Electrochemistry Application — Thousand-fold increase in O2electroreduction rates with conductive MOFs

7 measurement groups · 54 results

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

Capacitive CV-derived capacitance and ECSA

Voltammetry

0.4 mg cm^-2 Ni3(HITP)2 GDE · Electrode

CVs in N2 before potentiostatic electrolysis; ten cycles at 200, 100, 75, 50 and 20 mV s^-1; capacitance divided by 18 uF cm_real^-2 to estimate ECSA.

Atmosphere: N2
Geometry: GDE geometric footprint 0.8 cm^2.
Context: composite
Measurement source: SI p.S47 · Table S1 · Table S1

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
0.4 mg cm^-2 Co3(HITP)2 GDE capacitance	5.2 mF cm^-2	—	—	SI Table Exact Reported	SI p.S47 · Table S1 · Table S1
0.4 mg cm^-2 Cu3(HITP)2 GDE capacitance	5.0 mF cm^-2	—	—	SI Table Exact Reported	SI p.S47 · Table S1 · Table S1
0.1 mg cm^-2 Ni3(HITP)2 GDE capacitance	4.4 mF cm^-2	—	—	SI Table Exact Reported	SI p.S47 · Table S1 · Table S1
0.2 mg cm^-2 Ni3(HITP)2 GDE capacitance	13.5 mF cm^-2	—	—	SI Table Exact Reported	SI p.S47 · Table S1 · Table S1
0.4 mg cm^-2 Ni3(HITP)2 GDE capacitance	31.0 mF cm^-2	—	—	SI Table Exact Reported	SI p.S47 · Table S1 · Table S1
0.8 mg cm^-2 Ni3(HITP)2 GDE capacitance	57.0 mF cm^-2	—	—	SI Table Exact Reported	SI p.S47 · Table S1 · Table S1
0.8 mg cm^-2 Ni3(HITP)2 + 10% PTFE GDE capacitanceMarked as a best value within this paper	89.4 mF cm^-2	—	—	SI Table Exact Reported	SI p.S47 · Table S1 · Table S1
Co3(HITP)2 ECSA at 0.4 mg cm^-2	56 m2 g^-1	—	—	Text Exact Reported	SI p.S9 · Supplementary text 1 · Figure S18
Cu3(HITP)2 ECSA at 0.4 mg cm^-2	52 m2 g^-1	—	—	Text Exact Reported	SI p.S9 · Supplementary text 1 · Figure S18
Ni3(HITP)2 ECSA at 0.4 mg cm^-2Marked as a best value within this paper	338 m2 g^-1	—	—	Text Exact Reported	SI p.S9 · Supplementary text 1 · Figure S18
PTFE-modified Ni3(HITP)2 GDE ECSA increase over PTFE-free 0.8 mg cm^-2	20% higher	—	—	Text Rounded Reported	SI p.S12 · Supplementary text 3 · Figure S32 and Table S1
PTFE-modified Ni3(HITP)2 GDE roughness factorMarked as a best value within this paper	~4967	—	—	Text Approximate	SI p.S12 · Supplementary text 3 · Figure S32 and Table S1
0.4 mg cm^-2 Co3(HITP)2 GDE roughness factor	289	—	—	Figure Axis Exact Reported	main article p.977 · Figure caption/table · Figure 2F
0.4 mg cm^-2 Cu3(HITP)2 GDE roughness factor	278	—	—	Figure Axis Exact Reported	main article p.977 · Figure caption/table · Figure 2F
0.4 mg cm^-2 Ni3(HITP)2 GDE roughness factor	1722	—	—	Figure Axis Exact Reported	main article p.977 · Figure caption/table · Figure 2F

GDE flow electrolysis mass-loading series

0.1 mg cm^-2 Ni3(HITP)2 GDE · Electrode

PTFE-free Ni3(HITP)2 GDEs with 0.1, 0.2, 0.4 and 0.8 mg cm^-2 catalyst loading; potentiostatic O2 electrolysis and H2O2 titration.

