two major greenhouse gases, carbon dioxide (CO 2 ) and methane (CH 4 ), into industrially valuable chemical products. [1,2] Dry reforming of methane (DRM: CH 4 + CO 2 → 2H 2 + 2CO) is of the highest potential to utilize both the CH 4 and CO 2 . [3,4] Moreover, DRM products, hydrogen (H 2 ) or synthesis gas (CO/H 2 ), can be widely used in ammonia synthesis, methanol synthesis, Fischer-Tropsch synthesis, etc. However, the current DRM is usually conducted via heterogeneous catalysis at high temperatures over 800 °C to promote the strongly endothermic reaction (ΔH 298 K = +247 kJ mol −1 ). [5] Such high-temperature process results in huge consumption of fuels and short lifetime of DRM catalysts. [5][6][7] It is highly desirable to develop high-performance catalysts that drive DRM in a low-temperature range from 400 °C through 600 °C (low-temperature DRM or LT-DRM). But at such low temperatures the side reactions, including methane decomposition (CH 4 → 2H 2 + C(s); ΔH 298 K = +75 kJ mol −1 ), the Boudouard reaction (2CO → CO 2 + C(s): ΔH 298 K = −171 kJ mol −1 ), and reverse water gas shift (CO 2 + H 2 → CO + H 2 O; ΔH 298 K = +41.2 kJ mol −1 ), can compete with the DRM pathway, leading to severe catalyst degradation. [5,8,9] It is acknowledged that precious metals (PM: Pd, Pt, etc.), as catalytic centers, are highly active in DRM. Extensive studies have reported that they possessed higher activity and more resistant to carbon deposition than nickel (Ni)-based catalysts. [5,[10][11][12][13] However, high materials cost precluded widespread use of these PM-based catalysts in DRM. In contrast, low-cost Ni-based catalysts would be more promising in large-scale industrial DRM applications. In addition, there have been a number of attempts to develop magnesium oxide (MgO) as catalyst support or promoter in DRM because its basic nature can enhance chemisorption of CO 2 and inhibit carbon deposition. [14][15][16] Although considerable efforts have been spent on these designs, few studies have succeeded in fabrication of MgO catalysts with long-term stability in DRM. [17,18] Therefore, to realize high performance and long-term stability over the basic MgO support and low-cost Ni metal, it is very necessary to explore an efficient spatial structure for these two components.Here we present a nanoporous composite catalyst with an intertwined network structure consisting of fibrous Ni-and MgO phases (average thickness = 10 nm), i.e., n-Ni#MgO. The intertwined, porous network of n-Ni#MgO is fabricated from A nanoporous catalyst consisting of intertwined, fibrous networks of nickel and magnesium oxide, i.e., n-Ni#MgO, is fabricated from a Ni-Mg alloy via atmospheric treatments followed by acid leaching. The n-Ni#MgO efficiently catalyzes reforming of the two major greenhouse gases, methane (CH 4 ) and carbon dioxide (CO 2 ), in a low-temperature range (<600 °C). Moreover, it exhibits higher coking tolerance than conventional nickel-based catalysts and can rival commercial precious metal catalysts in terms of both the reaction act...