Electrochemistry Application

2.8-IrOx@Ni/Co-ZIF-67 / IrOx@Ni/Co-ZIF-67 · Nanosheet

CV curves obtained at scan rates 10, 20, 40, 60 and 80 mV s^-1 in non-Faradaic potential region; Cdl calculated from Delta j versus scan rate.

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated electrode in 1 M KOH
Context: active surface area comparison
Measurement source: article p6 · Results and discussion · Figure 4e; Figure S15

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Double-layer capacitance CdlMarked as a best value within this paper	5.23 mF cm^-2	—	—	Text Exact Reported	article p6 · Results and discussion · Figure 4e; Figure S15
Electrochemically active surface areaMarked as a best value within this paper	34.24 cm2	—	—	Text Exact Reported	article p6 · Results and discussion · Figure 4e; Figure S15

Non-faradaic CV for Cdl/ECSA

Ni/Co-ZIF-67-2 / Ni/Co-ZIF-67 · Nanosheet

CV curves obtained at scan rates 10, 20, 40, 60 and 80 mV s^-1 in non-Faradaic potential region; Cdl calculated from Delta j versus scan rate.

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated electrode in 1 M KOH
Context: active surface area comparison
Measurement source: article p6 · Results and discussion · Figure 4e; Figure S15

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Double-layer capacitance Cdl	2.05 mF cm^-2	—	—	Text Exact Reported	article p6 · Results and discussion · Figure 4e; Figure S15
Electrochemically active surface area	13.31 cm2	—	—	Text Exact Reported	article p6 · Results and discussion · Figure 4e; Figure S15

Non-faradaic CV for Cdl/ECSA

ZIF-67 nanosheet powder/control · Nanosheet

CV curves obtained at scan rates 10, 20, 40, 60 and 80 mV s^-1 in non-Faradaic potential region; Cdl calculated from Delta j versus scan rate.

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated electrode in 1 M KOH
Context: active surface area comparison
Measurement source: article p6 · Results and discussion · Figure 4e; Figure S15

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Double-layer capacitance Cdl	0.217 mF cm^-2	—	—	Text Exact Reported	article p6 · Results and discussion · Figure 4e; Figure S15
Electrochemically active surface area	1.49 cm2	—	—	Text Exact Reported	article p6 · Results and discussion · Figure 4e; Figure S15

Electrochemical impedance spectroscopy

Impedance spectroscopy

2.8-IrOx@Ni/Co-ZIF-67 / IrOx@Ni/Co-ZIF-67 · Nanosheet

EIS measured from 0.01 Hz to 100 kHz; Nyquist plot at 1.53 V and fitted with equivalent circuit from SI Figure S13.

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated electrode in 1 M KOH
Context: charge-transfer/electronic-communication comparison
Measurement source: article p5 · Electrochemical measurements / Results · Figure 4d; Figure S13

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
OER charge-transfer resistanceMarked as a best value within this paper	12.25 ohm	—	—	Text Exact Reported	article p5 · Results and discussion · Figure 4d

Electrochemical impedance spectroscopy

Impedance spectroscopy

Ni/Co-ZIF-67-2 / Ni/Co-ZIF-67 · Nanosheet

EIS measured from 0.01 Hz to 100 kHz; Nyquist plot at 1.53 V and fitted with equivalent circuit from SI Figure S13.

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated electrode in 1 M KOH
Context: charge-transfer/electronic-communication comparison
Measurement source: article p5 · Electrochemical measurements / Results · Figure 4d; Figure S13

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
OER charge-transfer resistance	52.49 ohm	—	—	Text Exact Reported	article p5 · Results and discussion · Figure 4d

Electrochemical impedance spectroscopy

Impedance spectroscopy

ZIF-67 nanosheet powder/control · Nanosheet

EIS measured from 0.01 Hz to 100 kHz; Nyquist plot at 1.53 V and fitted with equivalent circuit from SI Figure S13.

