Title : Unraveling the critical role of surface intermediates in methane reforming over Mo-based catalysts
Abstract:
Sustaining catalytic activity remains a fundamental challenge in methane reforming technologies, where uncontrolled reaction pathways and surface fouling typically lead to rapid deactivation. Dry methane reforming (DMR) offers a sustainable route to convert CO? and CH? into syngas, yet commercialization is severely constrained by coking and sintering. Ni?based catalysts are cost?effective but poorly stable, while noble metals, though more resistant, are economically unviable. Similarly, H?S?assisted methane reforming (H?SMR) provides a dual?purpose strategy to valorize sour natural gas into H? and sulfur products, but suffers from sulfur poisoning, coke deposition, and sintering under aggressive conditions. In this study, we investigate the reaction mechanism over Mo?based catalysts using H?S as a co?reactant. At 1173 K, the catalyst exhibited robust performance for 5 hours, maintaining a methane conversion of 63.7% and H? production of 688.8 μmol g-1 min-1 in stark contrast to pure methane cracking, where conversion plummeted from 43.6% to 14.3%. In situ DRIFTS analysis revealed that the reaction is governed by specific surface intermediates, wherein activated methane interacts with surface sulfur to form CH?S* species. This distinct pathway effectively channels carbon toward product formation rather than allowing accumulation on the catalyst surface, thus preserving active sites and sustaining catalytic cycles. Our findings elucidate the pivotal role of these intermediates in mitigating deactivation and provide a fundamental mechanistic basis for designing durable methane reforming catalysts. By integrating experimental insight with rational catalyst design, this work paves the way toward more resilient and efficient reforming technologies, particularly for processing sour feeds, and offers a promising strategy to overcome the long?standing trade?off between activity and stability in harsh reforming environments.
