Interlocking Fe3C-Mo2C interface engineering in carbon nanofibers for high-efficiency oxygen evolution catalysis under simulated seawater conditions

Given the scarcity of freshwater and the abundance of seawater resources, electrochemical seawater electrolysis is a more competitive and efficient method for hydrogen production, but it still remains challenging due to the lack of catalysts with efficient activity and corrosion resistance. Among various strategies to enhance catalytic activity, bimetallic carbides have emerged as a promising approach due to their synergistic effects and tunable electronic properties. In this paper, the Fe 3 C-Mo 2 C structure embedded on carbon nanofibers (referred to as Fe 3 C-Mo 2 C@CNFs/0.15) was successfully synthesized by the electrospinning-pyrolysis process. Fe 3 C-Mo 2 C@CNFs /0.15 exhibited superior OER activity in both alkaline freshwater and simulated seawater, with low overpotentials of 228   mV and 247   mV at 10   mA   cm -2 , and Tafel slopes of 34.0   mV dec -1 and 37.0   mV dec -1 , respectively, due to its abundant active sites, high conductivity, and fast kinetics. Moreover, the electrolytic cell with Fe 3 C-Mo 2 C @CNFs/0.15 as both cathode and anode achieved 10   mA   cm -2 at low cell voltages of 1.65   V and 1.69   V, respectively. It also demonstrated excellent long-term stability up to 48   h and corrosion resistance. This work not only provides a novel strategy for designing low-cost, high-performance OER electrocatalysts but also paves the way for practical applications in seawater electrolysis for sustainable hydrogen production.