Electrode-supported tubular solid-oxide electrochemical cell

A process comprising:

• providing a tubular solid-oxide electrochemical cell comprising:
• a porous cathode configured in a tubular shape, the porous cathode comprising a first mixed ionically/electronically conductive composite material comprising a solid-oxide electrolyte substance having ionic conductivity and a first electrochemically active substance having electronic conductivity;
• an electrolyte disposed as a thin-layer on at least part of a surface of the porous cathode, the electrolyte comprising the solid-oxide electrolyte substance;
• and
• a porous anode disposed on at least part of a surface of the electrolyte, the porous anode comprising a second mixed ionically/electronically conductive composite material comprising the solid-oxide electrolyte substance and a second electrochemically active substance having electronic conductivity;
• connecting the porous cathode and the porous anode to a power source;
• and
• applying a voltage across the porous cathode and the porous anode to perform a catalytic electrochemical synthesis of ammonia.