Synergistic enhancement of Raney-Ni catalyst for methane dry reforming viaelectrochemically e ngineered CoNi co-catalyst

Abstract

Dry reforming of methane (DRM) offers a promising route to convert biogas into syngas while capturing CO₂.However, the harsh reaction conditions (≥700 ◦C) lead to rapid deactivation of conventional Ni-based catalystsdue to carbon deposition and sintering. In this work, we explore the catalytic behavior of commercial Raney-Nifor DRM and introduce electrochemically synthesized CoNi microparticles as co-catalysts to enhance stabilityand performance. Catalyst screening was performed in a fixed-bed reactor using a CH₄:CO₂:N₂ = 3:2:10 feedmixture under atmospheric pressure. Raney-Ni showed high activity (CH₄ conversion >92 % at 700 ◦C), butsuffered from coke accumulation and deactivation after 5 h of continuous operation. CoNi–Raney-Ni compositeswere prepared via physical blending of CoNi and Raney-Ni powders, and tested at various compositions. Thebest-performing among the tested compositions (25 wt% CoNi) maintained high conversion (>90 %) and stablesyngas production (H₂/CO ≈ 1.0) over extended periods. Post-reaction analysis revealed extensive filamentouscarbon on pure Raney-Ni, while CoNi-containing catalysts exhibited smoother surfaces and suppressed graphiticcarbon, as confirmed by FE-SEM and Raman spectroscopy. Notably, CoNi alone showed minimal CH₄ activationbut enhanced CO₂ dissociation and limited carbon formation. These results demonstrate a synergistic effect,where CoNi promotes carbon gasification while Raney-Ni provides high CH₄ reactivity. This composite approachenables scalable, low-cost catalysts with improved coke tolerance for biogas reforming applications.