Electrochemistry Application — Ultrathin metal-organic framework array for efficient electrocatalytic water splitting

10 measurement groups · 46 results

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

Double-layer capacitance from CV

Voltammetry

NiFe-MOF/NF ultrathin nanosheet array electrode · Electrode

CVs at 2-10 mV s-1 in 0.86-0.97 V vs RHE; slope of current density vs scan rate.

Atmosphere: 0.1 M KOH
Geometry: Electrochemical surface-area proxy
Context: Electrochemical surface-area proxy
Measurement source: S23 · Supplementary Figure 21 · Supplementary Fig. 21

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Double-layer capacitance, bulk NiFe-MOF	0.016 F cm^-2	—	—	Text Rounded Reported	5 · Discussion · Supplementary Fig. 21
Double-layer capacitance, 2D NiFe-MOF nanosheetsMarked as a best value within this paper	0.036 F cm^-2	—	—	Text Rounded Reported	5 · Discussion · Supplementary Fig. 21

Electrochemical impedance spectroscopy

Impedance spectroscopy

NiFe-MOF/NF ultrathin nanosheet array electrode · Electrode

EIS in 0.1 M KOH; compared direct-grown NiFe-MOF, bulk NiFe-MOF/NF and calcined NiFe-MOF.

Atmosphere: 0.1 M KOH
Geometry: Electrode resistance in electrochemical cell
Context: Electrode resistance in electrochemical cell
Measurement source: S28 · Supplementary Figure 26 · Supplementary Fig. 26

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Internal resistance, bulk NiFe-MOF/NF	8.2 ohm	—	—	Text Rounded Reported	5 · Discussion · Supplementary Fig. 26
Internal resistance, calcined NiFe-MOF	3.6 ohm	—	—	Text Rounded Reported	S28 · Supplementary Figure 26 · Supplementary Fig. 26
Internal resistance, direct-grown NiFe-MOFMarked as a best value within this paper	2.8 ohm	—	—	Text Rounded Reported	S28 · Supplementary Figure 26 · Supplementary Fig. 26

Linear sweep voltammetry for HER

Voltammetry

NiFe-MOF/NF ultrathin nanosheet array electrode · Electrode

0.1 M KOH; HER polarisation to negative potentials; compared NiFe-MOF, Ni-MOF, bulk NiFe-MOF and calcined NiFe-MOF.

Atmosphere: 0.1 M KOH
Geometry: Three-electrode HER
Context: Binder-free NiFe-MOF/NF target and controls
Measurement source: 3 · Electrocatalytic oxygen and hydrogen evolution · Figure 4a

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
HER overpotential at 10 mA cm-2, bulk NiFe-MOF	196 mV	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 4a
HER overpotential at 10 mA cm-2, calcined NiFe-MOF	255 mV	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 4a
HER overpotential at 10 mA cm-2, Ni-MOF	177 mV	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 4a
HER overpotential at 10 mA cm-2, NiFe-MOFMarked as a best value within this paper	134 mV	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 4a
HER TOF at 400 mV overpotential, bulk NiFe-MOF	0.53 s^-1	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 4a
HER TOF at 400 mV overpotential, calcined NiFe-MOF	0.19 s^-1	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 4a
HER TOF at 400 mV overpotential, Ni-MOF	0.91 s^-1	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 4a
HER TOF at 400 mV overpotential, NiFe-MOFMarked as a best value within this paper	2.8 s^-1	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 4a

HER chronoamperometry and before/after LSV

Voltammetry Chronoamperometry

NiFe-MOF/NF ultrathin nanosheet array electrode · Electrode

Chronoamperometry at -0.2 V vs RHE for 2000 s in 0.1 M KOH; before/after LSV comparison.

