Electrochemistry Application — Modular O2 electroreduction activity in triphenylene-based metal-organic frameworks

10 measurement groups · 45 results

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

Electroactive surface area from double-layer capacitance

Cu3(HHTP)2/Nafion-modified glassy carbon electrode · Electrode

CVs in 0.1 M NaCl under N2 over 0 to 0.05 V vs SCE at scan rates 10, 8, 6, 4 and 2 mV/s; capacitive current at 0.025 V vs SCE plotted versus scan rate.

Atmosphere: N2
Geometry: MOF-modified glassy carbon electrode
Context: MOF/Nafion electrode
Measurement source: S7 · Electroactive surface area measurements

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Co3(HHTP)2 electroactive surface area	1.0 x 10^-7 F m^-2	—	—	Table Rounded Reported	5 · Results and discussion · Table 3
Cu3(HHTP)2 electroactive surface areaMarked as a best value within this paper	1.6 x 10^-6 F m^-2	—	—	Table Rounded Reported	5 · Results and discussion · Table 3
Cu3(HITP)2 electroactive surface area availability	N/A; ESA value could not be obtained due to instability	—	—	Table Qualitative	5 · Results and discussion · Table 3
Ni3(HHTP)2 electroactive surface area	1.0 x 10^-7 F m^-2	—	—	Table Rounded Reported	5 · Results and discussion · Table 3
Ni3(HITP)2 electroactive surface area	7.7 x 10^-7 F m^-2	—	—	Table Rounded Reported	5 · Results and discussion · Table 3

Exchange current density derived from Tafel equations

Tafel and polarisation analysis

Ni3(HITP)2/Nafion-modified glassy carbon electrode · Electrode

j0 values tabulated from activation-controlled ORR Tafel fits in pH 8 and pH 13.

Atmosphere: O2
Geometry: MOF-modified glassy carbon rotating disk electrode
Context: MOF/Nafion electrode
Measurement source: S16 · Additional Figures · Table S2

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Co3(HHTP)2 exchange current density at pH 13	6.35 x 10^-9 mA cm^-2	—	—	SI Table Exact Reported	S16 · Additional Figures · Table S2
Co3(HHTP)2 exchange current density at pH 8	8.44 x 10^-7 mA cm^-2	—	—	SI Table Exact Reported	S16 · Additional Figures · Table S2
Cu3(HHTP)2 exchange current density at pH 13	2.91 x 10^-7 mA cm^-2	—	—	SI Table Exact Reported	S16 · Additional Figures · Table S2
Cu3(HHTP)2 exchange current density at pH 8	2.08 x 10^-4 mA cm^-2	—	—	SI Table Exact Reported	S16 · Additional Figures · Table S2
Ni3(HHTP)2 exchange current density at pH 13	2.12 x 10^-7 mA cm^-2	—	—	SI Table Exact Reported	S16 · Additional Figures · Table S2
Ni3(HHTP)2 exchange current density at pH 8	1.19 x 10^-7 mA cm^-2	—	—	SI Table Exact Reported	S16 · Additional Figures · Table S2
Ni3(HITP)2 exchange current density at pH 13Marked as a best value within this paper	2.64 x 10^-4 mA cm^-2	—	—	SI Table Exact Reported	S16 · Additional Figures · Table S2
Ni3(HITP)2 exchange current density at pH 8Marked as a best value within this paper	4.10 x 10^-4 mA cm^-2	—	—	SI Table Exact Reported	S16 · Additional Figures · Table S2

Cyclic voltammetry on ITO substrate

Voltammetry

Trigonal MOF-modified ITO electrodes · Electrode

Co3(HHTP)2 and Ni3(HHTP)2 deposited on ITO; pH 13 and pH 8 under N2 and O2.

Atmosphere: N2 and O2
Geometry: ITO working electrode
Context: MOF on ITO substrate-control electrode
Measurement source: S11 · Additional Figures · Fig. S3

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Trigonal MOF activity on ITO	nominal ORR activity on more inert ITO substrate	—	—	Text Qualitative	2 · Results and discussion · Fig. S3

Potentiostatic ORR order in O2

Co3(HHTP)2/Nafion-modified glassy carbon electrode · Electrode

pH 8; current collected after changing electrolyte atmosphere from 10% O2/90% N2 to 100% O2/0% N2; log(I) versus log(partial pressure O2) slopes extracted at variable potentials.

