Electrochemistry Application — Single-Site, Single-Metal-Atom, Heterogeneous Electrocatalyst: Metal–Organic-Framework Supported Molybdenum Sulfide for Redox Mediator-Assisted Hydrogen Evolution Reaction

12 measurement groups · 23 results

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

bulk electrolysis without redox mediator and GC H2 quantification

MoSx-SIM-NDC-SALI/FTO electrode · Electrode

bulk electrolysis at -420 mV vs RHE; headspace sampled by GC; TOF based on all Mo species in film from ICP-OES and UV-vis decomposed film

Atmosphere: N2-purged electrolyte; GC headspace analysis
Geometry: 0.25 cm2 drop-cast FTO working electrode
Context: target electrode without mediator
Measurement source: 512 · Electrocatalytic Hydrogen Evolution

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
average TOF without redox mediator	0.17 +/- 0.03 min-1	—	+/- 0.03	Text Exact Reported	512 · Electrocatalytic Hydrogen Evolution

cyclic voltammetry with diquat redox mediator

Voltammetry

MoSx-SIM-NDC-SALI/FTO electrode · Electrode

pH 1.2 aqueous H2SO4 with 10 mM DQ2+, 25 mV/s; compared with no RM and 10 mM MV2+

Atmosphere: N2-purged electrolyte
Geometry: 0.25 cm2 drop-cast FTO working electrode
Context: target electrode, mediator identity dependence
Measurement source: 513 · Redox Mediator-Assisted Electrocatalysis · Figure 4b

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
DQ mediator CV effect	onset less negative but plateau current diminished vs MV2+	—	—	Text Qualitative	513 · Redox Mediator-Assisted Electrocatalysis · Figure 4b
DQ2+/+ formal potential	-289 mV vs RHE	—	—	Text Exact Reported	513 · Redox Mediator-Assisted Electrocatalysis

cyclic voltammetry control electrodes with methyl viologen

Voltammetry

MoOx-SIM-NDC-SALI/FTO electrode · Electrode

pH 1.2 aqueous H2SO4 with 10 mM MV2+, 25 mV/s; controls include MoOx-SIM-NDC-SALI, NDC-SALI, NU-1000 and FTO

Atmosphere: N2-purged electrolyte
Geometry: drop-cast FTO working electrodes and bare FTO
Context: pristine/control electrodes
Measurement source: 513 · Redox Mediator-Assisted Electrocatalysis · Figure 4a

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
control HER activity with 10 mM MV2+	controls incapable of HER at ca. -0.4 to -0.5 V vs RHE	—	—	Text Qualitative	513 · Redox Mediator-Assisted Electrocatalysis · Figure 4a

cyclic voltammetry with methyl viologen redox mediator

Voltammetry

MoSx-SIM-NDC-SALI/FTO electrode · Electrode

pH 1.2 aqueous H2SO4 with 10 mM MV2+, 25 mV/s; potentials vs RHE

Atmosphere: N2-purged electrolyte
Geometry: 0.25 cm2 drop-cast FTO working electrode
Context: target electrode, mediator-assisted HER
Measurement source: 513 · Redox Mediator-Assisted Electrocatalysis · Figure 4a

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
catalytic current density with 10 mM MV2+ at -500 mV vs RHE	ca. 2.5 mA/cm2	—	ca.	Text Approximate	513 · Redox Mediator-Assisted Electrocatalysis · Figure 4a
MV2+/+ formal potential	-360 mV vs RHE	—	—	Text Exact Reported	512 · Redox Mediator-Assisted Electrocatalysis

cyclic voltammetry with methyl viologen redox mediator

Voltammetry

MoSx-SIM without NDC/FTO electrode · Electrode

pH 1.2 aqueous H2SO4 with 10 mM MV2+, 25 mV/s; potentials vs RHE

Atmosphere: N2-purged electrolyte
Geometry: drop-cast FTO working electrode fabricated analogously
Context: NDC-free comparator electrode
Measurement source: 513 · Redox Mediator-Assisted Electrocatalysis · Figure 4a

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
catalytic current density with 10 mM MV2+ at -500 mV vs RHEMarked as a best value within this paper	approximately 3.4 mA/cm2 from Figure 4a	—	approximate visual read	Figure Axis Approximate	513 · Redox Mediator-Assisted Electrocatalysis · Figure 4a

cyclic voltammetry without redox mediator

Voltammetry

MoSx-SIM-NDC-SALI/FTO electrode · Electrode

aqueous H2SO4 at pH 1.2, 25 mV/s; three-electrode H-cell, Pt coil counter, Ag/AgCl/KCl reference; potentials reported vs RHE

Atmosphere: N2-purged electrolyte
Geometry: 0.25 cm2 drop-cast FTO working electrode
Context: target electrode without redox mediator
Measurement source: 512 · Electrocatalytic Hydrogen Evolution · Figure S5

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
framework electrical addressability	MOF itself is electrically insulating at hydrogen-evolution potentials	—	—	Text Qualitative	510 · Introduction

Faradaic efficiency from bulk electrolysis and GC H2 detection

MoSx-SIM-NDC-SALI/FTO electrode · Electrode

various MV2+ or DQ2+ concentrations during bulk electrolysis; H2 quantified by GC

Atmosphere: N2-purged electrolyte; Ar carrier gas for GC
Geometry: 0.25 cm2 drop-cast FTO working electrode
Context: target electrode product selectivity/current efficiency
Measurement source: 514 · Redox Mediator-Assisted Electrocatalysis · Figure S9

