Synthesis of Coffee Grounds‐Derived Nitrogen‐Doped Porous Carbon Layer@Cobalt–Iron Alloy for Green and Economic Hydrogen Evolution

In this study, a novel nitrogen‐doped porous biomass‐derived carbon layer@cobalt–iron alloy material (NPCL@Co‐Fe) was successfully fabricated through a simple and eco‐friendly approach. Specifically, waste biomass‐coffee grounds were utilized as the raw material, and their organic components were transformed into carbon materials with a porous layered structure via high‐temperature calcination. Subsequently, by exploiting the interaction between polypyrrole and cobalt‐iron metal ions, and in combination with the dimethylimidazole ligand, metal‐organic frameworks (MOFs) were loaded onto the porous carbon layer to form a porous carbon layer@polypyrrole@cobalt‐iron MOFs composite precursor. Eventually, through high‐temperature calcination of the precursor, uniform dispersion of metal nanoparticles and effective doping of nitrogen were accomplished, yielding the target material NPCL@Co‐Fe. Owing to the abundant defect sites and high specific surface area of the porous carbon layer, as well as the unique electronic structure and excellent electrocatalytic performance of the cobalt‐iron bimetal, the synergy between the two significantly enhanced the overall electrocatalytic activity and stability of the composite material. Experimental results indicated that this material displayed outstanding catalytic performance for the hydrogen evolution reaction (HER). The Tafel slope of the NPCL@Co 1 ‐Fe 1 is 117.0 mV/dec. This work provides an eco‐friendly and economical idea for the synthesis of nitrogen‐doped carbon materials supported nonprecious metal catalysts and achieves a relatively good electrocatalytic performance for HER to solve the problems of cumbersome steps and high preparation costs.