Electrochemistry Application — Host-guest molecular interaction promoted urea electrosynthesis over a precisely designed conductive metal-organic framework

6 measurement groups · 33 results

Reported values remain attached to the sample, method, conditions, extraction quality and source location that produced them.

Electrochemical impedance spectroscopy and CO-stripping

Impedance spectroscopy

Co-PMDA-2-mbIM electrode on carbon cloth · Electrode

EIS from 100 kHz to 1 Hz with 10 mV AC amplitude at -0.5 V vs RHE; CO-stripping used to assess CO poisoning stability.

Temperature: 298
Atmosphere: electrochemical electrolyte conditions
Geometry: PAR-STAT 2273 for EIS; three-electrode H-cell
Context: target and pristine control comparison
Measurement source: p004 · Electrochemical measurements · Fig. S30 and Fig. S36

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
CO-stripping peak of Co-PMDA	0.332 V vs RHE	—	—	Text Rounded Reported	p010 (journal p2093) · Results and discussion · Fig. S36
CO-stripping peak of Co-PMDA-2-mbIM	0.307 V vs RHE	—	—	Text Rounded Reported	p010 (journal p2093) · Results and discussion · Fig. S36
EIS comparison	Co-PMDA-2-mbIM has lower electron-transfer impedance and lower ion diffusion/transfer resistance than Co-PMDA	—	—	Text Qualitative	p008 (journal p2091) · Results and discussion · Fig. S30

UV-vis NOx/NH3 assays and gas chromatography of commercial and purified feed gases

UV-visible and optical absorption spectroscopy

Co-PMDA-2-mbIM electrode on carbon cloth · Electrode

Measurement source: p062 · Table S3 · Table S3

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
N2O concentration limit reported for feed-gas controls	0.05 ppm (limit of detection; not detected)	—	—	Table Exact Reported	p062 · Table S3 · Table S3
NH3 concentration limit reported for feed-gas controls	2.24 ng mL-1 (limit of detection; not detected)	—	—	Table Exact Reported	p062 · Table S3 · Table S3
NOx concentration from commercial CO2 feed	14.29 ng mL-1	—	—	Table Exact Reported	p062 · Table S3 · Table S3
NOx concentration from commercial 14N2 feed	11.43 ng mL-1	—	—	Table Exact Reported	p062 · Table S3 · Table S3
NOx concentration from purified CO2 feed	6.32 ng mL-1 (limit of detection; not detected)	—	—	Table Exact Reported	p062 · Table S3 · Table S3
NOx concentration from purified 14N2 feed	6.32 ng mL-1 (limit of detection; not detected)	—	—	Table Exact Reported	p062 · Table S3 · Table S3
Feed gas flow rate during contaminant controls	30 sccm	—	—	Table Exact Reported	p062 · Table S3 · Table S3
Volume of gas used during contaminant controls	21600 mL	—	—	Table Exact Reported	p062 · Table S3 · Table S3
Purging time during contaminant controls	720 min	—	—	Table Exact Reported	p062 · Table S3 · Table S3

Isotopically labelled nitrogen reduction reaction with UV-vis and 1H NMR product quantification

UV-visible and optical absorption spectroscopy Nuclear magnetic resonance

Co-PMDA-2-mbIM electrode on carbon cloth · Electrode

0.1 M KHCO3, 15N2 feed, H-type cell, Co-PMDA-2-mbIM electrode; potentials varied, optimum -0.5 V vs RHE.

Temperature: 298
Atmosphere: purified 15N2; N2 flow varied in SI tests
Geometry: two-compartment H-cell, Nafion 211 membrane, carbon cloth working electrode, graphite counter, Ag/AgCl reference
Context: target electrode
Measurement source: p005-p006 (journal p2088-p2089) · Results and discussion · Fig. S6-S7

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Best 15NRR Faradaic efficiencyMarked as a best value within this paper	15.15% at -0.5 V vs RHE	—	—	Text Rounded Reported	p006 (journal p2089) · Results and discussion · Fig. S6b
Best 15NH3 yield rateMarked as a best value within this paper	8.74 mmol h-1 g-1 at -0.5 V vs RHE	—	—	Text Rounded Reported	p006 (journal p2089) · Results and discussion · Fig. S6b

Chronoamperometry urea electrosynthesis control experiment

Chronoamperometry

Co-PMDA electrode on carbon cloth · Electrode

Same urea electrosynthesis conditions as Co-PMDA-2-mbIM but using guest-free Co-PMDA electrode.

