Synthesis · Carbon quantum dot-mediated binary metal-organic framework nanosheets for efficient oxygen evolution at ampere-level current densities in proton exchange membrane electrolyzers

7 structured synthesis routes

Completeness describes how fully the route could be reconstructed from the main article and supporting information.

Complete recipeSource: Main

Route 1: Hydrothermal

31254 · 2.2 Synthesis of CQDs

Solvents50 mL isopropanol; deionised water for dialysis

Additivesp-phenylenediamine; sodium trifluoromethanesulfonate

Temperature200

Time12

Work-upCool to about 20 C, filter through 0.22 um organic-phase microporous membrane, rotary evaporate, dialyse with deionised water for about 7 days.

ActivationDried at 80 C for measurements; stock solution stored for further synthesis.

Scalability contextAuthors call the CQD synthesis a straightforward and scalable one-step hydrothermal process.

Show 3 structured reagent records

Role	Reagent	Amount / concentration	Source
Other	p-phenylenediamine	500 mg	31254 · 2.2 Synthesis of CQDs
Other	sodium trifluoromethanesulfonate	500 mg	31254 · 2.2 Synthesis of CQDs
Solvent	isopropanol	50 mL	31254 · 2.2 Synthesis of CQDs

Complete recipeSource: Main

Route 2: Other

31254 · 2.3 Synthesis of NiFe-MOF

Metal precursors0.1 mmol Fe(NO3)3.9H2O only

Linker precursors0.3 mmol H2NDC

Solventsdeionised water and DMAC, as in NiFe-MOF route

AdditivesTEA, as in NiFe-MOF route

Atmosphereambient air / not specified

Temperaturenormal temperature

Time6

Work-upSame as NiFe-MOF route.

ActivationDried at 60 C for 12 h by analogy to NiFe-MOF route.

Show 2 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	Fe(NO3)3.9H2O	0.1 mmol	31254 · 2.3 Synthesis of NiFe-MOF
Linker	H2NDC	0.3 mmol	31254 · 2.3 Synthesis of NiFe-MOF

Complete recipeSource: SI

Route 3: Drop Cast

S2 · Electrochemical measurements

Solvents600 uL isopropanol; 400 uL water

Additives50 uL Nafion solution

Time0.5

Substrate orientationpolished glassy carbon electrode, 0.19625 cm2

Work-up10 uL catalyst ink dropped onto GC electrode.

ActivationCV activation from 0.926 to 1.826 V vs RHE for 15 cycles at 50 mV s-1 in 1.0 M KOH before LSV.

Show 4 structured reagent records

Role	Reagent	Amount / concentration	Source
Other	catalyst	5 mg	S2 · Electrochemical measurements
Solvent	isopropanol	600 uL	S2 · Electrochemical measurements
Solvent	water	400 uL	S2 · Electrochemical measurements
Additive	Nafion solution	50 uL	S2 · Electrochemical measurements

Complete recipeSource: Main

Route 4: Other

31254 · 2.3 Synthesis of NiFe-MOF

Metal precursors0.7 mmol Ni(Ac)2.4H2O only

Linker precursors0.3 mmol H2NDC

Solventsdeionised water and DMAC, as in NiFe-MOF route

AdditivesTEA, as in NiFe-MOF route

Atmosphereambient air / not specified

Temperaturenormal temperature

Time6

Work-upSame as NiFe-MOF route.

ActivationDried at 60 C for 12 h by analogy to NiFe-MOF route.

Show 2 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	Ni(Ac)2.4H2O	0.7 mmol	31254 · 2.3 Synthesis of NiFe-MOF
Linker	H2NDC	0.3 mmol	31254 · 2.3 Synthesis of NiFe-MOF

Complete recipeSource: Main

Route 5: Other

31254 · 2.4 Synthesis of NiFe-MOF-CQD

Metal precursors0.7 mmol Ni(Ac)2.4H2O (174.3 mg); 0.1 mmol Fe(NO3)3.9H2O (40.4 mg)

Linker precursors0.3 mmol H2NDC (64.8 mg)

Solvents35 mL deionised water for solution A; 35 mL DMAC for solution B; ethanol for rinsing

Additives1 mL original CQD solution injected into solution B; 1.6 mL TEA

Atmosphereambient air / not specified

Temperaturenormal temperature

Time6

Work-upSame as NiFe-MOF: centrifuged, rinsed with ethanol at least three times.

