In Situ Growing Double-Layer TiO₂ Nanorod Arrays on New-Type FTO Electrodes for Low-Concentration NH₃ Detection at Room Temperature

Abstract

A novel double-layer TiO2 nanorod array (NRA) gas sensor for room-temperature detection of NH3 was fabricated by employing etched fluorine-doped tin dioxide (FTO) glass as the in situ growing substrate and the new-type gas-sensing electrode via the facile droplet-coating and hydrothermal methods. Due to the synergistic effect of forces, special double-layer TiO2 NRAs with a cross-linked and bridgelike structure is formed, in which adequate point junctions can be generated to construct self-assembled electron pathways required for gas-sensing tests. Gas-sensing tests indicate that all samples obtained at different growth times have an excellent gas-sensing response to low-concentration NH3 at room temperature. Among them, the TiO2 NRAs obtained at 6 h (S2) exhibit the highest gas-sensing response to 100 ppm NH3 with a value of 102%. In addition, the growth mechanism, the gas reaction mechanism, and the effect of humidity on the gas-sensing performance are also discussed in the present paper.

Low-temperature operating ZnO-based NO2 sensors: a review

“…Therefore, it is essential to develop a gas sensor for the real-time detection and emission control of NO 2 . [1][2][3][4] For decades, metal oxide semiconductors (MOSs), including ZnO, 5,6 CuO, [7][8][9] SnO 2 , 10-12 TiO 2 , [13][14][15] Fe 2 O 3 , 16,17 In 2 O 3 , 18,19 and WO 3 , 20,21 have dominated the eld of toxic gas detection (including NO 2 detection) nanomaterials, because of their lowcost, non-toxicity and availability. [22][23][24][25][26][27] Among these materials, ZnO have been witnessed an immense exploration due to its wide band gap, large exciton binding energy, high mobility of conduction electrons, physical and chemical stability.…”

Titanium Disulfide Based Saturable Absorber for Generating Passively Mode-Locked and Q-Switched Ultra-Fast Fiber Lasers

“…Graphene possesses a wide absorption spectrum band due to its Dirac-like electronic band structure [ 22 , 23 ], but its zero-bandgap property also limits its wide potential applications [ 24 , 25 , 26 ]. Recently, based on the development of layered materials, novel nanomaterials such as transition metal dichalcogenides (TMDs), black phosphorus (BP), MXene, and topological insulators (TIs) have emerged as ultra-fast optical devices and shown excellent absorption performance [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ].…”

1D Titanium Dioxide: Achievements in Chemical Sensing

“…1D TiO 2 also showed good potentialities as NH 3 and H 2 S chemical sensors. Capability of detection of low concentrations of NH 3 at room temperature in different humidity environments has been proven [ 44 ]. The sensor exhibited good long-term stability (29 days), with a response of 102% toward 100 ppm of NH 3 .…”

“…Generally speaking, typical processes to produce TiO2 nanorod arrays inside a steel autoclave involve a Ti precursor, HCl solution and deionized water, heated up at 150 °C for at least 9 h, followed by thermal annealing [42,43]. Another interesting work by G. Zaho et al [44] reports about the growth of bridge-like structures of TiO2 NRs using isopropyl titanate as a precursor (Figure 4). Additionally, On the other hand, recently, many reports have been published on using hydrothermal synthesis for the growth of TiO 2 nanowires (NWs) and nanorods (NRs) of rutile and anatase phase [42][43][44].…”