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

4 measurement groups · 22 results

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

Energy-dispersive X-ray spectroscopy (EDS)

Elemental microanalysis and mapping

F-Ni MOF catalyst · Powder

EDS quantification of halogen contents in the X-Ni MOF catalyst series.

Context: target halogen-confined samples; results also include Cl-Ni, Br-Ni, and I-Ni values.
Measurement source: main p.2, article p.8707 · Results and discussion

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Br content in Br-Ni MOF	3.47 wt %	—	—	Text Exact Reported	main p.2, article p.8707 · Results and discussion
Cl content in Cl-Ni MOF	4.82 wt %	—	—	Text Exact Reported	main p.2, article p.8707 · Results and discussion
F content in F-Ni MOF	5.29 wt %	—	—	Text Exact Reported	main p.2, article p.8707 · Results and discussion
I content in I-Ni MOFMarked as a best value within this paper	7.57 wt %	—	—	Text Exact Reported	main p.2, article p.8707 · Results and discussion

Operando synchrotron-radiation FTIR

Infrared spectroscopy

Br-Ni MOF catalyst · Powder

Reflection IR setup at NSRL BL01B with ZnSe window; Br-Ni MOF and Ni MOF tested from 0.80 to 0.45 V vs RHE under O2-saturated ORR conditions; spectra in 800-1400 cm-1 region highlighted.

Atmosphere: O2-saturated electrolyte
Geometry: top-plate reflection IR setup; catalyst electrode pressed against ZnSe crystal window
Context: target Br-Ni sample compared with pristine Ni MOF control
Measurement source: SI p.S3-S4 · Operando SR-FTIR measurements · Figure 4c and Figure S18

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
*Ni MOF operando FTIR OOH band**	not observed at approx 1070 cm-1	—	—	Text Qualitative	main p.4, article p.8709 · Results and discussion · Figure S18
*Br-Ni operando FTIR OOH band**Marked as a best value within this paper	approx 1070 cm-1	—	—	Text Approximate	main p.4, article p.8709 · Results and discussion · Figure 4c

Operando Ni K-edge XAFS/XANES/EXAFS

X-ray absorption spectroscopy

Br-Ni MOF catalyst · Powder

Br-Ni catalyst-coated carbon cloths in O2-saturated alkaline solution; potentials 0.80, 0.70, 0.60, and 0.45 V vs RHE; fluorescence mode at BSRF 1W1B.

Atmosphere: O2-saturated alkaline solution
Geometry: homemade operando XAFS cell; catalyst-coated carbon cloth
Context: target Br-Ni sample
Measurement source: SI p.S3 · Operando XAFS measurements · Figure 4a-b and Figures S14-S17; Table S2

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
EXAFS fitted Ni-N bond length at 0.45 V	1.83 Angstrom	—	—	SI Table Exact Reported	SI p.S17 · Supporting Tables · Table S2
EXAFS fitted Ni-N coordination number at 0.45 V	N = 3.5	—	—	SI Table Exact Reported	SI p.S17 · Supporting Tables · Table S2
EXAFS fitted Ni-N bond length at 0.60 VMarked as a best value within this paper	1.84 Angstrom	—	—	SI Table Exact Reported	SI p.S17 · Supporting Tables · Table S2
EXAFS fitted Ni-N coordination number at 0.60 V	N = 3.6	—	—	SI Table Exact Reported	SI p.S17 · Supporting Tables · Table S2
EXAFS fitted Ni-N bond length at 0.70 V	1.83 Angstrom	—	—	SI Table Exact Reported	SI p.S17 · Supporting Tables · Table S2
EXAFS fitted Ni-N coordination number at 0.70 V	N = 3.8	—	—	SI Table Exact Reported	SI p.S17 · Supporting Tables · Table S2
EXAFS fitted Ni-N bond length at 0.80 V	1.81 Angstrom	—	—	SI Table Exact Reported	SI p.S17 · Supporting Tables · Table S2
EXAFS fitted Ni-N coordination number at 0.80 V	N = 4.0	—	—	SI Table Exact Reported	SI p.S17 · Supporting Tables · Table S2
Br-Ni FT-EXAFS peak at 0.60 VMarked as a best value within this paper	approx 1.44 Angstrom	—	—	Text Approximate	main p.4, article p.8709 · Results and discussion · Figure 4b
Br-Ni FT-EXAFS main peak at 0.80 V	approx 1.38 Angstrom	—	—	Text Approximate	main p.4, article p.8709 · Results and discussion · Figure 4b

X-ray photoelectron spectroscopy (XPS)

X-ray photoelectron spectroscopy

Br-Ni MOF catalyst · Powder

Ni 2p XPS for Ni MOF and X-Ni MOFs; Br 3d XPS for Br-Ni MOF before/after ORR.

Geometry: powder/catalyst electrode after reaction for Br 3d stability check
Context: target Br-Ni sample compared with pristine Ni MOF where applicable
Measurement source: main p.4, article p.8709 · Results and discussion · Figure 3d and Figure S13

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Br 3d peak assigned to Br anions	67.7 eV	—	—	Text Exact Reported	main p.4, article p.8709 · Results and discussion · Figure 3d
Br 3d peak assigned to C-Br	69.5 eV	—	—	Text Exact Reported	main p.4, article p.8709 · Results and discussion · Figure 3d
Fraction of Br in anionic formMarked as a best value within this paper	approx 62%	—	—	Text Approximate	main p.4, article p.8709 · Results and discussion · Figure 3d
Ni MOF Ni 2p1/2 binding energy	873.2 eV	—	—	Text Exact Reported	main p.2, article p.8707 · Results and discussion · Figure 1d
Ni MOF Ni 2p3/2 binding energy	856.2 eV	—	—	Text Exact Reported	main p.2, article p.8707 · Results and discussion · Figure 1d
Ni 2p red-shift for X-Ni MOFs relative to Ni MOF	approx 0.6 eV	—	—	Text Approximate	main p.2, article p.8707 · Results and discussion · Figure 1d