Fe nanoparticles assembled on N-doped porous carbon for superior overall water splitting

In traditional electrocatalysis research, the large size of transition metal particles often leads to self-aggregation, significantly impairing their conductivity and electrocatalytic performance. In this work, the advanced electrocatalysts have been developed by assembling high-content Fe nanoparticles on N-doped porous carbon (named as Fe/NPC-X) using a hydrothermal process combined with in situ reduction treatment. The synergistic interaction between Fe nanoparticles and N-doped carbon enhances electron transfer and increases the adsorption capacity for water molecules. The hierarchical porous structure of the material also enlarges the surface area available for reactants, optimizing both diffusion and catalytic efficiency. As a result, the developed bifunctional electrocatalysts, Fe/NPC-2 and Fe/NPC-3, demonstrate overpotentials of 80 mV and 255 mV for hydrogen and oxygen evolution reactions, respectively, at a current density of 10 mA/cm2. Moreover, the overall water splitting device (Fe/NPC-2 (+)||Fe/NPC-3 (-)) exhibits outstanding water-splitting performance, achieving a voltage of 1.553 V at 10 mA/cm2. Overall, this work presents a promising strategy to address the challenges associated with low content and large particle size of transition metals in bifunctional electrocatalysts, leading to highly efficient bifunctional electrocatalysts with enhanced catalytic activity and excellent cycling stability.