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated electrode in 1 M KOH
Context: charge-transfer/electronic-communication comparison
Measurement source: article p5 · Electrochemical measurements / Results · Figure 4d; Figure S13

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
OER charge-transfer resistance	157.71 ohm	—	—	Text Exact Reported	article p5 · Results and discussion · Figure 4d

LSV and Tafel analysis for OER

Commercial IrO2 benchmark electrode · Electrode

Three-electrode OER testing in 1 M KOH under ambient air; glassy carbon working electrode area 0.196 cm2 loaded with catalyst/Nafion/isopropanol ink at 0.2 mg cm^-2; Pt counter, Ag/AgCl/KCl reference; potentials converted to RHE; LSV scan rate 2 mV s^-1 without iR correction where specified.

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated glassy carbon electrode; loading 0.2 mg cm^-2
Context: target composite versus benchmark
Measurement source: article p5-p6 · Results and discussion · Figure 4a-c

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
OER overpotential at 10 mA cm^-2	304 mV	—	—	Text Exact Reported	article p5 · Results and discussion · Figure 4a,c
Tafel slope	49 mV dec^-1	—	—	Text Exact Reported	article p5 · Results and discussion · Figure 4b,c

LSV and Tafel analysis for OER

2.8-IrOx@Ni/Co-ZIF-67 / IrOx@Ni/Co-ZIF-67 · Nanosheet

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated glassy carbon electrode; loading 0.2 mg cm^-2
Context: target composite versus benchmark
Measurement source: article p5-p6 · Results and discussion · Figure 4a-c

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
OER overpotential at 10 mA cm^-2Marked as a best value within this paper	251 mV	—	—	Text Exact Reported	article p5 · Results and discussion · Figure 4a,c
Tafel slopeMarked as a best value within this paper	38 mV dec^-1	—	—	Text Exact Reported	article p5 · Results and discussion · Figure 4b,c

LSV screening for OER

1.6-IrOx@Ni/Co-ZIF-67 · Nanosheet

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated glassy carbon electrode; loading 0.2 mg cm^-2
Context: IrOx loading optimisation
Measurement source: article p5 · Results and discussion · Figure S12

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Relative OER activity in IrOx loading series	large catalytic current density compared with 6.5-IrOx@Ni/Co-ZIF-67, but not as high as optimized 2.8-IrOx@Ni/Co-ZIF-67	—	—	Text Qualitative	article p5 · Results and discussion · Figure S11 and S12

LSV screening for OER

6.5-IrOx@Ni/Co-ZIF-67 · Nanosheet

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated glassy carbon electrode; loading 0.2 mg cm^-2
Context: IrOx loading optimisation
Measurement source: article p5 · Results and discussion · Figure S12

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Relative OER activity in IrOx loading series	decreased catalytic activity despite dominant Ir3+ state	—	—	Text Qualitative	article p5 · Results and discussion · Figure S11 and S12

LSV and Tafel analysis for OER

Ni/Co-ZIF-67-1 · Nanosheet

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated glassy carbon rotating unspecified/static electrode; GC area 0.196 cm2
Context: pristine/mixed-metal support optimisation
Measurement source: article p2-p3 · Electrochemical measurements / Results · Figure 1d-e

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
OER overpotential at 10 mA cm^-2	347 mV	—	—	Text Exact Reported	article p3 · Results and discussion · Figure 1d
Tafel slope	118 mV dec^-1	—	—	Figure Axis Approximate	article p3 · Results and discussion · Figure 1e

LSV and Tafel analysis for OER

Ni/Co-ZIF-67-2 / Ni/Co-ZIF-67 · Nanosheet

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated glassy carbon rotating unspecified/static electrode; GC area 0.196 cm2
Context: pristine/mixed-metal support optimisation
Measurement source: article p2-p3 · Electrochemical measurements / Results · Figure 1d-e

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
OER overpotential at 10 mA cm^-2Marked as a best value within this paper	336 mV	—	—	Text Exact Reported	article p3 · Results and discussion · Figure 1d
Tafel slopeMarked as a best value within this paper	95 mV dec^-1	—	—	Text Exact Reported	article p3 · Results and discussion · Figure 1e