Atmosphere: O2 at cathode
Geometry: MOF-loaded AvCarb GDE in gas diffusion flow electrolyser.
Context: composite
Measurement source: main article p.978 · Results and Discussion · Figure 3 and Figure S20-S22

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
0.1 mg cm^-2 Ni3(HITP)2 GDE gravimetric H2O2 production rateMarked as a best value within this paper	6570 mol H2O2 kgMOF^-1 h^-1	—	—	Text Exact Reported	main article p.978 · Results and Discussion · Figure 3B
Highest mass activity in Ni3(HITP)2 GDE mass-loading seriesMarked as a best value within this paper	553 A g^-1 at the most cathodic applied potential for 0.1 mg cm^-2 electrode	—	—	Text Exact Reported	main article p.978 · Results and Discussion · Figure 3C
PTFE-free Ni3(HITP)2 GDE single-pass O2 conversion limit	30%	—	—	Text Rounded Reported	main article p.979 · Results and Discussion · Figure S22C
Ni3(HITP)2 high-loading GDE jORR plateau	ca. -110 mA cm^-2 for 0.4 and 0.8 mg cm^-2 GDEs at high driving force	—	—	Text Approximate	main article p.978 · Results and Discussion · Figure 3A
PTFE-free 0.8 mg cm^-2 Ni3(HITP)2 GDE mass activity comparator	~124 A g^-1	—	—	Text Approximate	main article p.980 · Results and Discussion · Figure S34C

GDE flow electrolysis ORR/H2O2 electrosynthesis for M3(HITP)2 series

0.4 mg cm^-2 Co3(HITP)2 GDE · Electrode

0.4 mg cm^-2 Ni3(HITP)2, Co3(HITP)2 and Cu3(HITP)2 GDEs compared under the same O2 GDE flow electrolysis conditions.

Atmosphere: O2 at cathode
Geometry: MOF-loaded AvCarb GDE in gas diffusion flow electrolyser.
Context: composite
Measurement source: SI p.S9 · Supplementary text 1 · Figures S16-S17

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Co3(HITP)2 GDE ORR onset potential at -5 mA cm^-2 criterion	-0.096 V vs SHE	—	—	Text Exact Reported	SI p.S9 · Supplementary text 1 · Figure 2G
Co3(HITP)2 maximum jH2O2	never exceeding -13 mA cm^-2	—	—	Text Approximate	SI p.S9 · Supplementary text 1 · Figure S17B
Co3(HITP)2 peak GDE jORR	-56 mA cm^-2	—	—	Text Exact Reported	SI p.S9 · Supplementary text 1 · Figure S17A
Cu3(HITP)2 GDE ORR onset potential at -5 mA cm^-2 criterion	-0.22 V vs SHE	—	—	Text Rounded Reported	SI p.S9 · Supplementary text 1 · Figure 2G
Cu3(HITP)2 maximum jH2O2	never exceeding -4 mA cm^-2	—	—	Text Approximate	SI p.S9 · Supplementary text 1 · Figure S17B
Cu3(HITP)2 peak GDE jORR	-52 mA cm^-2	—	—	Text Exact Reported	SI p.S9 · Supplementary text 1 · Figure S17A
Ni3(HITP)2 GDE ORR onset potential at -5 mA cm^-2 criterionMarked as a best value within this paper	0.017 V vs SHE	—	—	Text Exact Reported	SI p.S9 · Supplementary text 1 · Figure 2G

GDE flow electrolysis ORR/H2O2 electrosynthesis

0.4 mg cm^-2 Ni3(HITP)2 GDE · Electrode

Custom gas diffusion electrolyser, 1 M NaCl + 0.3 M sodium phosphate pH 7, electrolyte 0.2 mL min^-1, O2 1.5 mL min^-1, H2 anode 5 mL min^-1, effective area 0.8 cm^2; iR-corrected potentiostatic data unless noted.