Atmosphere: 0.1 M KOH
Geometry: Three-electrode HER
Context: NiFe-MOF/NF target electrode
Measurement source: 5 · Figure 4 caption · Figure 4b

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
HER chronoamperometric stability durationMarked as a best value within this paper	2000 s	—	—	Text Exact Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 4b
HER chronoamperometric potential	-0.2 V vs RHE	—	—	Caption Exact Reported	5 · Figure 4 caption · Figure 4b

Linear sweep voltammetry for OER

Voltammetry

NiFe-MOF/NF ultrathin nanosheet array electrode · Electrode

0.1 M KOH, three-electrode, scan rate 10 mV s-1, no iR correction; compared against Ni-MOF, Fe-MOF, bare NF, bulk NiFe-MOF, calcined NiFe-MOF, NiFe-MOF/GC and IrO2.

Atmosphere: 0.1 M KOH
Geometry: Three-electrode OER
Context: Binder-free NiFe-MOF/NF target and controls
Measurement source: 3 · Electrocatalytic oxygen and hydrogen evolution · Figure 3a; Supplementary Figs. 9-10

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
OER current density at 1.7 V vs RHE, IrO2	80 mA cm^-2	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution
OER current density at 1.7 V vs RHE, NiFe-MOFMarked as a best value within this paper	300 mA cm^-2	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution
OER overpotential at 10 mA cm-2, bulk NiFe-MOF	318 mV	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 3a; Supplementary Figs. 9-10
OER overpotential at 10 mA cm-2, calcined NiFe-MOF	336 mV	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 3a; Supplementary Figs. 9-10
OER overpotential at 10 mA cm-2, Fe-MOF/NF	354 mV	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 3a; Supplementary Figs. 9-10
OER overpotential at 10 mA cm-2, NiFe-MOF/GC	406 mV	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 3a; Supplementary Figs. 9-10
OER overpotential at 10 mA cm-2, IrO2	320 mV	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 3a; Supplementary Figs. 9-10
OER overpotential at 10 mA cm-2, nickel foam	370 mV	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 3a; Supplementary Figs. 9-10
OER overpotential at 10 mA cm-2, Ni-MOF	296 mV	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 3a; Supplementary Figs. 9-10
OER overpotential at 10 mA cm-2, NiFe-MOFMarked as a best value within this paper	240 mV	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 3a; Supplementary Figs. 9-10
OER turnover frequency at 400 mV overpotential, IrO2	0.14 s^-1	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution
OER turnover frequency at 400 mV overpotential, NiFe-MOFMarked as a best value within this paper	3.8 s^-1	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution

RRDE OER Faradaic efficiency/electron transfer

NiFe-MOF/NF ultrathin nanosheet array electrode · Electrode

RRDE in 0.1 M KOH; 1500 rpm; catalyst scratched from NF and coated on RRDE with Nafion; ring potential 0.4 V vs RHE in SI method.

Atmosphere: 0.1 M KOH
Geometry: RRDE disk/ring
Context: NiFe-MOF coated on RRDE for OER product/electron-transfer analysis
Measurement source: 3 · Electrocatalytic oxygen and hydrogen evolution · Figure 3c; Supplementary Figs. 13-14

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Average OER electron transfer numberMarked as a best value within this paper	3.95	—	—	Text Exact Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 3c
OER Faradaic efficiencyMarked as a best value within this paper	95 +/- 2.5%	—	—	Text Exact Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 3c; Supplementary Figs. 13-14

Chronoamperometry/CV/EIS OER durability

Impedance spectroscopy Voltammetry Chronoamperometry

NiFe-MOF/NF ultrathin nanosheet array electrode · Electrode

Chronoamperometry at 1.42 V vs RHE for 20000 s; CV 1000 cycles and EIS before/after cycling.

Atmosphere: 0.1 M KOH
Geometry: Three-electrode OER
Context: NiFe-MOF/NF target electrode
Measurement source: 4 · Figure 3 caption · Figure 3d

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
OER chronoamperometric stability potential	1.42 V vs RHE	—	—	Caption Exact Reported	4 · Figure 3 caption · Figure 3d
OER chronoamperometric stability durationMarked as a best value within this paper	20000 s	—	—	Text Exact Reported	1 · Abstract

Tafel analysis for OER

Tafel and polarisation analysis

NiFe-MOF/NF ultrathin nanosheet array electrode · Electrode

Tafel plots derived from OER LSVs and steady-state tests in 0.1 M KOH.