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Faradaic efficiency with 10 mM DQ2+	approximately 63%	—	visual estimate	Figure Axis Approximate	S11 · Characterization · Figure S9
Faradaic efficiency with 10 mM MV2+Marked as a best value within this paper	approximately 100%	—	visual estimate	Figure Axis Approximate	S11 · Characterization · Figure S9

foot-of-the-wave analysis (FOWA)

MoSx-SIM-NDC-SALI/FTO electrode · Electrode

FOWA on RM-assisted CVs in pH 1.2 H2SO4; oxide derivative used to estimate non-catalytic cathodic peak current background

Atmosphere: N2-purged electrolyte
Geometry: drop-cast FTO working electrode
Context: target electrode mediator-catalyst electron-transfer kinetics
Measurement source: 514 · Foot-of-the-wave Analysis · Table 1

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
second-order rate constant kRM with DQ2+	17 +/- 1 M-1 s-1	—	+/- 1	Table Exact Reported	514 · Foot-of-the-wave Analysis · Table 1
second-order rate constant kRM with MV2+	31 +/- 5 M-1 s-1	—	+/- 5	Table Exact Reported	514 · Foot-of-the-wave Analysis · Table 1
TOF at zero overpotential with DQ2+	19 x 10^-3 min-1	0.019 min-1	—	Table Exact Reported	514 · Foot-of-the-wave Analysis · Table 1
TOF at zero overpotential with MV2+	1.7 x 10^-3 min-1	0.0017 min-1	—	Table Exact Reported	514 · Foot-of-the-wave Analysis · Table 1

foot-of-the-wave analysis (FOWA)

MoSx-SIM without NDC/FTO electrode · Electrode

FOWA on NDC-free MoSx-SIM comparator under identical electrode fabrication

Atmosphere: N2-purged electrolyte
Geometry: drop-cast FTO working electrode
Context: NDC-free comparator kinetics
Measurement source: 514 · Foot-of-the-wave Analysis · Table 1

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
second-order rate constant kRM with DQ2+	23 +/- 3 M-1 s-1	—	+/- 3	Table Exact Reported	514 · Foot-of-the-wave Analysis · Table 1
second-order rate constant kRM with MV2+Marked as a best value within this paper	36 +/- 8 M-1 s-1	—	+/- 8	Table Exact Reported	514 · Foot-of-the-wave Analysis · Table 1
TOF at zero overpotential with DQ2+Marked as a best value within this paper	36 x 10^-3 min-1	0.036 min-1	—	Table Exact Reported	514 · Foot-of-the-wave Analysis · Table 1
TOF at zero overpotential with MV2+	2.8 x 10^-3 min-1	0.0028 min-1	—	Table Exact Reported	514 · Foot-of-the-wave Analysis · Table 1

solvent/electrolyte kinetic isotope effect by CV

Voltammetry

MoSx-SIM-NDC-SALI/FTO electrode · Electrode

pH 1.2 H2SO4/H2O vs pD 1.2 D2SO4/D2O, 10 mM MV2+, 25 mV/s

Atmosphere: N2-purged electrolyte
Geometry: 0.25 cm2 drop-cast FTO working electrode
Context: target electrode mechanistic isotope dependence
Measurement source: 514 · Redox Mediator-Assisted Electrocatalysis · Figure S10

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
kinetic isotope effect in plateau region	KIE exceeds 2 at more negative potentials	—	greater than	Text Approximate	514 · Redox Mediator-Assisted Electrocatalysis · Figure S10

bulk electrolysis TOF vs pH

MoSx-SIM-NDC-SALI/FTO electrode · Electrode

MV2+-mediated hydrogen evolution at -420 mV vs RHE; pH varied; TOF from H2 amounts

Atmosphere: N2-purged electrolyte; GC headspace analysis
Geometry: 0.25 cm2 drop-cast FTO working electrode
Context: target electrode proton activity dependence
Measurement source: 514 · Redox Mediator-Assisted Electrocatalysis · Figure 4d

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
apparent reaction order vs proton activity for NDC-free MoSx-SIM	slope approximately -0.53, R2 = 0.97	—	visual estimate	Figure Axis Approximate	513 · Redox Mediator-Assisted Electrocatalysis · Figure 4d
apparent reaction order vs proton activity	slope approximately -0.84, R2 = 0.98	—	visual estimate	Figure Axis Approximate	513 · Redox Mediator-Assisted Electrocatalysis · Figure 4d

constant-potential bulk electrolysis vs redox mediator concentration

MoSx-SIM-NDC-SALI/FTO electrode · Electrode

bulk electrolysis at -420 mV vs RHE; MV2+ or DQ2+ concentration varied; TOF from H2 amounts

Atmosphere: N2-purged electrolyte; GC headspace analysis
Geometry: 0.25 cm2 drop-cast FTO working electrode
Context: target electrode mediator concentration dependence
Measurement source: 513 · Redox Mediator-Assisted Electrocatalysis · Figure 4c

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
apparent reaction order vs DQ2+ concentration	slope approximately 0.47, R2 = 0.95	—	visual estimate	Figure Axis Approximate	513 · Redox Mediator-Assisted Electrocatalysis · Figure 4c
apparent reaction order vs MV2+ concentration	slope approximately 0.44, R2 = 0.93	—	visual estimate	Figure Axis Approximate	513 · Redox Mediator-Assisted Electrocatalysis · Figure 4c