The invention discloses a high-performance ultrathin 
nitride electro-catalyst with functions of producing 
hydrogen and 
oxygen by means of electrochemically totally decomposing water, a method for synthesizing the high-performance ultrathin 
nitrite electro-catalyst and application thereof. A 
chemical formula of the high-performance ultrathin 
nitride electro-catalyst is (Fe<X>Ni<1-X>)<4>N, and the x is larger than 0 and is smaller than 1. The 
nitrite electro-catalyst is of an ultrathin nanometer plate structure, the size of the 
nitrite electro-catalyst is 50-100nm, and the thickness of the nitrite electro-catalyst is 1.5-3nm. The method includes synthesizing NiFe 
hydrotalcite precursors at first; 
nitriding the NiFe 
hydrotalcite precursors at high temperatures under the protection of 
ammonia gas to obtain end products. The high-performance ultrathin 
nitride electro-catalyst, the method and the application have the advantages that series of nitrite have large specific surface areas, are good in 
electron conductance and are excellent in performance during electro-catalytic water total-
decomposition reaction, limiting currents are higher than limiting currents of Pt / C during electro-catalytic 
hydrogen evolution reaction (HER), and the performance of the nitride in various aspects are superior to the performance of corresponding 
oxide NiFe-MMO during 
oxygen evolution reaction (OER); the electro-catalyst is low in cost, easy and convenient to operate, simple in process and excellent in catalytic performance, and fundamental application research on materials in the field of electro-
catalysis can be provided.