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

Measurement evidence

Electrochemistry Application

Intrinsically Conductive π-d Conjugated Layers with Co–N4 Active Sites for Efficient Nitrate Electrocatalysis and Zinc-Nitrate Batteries · Namvar S., Arzani M., Sarkar A.M. et al. · ACS Applied Materials and Interfaces · 2026 · 24433-24443

9 measurement groups · 32 results

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

Zinc-nitrate battery electrochemical testing

Zn-NO3 battery cell with Co3(HITP)2-coated carbon-paper cathode · Unknown

H-type Zn-NO3 battery cell with Co3(HITP)2-coated carbon-paper cathode, Zn plate anode, 1 M KNO3 + 1 M KOH catholyte and 5 M KOH anolyte.

Geometry: Cathode 0.5 x 0.5 cm2; zinc anode 1 x 2 cm2; Nafion 115 separator
Context: Co3(HITP)2 battery cell application
Measurement source: S10 · Assembly of the zinc-nitrate battery · Figure 6; Figure S12

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Galvanostatic discharge current-density range	stepwise increasing current densities from 0 to 20 mA cm-2	—	0-20 mA cm-2	Text Range	p.24440 · Results and Discussion · Figure 6C
Long-term battery cycling duration	approximately 37 h from Figure 6D time axis	—	visual estimate	Visual Estimate Approximate	p.24440 · Figure 6 · Figure 6D
Long-term battery cycling current density	fixed current density of 5 mA cm-2 shown in Figure 6D	—	—	Figure Axis Exact Reported	p.24440 · Figure 6 · Figure 6D
Open-circuit potentialMarked as a best value within this paper	1.449 V	—	—	Caption Exact Reported	p.24440 · Figure 6 caption · Figure 6A
OCP stability duration	stable OCP over 12 h in caption; approximately 14 h in main text	—	12-14 h source discrepancy	Caption Range	p.24440 · Results and Discussion · Figure 6A
Maximum power densityMarked as a best value within this paper	approximately 5.3 mW cm-2	—	approximately	Text Approximate	p.24440 · Results and Discussion · Figure 6B

Cyclic voltammetry-derived double-layer capacitance

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

Current density plotted as a function of scan rate in a nonfaradaic region from CV measurements in 1 M KOH.

Geometry: Co3(HITP)2 and HITP electrodes
Context: Co3(HITP)2 composite electrode compared with HITP control
Measurement source: p.24437 · Results and Discussion · Figure 3C; Figure S7

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Double-layer capacitance of Co3(HITP)2Marked as a best value within this paper	Cdl = 3.5 mF cm-2	—	—	Text Exact Reported	p.24437 · Results and Discussion · Figure 3C
Double-layer capacitance of HITP control	0.3 mF cm-2	—	—	Text Exact Reported	p.24437 · Results and Discussion · Figure 3C

Chronoamperometry with indophenol-blue UV-vis ammonia quantification

UV-visible and optical absorption spectroscopy Chronoamperometry

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

Fixed-potential nitrate electrolysis for 30 min; 1 M KOH + 1 M KNO3; ammonia quantified by alkaline hypochlorite and phenol nitroprusside colourimetry after 30 min dark incubation.

Geometry: Drop-cast carbon paper electrode
Context: Co3(HITP)2 composite electrode
Measurement source: p.24436 · Results and Discussion · Figure 2B-C; Table S2

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Average ammonia Faradaic efficiency across potentials	average ammonia Faradaic efficiency of ~87% across a wide range of potentials	—	~	Text Approximate	p.24435 · Results and Discussion · Figure 2C
Faradaic efficiency at -0.4 V vs RHEMarked as a best value within this paper	~91% at -0.4 V vs RHE	—	~	Text Approximate	p.24433 · Abstract · Figure 2C
Faradaic efficiency at -0.8 V vs RHE	83.8%	—	—	SI Table Exact Reported	S11 · Table S2 · Table S2
Ammonia yield rate at -0.3 V vs RHE	about 10 mg cm-2 h-1 at -0.3 V vs RHE	—	about	Text Approximate	p.24436 · Results and Discussion · Figure 2B
Ammonia yield rate at -0.4 V vs RHE	approximately 15 mg cm-2 h-1 from Figure 2B	—	visual estimate	Visual Estimate Approximate	p.24436 · Figure 2 · Figure 2B
Ammonia yield rate at -0.5 V vs RHE	approximately 26 mg cm-2 h-1 from Figure 2B	—	visual estimate	Visual Estimate Approximate	p.24436 · Figure 2 · Figure 2B
Ammonia yield rate at -0.6 V vs RHE	approximately 35 mg cm-2 h-1 from Figure 2B	—	visual estimate	Visual Estimate Approximate	p.24436 · Figure 2 · Figure 2B
Ammonia yield rate at -0.7 V vs RHE	approximately 52 mg cm-2 h-1 from Figure 2B	—	visual estimate	Visual Estimate Approximate	p.24436 · Figure 2 · Figure 2B
Maximum ammonia yield rate at -0.8 V vs RHEMarked as a best value within this paper	56.8 mg cm-2 h-1 at -0.8 V vs RHE	—	—	Text Exact Reported	p.24436 · Results and Discussion · Figure 2B; Table S2

Repeated 15 min electrolysis cycling

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

20 consecutive 15 min electrolysis cycles at -0.4 V vs RHE.