Atmosphere: O2/N2 mixtures
Geometry: MOF-modified glassy carbon electrode
Context: MOF/Nafion electrode
Measurement source: S5 · Determination of the MOF-mediated ORR order in [O2] · Table S3, Fig. S7

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Co3(HHTP)2 ORR O2-order slope range at pH 8	0.60-0.94 across 0.403 to 0.003 V vs RHE	—	—	SI Table Range	S18 · Additional Figures · Table S3a
Cu3(HHTP)2 ORR O2-order slope range at pH 8	0.52-0.68 across 0.303 to 0.103 V vs RHE	—	—	SI Table Range	S18 · Additional Figures · Table S3c
Cu3(HITP)2 ORR O2-order slope range at pH 8	0.47-0.53 across 0.253 to 0.103 V vs RHE	—	—	SI Table Uncertain	S22 · Supplementary Notes and References · Table S3d
Ni3(HHTP)2 ORR O2-order slope range at pH 8	0.80-0.97 across 0.153 to -0.053 V vs RHE	—	—	SI Table Range	S18 · Additional Figures · Table S3b

Cyclic voltammetry for O2 electroreduction

Voltammetry

Cu3(HITP)2/Nafion-modified glassy carbon electrode · Electrode

MOF powders deposited on glassy carbon; pH 13 (0.1 M KOH) and pH 8 (0.1 M NaCl), O2 and N2 sparging, 2000 rpm, 5 mV/s unless otherwise noted.

Atmosphere: O2 and N2
Geometry: rotating disk glassy carbon electrode
Context: MOF/Nafion electrode
Measurement source: 2 · Results and discussion · Fig. 2

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Best initial ORR activity from CV screeningMarked as a best value within this paper	Cu3(HITP)2 exhibits the highest initial ORR activity in both pH environments	—	—	Text Qualitative	1 · Results and discussion · Fig. 2
Hexagonal MOFs outperform trigonal MOFs for ORR	Ni3(HITP)2 and Cu3(HHTP)2 reduce O2 with lower overpotential and higher current density than trigonal MOFs	—	—	Text Qualitative	1 · Results and discussion · Fig. 2

ORR proton order by galvanostatic pH titration

Galvanostatic cycling

Cu3(HHTP)2/Nafion-modified glassy carbon electrode · Electrode

Potential measured at constant current I = -10 uA while pH varied from 13.5 to 8.0 in 0.10 M KOH titrated with 1.0 M HClO4 under O2 at 2000 rpm.

Atmosphere: O2
Geometry: MOF-modified rotating electrode
Context: MOF/Nafion electrode
Measurement source: S5-S6 · ORR [H+] order study · Table 2, Fig. 4

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Co3(HHTP)2 ORR dE/dpH slope	0.004 V dec^-1	—	—	Table Exact Reported	3 · Results and discussion · Table 2
Cu3(HHTP)2 ORR dE/dpH slope	0.020 V dec^-1	—	—	Table Exact Reported	3 · Results and discussion · Table 2
Cu3(HITP)2 ORR dE/dpH slopeMarked as a best value within this paper	0.039 V dec^-1	—	—	Table Exact Reported	5 · Notes and references · Table 2 footnote
Ni3(HHTP)2 ORR dE/dpH slope	0.007 V dec^-1	—	—	Table Exact Reported	3 · Results and discussion · Table 2
Ni3(HITP)2 ORR dE/dpH slope	0.022 V dec^-1	—	—	Table Exact Reported	3 · Results and discussion · Table 2

Potentiostatic ORR durability

Cu3(HHTP)2/Nafion-modified glassy carbon electrode · Electrode

pH 13 electrolyte; one CV cycle to determine activation-controlled ORR window; potential held in that window for 8 h; percent current retained calculated.

Atmosphere: O2
Geometry: MOF-modified glassy carbon electrode
Context: MOF/Nafion electrode
Measurement source: S6 · Stability testing MOFs in pH 13 electrolyte · Table S1

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Co3(HHTP)2 current retained after 8 h ORR	62%	—	—	SI Table Exact Reported	S12 · Additional Figures · Table S1
Cu3(HHTP)2 current retained after 8 h ORR	73%	—	—	SI Table Exact Reported	S12 · Additional Figures · Table S1
Cu3(HITP)2 current retained after 8 h ORR	6%	—	—	SI Table Exact Reported	S12 · Additional Figures · Table S1
Ni3(HHTP)2 current retained after 8 h ORR	58%	—	—	SI Table Exact Reported	S12 · Additional Figures · Table S1
Ni3(HITP)2 current retained after 8 h ORRMarked as a best value within this paper	88%	—	—	SI Table Exact Reported	S12 · Additional Figures · Table S1

pH-dependent redox cyclic voltammetry under N2

Voltammetry

Cu3(HHTP)2/Nafion-modified glassy carbon electrode · Electrode

Unmodified glassy carbon blank followed by MOF-modified electrodes; CV from -1.1 to 0.7 V vs SCE for at least five pH values for redox-active analogues.

