Electrochemistry Application — Nano UiO-66 and UiO-66-NH2 MOFs as Bifunctional Electrocatalysts for Water-Splitting: A Comparative Study

12 measurement groups · 28 results

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

Cyclic voltammetry, double-layer capacitance, and ECSA

Voltammetry

U catalyst-coated nickel foam electrode · Electrode

CV potential range 0-0.7 V in 1 M KOH; scan rates 20, 40, 60, 80, and 100 mV/s for U; Cdl from DeltaJ/2 versus scan rate in non-Faradaic region at 1.4 V vs RHE; Cs = 0.04 mF/cm2.

Geometry: catalyst-coated nickel foam electrode
Context: UiO-66/carbon/PVDF/NF electrode
Measurement source: 11-12 · 3.7.4 CV and EIS · Fig. 10

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
double-layer capacitance	86.5 mF/cm2	—	—	Text Exact Reported	11 · 3.7.4 CV and EIS · Fig. 10c
electrochemical active surface area, main text	0.21 m2 g-1	—	—	Text Rounded Reported	11 · 3.7.4 CV and EIS · Fig. 10c
electrochemical active surface area, SI calculation	0.21625 m2 g-1	—	—	SI Table Exact Reported	3 · Electrochemical surface area (ECSA) calculations

Cyclic voltammetry, double-layer capacitance, and ECSA

Voltammetry

U-N catalyst-coated nickel foam electrode · Electrode

CV comparison at 40 mV/s in 1 M KOH; Cdl from DeltaJ/2 versus scan rate in non-Faradaic region at 1.4 V vs RHE; Cs = 0.04 mF/cm2.

Geometry: catalyst-coated nickel foam electrode
Context: UiO-66-NH2/carbon/PVDF/NF electrode
Measurement source: 11-12 · 3.7.4 CV and EIS · Fig. 10

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
double-layer capacitanceMarked as a best value within this paper	92 mF/cm2	—	—	Text Exact Reported	11 · 3.7.4 CV and EIS · Fig. 10c
relative CV integrated areaMarked as a best value within this paper	U-N has larger integrated CV area than U at 40 mV/s	—	—	Text Qualitative	11 · 3.7.4 CV and EIS · Fig. 10b
electrochemical active surface areaMarked as a best value within this paper	0.23 m2 g-1	—	—	SI Table Exact Reported	4 · Electrochemical surface area (ECSA) calculations

Electrochemical impedance spectroscopy / Nyquist analysis

Impedance spectroscopy

U catalyst-coated nickel foam electrode · Electrode

High frequencies 1 MHz to 100 Hz and lower-frequency Nyquist response; charge-transfer resistance compared qualitatively.

Geometry: catalyst-coated nickel foam electrode
Context: UiO-66/carbon/PVDF/NF electrode
Measurement source: 11-12 · 3.7.4 CV and EIS · Fig. 10d

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
relative charge-transfer resistance	U has larger semicircle radius and higher Rct than U-N	—	—	Qualitative Qualitative	12 · 3.7.4 CV and EIS · Fig. 10d

Electrochemical impedance spectroscopy / Nyquist analysis

Impedance spectroscopy

U-N catalyst-coated nickel foam electrode · Electrode

High frequencies 1 MHz to 100 Hz and lower-frequency Nyquist response; charge-transfer resistance compared qualitatively.

Geometry: catalyst-coated nickel foam electrode
Context: UiO-66-NH2/carbon/PVDF/NF electrode
Measurement source: 12 · 3.7.4 CV and EIS · Fig. 10d

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
relative charge-transfer resistanceMarked as a best value within this paper	U-N has smaller semicircle and lower Rct than U	—	—	Qualitative Qualitative	12 · 3.7.4 CV and EIS · Fig. 10d

HER linear sweep voltammetry and Tafel analysis

Voltammetry Tafel and polarisation analysis

U catalyst-coated nickel foam electrode · Electrode

Three-electrode HER test in 1 M KOH; LSV potential range 0 to -2 V converted to RHE; overpotential at -10 mA/cm2.

