Advances in Confined Catalysts for Methane Dry Reforming: From Design Strategies to Reaction Mechanisms

Abstract

Dry reforming of methane (DRM) converts two major greenhouse gases, CH4 and CO2, into syngas. The products (CO and H2) can be directly utilized as feedstock for chemical processes such as Fischer–Tropsch synthesis and methanol production. Transition metal-based catalysts stand as the most commonly employed for DRM on account of their low cost and excellent intrinsic activity. Nevertheless, the harsh high-temperature conditions readily trigger the sintering of metals and carbon deposition, resulting in rapid catalyst deactivation. This critical drawback severely restricts the large-scale industrial rollout of DRM. Relying on the synergistic effect of spatial confinement and interfacial electronic modulation, confined catalysts can efficiently suppress metal sintering and side reactions. In comparison, some confined catalysts achieve a CH4 conversion of over 90% at a lower temperature, and some catalysts nearly form no graphitic carbon during a long-term durability test of 120 h. In contrast, unconfined catalysts suffer from continuous activity deterioration. This review systematically summarizes recent research progress on confined catalysts for DRM. It thoroughly analyzes anti-coking mechanisms, design criteria and optimization strategies, and clarifies the intrinsic coupling rules among geometric confinement, interfacial electronic effects and multi-dimensional synergistic confinement mechanisms. A horizontal comparison is also conducted to evaluate the advantages and limitations of four categories of confined structures: carbon-based, zeolite-based, MOF-derived, and composite support catalysts. Forward-looking optimization directions are proposed by integrating advanced techniques. The conclusions obtained from this review can provide theoretical foundations and practical references for the rational development of high-performance confined catalysts and the industrial advancement of DRM.