화학공학소재연구정보센터
Science, Vol.345, No.6197, 637-640, 2014
AMMONIA SYNTHESIS Ammonia synthesis by N-2 and steam electrolysis in molten hydroxide suspensions of nanoscale Fe2O3
The Haber-Bosch process to produce ammonia for fertilizer currently relies on carbon-intensive steam reforming of methane as a hydrogen source. We present an electrochemical pathway in which ammonia is produced by electrolysis of air and steam in a molten hydroxide suspension of nano-Fe2O3. At 200 degrees C in an electrolyte with a molar ratio of 0.5 NaOH/0.5 KOH, ammonia is produced at 1.2 volts (V) under 2 milliamperes per centimeter squared (mA cm(-2)) of applied current at coulombic efficiency of 35% (35% of the applied current results in the six-electron conversion of N-2 and water to ammonia, and excess H-2 is cogenerated with the ammonia). At 250 degrees C and 25 bar of steam pressure, the electrolysis voltage necessary for 2 mA cm(-2) current density decreased to 1.0 V.