A-site non-stoichiometric defects engineering in xPt–La_0.9Fe_0.75Sn_0.25O_3−δ hollow nanofiber for high-performance formaldehyde sensor

Abstract

Artificially inducing abundant oxygen vacancies in perovskite-structured materials is an effective method to improve sensing activity.

Nonstoichiometric Doping of La0.9FexSn1–xO3 Hollow Microspheres for an Ultrasensitive Formaldehyde Sensor

“…The reduction of resistance can be attributed to the dissociation of a small amount of H 2 O molecules on the surface of the LFS microspheres, and the dissociated electrons enter the LFS through the carrier channel to combine with holes, resulting in a decrease in the overall resistance of the sensor (eq 7). 36 The decrease in the sensor's response value is attributed to the fact that H 2 O molecules occupy part of the active sites. 37 Because the working temperature of the LFS sensor is much higher than the boiling point of water, the probability of water molecules being adsorbed on the sensor electrode is greatly reduced, and the moisture resistance of the sensor is improved (Figure S4e).…”

Enhanced toluene sensing performances over commercial Co3O4 modulated by oxygen vacancy via NaBH4-assisted reduction approach

“…Meanwhile, a decrease in the band gap reduces the excitation energy of the carrier from the valence band to the conduction band, which is beneficial for reducing the power dissipation of the sensor. 65…”

“…Meanwhile, a decrease in the band gap reduces the excitation energy of the carrier from the valence band to the conduction band, which is beneficial for reducing the power dissipation of the sensor. 65 The second reason for the improvement in the toluene sensing performances of Co 68 Meanwhile, the higher reduction temperature of the peak indicates the weaker oxidation ability of Co 2+ , which can be ascribed to the stronger electron-donating ability of Co 2+ on the catalyst surface. 69 Notably, besides this reduction peak, another peak at about 220 1C was also observed for Co 3 O 4 -R-5, which can be ascribed to the reduction of surface oxygen species (O 2À or O À ) adsorbed on oxygen vacancies.…”

Advances in Perovskite Oxides for Chemiresistive Sensors

“…5,16 The inherent versatility of PO, which allows for the inclusion of various metallic elements and the presence of active centers at B-sites, coupled with the abundant oxygen vacancies resulting from nonstoichiometry, facilitates the adsorption of chemisorbed oxygen species (O 2 − , O − , and O 2− ) on their surfaces. 17,18 These distinctive characteristics make them highly effective as chemiresistive gas sensing layers and catalysts. PO-based chemiresistive sensors generally share sensing mechanisms similar to those used in other chemiresistive sensors based on binary metal oxides such as SnO 2 , WO 3 , Co 3 O 4 , ZnO, etc.…”

“…Almost all elements from the periodic table, excluding noble gases, can occupy either the A or B site in the perovskite structure (Figure b). These combinations lead to the formation of various crystal structures and stoichiometries. , The inherent versatility of PO, which allows for the inclusion of various metallic elements and the presence of active centers at B-sites, coupled with the abundant oxygen vacancies resulting from nonstoichiometry, facilitates the adsorption of chemisorbed oxygen species (O 2 – , O – , and O 2– ) on their surfaces. , These distinctive characteristics make them highly effective as chemiresistive gas sensing layers and catalysts. PO-based chemiresistive sensors generally share sensing mechanisms similar to those used in other chemiresistive sensors based on binary metal oxides such as SnO 2 , WO 3 , Co 3 O 4 , ZnO, etc. , When O 2 molecules from the ambient air are adsorbed onto the surface of PO and the operation temperature of the sensor is raised, it leads to the formation of chemisorbed oxygen species on the PO surface, causing the trapping of electrons within the PO material. − This process generates hole accumulation layers in p-type oxides and electron depletion regions in n-type oxides, depending on the type of PO.…”