LSV and Tafel analysis for OER

Ni/Co-ZIF-67-3 · Nanosheet

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated glassy carbon rotating unspecified/static electrode; GC area 0.196 cm2
Context: pristine/mixed-metal support optimisation
Measurement source: article p2-p3 · Electrochemical measurements / Results · Figure 1d-e

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
OER overpotential at 10 mA cm^-2	391 mV	—	—	Text Exact Reported	article p3 · Results and discussion · Figure 1d
Tafel slope	231 mV dec^-1	—	—	Figure Axis Approximate	article p3 · Results and discussion · Figure 1e

LSV and Tafel analysis for OER

Ni/Co-ZIF-67-4 · Nanosheet

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated glassy carbon rotating unspecified/static electrode; GC area 0.196 cm2
Context: pristine/mixed-metal support optimisation
Measurement source: article p2-p3 · Electrochemical measurements / Results · Figure 1d-e

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
OER overpotential at 10 mA cm^-2	446 mV	—	—	Text Exact Reported	article p3 · Results and discussion · Figure 1d
Tafel slope	307 mV dec^-1	—	—	Figure Axis Approximate	article p3 · Results and discussion · Figure 1e

LSV and Tafel analysis for OER

ZIF-67 nanosheet powder/control · Nanosheet

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated glassy carbon rotating unspecified/static electrode; GC area 0.196 cm2
Context: pristine/mixed-metal support optimisation
Measurement source: article p2-p3 · Electrochemical measurements / Results · Figure 1d-e

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
OER overpotential at 10 mA cm^-2	382 mV	—	—	Text Exact Reported	article p3 · Results and discussion · Figure 1d
Tafel slope	136 mV dec^-1	—	—	Figure Axis Approximate	article p3 · Results and discussion · Figure 1e

Chronopotentiometry stability test

1.6-IrOx@Ni/Co-ZIF-67 · Nanosheet

1.6-IrOx@Ni/Co-ZIF-67 tested at constant current density of 10 mA cm^-2 for 24 h in the OER configuration; potential vs RHE read from Figure S18.

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated glassy carbon electrode in 1 M KOH
Context: IrOx loading-series stability comparison
Measurement source: SI p11 · Figure S18 · Figure S18

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Chronopotentiometry potential range during loading-series stability test	approximately 1.49-1.50 V vs RHE over 24 h	—	—	Figure Axis Range	SI p11 · Figure S18 · Figure S18

Chronopotentiometry stability test

2.8-IrOx@Ni/Co-ZIF-67 / IrOx@Ni/Co-ZIF-67 · Nanosheet

Chronopotentiometry at constant current density 10 mA cm^-2 for 24 h in 1 M KOH.

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated electrode in 1 M KOH
Context: target composite durability
Measurement source: article p6 · Results and discussion · Figure 4f; Figure S17

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Stability-test current density	10 mA cm^-2	—	—	Caption Exact Reported	article p6 · Figure caption · Figure 4f
Stability-test duration	24 h	—	—	Caption Exact Reported	article p6 · Figure caption · Figure 4f
Chronopotentiometry potential during stability	approximately 1.49-1.50 V vs RHE over 24 h	—	—	Figure Axis Approximate	article p6 · Results and discussion · Figure 4f
Durability qualitative outcome	current density barely decreased over 24 h; LSV before/after showed almost same feature	—	—	Text Qualitative	article p6 · Results and discussion · Figure 4f; Figure S17

Chronopotentiometry stability test

6.5-IrOx@Ni/Co-ZIF-67 · Nanosheet

6.5-IrOx@Ni/Co-ZIF-67 tested at constant current density of 10 mA cm^-2 for 24 h in the OER configuration; potential vs RHE read from Figure S18.

Temperature: ambient
Atmosphere: ambient air
Geometry: catalyst-coated glassy carbon electrode in 1 M KOH
Context: IrOx loading-series stability comparison
Measurement source: SI p11 · Figure S18 · Figure S18

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Chronopotentiometry potential range during loading-series stability test	approximately 1.54-1.55 V vs RHE over 24 h	—	—	Figure Axis Range	SI p11 · Figure S18 · Figure S18

Chronopotentiometry stability test