anatase | Anodization | 110 | SO2F2, 50 ppm | (ΔR/R0)·100%, 19.95% | - | [114] |
| Tubular Pd-TiO2 |
Anatase | Anodization | 200 | Ethanol, 10–3000 ppm | (ΔR/R0)·100%, 297–21,253% | 10.2/7.1 s | [115] |
| Tubular Pt-TiO2 |
Anatase | Anodization | 150 | SO2F2, 30–100 ppm | (ΔR/R0)·100%, ~8.65–38% | - | [116] |
| Tubular Ni-TiO2 |
Anatase | Anodization | 200 | H2, 1000 ppm | (ΔR/R0)·100%, 40% | - | [121] |
| Tubular Ni-TiO2 |
Anatase | Anodization | 200 | H2, 1000 ppm | (ΔR/R0)·100%, 13.7% | 80/- s | [122] |
| Tubular Cr-TiO2 |
Anatase | Anodization, soaking, thermal treatment | 500 | NO2, 10–100 ppm | ΔR/R0, ~2–3.5 | -/8–24 min | [123] |
| Tubular Nb-TiO2 |
Anatase, rutile | Anodization | 400 | Ethanol, 50 ppm | ΔG/G0, ~6 | 120/120 s | [20] |
| Tubular Nb-TiO2 |
Anatase | Anodization | 300 | Acetone, 25 ppm | ΔG/G0,~7 | - | [65] |
| Tubular TiO2 |
Anatase | Anodization | 200 | Ethanol, 5000 ppm | (ΔG/G0)·100%, ~300% | - | [124] |
| Tubular C-TiO2 |
Anatase | Anodization, thermal treatment | 100 | H2, 5000 ppm | ΔG/G0, ~2 | - | [125] |
| Tubular Al-V-TiO2 |
Anatase | Anodization | 300 | H2, 1000 ppm | (ΔR/R0)·100%, 50% | - | [126] |
| Tubular MoS2-TiO2 |
Anatase | Anodization, hydrothermal growth | 150 | Ethanol, 100 ppm | R/R0, 14.2 | - | [127] |
| Porous Ag-SnO2-TiO2 |
Anatase TiO2 | Chemical approaches, thermal treatment | 275 | Ethanol, 50 ppm | R0/R, ~53 | 3.5/7 s | [128] |
| Porous Ti3+-TiO2 |
Anatase, rutile | Chemical approaches, thermal treatment | Room temperature | CO, 100 ppm | R0/R, ~1.6 | - | [129] |
| Tubular, polypyrrole based polymer-TiO2 | - | Anodization, electropolymerization | Room temperature | CH2O, 1 ppm | ΔG/G0, 13% | - | [57] |