Electrochemistry Application — Self-Nanocavity-Confined Halogen Anions Boosting the High Selectivity of the Two-Electron Oxygen Reduction Pathway over Ni-Based MOFs

5 measurement groups · 31 results

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

Electrochemical impedance spectroscopy (EIS), Bode phase and Nyquist plots

Impedance spectroscopy

Br-Ni MOF catalyst · Powder

Br-Ni MOF measured at 0.80, 0.70, 0.60, and 0.45 V in 0.1 M KOH.

Atmosphere: alkaline ORR electrolyte
Geometry: electrochemical cell
Context: target Br-Ni sample
Measurement source: main p.4-p.5, article p.8709-p.8710 · Results and discussion · Figure 4d and Figure S19

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Br-Ni Bode phase single-peak frequency range	10-1000 Hz	—	range	Text Range	main p.4-p.5, article p.8709-p.8710 · Results and discussion · Figure 4d and Figure S19

Three-phase flow-cell H2O2 electrosynthesis

Br-Ni MOF catalyst · Powder

Commercial flow cell with GDL electrode used to increase local gaseous O2 concentration; Br-Ni MOF tested under applied current densities up to 25 mA/cm2.

Atmosphere: gaseous O2 feed
Geometry: flow cell with gas diffusion layer electrode
Context: target Br-Ni sample
Measurement source: main p.3, article p.8708 · Results and discussion · Figure S10

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Br-Ni flow-cell Faradaic efficiency at 25 mA/cm2	approx 80-85% read from Figure S10b	—	visual estimate from plotted right axis	Figure Axis Approximate	SI p.S11-S12 · Supporting Figures · Figure S10b
Br-Ni flow-cell H2O2 production rate at 25 mA/cm2Marked as a best value within this paper	1534 mmol gcat-1 h-1 at 25 mA/cm2	—	—	Text Rounded Reported	main p.3, article p.8708 · Results and discussion · Figure S10

H-cell electrolysis with Ce4+ UV-vis titration

UV-visible and optical absorption spectroscopy

Br-Ni MOF catalyst · Powder

50 uL catalyst ink on carbon paper; three-electrode H-cell separated by Nafion 117; cathode/anode each 70 mL 0.1 M KOH; O2 purged at least 30 min; ORR at 0.4 V vs RHE and 1600 rpm for 60 min; aliquots sampled at 0-60 min.

Atmosphere: O2-saturated 0.1 M KOH
Geometry: two-chamber H-cell with Nafion 117 membrane
Context: target X-Ni samples compared with pristine Ni MOF control
Measurement source: SI p.S6-S7 · Detailed Contents for Chemical Quantification of H2O2 product · Figures S7-S9

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Br-Ni H2O2 Faradaic efficiencyMarked as a best value within this paper	approx 86%	—	—	Text Approximate	main p.3, article p.8708 · Results and discussion · Figure 2d and Table S1
Br-Ni cumulative H2O2 concentration after 60 minMarked as a best value within this paper	approx 73 mg/L	—	—	Text Approximate	main p.3, article p.8708 · Results and discussion · Figure 2c and Figures S8-S9
Br-Ni H-cell cumulative H2O2 yield rateMarked as a best value within this paper	596 mmol gcat-1 h-1 at 0.4 V vs RHE	—	—	Text Rounded Reported	main p.3, article p.8708 · Results and discussion · Figure 2c and Table S1
Ni MOF H2O2 Faradaic efficiency	approx 30%	—	—	Text Approximate	main p.3, article p.8708 · Results and discussion · Figure 2d
Ni MOF cumulative H2O2 concentration after 60 min	approx 25 mg/L	—	—	Text Approximate	main p.3, article p.8708 · Results and discussion · Figure 2c
X-Ni cumulative H2O2 concentration range after 60 min	40-75 mg/L	—	range	Text Range	main p.3, article p.8708 · Results and discussion · Figure 2c and Figures S8-S9

RRDE linear sweep voltammetry and H2O2 selectivity calculation

Voltammetry

Br-Ni MOF catalyst · Powder

O2-saturated 0.1 M KOH; CHI760E workstation; RRDE electrodes; LSV at 20 mV/s after cycling; catalyst loading about 0.2 mg/cm2; 1600 rpm for Figure 2.