Atmosphere: 0.1 M KOH
Geometry: Three-electrode OER
Context: Binder-free NiFe-MOF/NF target and controls
Measurement source: 3 · Electrocatalytic oxygen and hydrogen evolution · Figure 3b; Supplementary Figs. 11-12

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
OER Tafel slope, bulk NiFe-MOF	56 mV dec^-1	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 3b; Supplementary Fig. 11
OER Tafel slope, IrO2 from LSV	43 mV dec^-1	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 3b; Supplementary Fig. 11
OER Tafel slope, Ni-MOF	45 mV dec^-1	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 3b; Supplementary Fig. 11
OER Tafel slope, NiFe-MOFMarked as a best value within this paper	34 mV dec^-1	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Figure 3b; Supplementary Fig. 11
OER steady-state Tafel slope, IrO2	46 mV dec^-1	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Supplementary Fig. 12
OER steady-state Tafel slope, NiFe-MOFMarked as a best value within this paper	38 mV dec^-1	—	—	Text Rounded Reported	3 · Electrocatalytic oxygen and hydrogen evolution · Supplementary Fig. 12

Two-electrode full water-splitting LSV

Voltammetry

Two-electrode cell using two NiFe-MOF electrodes · Electrode

Two NiFe-MOF electrodes as anode and cathode; 0.1 M KOH; scan rate 10 mV s-1; compared Pt/C cathode + IrO2 anode.

Atmosphere: 0.1 M KOH
Geometry: Two-electrode full cell
Context: Two-electrode NiFe-MOF cell
Measurement source: 3 · Electrocatalytic overall water splitting · Figure 4c

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Full-water-splitting Tafel slope, Pt/C + IrO2 benchmark	267 mV dec^-1	—	—	Text Rounded Reported	3 · Electrocatalytic overall water splitting · Supplementary Fig. 17
Full-water-splitting Tafel slope, NiFe-MOF cellMarked as a best value within this paper	256 mV dec^-1	—	—	Text Rounded Reported	3 · Electrocatalytic overall water splitting · Supplementary Fig. 17
Full-cell voltage at 10 mA cm-2, Pt/C + IrO2 benchmark	about 1.62 V (70 mV higher than NiFe-MOF)	—	—	Calculated From Reported Approximate	3 · Electrocatalytic overall water splitting · Figure 4c
Full-cell voltage at 10 mA cm-2, two NiFe-MOF electrodesMarked as a best value within this paper	1.55 V	—	—	Text Rounded Reported	3 · Electrocatalytic overall water splitting · Figure 4c

Full water-splitting stability and product analysis

Two-electrode cell using two NiFe-MOF electrodes · Electrode

Chronoamperometry at 1.5 V for 20 h; XRD/SEM before and after; GC product analysis in N2 atmosphere.

Atmosphere: 0.1 M KOH
Geometry: Two-electrode full cell
Context: Two-electrode NiFe-MOF cell
Measurement source: 4 · Electrocatalytic overall water splitting · Figure 4d; Supplementary Figs. 16,18,19

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Full-cell chronoamperometric stability durationMarked as a best value within this paper	20 h	—	—	Text Exact Reported	4 · Electrocatalytic overall water splitting · Figure 4d
Full-cell stability voltage	1.5 V	—	—	Text Exact Reported	4 · Electrocatalytic overall water splitting · Figure 4d
GC hydrogen peak retention time	0.8 min	—	—	Caption Rounded Reported	S18 · Supplementary Figure 16 · Supplementary Fig. 16
GC products other than N2, O2 and H2	no other gases detected	—	—	Caption Qualitative	S18 · Supplementary Figure 16 · Supplementary Fig. 16
GC oxygen peak retention time	around 1.1 min	—	—	Caption Approximate	S18 · Supplementary Figure 16 · Supplementary Fig. 16