Atmosphere: N2
Geometry: MOF-modified glassy carbon electrode
Context: MOF/Nafion electrode
Measurement source: S6 · Probing the pH-dependent redox potentials of the MOFs · Fig. S8-S10

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Cu3(HHTP)2 peak oxidation potential pH slope under N2	m = -0.093 V dec^-1	—	—	Figure Axis Rounded Reported	S19 · Additional Figures · Fig. S8b
Cu3(HITP)2 peak oxidation potential pH slope under N2	m = -0.074 V dec^-1	—	—	Figure Axis Rounded Reported	S20 · Additional Figures · Fig. S9b
Trigonal MOFs redox activity under N2	Co3(HHTP)2 and Ni3(HHTP)2 show no redox activity in pH 8 CV	—	—	Caption Qualitative	S21 · Additional Figures · Fig. S10

Rotating ring-disk electrode faradaic efficiency for 2e- ORR

Ni3(HITP)2/Nafion-modified glassy carbon electrode · Electrode

pH 8; MOF-modified disk held from 0.67 to 0.38 V vs RHE in 20 mV steps under O2 at 2000 rpm; Pt ring at 1.23 V vs RHE; FE calculated from ring and disk currents.

Atmosphere: O2
Geometry: Pt ring/glassy carbon disk RRDE
Context: MOF/Nafion electrode
Measurement source: S7 · Faradaic efficiency for 2e- ORR with MOFs · Fig. S5

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Co3(HHTP)2 maximum 2e- ORR faradaic efficiency at pH 8	approximately 13% from Fig. S5b	—	visual estimate, roughly +/-2 percentage points	Visual Estimate Approximate	S14 · Additional Figures · Fig. S5b
Cu3(HHTP)2 maximum 2e- ORR faradaic efficiency at pH 8	approximately 75% from Fig. S5d	—	visual estimate, roughly +/-5 percentage points	Visual Estimate Approximate	S14 · Additional Figures · Fig. S5d
Ni3(HHTP)2 maximum 2e- ORR faradaic efficiency at pH 8	approximately 53% from Fig. S5c	—	visual estimate, roughly +/-4 percentage points	Visual Estimate Approximate	S14 · Additional Figures · Fig. S5c
Ni3(HITP)2 maximum 2e- ORR faradaic efficiency at pH 8Marked as a best value within this paper	approximately 85% at low overpotential from Fig. S5a	—	visual estimate, roughly +/-5 percentage points	Visual Estimate Approximate	S14 · Additional Figures · Fig. S5a

Activation-controlled Tafel analysis from Koutecky-Levich data

Tafel and polarisation analysis

Ni3(HITP)2/Nafion-modified glassy carbon electrode · Electrode

pH 8 and pH 13 ORR; CV under N2 and O2, potentiostatic steps over ORR window, rotation speeds 625, 816 and 1189 rpm.

Atmosphere: O2
Geometry: MOF-modified glassy carbon rotating disk electrode
Context: MOF/Nafion electrode
Measurement source: S5 · Koutecky-Levich and Tafel studies · Table 1, Fig. 3

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Co3(HHTP)2 ORR Tafel slope at pH 13Marked as a best value within this paper	0.081 V dec^-1	—	—	Table Exact Reported	3 · Results and discussion · Table 1
Co3(HHTP)2 ORR Tafel slope at pH 8	0.120 V dec^-1	—	—	Table Exact Reported	3 · Results and discussion · Table 1
Cu3(HHTP)2 ORR Tafel slope at pH 13	0.110 V dec^-1	—	—	Table Exact Reported	3 · Results and discussion · Table 1
Cu3(HHTP)2 ORR Tafel slope at pH 8	0.170 V dec^-1	—	—	Table Exact Reported	3 · Results and discussion · Table 1
Ni3(HHTP)2 ORR Tafel slope at pH 13	0.110 V dec^-1	—	—	Table Exact Reported	3 · Results and discussion · Table 1
Ni3(HHTP)2 ORR Tafel slope at pH 8	0.120 V dec^-1	—	—	Table Exact Reported	3 · Results and discussion · Table 1
Ni3(HITP)2 ORR Tafel slope at pH 13	0.128 V dec^-1	—	—	Table Exact Reported	3 · Results and discussion · Table 1
Ni3(HITP)2 ORR Tafel slope at pH 8	0.124 V dec^-1	—	—	Table Exact Reported	3 · Results and discussion · Table 1