Geometry: Drop-cast carbon paper electrode
Context: Co3(HITP)2 composite electrode
Measurement source: p.24436 · Results and Discussion · Figure 2D

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Number of repeated electrolysis cycles	20 consecutive 15 min electrolysis cycles	—	—	Text Exact Reported	p.24436 · Results and Discussion · Figure 2D
NH3 yield range over 20 cycles	values varying only slightly between ~12 and ~15 mg cm-2 h-1	—	~12-~15 mg cm-2 h-1	Text Range	p.24436 · Results and Discussion · Figure 2D

LSV and chronoamperometry under varied KOH/KCl electrolyte composition

Voltammetry Chronoamperometry

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

1 M KNO3 with 0, 0.1 or 1 M KOH; KOH versus KCl controls; 0.1 M and 1 M KOH yield/FE compared across potentials; SI includes 1, 2, 3 and 5 M KOH at -0.5 V vs RHE.

Geometry: Co3(HITP)2 carbon-paper electrode
Context: Co3(HITP)2 composite electrode
Measurement source: p.24439-p.24440 · Results and Discussion · Figure 5; Figure S11

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
NH3 yield in 1 M KOH at -0.8 V vs RHEMarked as a best value within this paper	56.8 mg h-1 cm-2 at -0.8 V vs RHE	—	—	Text Exact Reported	p.24440 · Results and Discussion · Figure 5C
KOH versus KCl current-density effect	1 M KCl or 0.1 M KCl gave substantially lower current density than 1 M KOH despite similar ionic strength	—	—	Text Qualitative	p.24440 · Results and Discussion · Figure 5B
Faradaic efficiency at 5 M KOH and -0.5 V vs RHE	approximately 54% from Figure S11B	—	visual estimate	Visual Estimate Approximate	S10 · Figure S11 caption · Figure S11B
NH3 yield at 5 M KOH and -0.5 V vs RHE	approximately 73 mg h-1 cm-2 from Figure S11B	—	visual estimate	Visual Estimate Approximate	S10 · Figure S11 caption · Figure S11B

Long-term chronoamperometry

Chronoamperometry

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

Continuous electrolysis at -0.4 V vs RHE for 20 h.

Geometry: Co3(HITP)2 carbon-paper electrode
Context: Co3(HITP)2 composite electrode
Measurement source: p.24437 · Results and Discussion · Figure 3E

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Long-term current density	approximately -240 mA cm-2, nearly constant over 20 h from Figure 3E	—	visual estimate	Visual Estimate Approximate	p.24437 · Figure 3 · Figure 3E
Long-term chronoamperometry duration	20 h	—	—	Text Exact Reported	p.24438 · Results and Discussion · Figure 3E

Linear sweep voltammetry (LSV)

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

H-type cell, Ag/AgCl reference, Pt mesh counter, Nafion 115 membrane; 1 M KOH with or without 1 M KNO3; about 10 mL electrolyte per chamber.

Geometry: Drop-cast carbon paper electrode, mass loading about 0.5 mg cm-2, exposed area about 0.25-0.36 cm2
Context: Co3(HITP)2 composite electrode with electrolyte controls
Measurement source: p.24436 · Results and Discussion · Figure 2A

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Current density in nitrate-free KOH at -0.8 V vs RHE	~360 mA cm-2 in 1 M KOH	—	~	Text Approximate	p.24436 · Results and Discussion · Figure 2A
Current density in nitrate electrolyte at -0.8 V vs RHEMarked as a best value within this paper	~830 mA cm-2 at -0.8 V vs RHE in 1 M KNO3 + 1 M KOH	—	~	Text Approximate	p.24436 · Results and Discussion · Figure 2A

Time-dependent nitrate removal and ammonia generation chronoamperometry

Chronoamperometry

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

150 min chronoamperometry at -0.4 V vs RHE; nitrate determined by UV-vis using A = A220 - 2A275 after HCl and sulfamic acid addition.

Geometry: Co3(HITP)2 carbon-paper electrode
Context: Co3(HITP)2 composite electrode
Measurement source: S5-S6 · Nitrate detection · Figure 3D; Figure S6

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Produced ammonia concentration as NH3-N	about 93.29 ppm of NH3-N	—	about	Text Rounded Reported	p.24438 · Results and Discussion · Figure 3D
Nitrate conversion after 150 minMarked as a best value within this paper	~100% conversion rate	—	~	Text Approximate	p.24438 · Results and Discussion · Figure 3D
Initial nitrate concentration as NO3-N	initial 160 ppm of NO3-N	—	—	Text Exact Reported	p.24438 · Results and Discussion · Figure 3D

Control nitrate electrolysis with UV-vis ammonia quantification

UV-visible and optical absorption spectroscopy

Bare carbon paper electrode control · Electrode

Post-catalysis electrolytes compared for Co3(HITP)2 in 1 M KNO3 + 1 M KOH, bare carbon paper in 1 M KNO3 + 1 M KOH, and Co3(HITP)2 in 1 M KOH blank electrolyte.

Geometry: Bare carbon paper control and Co3(HITP)2 electrode comparison
Context: Control experiment against Co3(HITP)2 composite electrode
Measurement source: p.24437 · Results and Discussion · Figure 3A

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Nitrate-free electrolyte ammonia control	near zero and below the detection limit in 1 M KOH nitrate-free electrolyte	—	below detection limit	Text Qualitative	p.24437 · Results and Discussion · Figure 3A
Co3(HITP)2 ammonia signal relative to bare carbon paper	ammonia detected from Co3(HITP)2 catalyst was approximately 12 times greater than bare carbon paper	—	approximately	Text Approximate	p.24437 · Results and Discussion · Figure 3A