In the new concept, the oxyen evolution reaction is replaced by a thermodynamically more favourable urea oxidation reaction. A consortium from CAS Institute of Physical Science designed a Ni2Mn-Hy/CFC electrode with urea oxidation activity, which was assembled as cathode material into a rechargeable Zn-air battery, exhibiting almost 0.3 V lower charging voltage in the presence of urea compared to the battery without urea, consequently obtaining about 12%~21% energy saving in the charging process. Combined with a Ni2P/CFC electrode with bifunctional electrocatalytic activities for hydrogen evolution and and urea oxidation, an efficient two-electrode system for high-efficiency H2 production and simultaneous urea decomposition was constructed using Ni2P/CFC as anode and cathode. Compared to pure water-spitting, the urea electrolysis system significantly reduced the cell voltage by about 200 mV and reached benchmark current densities of 10 mA cm-2, while degrading the urea in the waste water.

CAS news release, November 2, 2017