Synthesis · Composition-dependent electrocatalytic activities of NiFe-based selenides for the oxygen evolution reaction

9 structured synthesis routes

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

Partial recipeSource: Main

Route 1: Drop Cast

p002 · Experimental methods, Electrochemical measurement

Metal precursorsNi-Fe-Se1:1-180 catalyst component

Linker precursorsnone

Solventsisopropanol; Nafion/isopropyl alcohol solution

AdditivesVulcan XC-72; PTFE; Nafion binder; N,S-CNT ORR catalyst

Atmosphereambient drying; gas-diffusion layer dried under vacuum overnight before catalyst loading

Temperatureroom temperature drying; vacuum drying overnight for gas diffusion layer

Timeovernight vacuum drying for gas diffusion layer; catalyst layer dried naturally at room temperature

Substrate orientationgas diffusion layer air cathode

Work-upVulcan XC-72, PTFE and isopropanol ground, pressed with twin roller, dried, cut; catalyst ink loaded and dried

Activationnone reported after electrode drying

Scalability contextHome-made Zn-air cell; no manufacturing scale-up reported.

Show 6 structured reagent records

Role	Reagent	Amount / concentration	Source
Additive	Vulcan XC-72	400 mg	p002 · Experimental methods, Electrochemical measurement
Additive	PTFE	100 mg	p002 · Experimental methods, Electrochemical measurement
Solvent	isopropanol	appropriate amount	p002 · Experimental methods, Electrochemical measurement
Additive	Nafion/isopropyl alcohol solution	not specified for air cathode loading	p002 · Experimental methods, Electrochemical measurement
Other	Ni-Fe-Se1:1-180	not specified in main text for composite air cathode	p002 · Experimental methods, Electrochemical measurement
Other	N,S-CNT	not specified in main text	p002 · Experimental methods, Electrochemical measurement

Partial recipeSource: Main

Route 2: Hydrothermal

p002 · Experimental methods, Synthesis of Ni-Fe-Se

Metal precursorsNiFe-PBA precursor

Linker precursorscyanide framework in NiFe-PBA precursor

Solventswater and hydrazine hydrate mixture (same route as Ni-Fe-Se)

Additiveshydrazine hydrate; no Se powder

Atmospheresealed autoclave; post-annealing atmosphere not separately specified but stated as same method

Temperaturesame method as Ni-Fe-Se; likely 180 °C hydrothermal and 300 °C post-treatment

Timesame method as Ni-Fe-Se; likely 5 h hydrothermal and 1 h post-treatment

Oxidant / reductanthydrazine hydrate

Work-upsame method as Ni-Fe-Se without Se powder

Activationsame method as Ni-Fe-Se without Se powder

Scalability contextNo scale-up details reported.

Show 3 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	NiFe-PBA	same as Ni-Fe-Se route	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Solvent	water	same as Ni-Fe-Se route	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Reductant	hydrazine hydrate	same as Ni-Fe-Se route	p002 · Experimental methods, Synthesis of Ni-Fe-Se

Complete recipeSource: Main

Route 3: Other

p002 · Experimental methods, Synthesis of Ni-Fe-Se

Metal precursorsnickel chloride hexahydrate; potassium ferricyanide

Linker precursorscyanide supplied by potassium ferricyanide

Solventsdeionized water

Additivestri-sodium citrate dihydrate

Atmosphereambient air (not otherwise specified)

Temperatureroom temperature; drying at 60 °C

Timeageing 10 h; drying overnight

Oxidant / reductantpotassium ferricyanide

Work-upcentrifugation; washing with water and ethanol several times

Activationdried at 60 °C overnight

Scalability contextAqueous room-temperature precipitation; no scale-up details reported.

Show 4 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	nickel chloride hexahydrate	0.6 mmol	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Additive	tri-sodium citrate dihydrate	0.9 mmol	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Solvent	deionized water	20 mL for solution A; 20 mL for solution B	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Metal Source	potassium ferricyanide	0.4 mmol	p002 · Experimental methods, Synthesis of Ni-Fe-Se

Partial recipeSource: Main

Route 4: Hydrothermal

p002 · Experimental methods, Synthesis of Ni-Fe-Se

Metal precursorsNiFe-PBA precursor

Linker precursorscyanide framework in NiFe-PBA precursor

Solventswater (6 mL) and hydrazine hydrate (4 mL)

AdditivesSe powder; hydrazine hydrate

Atmospherehydrothermal step in sealed Teflon-lined autoclave; post-annealing in N2

Temperature140 °C hydrothermal; 300 °C tube furnace

Time5 h hydrothermal; 1 h annealing

Oxidant / reductanthydrazine hydrate reductant; Se powder reduced to selenide

Work-upcooled naturally; precipitate collected by centrifugation; washed with water and ethanol; dried at 60 °C under vacuum overnight

Activationheated to 300 °C and maintained 1 h in N2 atmosphere

Scalability context50 mL Teflon-lined stainless steel autoclave used; no scale-up study reported.

Show 4 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	NiFe-PBA	100 mg	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Solvent	water	6 mL	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Reductant	hydrazine hydrate	4 mL	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Other	Se powder	100 mg	p002 · Experimental methods, Synthesis of Ni-Fe-Se

Partial recipeSource: Main

Route 5: Hydrothermal

p002 · Experimental methods, Synthesis of Ni-Fe-Se

Metal precursorsNiFe-PBA precursor

Linker precursorscyanide framework in NiFe-PBA precursor

Solventswater (6 mL) and hydrazine hydrate (4 mL)

AdditivesSe powder; hydrazine hydrate

Atmospherehydrothermal step in sealed Teflon-lined autoclave; post-annealing in N2

Temperature160 °C hydrothermal; 300 °C tube furnace

Time5 h hydrothermal; 1 h annealing

Oxidant / reductanthydrazine hydrate reductant; Se powder reduced to selenide

Work-upcooled naturally; precipitate collected by centrifugation; washed with water and ethanol; dried at 60 °C under vacuum overnight

Activationheated to 300 °C and maintained 1 h in N2 atmosphere

Scalability context50 mL Teflon-lined stainless steel autoclave used; no scale-up study reported.

