Rapid hydrogen sensing response and aging of α-MoO 3 nanowires paper sensor

Hydrogen gas sensor based on mesoporous In2O3 with fast response/recovery and ppb level detection limit

“…Although the hydrogen sensors based on TiO2 thin film [26] and CuO nanowire networks [29] showed faster response values compared with this study, their response times were reported to be 120 s and 60 s, respectively, which are much longer than what the mesoporous In2O3 based sensor has achieved in this study. Hydrogen gas sensor based on the MoO3 nanowires [27] also showed fast response and recovery times of 3.0 s and 2.7 s, respectively, but its response value was only 0.85 ((Rair-RH2)/RH2) to 15000 ppm of hydrogen, and its reported detection limit was 100 ppm. Clearly the mesoporous In2O3 based sensor fabricated in this study shows much better sensing performance for hydrogen detection, which is mainly attributed to the formation of mesoporous structures, the large specific surface areas and numerous chemisorbed oxygen ions on the surfaces of the mesoporous In2O3.…”

“…Many different types of semiconducting metal oxides have been investigated in the literature as potential materials for fabricating hydrogen gas sensors. These are summarized in Table 1, and mainly include WO3 [11][12][13][14], ZnO [15][16][17][18], NiO [19][20][21], SnO2 [22][23][24], TiO2 [25,26], MoO3 [27,28], CuO [29], MgO [30] and In2O3 [31,32].…”

“…H2 + O − (ads) = H2O + e − (100 o C ~ 300 o C) WO3 thin films 200 1000 9 a 60s/80s - [11] WO3 nanosheets 250 1% 80% b 120s/235s - [12] WO3 nanotube 450 500 17.6 a 25s/-10 ppm [13] WO3 thin films 300 3600 1.32 a 12s/40s - [14] ZnO nanorods 180 500 264% b 127s/203s - [15] ZnO nanorods 150 10000 77% b 10s/116s - [16] ZnO nanorods 100 10000 67% b 14s/100s - [17] ZnO nanorod array 250 1000 1370% b 20s/25s - [18] NiO nanostructure 150 1000 119.63% b 6s/0.5s 30 ppm [19] NiO nanowires 300 1000 91% b 88s/39s 50 ppm [20] NiO thin film 175 1000 46.3 a 81s/322s - [21] SnO2 thin film 300 250 28 a 15s/4s 100 ppm [22] SnO2 nanofibers 150 10000 2.4 a 21s/33s 600 ppm [23] Honeycombed SnO2 340 1 8.4 a 4s/10s 0.05 ppm [24] p-TiO2 thin film 150 1000 28.5% b 2.4s/34.6s - [25] TiO2 thin film 225 10000 8100 a 120s/420s - [26] a-MoO3 nanowires 260 15000 0.85 c 3.0s/2.7s 100 ppm [27] CuO NW networks 300 100 340 a 60s/2s - [29] MgO nanocube 200 5000 25.4 a 140 s/130 s - [30] In2O3 flower-like spherical nanostructure 210 100 1.4 a 11s/12s 10 ppm [31] In2O3 nanowires 200 500 0.1 c 31s/80s 500 ppm [32] Note: a : Rair/RH2; b : 100(Rair-RH2)/RH2; c : (Rair-RH2)/RH2 4 Decrease of the electrical resistance of sensors is corresponding to the change of hydrogen concentration. As summarized in Table 1, there are many types of hydrogen gas sensors based on various semiconducting metal oxides.…”

“…As summarized in Table 1, there are many types of hydrogen gas sensors based on various semiconducting metal oxides. Some of them have fast response/recovery rates for hydrogen sensing, such as those based on a-MoO3 nanowires [27] and p-TiO2 thin film [25], but their response values are low and their detection limits are normally higher than ppm level. Although high response values to hydrogen have been achieved in those sensors made of certain types of metal oxides…”

An Ultrasensitive and Ultraselective Hydrogen Sensor Based on Defect‐Dominated Electron Scattering in Pt Nanowire Arrays

“…Unfortunately, H 2 is prone to leakage due to its small molecular volume, and difficult to be detected because H 2 is colorless and odorless . As a result, efficient detection of H 2 is desperately needed during the production, storage, and utilization processes of H 2 source …”