Large-Area and Visible-Light-Driven Heterojunctions of In₂O₃/Graphene Built for ppb-Level Formaldehyde Detection at Room Temperature

Abstract

Achieving convenient and accurate detection of indoor ppb-level formaldehyde is an urgent requirement to ensure a healthy working and living environment for people. Herein, ultrasmall In 2 O 3 nanorods and supramolecularly functionalized reduced graphene oxide are selected as hybrid components of visible-light-driven (VLD) heterojunctions to fabricate ppb-level formaldehyde (HCHO) gas sensors (named InAG sensors). Under 405 nm visible light illumination, the sensor exhibits an outstanding response toward ppb-level HCHO at room temperature, including the ultralow practical limit of detection (pLOD) of 5 ppb, high response (R a /R g = 2.4, 500 ppb), relatively short response/recovery time (119 s/179 s, 500 ppb), high selectivity, and long-term stability. The ultrasensitive room temperature HCHO-sensing property is derived from visible-lightdriven and large-area heterojunctions between ultrasmall In 2 O 3 nanorods and supramolecularly functionalized graphene nanosheets. The performance of the actual detection toward HCHO is evaluated in a 3 m 3 test chamber, confirming the practicability and reliability of the InAG sensor. This work provides an effective strategy for the development of low-power-consumption ppb-level gas sensors.

Pd Nanoclusters-Sensitized MIL-125/TiO2 Nanochannel Arrays for Sensitive and Humidity-Resistant Formaldehyde Detection at Room Temperature

“…In this system, PdNCs work as the cocatalyst of MTiNCs under UV irradiation and the charger-transfer sites to accelerate the sensing reaction of HCHO (eq ). HCHO + O 2 − false( h v false) → CO 2 + H 2 normalO + e − …”

Electrochemical protein biosensors for disease marker detection: progress and opportunities

“…Graphene is a 2D material with sp² hybridized carbon atoms closely arranged to form a honeycomb lattice structure. The unique 2D structure of graphene gives it a large specific surface area and excellent electrical conductivity 44 , and theoretically, all the carbon atoms on the surface can be in contact with the target molecule. Functionalized graphene containing specified functional groups on its surface can be prepared by physicochemical modification to increase the surface activity and biocompatibility 45 .…”

Ultrasensitive and Exclusive Chemiresistors with a ZIF-67-Derived Oxide Cage/Nanofiber Co3O4/In2O3 Heterostructure for Acetone Detection

“…To date, various chemiresistive gas sensors, including metal oxide semiconductors (MOSs), ,,, metal dichalcogenides, , transition metal carbides or carbonitrides (Mxenes), , and carbonaceous materials, have attracted considerable attention. Among them, MOSs, such as In 2 O 3 , ,, ZnO, ,, SnO 2 , , WO 3 , CeO 2 , , Co 3 O 4 , and CuO, owing to their low cost, fast response time, simple fabrication, excellent stability, and rich active sites, have been widely used for detecting VOCs. In 2 O 3 , a typical n-type semiconductor with a wide band gap of 2.6 eV, has good electrical and chemical stability.…”

“…Sensing materials are considered the most crucial component of chemiresistive gas sensors. To date, various chemiresistive gas sensors, including metal oxide semiconductors (MOSs), 9,11,15,16 metal dichalcogenides, 17,18 transition metal carbides or carbonitrides (Mxenes), 19,20 and carbonaceous materials, 21 have attracted considerable attention. Among them, MOSs, such as In 2 O 3 , 15,21,22 ZnO, 9,23,24 SnO 2 , 11,25 WO 3 , 26 CeO 2 , 16,27 Co 3 O 4 , 28 and CuO, 29 owing to their low cost, fast response time, simple fabrication, excellent stability, and rich active sites, have been widely used for detecting VOCs.…”

“…In 2 O 3 , a typical n-type semiconductor with a wide band gap of 2.6 eV, has good electrical and chemical stability. Due to its nontoxicity, high conductivity, high stability, and abundant surface defects, In 2 O 3 is an ideal candidate for gas sensing applications, especially for detecting acetone. ,, One-dimensional (1D) nanostructures, such as nanorods, nanotubes, and nanofibers, , characterized by a large specific surface area and nanometer-sized structures, are especially conducive to the adsorption and reaction of gas molecules and the transport and transfer of charges; thus, they have been regarded as exceptional candidates for constructing gas sensors. However, pristine In 2 O 3 nanostructures exhibit relatively poor response, low selectivity, and low detection limit toward acetone.…”