Show 4 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	NiFe-PBA	100 mg	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Solvent	water	6 mL	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Reductant	hydrazine hydrate	4 mL	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Other	Se powder	100 mg	p002 · Experimental methods, Synthesis of Ni-Fe-Se

Complete recipeSource: Main

Route 6: Hydrothermal

p002 · Experimental methods, Synthesis of Ni-Fe-Se

Metal precursorsNiFe-PBA precursor

Linker precursorscyanide framework in NiFe-PBA precursor

Solventswater (6 mL) and hydrazine hydrate (4 mL)

AdditivesSe powder; hydrazine hydrate

Atmospherehydrothermal step in sealed Teflon-lined autoclave; post-annealing in N2

Temperature180 °C hydrothermal; 300 °C tube furnace

Time5 h hydrothermal; 1 h annealing

Oxidant / reductanthydrazine hydrate reductant; Se powder reduced to selenide

Work-upcooled naturally; precipitate collected by centrifugation; washed with water and ethanol; dried at 60 °C under vacuum overnight

Activationheated to 300 °C and maintained 1 h in N2 atmosphere

Scalability context50 mL Teflon-lined stainless steel autoclave used; no scale-up study reported.

Show 4 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	NiFe-PBA	100 mg	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Solvent	water	6 mL	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Reductant	hydrazine hydrate	4 mL	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Other	Se powder	100 mg	p002 · Experimental methods, Synthesis of Ni-Fe-Se

Partial recipeSource: Main

Route 7: Hydrothermal

p002 · Experimental methods, Synthesis of Ni-Fe-Se

Metal precursorsNiFe-PBA precursor

Linker precursorscyanide framework in NiFe-PBA precursor

Solventswater (6 mL) and hydrazine hydrate (4 mL)

AdditivesSe powder; hydrazine hydrate

Atmospherehydrothermal step in sealed Teflon-lined autoclave; post-annealing in N2

Temperature200 °C hydrothermal; 300 °C tube furnace

Time5 h hydrothermal; 1 h annealing

Oxidant / reductanthydrazine hydrate reductant; Se powder reduced to selenide

Work-upcooled naturally; precipitate collected by centrifugation; washed with water and ethanol; dried at 60 °C under vacuum overnight

Activationheated to 300 °C and maintained 1 h in N2 atmosphere

Scalability context50 mL Teflon-lined stainless steel autoclave used; no scale-up study reported.

Show 4 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	NiFe-PBA	100 mg	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Solvent	water	6 mL	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Reductant	hydrazine hydrate	4 mL	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Other	Se powder	100 mg	p002 · Experimental methods, Synthesis of Ni-Fe-Se

Partial recipeSource: Main

Route 8: Hydrothermal

p002 · Experimental methods, Synthesis of Ni-Fe-Se

Metal precursorsNiFe-PBA precursor

Linker precursorscyanide framework in NiFe-PBA precursor

Solventswater (6 mL) and hydrazine hydrate (4 mL)

AdditivesSe powder; hydrazine hydrate

Atmospherehydrothermal step in sealed Teflon-lined autoclave; post-annealing in N2

Temperature180 °C hydrothermal; 300 °C tube furnace

Time5 h hydrothermal; 1 h annealing

Oxidant / reductanthydrazine hydrate reductant; Se powder reduced to selenide

Work-upcooled naturally; precipitate collected by centrifugation; washed with water and ethanol; dried at 60 °C under vacuum overnight

Activationheated to 300 °C and maintained 1 h in N2 atmosphere

Scalability context50 mL Teflon-lined stainless steel autoclave used; no scale-up study reported.

Show 4 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	NiFe-PBA	100 mg	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Solvent	water	6 mL	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Reductant	hydrazine hydrate	4 mL	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Other	Se powder	approximately 300 mg if NiFe-PBA is 100 mg; exact amount not stated in main text	p002 · Experimental methods, Synthesis of Ni-Fe-Se

Partial recipeSource: Main

Route 9: Hydrothermal

p002 · Experimental methods, Synthesis of Ni-Fe-Se

Metal precursorsNiFe-PBA precursor

Linker precursorscyanide framework in NiFe-PBA precursor

Solventswater (6 mL) and hydrazine hydrate (4 mL)

AdditivesSe powder; hydrazine hydrate

Atmospherehydrothermal step in sealed Teflon-lined autoclave; post-annealing in N2

Temperature180 °C hydrothermal; 300 °C tube furnace

Time5 h hydrothermal; 1 h annealing

Oxidant / reductanthydrazine hydrate reductant; Se powder reduced to selenide

Work-upcooled naturally; precipitate collected by centrifugation; washed with water and ethanol; dried at 60 °C under vacuum overnight

Activationheated to 300 °C and maintained 1 h in N2 atmosphere

Scalability context50 mL Teflon-lined stainless steel autoclave used; no scale-up study reported.

Show 4 structured reagent records

Role	Reagent	Amount / concentration	Source
Metal Source	NiFe-PBA	100 mg	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Solvent	water	6 mL	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Reductant	hydrazine hydrate	4 mL	p002 · Experimental methods, Synthesis of Ni-Fe-Se
Other	Se powder	approximately 33 mg if NiFe-PBA is 100 mg; exact amount not stated in main text	p002 · Experimental methods, Synthesis of Ni-Fe-Se