Inner–Outer Surface Anchoring of Ultrafine Bi(Tri)-Metallic Molybdates on N-, B-, and F-Doped Hollow-Core Carbon Nanofibers: Cost-Effective Nanocomposites with Low-Metal Loading for Energy and Environmental Applications

The simple and environmentally friendly fabrication of cost-effective nanocomposites with low-metal usage is a promising approach for high-performance supercapacitors. Most developed nanocomposites rely on expensive carbon materials, such as graphene and carbon nanotubes, high metal loading (> 50 wt%), and complex preparation protocols. In this study, we present a straightforward method for fabricating noble-metal-free bimetallic and trimetallic molybdates (FeMo and NiCoMo) anchored on heteroatom-doped hollow-core carbon nanofibers (HCNFs). Heteroatoms such as B, F, and N were successfully doped into the HCNFs. The homogenous anchoring of FeMo- or NiCoMo-oxide nanoparticles on both the inner and outer surfaces of the HCNFs was confirmed—this is, to the best of our knowledge, the first report of such a structure. In a three-electrode system, NiCoMo–HCNFs demonstrated an excellent specific capacitance of 1419.2 F/g and a capacitance retention of 86.0% after 10,000 cycles. The fabricated device exhibited a high specific capacitance of 225.7 F/g, power density of 45.5 W/kg, and energy density of 10,089.3 Wh/kg, with 86.1% capacitance retention after 10,000 cycles. For the reduction of 4-nitrophenol, the FeMo–HCNFs and NiCoMo–HCNFs achieved excellent k_app values of 30.14 and 87.71 × 10⁻² s⁻¹, respectively. Due to their simple preparation, cost-effectiveness, high activity, and robustness, FeMo–HCNFs and NiCoMo–HCNFs are promising candidates for energy storage and environmental catalysis applications.

Graphical Abstract

Bimetallic and Trimetallic molybdates supported on hollow-core carbon fibers for energy and catalysis applications.