Dimensional Organization of Catalyst Supports for Dry Reforming of Methane: Spatial Coupling of Metal Stability, Oxygen Supply, and Mass Transfer

Dry reforming of methane DRM converts CH4 and CO2 into syngas but remains limited by metal sintering, carbon accumulation, and interfacial instability at high temperatures. These limitations depend not only on the intrinsic properties of the active metal, but also on the spatial coupling among CH4–activation sites, CO2–activation or oxygen–supply regions, and species–transport pathways. This review therefore focuses on how these functional units are spatially organized and kinetically coupled in DRM catalysts, using support dimensionality as a geometric framework for comparison rather than as an independent determinant of catalytic performance. One–, two–, and three–dimensional supports provide distinct combinations of site proximity, interfacial continuity, confinement, connectivity, and transport geometry, thereby offering different routes to coordinate carbon formation, oxygen supply, and intermediate transport. Across these architectures, we compare how such spatial characteristics regulate the coupling between carbon–forming and oxygen–supplying processes, working–state reconstruction, local carbon–oxygen kinetic matching, and effective transport distances between bifunctional sites. Finally, general design principles are extracted across dimensional categories, together with future directions involving operando characterization, comparable model systems, and multiscale transport analysis for durable DRM catalysts.