Ultrasensitive Formaldehyde Sensor Based on SnO₂ with Rich Adsorbed Oxygen Derived from a Metal Organic Framework

Abstract

SnO 2 has been a commonly researched gas-sensing material due to its low cost, good performance, and good stability. However, gas sensors based on pure SnO 2 usually show a low response or high working temperature. In this work, laminar SnO 2 was obtained by using a Sn-based metal organic framework(Sn-MOF)@SnO 2 as a precursor. Sn-MOF@SnO 2 is prepared at low temperatures using water and dimethylformamide as a solvent, which is simple, low cost, and easily reproducible. After sintering, Sn-MOF@SnO 2 is derived to SnO 2 with rich adsorbed oxygen, large specific surface area, and unique nanoparticle piled pores, thus showing excellent gas-sensing properties. The prepared SnO 2 has an ultrahigh response value of 10,000 to 10 ppm formaldehyde at an optimal working temperature of 120 °C, a fast response/ recovery time of 33 s/142 s, and an actual detection limit of lower than 10 ppb as well as high selectivity and high stability. Density functional theory calculations show that the exposed (110) plane of oxygen-rich vacancies in laminar SnO 2 can effectively increase the coadsorption capacity of O 2 and formaldehyde molecules, thereby improving the formaldehyde gas-sensing performance of the material. The present original approach paves the way to design advanced materials with excellent gas-sensing properties as well as broad application prospects in formaldehyde monitoring.

Unique Pd/PdO–In2O3 heterostructures for the highly efficient detection of triethylamine

“…28 The O 1s spectra of In 2 O 3 , 0.8% Pd–In 2 O 3 , 0.8% Pd/PdO–In 2 O 3 were compared (Fig. 6d), the results show that 0.8% Pd/PdO–In 2 O 3 has a higher adsorbed oxygen content, which can provide more reactive species for the gas-sensing reaction, 29,30 this is an important reason for the better gas-sensing performance of 0.8% Pd/PdO–In 2 O 3 .…”

Nanopalladium-Decorated Sn-Na MOF Catalyst for Upgrading Biosugars to 5-Hydroxymethylfurfural in an Aqueous Medium

“…The Sn-based MOF having four Sn−O coordination bonds in a disphenoidal environment has been reported for lithium storage. 38 Similarly, Sn-MOF@ SnO 2 has been used as a precursor for producing SnO 2 as a formaldehyde sensor, 39 and another Sn-MOF has been reported for capturing monophosphopeptides selectively. 40 The Sn-Na MOF was obtained as a colorless hexagonshaped crystalline product.…”

Dual Improvement in Sensitivity and Humidity Tolerance of a NO2 Sensor Based on 3-Aminopropyltriethoxysilane Self-Assembled Monolayer-Functionalized SnSe2 for Explosive Photolysis Gas Detection

“…10−13 Most of the sensitive components of chemiresistive gas sensors are based on metal oxide semiconductors (MOSs). 14 However, due to the intrinsic properties of MOSs, MOS-based sensors typically operate at high temperatures (>150 °C), 15,16 which can be dangerous in the detection of explosives. Additionally, in order to avoid static sparks, explosives are typically stored in surroundings with high levels of humidity, significantly impairing the response of MOS-based gas sensors.…”

“…Chemiresistive-type gas sensors are among the most commonly used due to their high sensitivity, fast reaction, and low detection limit, resulting in them being able to quickly and effectively detect low concentrations of NO 2 that are formed when nitro explosives decompose under UV light. − Most of the sensitive components of chemiresistive gas sensors are based on metal oxide semiconductors (MOSs) . However, due to the intrinsic properties of MOSs, MOS-based sensors typically operate at high temperatures (>150 °C), , which can be dangerous in the detection of explosives. Additionally, in order to avoid static sparks, explosives are typically stored in surroundings with high levels of humidity, significantly impairing the response of MOS-based gas sensors. − To achieve safe and efficient detection of explosives, it is necessary to investigate novel gas-sensitive materials that operate at both room temperature and high humidity levels.…”