A membrane electrode assembly includes an anode having a first catalyst layer on a first gas-liquid diffusion layer, a cathode having a second catalyst layer on a second gas-liquid diffusion layer, and an anionic exchange membrane between the first catalyst layer of the anode and the second catalyst layer of the cathode. The first catalyst layer has a chemical structure of M′aM″bN2 or M′cM″dCe, wherein M′ is Ni, Co, Fe, Mn, Cr, V, Ti, Cu, or Zn, M″ is Nb, Ta, or a combination thereof, 0.7≤a≤1.7, 0.3≤b≤1.3, a+b=2, 0.24≤c≤1.7, 0.3≤d≤1.76, and 0.38≤e≤3.61, wherein M′aM″bN2 is a cubic crystal system and M′cM″d Ce is a cubic crystal system or amorphous.