Imine Bond-Based Fluorescent Nanofilms toward High-Performance Detection and Efficient Removal of HCl and NH₃

Abstract

A new kind of imine bond-based fluorescent nanofilm was developed as multifunctional materials for high-performance detection and efficient removal of hydrogen chloride (HCl) and ammonia (NH 3 ). The flexible, uniform, and photochemically stable nanofilms as prepared showed fast (<1 and <0.5 s), sensitive (<150 ppb and <1.5 ppm), and selective response to HCl and NH 3 , respectively, and the removal efficiencies to HCl and NH 3 are 187.5 and 37.5% (w/w), respectively. A reversible earthy-red to green fluorescence color change upon adsorption of NH 3 or HCl enabled visualized monitoring of the two gases in the air. Mechanism studies revealed that the adsorption of HCl is a result of hydrogen bond formation between the analyte and the imine groups. Adsorption of NH 3 , however, is a result of chemical reaction with the preadsorbed HCl. The applicability of the detection and removal strategies as developed was further verified by conducting the tests on real-life or simulated scenarios.

Si Nanowire-Based Schottky Sensors for Selective Sensing of NH3 and HCl via Impedance Spectroscopy

“…Selective approach for the detection of HCl and NH 3 was recently demonstrated with imine bond-based fluorescent nanofilm . The approach allows formation of color variable flexible films but does not support simultaneous detection of the two analytes.…”

“…27,31,32 Selective approach for the detection of HCl and NH 3 was recently demonstrated with imine bond-based fluorescent nanofilm. 33 The approach allows formation of color variable flexible films but does not support simultaneous detection of the two analytes. Similar approach was reported with fluorescent triazine-based covalent organic polymer (COP-1) 34 suffering the similar drawbacks.…”

Fast and Selective Luminescent Sensing by Langmuir–Schaeffer Films Based on Controlled Assembly of Perylene Bisimide Modified with A Cyclometalated AuIII Complex

“…The performance of FFSs relies on designing innovative sensing luminophores and fabricating efficient adlayer structures for mass transfer [2–4] . Common methods used to fabricate luminescent films include spin‐coating, [5] self‐doping, [6] drop‐coating, [2] electrospinning, [7] molecular gel‐based self‐assembly, [8] and liquid‐air polymerization, [9] but the packing models of luminophores on adlayer have not been clearly investigated. The Langmuir–Blodgett/Schaeffer (LB/LS) technique, a unique method for controlling molecular assembly, allows the formation of highly ordered monomolecular film on a solid substrate [10,11] .…”

Efficient Optoelectronic Sensing of HCl Vapor and Effective Iodine Capture/Storage by Hybrid Porous Organic Polymers Incorporating Triptycene and Phosphazene Motifs

“…Hence, all HPOP samples were excited at this wavelength (λ ex = 440 nm) for collection of fluorescence data in both solid and solution states. The reversible color changes in HPOP powders upon treatment with HCl/ammonia and fluorescence quenching of HPOPs@HCl with ammonia could be monitored with the unaided eye upon illumination with normal white light or under UV (365 nm) light, respectively (Figure e,f) . The time taken for the color to stabilize in the presence of HCl and NH 3 was 6 and 4 s, respectively, indicating that these visual changes happen quite rapidly.…”

“…The reversible color changes in HPOP powders upon treatment with HCl/ammonia and fluorescence quenching of HPOPs@HCl with ammonia could be monitored with the unaided eye upon illumination with normal white light or under UV (365 nm) light, respectively (Figure 3e,f). 45 The time taken for the color to stabilize in the presence of HCl and NH 3 was 6 and 4 s, respectively, indicating that these visual changes happen quite rapidly. Thus, HPOP-1/HPOP-2 could be classified as "turn-on" sensors due to the sharp contrast in fluorescence readout after HCl and ammonia treatment.…”