Ordered Mesoporous Tin Oxide Semiconductors with Large Pores and Crystallized Walls for High-Performance Gas Sensing

Abstract

Owing to their distinct chemical and physical properties, mesoporous metal oxide semiconductors have shown great application potential in catalysis, electrochemistry, energy conversion, and energy storage. In this study, mesoporous crystalline SnO materials have been synthesized through an evaporation-induced co-assembly (EICA) method using poly(ethylene oxide)-b-polystyrene diblock copolymers as the template, tin chlorides as the tin sources, and tetrahydrofuran as the solvent. By controlling conditions of the co-assembly process and employing a carbon-supported thermal treatment strategy, highly ordered mesoporous SnO materials with a hexagonal mesostructure (space group P6/mmc) and crystalline pore walls can be obtained. The mesoporous SnO is employed for fabricating gas sensor nanodevices which exhibit an excellent sensing performance toward HS with high sensitivity (170, 50 ppm) and superior stability, owing to its high surface area (98 m/g), well-connected mesopores of ca. 18.0 nm, and high density of active sites in the crystalline pore walls. The chemical mechanism study reveals that both SO and SnS are generated during the gas sensing process on the SnO-based sensors.

Effect of Surfactants on the Microstructures of Hierarchical SnO2 Blooming Nanoflowers and their Gas-Sensing Properties

“…8 ), while S PVP and S TritonX-100 exhibit the higher gas response to H 2 S due to their polyporous flower-like nanostructures, proving good selectivity of S TritonX-100 and S PVP toward H 2 S. The good selectivity of the samples to H 2 S can be explained as follows: when the SnO 2 sensor is exposed in H 2 S gas, both chemisorbed oxygen species and SnO 2 nanostructure react with H 2 S during sensing measurement to form SO 2 and SnS 2 , respectively. Compared with SnO 2 , the body resistance of SnS 2 is relatively smaller, leading to the sensitivity enhancement of the gas sensor [ 39 ]. On the contrary, the SnO 2 sensor does not react with any other target gases, such as formaldehyde, methanol, ethanol, and acetone.…”

Biomolecule‐Assisted Synthesis of Hierarchical Multilayered Boehmite and Alumina Nanosheets for Enhanced Molybdenum Adsorption

“…Mesoporous oxides with nanometric dimensions have shown potential in energy storage, catalysis, sensing, and adsorption . Since the discovery of mesoporous silica at the beginning of the 1990s, many different mesoporous oxides have been reported, such as TiO 2 , Fe 2 O 3 , NiO, and Co 3 O 4 .…”

“…To date, mesoporousm aterials have been developed by using various synthetic methods, including soft-templating, [1][2][3] hard-templating, [4][5][6] free-templating, [7,8] nano-casting, [9,10] and electrochemi- International Center for Materials Nanoarchitectonics( WPI-MANA) and International Center for Young Scientists (ICYS) NationalInstitute for Materials Science (NIMS) 1-1 Namiki, Tsukuba, Ibaraki305-0044 (Japan) E-mail:KANETI.Valentino@nims.go.jp cal methods [11,12] with various degree of control over the shape, porosity,a nd surfacea rea.D ue to their unique physicochemicalp roperties, mesoporous materials have been employed for aw ide variety of applications, including environmental (e.g.,p hotocatalysis, [13,14] adsorption or separation of heavy metals, [15,16] and carbon monoxide oxidation [17,18] ), chemical (e.g.,h ydrogen evolution reaction (HER), [19] oxygen reduction reaction( ORR), [20] and oxygen evolution reaction (OER) [21] ) as well as biomedical applications( e.g.,m agnetic resonance imaging (MRI), [22] ultrasound imaging, and photothermal therapy [23] and immunosensor [24] ). Mesoporouso xides with nanometric dimensions have shown potential in energy storage, [25,26] catalysis, [27,28] sensing, [29,30] and adsorption. [31] Since the discoveryo fm esoporous silica at the beginning of the 1990s, many different mesoporous oxidesh ave been reported, such as TiO 2 , [13,14] Fe 2 O 3 , [30,32] NiO, [3,33] and...…”

sp2-Hybridized Carbon-Containing Block Copolymer Templated Synthesis of Mesoporous Semiconducting Metal Oxides with Excellent Gas Sensing Property

“…37,38 Recently, with the assistance of HCl-AcAc dual-ligand, ordered mesoporous crystalline SnO 2 can be obtained via classic EICA method with robust PEO-b-PS copolymer directed coassembly. 39 The acetylacetone-stabilized inorganic species were found to be ultrafine SnO 2 nanoclusters (ca. 2.5 nm), because the SnCl 4 precursor could be hydrolyzed even in the presence of trace water in THF.…”

“…In our recent research, we proved that the gas sensing behavior is dependent on the crystal size of metal oxides in the pore wall of OMSMOs (Figure 8b). 39 In this regard, metal oxide homojunctions were generated between nanograins in the crystalline mesoporous framework, which could accelerate the diffusion of active oxygen species, and these oxygen species usually covered the surface of nanograins. It can capture electrons of these nanograins and generate electron depletion layer, generating potential barriers among the grain boundaries.…”