Stable Electrothermal Reforming of Undiluted CH4/CO2 by Integrating Encapsulated Ni Nanoparticles with Internal Joule Heating

Abstract

Methane dry reforming (DRM) serves as a promising solution for mitigating carbon emission by valorizing two greenhouse gases (GHGs), methane and carbon dioxide, into value added syngas. However, the industrialization of DRM is practically hindered by extreme energy consumption, rapid coke formation, and severe metal sintering. All three limitations rooted in the high operation temperature required for overcoming the strong reaction endothermicity (ΔH = 247 kJ/mol). Herein, we presented an approach to address these bottlenecks via a highly efficient and stable electrothermal DRM (EDRM) process employing solely electricity-induced heat (Joule heating) as the heat source and adopting highly active structured Ni-embedded zeolite as catalysts. Using undiluted mixture of CH₄ and CO₂ as feedstock, EDRM exhibited superior space-time yield of syngas (17850 L_syngas/(g_Ni h)) that surpassed the documented conventional DRM with Ni-based catalysts, together with a remarkable stability during 330 h time on stream at 800 °C without observable deactivation or coke deposition. The high activity (5.1 mmol/min) and stability were attributed to in-situ heat supply with high energy transfer efficiency (22.7%) and high resistance to temperature drop by reaction heat (less than ±3 °C), together with the embedding of Ni nanoparticles by zeolite that prevented metal from sintering. Meanwhile, mechanistic studies revealed that the high catalytic activity and stability of the Ni-embedded zeolite catalyst was achieved via a unique synergy between closely contacted silanol groups of the zeolite framework and embedded Ni particles that induced a carbonate-mediated pathway for efficient CO₂ activation and rapid carbon consumption. This study not only presented a renewable energy-driven GHGs utilization strategy with industrial scalability but also highlighted the fundamental significance of electrothermal catalysis as an emerging interdisciplinary frontier bridging electrochemistry and thermal catalysis.