Spectroscopy — Intrinsically Conductive π-d Conjugated Layers with Co–N4 Active Sites for Efficient Nitrate Electrocatalysis and Zinc-Nitrate Batteries

5 measurement groups · 26 results

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

In situ ATR-SEIRAS

Infrared spectroscopy

Co3(HITP)2 film on SEIRAS-active Au@Si substrate · Thin Film

0.1 M KOH + 0.5 M KNO3 electrolyte, constant potential -0.5 V vs RHE in main text; SI reports -1.5 V vs Ag/AgCl reference spectrum; 64 scans per spectrum, about 30 s acquisition, spectra over 1-30 min.

Temperature: 297 +/- 1 K
Geometry: Co3(HITP)2/Nafion film on SEIRAS-active Au@Si ATR prism; incident angle 60 deg, 4 cm-1 resolution
Context: Co3(HITP)2 SEIRAS film
Measurement source: p.24438 · Results and Discussion · Figure 4

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Cobalt-nitrosyl or NH3 deformation region	weak positive shoulders between 1670-1694 cm-1 assigned to Co-NO vibrations or coupled NH3 deformation modes	—	1670-1694 cm-1	Text Range	p.24439 · Results and Discussion · Figure 4
HNO or nitrate-fragment band	1540 cm-1 band attributed to asymmetric nu(N=O) vibration of HNO or adsorbed nitrate fragment	—	—	Text Exact Reported	p.24438 · Results and Discussion · Figure 4
NH2 scissoring band	1504 cm-1 band represents scissoring vibration of NH2	—	—	Text Exact Reported	p.24438 · Results and Discussion · Figure 4
Adsorbed NH3 deformation band	1428 cm-1 band corresponds to asymmetric deformation of adsorbed NH3	—	—	Text Exact Reported	p.24438 · Results and Discussion · Figure 4
NH3 formation N-H bending band	1442 cm-1 band reflects N-H bending associated with NH3 formation	—	—	Text Exact Reported	p.24438 · Results and Discussion · Figure 4
NHx deformation band	1462 cm-1 vibration originates from NH deformation of transient NHx species	—	—	Text Exact Reported	p.24438 · Results and Discussion · Figure 4
Nitrate consumption band	negative band at 1363 cm-1 assigned to consumption of surface nitrate, nu3(NO3-)	—	—	Text Exact Reported	p.24438 · Results and Discussion · Figure 4
Nitro-type intermediate band	positive band at 1249 cm-1 assigned to antisymmetric stretching of NO2 nitro-type intermediate	—	—	Text Exact Reported	p.24438 · Results and Discussion · Figure 4
Chelated nitrito or NH2 wagging band	positive band at 1299 cm-1 assigned to chelated nitrito (*ONO) configuration or NH2 wagging vibration	—	—	Text Exact Reported	p.24438 · Results and Discussion · Figure 4
ATR-SEIRAS time window	spectra collected over 1-30 min under continuous polarization	—	1-30 min	Caption Range	p.24438 · Figure 4 caption · Figure 4
Interfacial water band	negative band at 1620 cm-1 assigned to depletion or reorientation of interfacial water	—	—	Text Exact Reported	p.24439 · Results and Discussion · Figure 4

NMR isotope labelling

Nuclear magnetic resonance

Co3(HITP)2 drop-cast carbon paper electrode · Electrode

14N and 15N-labelled nitrate sources; Bruker Avance 400 MHz NMR used to identify ammonium isotopologues.

Context: Co3(HITP)2 composite electrode after nitrate electrolysis
Measurement source: S3 · Nuclear Magnetic Resonance · Figure 2E

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
NMR isotope source confirmation	14NO3- system displays characteristic triplet signal corresponding to 14NH4+, confirming ammonia originates from nitrate source; 15N labelling also used	—	—	Text Qualitative	p.24437 · Results and Discussion · Figure 2E

Post-cycling XPS and SEM

X-ray photoelectron spectroscopy Scanning electron microscopy

Co3(HITP)2 drop-cast carbon paper electrode · Electrode

High-resolution Co and N XPS and SEM images after nitrate-reduction cycling; SEM after zinc-nitrate battery cycling in SI.

