Liu C., Gu Y., Liu C. et al. · ACS Sensors · 2021 · 429-438
Open a family to keep every result attached to its sample, method and conditions.
Paraphrased for this database from the authors’ stated interpretations — never quoted verbatim — and kept separate from reported measurements.
Defect engineering through missing-linker incorporation is proposed as a general strategy to tune conductive MOF sensing properties and solve slow response in organic chemical sensors.
Caveat: Generality is supported by four metal-centre analogues but only Ni is deeply characterised for full mechanism and device metrics.
429 · Abstract · Linked to 4 structured results
Nafion functionalization improves aNi-HAB humidity response, linearity, detection limit and selectivity for water over organic vapours.
Caveat: Detailed Nafion deposition recipe and detection-limit number are not reported in the text provided.
433 · Relative humidity detection · Figure 4 · Linked to 3 structured results
Among Ni, Cu, Co and Fe missing-linker M-HAB analogues, Ni gives the best balance between sensitivity and analyte selectivity.
Caveat: Some supporting M-series response values are visually estimated from log-scale calibration plots.
433 · Relative humidity detection · Figure 3 · Linked to 4 structured results
Missing-linker/hydroxyl defect sites in aNi-HAB enable faster water adsorption/desorption and much faster RH response/recovery than crystalline cNi-HAB.
Caveat: Mechanistic link is supported by DFT and transient-current interpretation, not by direct atomistic operando observation.
435 · Conclusion · Linked to 6 structured results
The aNi-HAB humidity response is attributed mainly to proton/ionic transport plus electronic steady-state current, whereas cNi-HAB response is more charge-transfer based.
Caveat: The authors explicitly note the charge-transfer pathway might also exist in aNi-HAB.
434 · Mechanism evaluations · Figure 5 · Linked to 4 structured results
Names and aliases are kept exactly within the paper’s own identity model.
| Material | Composition | Structure context | Source |
|---|---|---|---|
| missing-linker amorphous Co-HAB (aCo-HAB)Browse family: Co₃(HAB)₂ / Co–HAB | Co-HAB missing-linker framework; empirical formula not reportedCo ions · oxidized hexaaminobenzene-derived linker mixture | 2D · PristineIsostructural missing-linker amorphous M-HAB analogue used for vapour/RH response comparison. | 432-433 · Relative humidity detection · Figure 3c |
| missing-linker amorphous Cu-HAB (aCu-HAB)Browse family: Cu₃(HAB)₂ / Cu–HAB | Cu-HAB missing-linker framework; empirical formula not reportedCu ions · oxidized hexaaminobenzene-derived linker mixture | 2D · PristineIsostructural missing-linker amorphous M-HAB analogue used for vapour/RH response comparison. | 432-433 · Relative humidity detection · Figure 3b |
| missing-linker amorphous Fe-HAB (aFe-HAB) | Fe-HAB missing-linker framework; empirical formula not reportedFe ions · oxidized hexaaminobenzene-derived linker mixture | 2D · PristineIsostructural missing-linker amorphous M-HAB analogue used for vapour/RH response comparison. | 432-433 · Relative humidity detection · Figure 3d |
| missing-linker amorphous Ni-HAB (aNi-HAB)Browse family: Ni₃(HAB)₂ / Ni–HAB | Ni-HAB framework with missing amine/missing-linker and hydroxylated defect sites; empirical formula not reportedNi ions · oxidized hexaaminobenzene mixture, modelled mainly as pentaaminobenzene-derived HAB | 2D · PristineIntrinsically amorphous, missing-linker conductive 2D MOF; defective/hydroxylated Ni-HAB structure with Ni:N about 1:2.9. | 431 · Synthesis of conductive 2D MOF with missing-linker characteristic · Figure 1b,f |
| crystalline Ni-HAB (cNi-HAB)Browse family: Ni₃(HAB)₂ / Ni–HAB | Ni-HAB; ideal Ni:N = 1:4 stated for crystalline structureNi ions · hexaaminobenzene (HAB) | 2D · PristineCrystalline conductive 2D Ni-HAB reference with ordered XRD pattern. | 431 · Synthesis of conductive 2D MOF with missing-linker characteristic · Figure 1a,f |
| DFT slab model of aNi-HAB with hydroxyl defectsBrowse family: Ni₃(HAB)₂ / Ni–HAB | periodic aNi-HAB slab with missing-linker/hydroxyl defect sites; 26.8 x 26.8 x 20 Angstrom^3 cellNi ions with broken local symmetry at defect sites · pentaaminobenzene-derived defective linker model with hydroxyl groups | 2D · Model SystemComputational model for defective aNi-HAB electronic structure and H2O adsorption sites. | 6 · Figure S1 caption/text · Figure S1 |
| DFT slab model of cNi-HABBrowse family: Ni₃(HAB)₂ / Ni–HAB | periodic cNi-HAB monolayer slab, 26.8 x 26.8 x 20 Angstrom^3 cellNi ions in ideal D4h local symmetry · ideal HAB linker network | 2D · Model SystemComputational model system for band structure, DOS and water adsorption at Ni-site/N-site. | 434-435 · DFT Calculations · Figure 6; Figure S8 |
| Nafion-functionalized aNi-HABBrowse family: Ni₃(HAB)₂ / Ni–HAB | Nafion layer on missing-linker aNi-HAB filmNi ions in aNi-HAB · oxidized HAB-derived framework plus perfluorosulfonate Nafion overlayer | 2D · CompositeComposite sensing film with a Nafion functional layer deposited on the as-prepared MOF film. | 433 · Relative humidity detection · Figure 4a-c |
Sample form, processing state and composition status define the context for measurements.
