Noble metal-free Ni-Mn-W electrocatalysts on activated carbon for efficient glycerol electrooxidation

Glycerol electrooxidation reaction (GEOR) is a promising anodic process for direct glycerol fuel cells (DGFCs), but its practical efficiency is limited by sluggish kinetics and catalyst deactivation. Herein, noble metal-free nickel (Ni) based electrocatalysts supported on activated carbon (AC) were synthesized by a sodium borohydride (NaBH 4 ) assisted reduction route. Bimetallic NiMn@AC and NiW@AC catalysts were first prepared to clarify the role of manganese (Mn) and tungsten (W), followed by trimetallic NiMnW@AC catalysts to exploit their combined effect. The porous AC support preserved high surface accessibility, while Ni, Mn, and W incorporation produced dispersed mixed metal‑oxygen surface domains. Among the bimetallic catalysts, Ni90W10@AC exhibited the highest activity, whereas Ni70Mn10W20@AC showed the highest overall GEOR performance. It delivered 13.85 mA cm −2 at 0.80 V in cyclic voltammetry and 8.36 mA cm −2 at 0.80 V in linear sweep voltammetry, also reached 5 mA cm −2 at only 0.50 V and maintained a stabilized current density of 4.43 mA cm −2 . ECSA normalization confirmed that the superior response of Ni70Mn10W20@AC was not solely due to a larger accessible surface area. During a 3 h chronoamperometric test, it maintained 3.04 mA cm −2 , retaining 92.7% of the current measured at 1000 s. Post-reaction characterization indicated moderate surface reorganization while largely preserving the carbon-supported Ni-Mn-W structure, with no detectable Ni, Mn, or W leaching. The enhanced performance is attributed to an optimized Ni-Mn-W interfacial environment on the porous AC framework.