Geometry: catalyst ink on nickel foam, 1 x 1 cm2 coated area
Context: UiO-66/carbon/PVDF/NF electrode
Measurement source: 9-10 · 3.7.2 Hydrogen evolution reaction (HER) · Fig. 8; Table 3

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
HER LSV potential at -10 mA/cm2Marked as a best value within this paper	-0.143 V vs RHE	—	—	Text Exact Reported	9 · 3.7.2 Hydrogen evolution reaction (HER) · Fig. 8a
HER overpotential at 10 mA/cm2Marked as a best value within this paper	143 mV @10 mA/cm2	—	—	Table Exact Reported	9 · 3.7.2 Hydrogen evolution reaction (HER) · Table 3
HER Tafel slopeMarked as a best value within this paper	117 mV/dec	—	—	Table Exact Reported	9 · 3.7.2 Hydrogen evolution reaction (HER) · Table 3

HER linear sweep voltammetry and Tafel analysis

Voltammetry Tafel and polarisation analysis

U-N catalyst-coated nickel foam electrode · Electrode

Three-electrode HER test in 1 M KOH; LSV potential range 0 to -2 V converted to RHE; overpotential at -10 mA/cm2.

Geometry: catalyst ink on nickel foam, 1 x 1 cm2 coated area
Context: UiO-66-NH2/carbon/PVDF/NF electrode
Measurement source: 9-10 · 3.7.2 Hydrogen evolution reaction (HER) · Fig. 8; Table 3

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
HER LSV potential at -10 mA/cm2	-0.179 V vs RHE	—	—	Text Exact Reported	9 · 3.7.2 Hydrogen evolution reaction (HER) · Fig. 8a
HER overpotential at 10 mA/cm2	179 mV @10 mA/cm2	—	—	Table Exact Reported	9 · 3.7.2 Hydrogen evolution reaction (HER) · Table 3
HER Tafel slope	218 mV/dec	—	—	Table Exact Reported	9 · 3.7.2 Hydrogen evolution reaction (HER) · Table 3

HER chronoamperometric stability

Chronoamperometry

U catalyst-coated nickel foam electrode · Electrode

Long-term stability test for U over 10 h at potential corresponding to -10 mA/cm2.

Geometry: catalyst-coated nickel foam electrode
Context: UiO-66/carbon/PVDF/NF electrode
Measurement source: 9-10 · 3.7.2 Hydrogen evolution reaction (HER) · Fig. 8d

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
HER current density retentionMarked as a best value within this paper	1.73 mA/cm2 over 10 h	—	—	Text Exact Reported	9 · 3.7.2 Hydrogen evolution reaction (HER) · Fig. 8d
HER chronoamperometry current fluctuation, first 5 h	DeltaI = 1.23 mA/cm2	—	—	Text Exact Reported	9 · 3.7.2 Hydrogen evolution reaction (HER) · Fig. 8d
HER chronoamperometry current fluctuation, 5-10 h	DeltaI = 0.55 mA/cm2	—	—	Text Exact Reported	9 · 3.7.2 Hydrogen evolution reaction (HER) · Fig. 8d

OER linear sweep voltammetry and Tafel analysis

Voltammetry Tafel and polarisation analysis

U catalyst-coated nickel foam electrode · Electrode

Three-electrode cell with Ag/AgCl reference, Pt counter, catalyst-coated nickel foam working electrode; 1 M KOH, pH about 14; OER LSV 0 to 1 V, converted to RHE, 5 mV/s; values compared at 20 mA/cm2.

Geometry: catalyst ink on nickel foam, 1 x 1 cm2 coated area
Context: UiO-66/carbon/PVDF/NF electrode
Measurement source: 8-9 · 3.7.1 Oxygen evolution reaction (OER) · Fig. 7; Table 2

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
OER overpotential at 20 mA/cm2	418 mV @20 mA/cm2	—	—	Table Exact Reported	8-9 · 3.7.1 Oxygen evolution reaction (OER) · Table 2
OER Tafel slope	236 mV/dec	—	—	Table Exact Reported	8-9 · 3.7.1 Oxygen evolution reaction (OER) · Table 2

OER linear sweep voltammetry and Tafel analysis

Voltammetry Tafel and polarisation analysis

U-N catalyst-coated nickel foam electrode · Electrode

Three-electrode cell with Ag/AgCl reference, Pt counter, catalyst-coated nickel foam working electrode; 1 M KOH, pH about 14; OER LSV 0 to 1 V, converted to RHE, 5 mV/s; values compared at 20 mA/cm2.