Atmosphere: O2 at cathode
Geometry: MOF-loaded AvCarb GDS2230 GDE compressed against interdigitated flow field.
Context: composite
Measurement source: main article pp.976-977 · Results and Discussion · Figure 2A-D

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Ni3(HITP)2 GDE H2O2 Faradaic efficiency at maximum jH2O2Marked as a best value within this paper	85% FE for H2O2 at -0.36 V	—	—	Text Rounded Reported	main article p.977 · Results and Discussion · Figure 2D
Ni3(HITP)2 GDE H2O2 product stream concentrationMarked as a best value within this paper	108 mM (~3270 ppm) H2O2 at -0.36 V	—	—	Text Exact Reported	main article p.978 · Results and Discussion · Figure 2D
Ni3(HITP)2 GDE jH2O2 improvement over RRDE	740-fold improvement	—	—	Text Rounded Reported	main article p.977 · Results and Discussion · Figure 2D
Ni3(HITP)2 GDE jH2O2 at 0.01 V	-1.2 mA cm^-2 at 0.01 V	—	—	Text Exact Reported	main article p.977 · Results and Discussion · Figure 2D
Ni3(HITP)2 GDE jORR at -0.29 V	-62 mA cm^-2 at -0.29 V	—	—	Text Rounded Reported	main article p.977 · Results and Discussion · Figure 2B
Ni3(HITP)2 GDE jORR improvement over RRDE	approximately 310-fold improvement	—	—	Text Approximate	main article p.977 · Results and Discussion · Figure 2C
Ni3(HITP)2 GDE mass activity at -0.36 V	259 A g^-1 at -0.36 V	—	—	Text Exact Reported	main article p.978 · Results and Discussion · Figure 2C
Ni3(HITP)2 GDE maximum jH2O2Marked as a best value within this paper	-88.5 mA cm^-2 at -0.36 V	—	—	Text Exact Reported	main article p.977 · Results and Discussion · Figure 2D
Ni3(HITP)2 GDE maximum jORRMarked as a best value within this paper	-103 mA cm^-2 at -0.36 V	—	—	Text Exact Reported	main article p.977 · Results and Discussion · Figure 2C

GDE flow electrolysis with PTFE-modified catalyst layer

0.8 mg cm^-2 Ni3(HITP)2 + 10 wt% PTFE GDE · Electrode

0.8 mg cm^-2 Ni3(HITP)2 + 10 wt% PTFE GDE measured under GDE flow electrolysis; compared with PTFE-free electrodes.

Atmosphere: O2 at cathode
Geometry: MOF/PTFE/Nafion-loaded AvCarb GDE in gas diffusion flow electrolyser.
Context: composite
Measurement source: main article pp.979-980 · Results and Discussion · Figures S31-S34

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
PTFE-modified Ni3(HITP)2 GDE single-pass O2 conversionMarked as a best value within this paper	48% at O2 flow rate of 1.5 mL min^-1	—	—	Text Exact Reported	main article p.979 · Results and Discussion · Figure S34F
PTFE-modified Ni3(HITP)2 GDE total current densityMarked as a best value within this paper	-170 mA cm^-2 at -0.27 V	—	—	Text Exact Reported	main article p.979 · Results and Discussion · Figure S34A
PTFE increased apparent mass-transport-limited currentMarked as a best value within this paper	from -110 to -180 mA cm^-2	—	—	Text Rounded Reported	main article p.980 · Results and Discussion · Figure S34
PTFE-modified Ni3(HITP)2 GDE mass activity	212 A g^-1	—	—	Text Exact Reported	main article p.980 · Results and Discussion · Figure S34C

H-cell/RRDE ORR electrochemistry

0.4 mg cm^-2 Ni3(HITP)2 on glassy-carbon RRDE disk · Electrode

Two-compartment H-cell, 1.0 M NaCl + 0.3 M sodium phosphate at pH 7, O2 or N2 bubbled; RRDE rotated at 1000 or 1500 rpm; Pt ring at +0.91 V vs SHE for H2O2 detection.

