Experimental Procedure
Materials:
Carbon dioxide gas (CO₂) – high purity
Ammonia solution (NH₃, 25%) – 20 mL
Potassium bicarbonate (KHCO₃) – 5.0 g
Deionized water – 100 mL
Copper nanoparticle-coated carbon cloth (working electrode)
Platinum mesh (counter electrode)
Ag/AgCl (reference electrode)
Potentiostat (for voltage control)
Electrolyte Preparation:
Dissolve 5.0 g of KHCO₃ in 100 mL of deionized water to prepare the electrolyte solution.
Add 20 mL of 25% ammonia solution to the electrolyte.
Saturate the solution with CO₂ gas for 30 minutes while stirring.
Electrochemical Setup:
Assemble a three-electrode electrochemical cell:
Working electrode: Cu/C (copper-coated carbon cloth)
Counter electrode: Platinum mesh
Reference electrode: Ag/AgCl
Pour the electrolyte into the cell.
Maintain the temperature at 25 °C (room temperature).
Apply a constant potential of –0.9 V vs Ag/AgCl using the potentiostat.
Allow electrolysis to proceed for 4 hours under continuous CO₂ bubbling (slow rate).
Reaction Mechanism (simplified):
Electrochemical reduction of CO₂ forms intermediates like formate (HCOO⁻) or formaldehyde (HCHO).
These species react with ammonia in situ to form methylamine (CH₃NH₂):
HCHO (from CO₂)+NH3→CH3NH2+𝐻2𝑂
HCHO (from CO₂)+NH3→CH 3NH2+H2O
Product Collection and Analysis:
After 4 hours, collect the reaction mixture.
Filter the solution to remove any solid residues.
Use distillation or extraction with diethyl ether to isolate methylamine.
Expected Yield (approximate):
From 20 mL NH₃ and 4 hours of electrolysis, you can expect to produce around 0.5–1.0 g of methylamine under optimal conditions.
Materials:
Carbon dioxide gas (CO₂) – high purity
Ammonia solution (NH₃, 25%) – 20 mL
Potassium bicarbonate (KHCO₃) – 5.0 g
Deionized water – 100 mL
Copper nanoparticle-coated carbon cloth (working electrode)
Platinum mesh (counter electrode)
Ag/AgCl (reference electrode)
Potentiostat (for voltage control)
Electrolyte Preparation:
Dissolve 5.0 g of KHCO₃ in 100 mL of deionized water to prepare the electrolyte solution.
Add 20 mL of 25% ammonia solution to the electrolyte.
Saturate the solution with CO₂ gas for 30 minutes while stirring.
Electrochemical Setup:
Assemble a three-electrode electrochemical cell:
Working electrode: Cu/C (copper-coated carbon cloth)
Counter electrode: Platinum mesh
Reference electrode: Ag/AgCl
Pour the electrolyte into the cell.
Maintain the temperature at 25 °C (room temperature).
Apply a constant potential of –0.9 V vs Ag/AgCl using the potentiostat.
Allow electrolysis to proceed for 4 hours under continuous CO₂ bubbling (slow rate).
Reaction Mechanism (simplified):
Electrochemical reduction of CO₂ forms intermediates like formate (HCOO⁻) or formaldehyde (HCHO).
These species react with ammonia in situ to form methylamine (CH₃NH₂):
HCHO (from CO₂)+NH3→CH3NH2+𝐻2𝑂
HCHO (from CO₂)+NH3→CH 3NH2+H2O
Product Collection and Analysis:
After 4 hours, collect the reaction mixture.
Filter the solution to remove any solid residues.
Use distillation or extraction with diethyl ether to isolate methylamine.
Expected Yield (approximate):
From 20 mL NH₃ and 4 hours of electrolysis, you can expect to produce around 0.5–1.0 g of methylamine under optimal conditions.
