Oxide/ZIF‐8 Hybrid Nanofiber Yarns: Heightened Surface Activity for Exceptional Chemiresistive Sensing

Abstract

Though highly promising as powerful gas sensors, oxide semiconductor chemiresistors have low surface reactivity, which limits their selectivity, sensitivity, and reaction kinetics, particularly at room temperature (RT) operation. It is proposed that a hybrid design involving the nanostructuring of oxides and passivation with selective gas filtration layers can potentially overcome the issues with surface activity. Herein, unique bi‐stacked heterogeneous layers are introduced; that is, nanostructured oxides covered by conformal nanoporous gas filters, on ultrahigh‐density nanofiber (NF) yarns via sputter deposition with indium tin oxide (ITO) and subsequent self‐assembly of zeolitic imidazolate framework (ZIF‐8) nanocrystals. The NF yarn composed of ZIF‐8‐coated ITO films can offer heightened surface activity at RT because of high porosity, large surface area, and effective screening of interfering gases. As a case study, the hybrid sensor demonstrated remarkable sensing performances characterized by high NO selectivity, fast response/recovery kinetics (>60‐fold improvement), and large responses (12.8‐fold improvement @ 1 ppm) in comparison with pristine yarn@ITO, especially under highly humid conditions. Molecular modeling reveals an increased penetration ratio of NO over O2 to the ITO surface, indicating that NO oxidation is reliably prevented and that the secondary adsorption sites provided by the ZIF‐8 facilitate the adsorption/desorption of NO, both to and from ITO.

Interfacial engineered superelastic metal-organic framework aerogels with van-der-Waals barrier channels for nerve agents decomposition

“…The left and right walls were subjected to constant forces at a rate of 0.05 Å ps −1 in the opposite direction along the Z axis. Periodic boundary conditions were applied in the other two directions to reduce the edge effects 21 . We verified that the silica sol attained a stable state after the 50 ps simulation by tracking the changes in system energies and wall stress.…”

Unfolding the hydrogen gas sensing mechanism across 2D Pnictogen/Graphene heterostructure sensors

“…The high selectivity of the Sb/G sensor could be attributed to abundant active sites provided by antimonene, and large conducting pathways and superficial eprovided by graphene for the adsorption process [50]. However, the introduction of antimonene on underlying graphene layers could physically filter the gas molecules such as O2: 3.46 Å, HCHO: 4.3Å, NO2: 3.30Å and let through the smaller molecules (H2: 2.89 Å, NO: 3.17Å, CO:3.19Å, NH3: 3.26Å) [51][52][53].…”

Space‐Confined Metal Ion Strategy for Carbon Materials Derived from Cobalt Benzimidazole Frameworks with High Desalination Performance in Simulated Seawater

“…Zeolite imidazole frameworks (ZIFs), a subfamily of MOFs, [14,15] are considered ideal precursor materials for electrochemical applications. [16,17] Cobalt benzimidazole frameworks (CoZIF9) can reportedly be used for energy storage/ conversion [18,19] because of the high density of cobalt sites and nitrogen-rich organic imidazole units.…”