| Sample | Form and role | Processing and geometry | Source |
|---|---|---|---|
| aCo-HAB chemiresistive deviceresearch_0475__mat__mat_aco_hab | Electrode · Target Sample · Pristine Framework | missing-linker Co-HAB made by M-HAB route and fabricated into corresponding sensory devicesensor chip; detailed electrode stack implied by same device approach | 432-433 · Relative humidity detection · Figure 3c |
| aCu-HAB chemiresistive deviceresearch_0475__mat__mat_acu_hab | Electrode · Target Sample · Pristine Framework | missing-linker Cu-HAB made by M-HAB route and fabricated into corresponding sensory devicesensor chip; detailed electrode stack implied by same device approach | 432-433 · Relative humidity detection · Figure 3b |
| aFe-HAB chemiresistive deviceresearch_0475__mat__mat_afe_hab | Electrode · Target Sample · Pristine Framework | missing-linker Fe-HAB made by M-HAB route and fabricated into corresponding sensory devicesensor chip; detailed electrode stack implied by same device approach | 432-433 · Relative humidity detection · Figure 3d |
| aNi-HAB chemiresistive deviceresearch_0475__mat__mat_ani_hab | Electrode · Target Sample · Pristine Framework | 0.5 mg/mL aqueous dispersion drop-cast; hotplate treated at 80 deg C for 10 min before sensingSi chip with pre-patterned Ti-Au (20/50 nm) electrodes · thin film; thickness not reported | 3 · Fabrication of the sensory devices · Figure S2c,d |
| as-synthesized missing-linker aNi-HAB solidresearch_0475__mat__mat_ani_hab | Powder · Target Sample · Pristine Framework | black precipitate; washed, dried under nitrogen and vacuum activated | 2 · Methods |
| cNi-HAB chemiresistive deviceresearch_0475__mat__mat_cni_hab | Electrode · Pristine Control · Pristine Framework | fabricated as for aNi-HAB device; hotplate treated at 80 deg C for 10 min before sensingSi chip with pre-patterned Ti-Au (20/50 nm) electrodes · thin film; thickness not reported | 3 · Fabrication of the sensory devices |
| crystalline cNi-HAB solidresearch_0475__mat__mat_cni_hab | Powder · Pristine Control · Pristine Framework | black solid precipitated at 65 deg C; washed with water/methanol and kept in methanol | 2-3 · Preparation of Crystalline Ni-HAB |
| aNi-HAB defective DFT slabresearch_0475__mat__mat_model_ani_hab_slab | Model · Model System · Model | geometry-optimized computational model with missing-linker/hydroxyl defectsperiodic boundary condition slab · cell size 26.8 x 26.8 x 20 Angstrom^3 | 434 · Mechanism evaluations · Figure 6 |
| cNi-HAB DFT slabresearch_0475__mat__mat_model_cni_hab_slab | Model · Model System · Model | geometry-optimized computational modelperiodic boundary condition slab · cell size 26.8 x 26.8 x 20 Angstrom^3 | 4-5 · Theoretical calculation · Figure S8 |
| 1% Nafion-modified aNi-HAB deviceresearch_0475__mat__mat_nafion_ani_hab | Electrode · Composite Sample · Composite | Nafion layer deposited on top of the as-prepared MOF film; 1% mass fraction identified as optimalaNi-HAB film on Si/Ti-Au chemiresistive chip · Nafion layer thickness not reported | 433 · Relative humidity detection · Figure 4 |