Atmosphere: O2 or N2 saturated electrolyte
Geometry: 5 mm glassy-carbon disk with Pt ring RRDE.
Context: composite
Measurement source: main article pp.976-977 · Results and Discussion · Figure 2B-D and Figure S6

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Ni3(HITP)2 RRDE H2O2 FE at -0.54 V	21% (-0.085 mA cm^-2) at -0.54 V	—	—	Text Rounded Reported	main article p.976 · Results and Discussion · Figure S6C
Ni3(HITP)2 RRDE peak H2O2 Faradaic efficiency	60% at 0.09 V	—	—	Text Rounded Reported	main article p.976 · Results and Discussion · Figure S6C
Ni3(HITP)2 RRDE H2O2 partial current at peak FE	-0.121 mA cm^-2 at 0.09 V	—	—	Text Exact Reported	main article p.976 · Results and Discussion · Figure S6C
Ni3(HITP)2 RRDE limiting ORR current density	jORR = -0.4 mA cm^-2	—	—	Text Rounded Reported	main article p.976 · Results and Discussion · Figure 2C
Ni3(HITP)2 RRDE jORR at -0.29 V	-0.6 mA cm^-2 at -0.29 V	—	—	Text Rounded Reported	main article p.977 · Results and Discussion · Figure 2B
Ni3(HITP)2 RRDE ORR onset potential	-0.05 V vs SHE	—	—	Text Rounded Reported	main article p.976 · Results and Discussion · Figure 2B inset
Ni3(HITP)2 RRDE ORR plateau current density	around -0.6 mA cm^-2 beginning at -0.2 V	—	—	Text Approximate	main article p.976 · Results and Discussion · Figure 2B inset

Scanning electrochemical cell microscopy (SECCM) ORR mapping

Ni3(HITP)2 particles on ITO for SECCM · Electrode

50 nm diameter nanopipette containing 100 mM NaCl + 30 mM sodium phosphate pH 7; hopping-mode LSV from 0.1 to -0.8 V at 2 V s^-1; measured in N2 or ambient air.

Atmosphere: N2 control or ambient air, PO2 approximately 0.2 bar
Geometry: Nanodroplet contact on Ni3(HITP)2 particles supported on ITO; assumed droplet radius 25 nm.
Context: model_system
Measurement source: main article p.979 · Results and Discussion · Figure 4 and Figure S24-S30

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
SECCM Ni3(HITP)2 average current under air at -0.36 V	-25 pA	—	—	Text Exact Reported	main article p.979 · Results and Discussion · Figure 4B-C
SECCM apparent mass contacted by droplet	2.5 x 10^-15 grams	—	—	Calculated From Reported Exact Reported	SI p.S11 · Supplementary text 2 · Figure S29
SECCM Ni3(HITP)2 geometric jORRMarked as a best value within this paper	-1273 mA cm^-2	—	—	Calculated From Reported Exact Reported	main article p.979 · Results and Discussion · Figure 4D
SECCM lower-bound Ni3(HITP)2 mass activityMarked as a best value within this paper	11250 A g^-1 at -0.36 V vs SHE	—	—	Calculated From Reported Exact Reported	main article p.979 · Results and Discussion · Figure S30
SECCM capacitance-based Ni3(HITP)2 mass activity estimate	10,000 A g^-1	—	—	Calculated From Reported Rounded Reported	SI p.S11 · Supplementary text 2 · Figure S29
SECCM Ni3(HITP)2 average current under N2 at -0.36 V	ca. -1 pA	—	—	Text Approximate	main article p.979 · Results and Discussion · Figure S24 and Figure S29
SECCM maximum ECSA contacted by droplet	approximately 2 x 10^-8 cm^2	—	—	Calculated From Reported Approximate	SI p.S11 · Supplementary text 2 · Figure S29