Geometry: Post-catalysis and post-battery Co3(HITP)2 samples
Context: Co3(HITP)2 after electrochemical operation
Measurement source: S5 and S10 · XPS results after cycling experiment; Assembly of the zinc-nitrate battery · Figure S4; Figure S5; Figure S12

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Post-battery SEM morphology stability	No morphological changes in Co3(HITP)2 after long-term battery cycling	—	—	Text Qualitative	p.24440 · Results and Discussion · Figure S12
Post-cycling SEM morphology stability	Co3(HITP)2 morphology remained nearly unchanged after post-cycling SEM imaging	—	—	Text Qualitative	p.24436-p.24437 · Results and Discussion · Figure S5
Post-cycling XPS stability	No noticeable changes in metal oxidation states after cycling	—	—	Text Qualitative	p.24436 · Results and Discussion · Figure S4

Raman spectroscopy and FT-IR spectroscopy

Infrared spectroscopy Raman spectroscopy

Co3(HITP)2 powder · Powder

Confocal Raman spectroscopy with 532 nm excitation and 720 nm spot size; FT-IR comparison against HITP linker.

Geometry: Powder spectroscopy
Context: pristine Co3(HITP)2 powder with HITP comparison
Measurement source: S2 · Raman Spectroscopy · Figure 1G-H

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
FT-IR C=N/C=C band	Peak at 1630 cm-1 in both spectra attributed to C=N or C=C stretching	—	—	Text Exact Reported	p.24435 · Results and Discussion · Figure 1H
FT-IR ligand N-H disappearance	Ligand amino N-H stretching peaks at 3339 and 3226 cm-1 disappear in Co3(HITP)2	—	3339 and 3226 cm-1	Text Exact Reported	p.24435 · Results and Discussion · Figure 1H
Raman aromatic stretching band	Prominent band at approximately 1350 cm-1	—	approximately	Text Approximate	p.24435 · Results and Discussion · Figure 1G
Raman aromatic stretching band	Prominent band at approximately 1575 cm-1	—	approximately	Text Approximate	p.24435 · Results and Discussion · Figure 1G
Raman Co-N vibration region	Bands in the 700-720 cm-1 region assigned to Co-N vibrations	—	700-720 cm-1	Text Range	p.24435 · Results and Discussion · Figure 1G
Raman figure-labelled ID/IG	ID/IG = 0.93 shown inside Figure 1G	—	—	Figure Axis Exact Reported	p.24434 · Figure 1 · Figure 1G

X-ray photoelectron spectroscopy (XPS)

X-ray photoelectron spectroscopy

Co3(HITP)2 powder · Powder

Thermo Scientific NEXSA G2 XPS; Co 2p and N 1s high-resolution peak fitting.

Geometry: Powder sample
Context: pristine Co3(HITP)2 powder
Measurement source: S3 · X-ray Photoelectron spectroscopy (XPS) · Figure 1E-F

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Co 2p1/2 XPS peak	Co 2p1/2 peak at approximately 796.1 eV	—	approximately	Text Approximate	p.24435 · Results and Discussion · Figure 1E
Co 2p3/2 XPS peak	Co 2p3/2 peak at approximately 780.7 eV	—	approximately	Text Approximate	p.24435 · Results and Discussion · Figure 1E
Co mixed valence assignment	Co 2p deconvoluted into Co2+ and Co3+ components with satellite peaks	—	—	Text Qualitative	p.24435 · Results and Discussion · Figure 1E
N 1s C-N peak	C-N peak at approximately 399.8 eV	—	approximately	Text Approximate	p.24435 · Results and Discussion · Figure 1F
N 1s Co-N peak	Co-N peak at approximately 398.6 eV	—	approximately	Text Approximate	p.24435 · Results and Discussion · Figure 1F