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.
The advantages of existing ordered mesoporous materials have not yet been fully realized, due to their limited accessibility of in‐pore surface and long mass‐diffusion length. A general, controllable, and scalable synthesis of a family of two‐dimensional (2D) single‐layer ordered mesoporous materials (SOMMs) with completely exposed mesopore channels, significantly improved mass diffusion, and diverse framework composition is reported here. The SOMMs are synthesized via a surface‐limited cooperative assembly (SLCA) on water‐removable substrates of inorganic salts (e.g., NaCl), combined with vacuum filtration. As a proof of concept, the obtained CeO2‐based SOMMs show superior catalytic performance in CO oxidation with high conversion efficiency, ≈33 times higher than that of conventional bulk mesoporous CeO2. This SLCA is a promising approach for developing next‐generation porous materials for various applications.
Semiconducting
metal oxides have attracted increasing attention in various fields
due to their intrinsic properties. In this study, a facile solvent
evaporation-induced multicomponent co-assembly approach coupled with
a carbon-supported crystallization strategy is employed to controllably
synthesize crystalline mesoporous nickel oxide-doped tungsten oxides
in an acidic THF/H2O solution with poly(ethylene oxide)-b-polystyrene diblock copolymers (PEO-b-PS) as the structure-directing agent, tungsten(VI) chlorides as
WO3 precursors, and Ni(AcAc)2 as the NiO precursor.
The obtained materials possess a face-centered cubic mesoporous structure,
large pore size (∼30 nm), high surface area (30–50
m2 g–1), large pore volume (0.15–0.19
cm3 g–1), and ultralarge pore windows
(12–16 nm) connecting adjacent mesopores, and the mesoporous
WO3 framework was decorated by ultrafine NiO nanocrystals.
Due to their well-connected porous structure and high surface areas with rich WO3–NiO interfaces, the composite materials
exhibit superior gas sensing performance with an ultrafast response
(∼4 s), high sensitivity (R
a/R
g = 58 ± 5.1), and selectivity
to 50 ppm H2S at a relatively low working temperature (250
°C). The chemical mechanism study reveals complicated surface
reactions of WO3/NiO-based gas sensors, and SO2, WS2, and NiS intermediates were found to be generated
during the gas sensing process.
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