Mo ₂ C and WP Embedded in P-Doped Janus Carbon Fibers as a Highly Active Electrocatalyst for Acidic and Alkaline Hydrogen Evolution Reactions

Reasonable construction and design of cost-cutting electrocatalysts with superior performance for the hydrogen evolution reaction (HER) are meaningful for water splitting. Herein, molybdenum carbide (Mo₂C) and tungsten phosphide (WP) supported with P-doped carbon Janus fibers ([Mo₂C/C]//[WP/C]-JPCFs) are successfully fabricated by using side-by-side electrospinning technology and the calcination process. On account of the special electronic interactions between WP and Mo₂C in the Janus heterostructure interface, a large number of high-quality HER active sites are uniformly distributed on the interface. In addition, doping P atoms in carbon materials can disrupt the electroneutrality of carbon materials, thereby importing more active sites. Surprisingly, the [Mo₂C/C]//[WP/C]-JPCFs catalyst delivers ultralow overpotentials toward the HER in both acidic and alkaline electrolytes, requiring only 38 mV and 33 mV to achieve a current density of 10 mA·cm⁻², respectively. Such impressive catalytic performance is either comparable to or even superior to that of the commercial 20% Pt/C catalyst. The outstanding performance is comparable to or even better than the commercially available 20% Pt/C catalyst, making the [Mo₂C/C]//[WP/C]-JPCFs catalyst the most outstanding nonprecious metal/carbon-based catalyst for HER to date. The [Mo₂C/C]//[WP/C]-JPCFs catalyst also displays significant stability. The study provides an approach for synthesizing simple and low-cost, efficient HER electrocatalysts.