Amalgam electrode, producing method thereof, and method of electrochemical reduction of carbon dioxide using the same

An electrochemical cell for electrochemical reduction of carbon dioxide comprising:

• a reduction electrode unit comprising an amalgam electrode configured to reduce carbon dioxide that flows to the amalgam electrode so as to form at least one of formic acid and formate salt,
• the amalgam electrode comprising:
• a conductive portion,
• a support portion having a first end that is directly connected to the conductive portion, and a second end oppositely disposed from the first end,
• the conductive portion being thicker than the second end of the support portion, and
• an amalgam portion supported by and in direct contact with the support portion, the amalgam portion comprising:
• from about 35 wt % to about 55 wt % mercury;
• from about 14 wt % to about 34 wt % silver;
• from about 7 wt % to about 17 wt % tin;
• and
• from about 4 wt % to about 24 wt % copper,
• an oxidation electrode unit comprising a counter electrode operably connected to the amalgam electrode;
• a solution at least partially contacting the amalgam portion of the amalgam electrode, the solution comprising dissolved carbon dioxide and an electrolyte selected from the group consisting of KHCO3, NaHCO3, K2SO4, NaCl, KCl and combinations thereof;
• a source of carbon dioxide configured to flow carbon dioxide into the solution;
• and
• a galvanostat configured to apply a static current ranging from 2 mA/cm2 to 10 mA/cm2 between the amalgam electrode and the counter electrode when in operation to reduce the carbon dioxide.