Dispersed Fe–Co ₃ O ₄ /MXene Hybrid Electrocatalysts for Alkaline HER: Structure–Property Relationships Revealed by Experiments and Theory

Developing efficient non-noble metal electrocatalysts for the hydrogen evolution reaction (HER) in alkaline media is essential for advancing sustainable energy technologies. Here, we report a three-pronged synergistic design paradigm that integrates Fe doping, morphology engineering, and MXene hybridization to construct a high-performance hybrid catalyst. Dispersed Fe-doped Co 3 O 4 (DFC) nanoparticles are synthesized through hydrothermal treatment and ultrasonic disruption, and subsequently assembled with Ti 3 C 2 T x MXene to form a dispersed Fe–Co 3 O 4 @Ti 3 C 2 T x MXene composite structure (DFC-M). The optimized DFC-30M exhibits a low overpotential of 133.9 mV at 10 mA/cm 2, a Tafel slope of 113.5 mV/dec, and excellent durability in 1 M KOH. The hierarchical porous network of DFC-30M facilitates the exposure of catalytic active sites and enhances both mass and charge transport. Density functional theory (DFT) calculations reveal that Fe doping and MXene hybridization independently modulate the electronic structure of Co 3 O 4, thereby reducing the reaction energy barrier and improving electrical conductivity. Furthermore, their surface–interface interaction synergistically lowers the interfacial Schottky barrier and promotes efficient interfacial charge transfer. These findings elucidate how compositional, morphological, and interfacial factors influence the HER performance of Fe–Co 3 O 4 /MXene hybrids, providing mechanistic insights to guide the rational optimization of their catalytic activity.