Temperature: 298
Atmosphere: purified N2 + CO2
Geometry: H-type cell three-electrode configuration
Context: pristine control electrode
Measurement source: p008 (journal p2091) · Results and discussion · Fig. 4f

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Co-PMDA control urea Faradaic efficiency	6.01%	—	—	Text Rounded Reported	p008 (journal p2091) · Results and discussion · Fig. 4f
Co-PMDA control urea yield rate	1.88 mmol h-1 g-1	—	—	Text Rounded Reported	p008 (journal p2091) · Results and discussion · Fig. 4f

Chronoamperometry urea electrosynthesis with diacetyl monoxime, indophenol blue, NMR and GC analysis

Nuclear magnetic resonance Chronoamperometry

Co-PMDA-2-mbIM electrode on carbon cloth · Electrode

0.1 M KHCO3, purified N2 + CO2 feed, chronoamperometry from -0.3 to -0.7 V vs RHE for 2 h; best at -0.5 V vs RHE.

Temperature: 298
Atmosphere: purified N2 + CO2, each 30 sccm in SI setup
Geometry: gas-tight H-type cell, three-electrode configuration
Context: target electrode
Measurement source: p006-p007 (journal p2089-p2090) · Results and discussion · Fig. 4

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
20 h chronoamperometry stability	almost no decay in current density or electrocatalytic performance	—	almost no decay	Text Qualitative	p006 (journal p2089) · Results and discussion · Fig. S18c and Fig. S19
CO2RR FE for CO	up to 48% for converting CO2 into CO	—	up to	Caption Rounded Reported	SI text · Figure captions · Fig. S15
Recycling stability	five consecutive cycles without obvious decay	—	almost no decay	Text Qualitative	p006 (journal p2089) · Results and discussion · Fig. S19
Urea yield enhancement versus Co-PMDA	approximately 7.7-fold	—	—	Calculated From Reported Approximate	p008 (journal p2091) · Results and discussion · Fig. 4f
Best urea Faradaic efficiencyMarked as a best value within this paper	48.97% at -0.5 V vs RHE	—	—	Text Rounded Reported	p006 (journal p2089) · Results and discussion · Fig. 4b
Best urea yield rateMarked as a best value within this paper	14.47 mmol h-1 g-1 at -0.5 V vs RHE	—	—	Text Rounded Reported	p006 (journal p2089) · Results and discussion · Fig. 4b
Closed-system 14urea/15urea yield	only 0.22 ppm; almost no NOx detected	—	only	Text Approximate	p006 (journal p2089) · Results and discussion · Fig. S20d-i

Chronoamperometric urea electrosynthesis quantified across applied potentials

Chronoamperometry

Co-PMDA-2-mbIM electrode on carbon cloth · Electrode

Measurement source: p007 (journal p2090) · Results and discussion · Fig. 4b

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Urea Faradaic efficiency at -0.3 V vs RHE	10.0% at -0.3 V vs RHE	—	—	Figure Axis Approximate	p007 (journal p2090) · Results and discussion · Fig. 4b
Urea Faradaic efficiency at -0.4 V vs RHE	22.0% at -0.4 V vs RHE	—	—	Figure Axis Approximate	p007 (journal p2090) · Results and discussion · Fig. 4b
Urea Faradaic efficiency at -0.5 V vs RHE	48.97% at -0.5 V vs RHE	—	—	Text Exact Reported	p007 (journal p2090) · Results and discussion · Fig. 4b
Urea Faradaic efficiency at -0.6 V vs RHE	15.0% at -0.6 V vs RHE	—	—	Figure Axis Approximate	p007 (journal p2090) · Results and discussion · Fig. 4b
Urea Faradaic efficiency at -0.7 V vs RHE	5.0% at -0.7 V vs RHE	—	—	Figure Axis Approximate	p007 (journal p2090) · Results and discussion · Fig. 4b
Urea yield rate at -0.3 V vs RHE	0.9 mmol h-1 g-1 at -0.3 V vs RHE	—	—	Figure Axis Approximate	p007 (journal p2090) · Results and discussion · Fig. 4b
Urea yield rate at -0.4 V vs RHE	4.0 mmol h-1 g-1 at -0.4 V vs RHE	—	—	Figure Axis Approximate	p007 (journal p2090) · Results and discussion · Fig. 4b
Urea yield rate at -0.5 V vs RHE	14.47 mmol h-1 g-1 at -0.5 V vs RHE	—	—	Text Exact Reported	p007 (journal p2090) · Results and discussion · Fig. 4b
Urea yield rate at -0.6 V vs RHE	8.2 mmol h-1 g-1 at -0.6 V vs RHE	—	—	Figure Axis Approximate	p007 (journal p2090) · Results and discussion · Fig. 4b
Urea yield rate at -0.7 V vs RHE	7.7 mmol h-1 g-1 at -0.7 V vs RHE	—	—	Figure Axis Approximate	p007 (journal p2090) · Results and discussion · Fig. 4b