A frogspawn inspired twin Mo2C/Ni composite with a conductive fibrous network as a robust bifunctional catalyst for advanced anion exchange membrane electrolyzers

Abstract

Anion exchange membrane water electrolysis (AEMWE) is considered one of the most cost-effective methods for producing green hydrogen. However, the performance of AEMWE is still restrained by the slow reaction kinetics and poor ion/electron transport of catalysts. Herein, inspired by frogspawn, Mo₂C nanoparticles coupled with Ni were in situ embedded into a N-doped porous carbon nanofiber network (Mo₂C/NCNTs@Ni) by chemical crosslinking electrospinning combined with carbonization. The unique bionic structure can guarantee favorable overall structural flexibility and fast ion/electron transport kinetics. As a result of the robust hydrogen binding energy of Mo₂C, as well as the synergistic impact between Ni and Mo₂C nanoparticles and the conductive network resembling frogspawn, the catalyst developed demonstrates excellent performance in both the HER and OER. When employed as a bifunctional catalyst in water electrolysis, Mo₂C/NCNTs@Ni delivers overpotentials of 155 mV and 320 mV at 10 mA cm⁻² for the HER and OER, respectively. In addition, the Mo₂C/NCNTs@Ni also displays excellent long-term durability during a continuous operation test under different currents for 50 h. The assembled AEMWE electrolyzers with Mo₂C/NCNTs@Ni as both the anode and cathode can achieve a current density of 82.5 mA cm⁻² at 1.99 V, indicating great potential for industrial water splitting. These results give an insight for the development of advanced bifunctional electrocatalysts for the next generation of green and efficient H₂ production by water electrolysis.