ActivationDried at 60 C for 12 h.

Scalability contextBottom-up ultrasound-assisted route gives ultrathin nanosheets directly and avoids complex exfoliation.

Show 5 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	Ni(Ac)2.4H2O	0.7 mmol; 174.3 mg	31254 · 2.4 Synthesis of NiFe-MOF-CQD
Metal Source	Fe(NO3)3.9H2O	0.1 mmol; 40.4 mg	31254 · 2.4 Synthesis of NiFe-MOF-CQD
Linker	H2NDC	0.3 mmol; 64.8 mg	31254 · 2.4 Synthesis of NiFe-MOF-CQD
Additive	original carbon quantum dot solution	1 mL	31254 · 2.4 Synthesis of NiFe-MOF-CQD
Base	TEA	1.6 mL	31254 · 2.4 Synthesis of NiFe-MOF-CQD

Complete recipeSource: Main

Route 6: Other

31254 · 2.3 Synthesis of NiFe-MOF

Metal precursors0.7 mmol Ni(Ac)2.4H2O (174.3 mg); 0.1 mmol Fe(NO3)3.9H2O (40.4 mg)

Linker precursors0.3 mmol H2NDC (64.8 mg)

Solvents35 mL deionised water for solution A; 35 mL DMAC for solution B; ethanol for rinsing

Additives1.6 mL TEA

Atmosphereambient air / not specified

Temperaturenormal temperature

Time6

Work-upCentrifuged, rinsed with ethanol at least three times.

ActivationDried at 60 C for 12 h.

Scalability contextAuthors describe the method as bottom-up and avoiding conventional exfoliation.

Show 6 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	Ni(Ac)2.4H2O	0.7 mmol; 174.3 mg	31254 · 2.3 Synthesis of NiFe-MOF
Metal Source	Fe(NO3)3.9H2O	0.1 mmol; 40.4 mg	31254 · 2.3 Synthesis of NiFe-MOF
Linker	H2NDC	0.3 mmol; 64.8 mg	31254 · 2.3 Synthesis of NiFe-MOF
Solvent	deionized water	35 mL	31254 · 2.3 Synthesis of NiFe-MOF
Solvent	DMAC	35 mL	31254 · 2.3 Synthesis of NiFe-MOF
Base	TEA	1.6 mL	31254 · 2.3 Synthesis of NiFe-MOF

Partial recipeSource: Main

Route 7: Other

31254 · 2.5 Synthesis of PEM-WE

Solventsisopropanol, deionised water

Additives5 wt% Nafion solution; Pt/C cathode catalyst

Time1

Substrate orientationOpposite sides of Nafion 115 membrane

Work-upUniform anode and cathode catalyst inks applied to opposite sides of Nafion 115 by ultrasonic spraying.

Scalability contextApplied in a 58 cm2 effective-area PEM electrolyser at ampere-level current density.

Show 4 structured reagent records

Role	Reagent	Amount / concentration	Source
Other	NiFe-MOF-CQD	anode loading 2.5 mg cm-2	31254 · 2.5 Synthesis of PEM-WE
Other	Pt/C	cathode loading 0.25 mgPt cm-2 · 40 wt% Pt	31254 · 2.5 Synthesis of PEM-WE
Solvent	isopropanol : water : 5% Nafion	25 : 25 : 4 ratio	31254 · 2.5 Synthesis of PEM-WE
Other	Nafion 115 membrane	127 um; effective area 58 cm2	31254 · 2.5 Synthesis of PEM-WE