Synthesis · Electrochemical Synthesis of Cu3(HHTP)2Metal–Organic Frameworks from Cu Nanoparticles for Chemiresistive Gas Sensing

3 structured synthesis routes

Completeness describes how fully the route could be reconstructed from the main article and supporting information.

Complete recipeSource: Main

Route 1: Electrochemical

3 · 2.3 Characterization Techniques · Figure 3d

Metal precursorsBulk Cu tape (RS Pro conductive metallic tape) on a 4x4 cm glass slide, both sides covered

Linker precursorsHHTP (same growth solution as route_echem_np)

Solvents4:1 (v/v) ethanol : deionised water (same solution)

AdditivesTBMAMS electrolyte 0.021 M (same solution)

AtmosphereN2-degassed solution (same procedure)

Temperatureroom temperature

Time2

Substrate orientationCu-tape-covered glass slide used in place of the Cu-NP IDE as the working electrode

Oxidant / reductantAnodic oxidation at +0.435 V (same electrode setup as route_echem_np)

Work-upCu tape turned black; black material scraped off the foil to yield powder for PXRD

Scalability contextThis is the scale-up variant of the NP route, introduced specifically to obtain enough Cu3(HHTP)2 powder for PXRD when scraping the IDEs failed.

Show 4 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	bulk Cu tape (RS Pro conductive metallic tape)	4x4 cm glass slide, both sides	3 · 2.3 Characterization Techniques · Figure 3d
Linker	HHTP	2.6 mM (same growth solution)	3 · 2.3 Characterization Techniques · Figure 3d
Electrolyte	TBMAMS	0.021 M (same growth solution)	3 · 2.3 Characterization Techniques · Figure 3d
Solvent	ethanol / deionized water	4:1 by volume	3 · 2.3 Characterization Techniques · Figure 3d

Complete recipeSource: Both

Route 2: Electrochemical

3 · 2.2 Electrochemical Growth

Metal precursorsSputtered metallic Cu nanoparticles (10-50 nm; 7000 ng/cm2) on Pt/glass IDE, oxidised in situ to Cu2+

Linker precursors2,3,6,7,10,11-hexahydroxytriphenylene (HHTP), Fluorochem Ltd.

Solvents4:1 (v/v) ethanol : deionised water

Additivestributyl methylammonium methyl sulfate (TBMAMS) supporting electrolyte, 0.021 M

AtmosphereN2-degassed solution (bubbled 10 min before applying potential); no O2 bubbling required

Temperatureroom temperature (not explicitly stated for the growth cell)

Timegrowth times between 1 min and 4 h; 2 h used for XPS/Raman/sensing sample

Substrate orientationCu-nanoparticle-decorated IDE used directly as working electrode (two sides connected together)

Oxidant / reductantAnodic (electrochemical oxidation) at +0.435 V vs RHE via chronoamperometry; Cu oxidised to Cu2+, HHTP oxidised catechol->semiquinone

Work-upCharacterised in situ on the IDE; for sensing, samples soaked in acetone overnight then dried 10 min at 80 C

ActivationCu nanoparticle precursor annealed 2 h at 200 C prior to growth (necking, adhesion); acetone soak to remove residual pore solvent before sensing

Scalability contextMOF-on-IDE cannot yield enough material for PXRD; a parallel scaled-up variant on bulk Cu tape (4x4 cm glass slide) was used (route_echem_cutape). Method claimed generalisable to other metal/ligand combinations and substrates.

Show 4 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	Cu nanoparticles (magnetron sputtered, 10-50 nm)	7000 ng cm-2 (~8 nm equivalent dense film)	3 · 2.2 Electrochemical Growth
Linker	2,3,6,7,10,11-hexahydroxytriphenylene (HHTP), Fluorochem Ltd.	2.6 mM	3 · 2.2 Electrochemical Growth
Electrolyte	tributyl methylammonium methyl sulfate (TBMAMS), Santa Cruz Biotechnology	0.021 M	3 · 2.2 Electrochemical Growth
Solvent	ethanol / deionized water	4:1 by volume	3 · 2.2 Electrochemical Growth

Partial recipeSource: SI

Route 3: Drop Cast

5 · SI 4. Solution-synthesized MOF NH3 Sensing · Figure S4

Solventsisopropyl alcohol (IPA) dispersion for drop-casting

Atmosphereambient

Temperature80 (drying)

Substrate orientationDrop-cast onto the same type of Pt/glass IDEs used for the electrochemical route

Work-upAcetone soak overnight; dried 10 min at 80 C

Activationacetone soak to draw residual solvent from pores

Scalability contextDeposition/processing route for the comparison control only; the underlying solution synthesis of the Cu3(HHTP)2 powder is not described in this paper.

Show 3 structured reagent records

Role	Reagent	Amount / concentration	Source
Other	Cu3(HHTP)2 powder (solution-synthesised, source recipe not given)	1.5 mg total (30 x 5 uL of 10 mg/mL) · 10 mg mL-1 in IPA	5 · SI 4. Solution-synthesized MOF NH3 Sensing · Figure S4
Solvent	isopropyl alcohol (IPA)	Not specified	5 · SI 4. Solution-synthesized MOF NH3 Sensing · Figure S4
Solvent	acetone (pore-cleaning soak)	overnight soak	5 · SI 4. Solution-synthesized MOF NH3 Sensing · Figure S4