Atmosphere: O2-saturated electrolyte
Geometry: three-electrode RRDE; catalyst ink on 4 mm rotating ring-disk electrode; Pt ring current collection efficiency N = 0.37
Context: target X-Ni samples compared with pristine Ni MOF control
Measurement source: SI p.S4-S5 · Electrochemical Measurements; Selectivity and Electron Transfer Number · Figure 2 and Figures S3-S6

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Optimised H2O2 selectivity of Br-Ni MOFMarked as a best value within this paper	approx 90%	—	—	Text Approximate	main p.3, article p.8708 · Results and discussion · Figure 2b and Table S1
Br-Ni MOF Koutecky-Levich electron-transfer numberMarked as a best value within this paper	n = 2.21	—	—	Figure Axis Exact Reported	SI p.S10 · Supporting Figures · Figure S6c
Br-Ni disk limiting current at 0.2 V vs RHE	approx -1.3 mA/cm2 at 0.2 V vs RHE	—	—	Text Approximate	main p.3, article p.8708 · Results and discussion · Figure 2a
X-Ni ring limiting current at 0.2 V vs RHEMarked as a best value within this paper	approx 0.20 mA/cm2 at 0.2 V vs RHE	—	—	Text Approximate	main p.3, article p.8708 · Results and discussion · Figure 2a
Cl-Ni MOF Koutecky-Levich electron-transfer number	n = 2.50	—	—	Figure Axis Exact Reported	SI p.S10 · Supporting Figures · Figure S6b
Cl-Ni H2O2 selectivity near 0.4 V vs RHE	approx 55-60% read from Figure 2b	—	visual estimate from plotted axis	Figure Axis Approximate	main p.3, article p.8708 · Results and discussion · Figure 2b
F-Ni MOF Koutecky-Levich electron-transfer number	n = 2.54	—	—	Figure Axis Exact Reported	SI p.S10 · Supporting Figures · Figure S6a
F-Ni H2O2 selectivity near 0.4 V vs RHE	approx 55-60% read from Figure 2b	—	visual estimate from plotted axis	Figure Axis Approximate	main p.3, article p.8708 · Results and discussion · Figure 2b
I-Ni MOF Koutecky-Levich electron-transfer number	n = 2.58	—	—	Figure Axis Exact Reported	SI p.S10 · Supporting Figures · Figure S6d
I-Ni H2O2 selectivity near 0.4 V vs RHE	approx 65-70% read from Figure 2b	—	visual estimate from plotted axis	Figure Axis Approximate	main p.3, article p.8708 · Results and discussion · Figure 2b
H2O2 selectivity of Ni MOF	40%	—	—	Text Rounded Reported	main p.1, article p.8706 · Abstract · Figure 2b
Ni MOF Koutecky-Levich electron-transfer number	n = 3.21	—	—	Figure Axis Exact Reported	SI p.S9 · Supporting Figures · Figure S5
Ni MOF disk limiting current at 0.2 V vs RHE	approx -2.2 mA/cm2 at 0.2 V vs RHE	—	—	Text Approximate	main p.3, article p.8708 · Results and discussion · Figure 2a
Ni MOF ring limiting current at 0.2 V vs RHE	approx 0.14 mA/cm2 at 0.2 V vs RHE	—	—	Text Approximate	main p.3, article p.8708 · Results and discussion · Figure 2a
RRDE collection efficiency	N = 0.37	—	—	Text Exact Reported	SI p.S5 · Detailed Protocols for Calibrating the Collection Efficiency of RRDE · Figure S3
X-Ni selectivity enhancement over Ni MOF	150-230%	—	range	Text Range	main p.3, article p.8708 · Results and discussion · Figure 2b

Tafel analysis, chronoamperometry, and post-durability RRDE comparison

Tafel and polarisation analysis Chronoamperometry

Br-Ni MOF catalyst · Powder

Br-Ni MOF and Ni MOF compared for Tafel slopes and FE evolution; Br-Ni MOF operated for 15 h ORR durability testing.

Atmosphere: O2-saturated alkaline electrolyte
Geometry: three-electrode electrochemical cell/RRDE
Context: target Br-Ni sample compared with pristine Ni MOF control
Measurement source: main p.3-p.4, article p.8708-p.8709 · Results and discussion · Figure 3 and Figure S11

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Br-Ni long-term ORR durability timeMarked as a best value within this paper	15 h	—	—	Text Exact Reported	main p.4, article p.8709 · Results and discussion · Figure 3c and Figure S11
Br-Ni stable H2O2 FE after first 20 minMarked as a best value within this paper	86%	—	—	Text Rounded Reported	main p.3-p.4, article p.8708-p.8709 · Results and discussion · Figure 3b
Br-Ni Tafel slopeMarked as a best value within this paper	88 mV decade-1	—	—	Text Exact Reported	main p.3, article p.8708 · Results and discussion · Figure 3a
Ni MOF FE at start of last 30 min	27%	—	—	Text Rounded Reported	main p.4, article p.8709 · Results and discussion · Figure 3b
Ni MOF FE at end of last 30 min	22.5%	—	—	Text Exact Reported	main p.4, article p.8709 · Results and discussion · Figure 3b
Ni MOF Tafel slope	186 mV decade-1	—	—	Text Exact Reported	main p.3, article p.8708 · Results and discussion · Figure 3a