The catalytic-induced sensing effect of triangular CeO₂ nanoflakes for enhanced BTEX vapor detection with conventional ZnO gas sensors

Abstract

A novel bi-layer sensing structure is proposed for trace BTEX detection, where an insulated CeO2 catalyst is coated onto the top-surface of a conventional ZnO sensing layer.

Exclusive and ultrasensitive detection of formaldehyde at room temperature using a flexible and monolithic chemiresistive sensor

“…Furthermore, it is challenging to find catalysts for the highly selective promotion of the formaldehyde sensing reaction or to design a catalytic filtering layer to oxidize only ethanol without oxidizing formaldehyde. Indeed, the catalytic filtering layer formed on the top of the sensing film decreased both responses to ethanol and formaldehyde 17 , 18 . This means that the exclusive detection of formaldehyde via catalyst loading or by using a catalytic filtering layer is highly challenging even in photo-assisted gas sensing at room temperature, which requires a new strategy such as molecular sieving.…”

“…The loading of various catalysts or the compositional control of sensing materials have been explored but have led to the enhancement of the responses toward ethanol and formaldehyde 13 – 16 . Furthermore because ethanol and formaldehyde exhibit similarly high reactivity, it is difficult to eliminate only ethanol through oxidative filtering using an catalytic overlayer 17 , 18 . In this perspective, the exclusive detection of trace formaldehyde using oxide chemiresistors has been a long-standing challenge.…”

MoO3 Structures Transition from Nanoflowers to Nanorods and Their Sensing Performances

“…While the other peak at 531.4 eV were assigned to the oxygen ions species such as O − , O 2− , and O 2 − . Compared to the lattice oxygen, the absorbed O x − are active to ethanol, so they play a key role in enhancing the sensing performance [34,35].…”

Inorganic-Diverse Nanostructured Materials for Volatile Organic Compound Sensing

“…Nanobelts (Fe doped MoO 3 nanobelts and Au decorated ZnO/In 2 O 3 belt-tooth nanostructure), nanocages (ZnO/ZnCo 2 O 4 hollow nanocages), nanosheets (Au functionalizedWO 3 ·H 2 O NShs, porous h-BN 3D NShs, and Nb-doped NiO NShs), nanoflakes (CdO hexagonal nanoflakes and ZnO-CeO 2 triangular nanoflakes), and nanospheres (ZnFe 2 O 4 NSPs and Pt doped CoCr 2 O 4 hollow NSPs) were demonstrated to volatile hydrocarbons quantitation by the researchers as noted in Table 5 [ 370 , 371 , 372 , 373 , 374 , 375 , 376 , 377 , 378 , 379 ]. Among them, Nb-doped NiO NShs and CoCr 2 O 4 hollow NSPs [ 375 , 379 ] are highly notable with their sensor responses to xylene vapor (R a /R g = 335.1 for 100 ppm at 370 °C and R a /R g = 559 for 5 ppm at 275 °C, respectively) with LODs down to sub-ppm level (0.002 ppm and 0.0187 ppm, correspondingly).…”