Geometry: catalyst ink on nickel foam, 1 x 1 cm2 coated area
Context: UiO-66-NH2/carbon/PVDF/NF electrode
Measurement source: 8-9 · 3.7.1 Oxygen evolution reaction (OER) · Fig. 7; Table 2

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
OER overpotential at 20 mA/cm2Marked as a best value within this paper	370 mV @20 mA/cm2	—	—	Table Exact Reported	8-9 · 3.7.1 Oxygen evolution reaction (OER) · Table 2
OER Tafel slopeMarked as a best value within this paper	215 mV/dec	—	—	Table Exact Reported	8-9 · 3.7.1 Oxygen evolution reaction (OER) · Table 2

OER CV cycling followed by chronoamperometry

Voltammetry Chronoamperometry

U-N catalyst-coated nickel foam electrode · Electrode

U-N OER stability: 200 CV cycles at 100 mV/s, then chronoamperometry for 10 h at constant potential corresponding to 20 mA/cm2.

Geometry: catalyst-coated nickel foam electrode
Context: UiO-66-NH2/carbon/PVDF/NF electrode
Measurement source: 8 · 3.7.1 Oxygen evolution reaction (OER) · Fig. 7d

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
OER current density retentionMarked as a best value within this paper	0.265 mA/cm2 over 10 h	—	—	Text Exact Reported	8 · 3.7.1 Oxygen evolution reaction (OER) · Fig. 7d
OER chronoamperometry current fluctuation, first 5 h	DeltaI = 0.114 mA/cm2 for initial 5 h	—	—	Text Exact Reported	8 · 3.7.1 Oxygen evolution reaction (OER) · Fig. 7d
OER chronoamperometry current fluctuation, subsequent 5 h	DeltaI = 0.197 mA/cm2 for subsequent 5 h	—	—	Text Exact Reported	8 · 3.7.1 Oxygen evolution reaction (OER) · Fig. 7d

Polarisation curves before and after accelerated cycling

U catalyst-coated nickel foam electrode · Electrode

Initial LSV at 5 mV/s; 1000 continuous CV cycles at 100 mV/s; repeated LSV at 5 mV/s for OER and HER overpotential shifts.

Geometry: catalyst-coated nickel foam electrode
Context: UiO-66/carbon/PVDF/NF electrode
Measurement source: 10-11 · 3.7.3 Polarization measurements for OER and HER · Fig. 9

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
HER overpotential increase after 1000 cyclesMarked as a best value within this paper	4 mV	—	—	Text Exact Reported	11 · 3.7.3 Polarization measurements for OER and HER · Fig. 9c
OER overpotential increase after 1000 cyclesMarked as a best value within this paper	8 mV	—	—	Text Exact Reported	11 · 3.7.3 Polarization measurements for OER and HER · Fig. 9a

Polarisation curves before and after accelerated cycling

U-N catalyst-coated nickel foam electrode · Electrode

Initial LSV at 5 mV/s; 1000 continuous CV cycles at 100 mV/s; repeated LSV at 5 mV/s for OER and HER overpotential shifts.

Geometry: catalyst-coated nickel foam electrode
Context: UiO-66-NH2/carbon/PVDF/NF electrode
Measurement source: 10-11 · 3.7.3 Polarization measurements for OER and HER · Fig. 9

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
HER overpotential increase after 1000 cycles	6 mV	—	—	Text Exact Reported	11 · 3.7.3 Polarization measurements for OER and HER · Fig. 9d
OER overpotential increase after 1000 cycles	33 mV	—	—	Text Exact Reported	11 · 3.7.3 Polarization measurements for OER and HER · Fig. 9b