Effect of catalyst synthesis strategy on the structure and performance of Ni–Co bimetallic catalysts for dry reforming of methane

The design of stable and efficient catalysts for dry reforming of methane (DRM) is hindered by severe carbon deposition and metal sintering under high-temperature conditions. In this work, Ni–Co bimetallic catalysts were synthesized through three different approaches, including impregnation, exsolution, and sequential metal loading. The objective was to understand how the synthesis route and metal loading sequence influence alloy formation, active site distribution, and overall catalytic performance. The NiCoAl 2 O 3 –One(Exs), prepared by a one-pot exsolution method, exhibited strong metal-support interactions (SMSI), uniform metal dispersion, and superior coke resistance, maintaining high CH 4 and CO 2 conversions during the long-term DRM reaction. Catalysts synthesized via impregnation exhibited higher initial activity at low temperatures due to abundant surface-exposed metal species but suffered from faster deactivation. The sequentially impregnated Al 2 O 3 –Ni-Co(step-Imp) catalyst exhibited relatively stable activity under high gas hourly space velocity conditions, indicating that the order of metal loading plays a crucial role in catalyst durability. These findings underscore the critical role of synthesis methodology in modulating catalyst structure and performance, offering valuable insights for the rational design of robust Ni–Co alloy catalysts for DRM and other thermochemically demanding reactions. • Ni–Co bimetallic catalysts were synthesized via impregnation, exsolution, and sequential loading. • Impregnation-derived catalysts exhibited higher initial activity due to surface-exposed metal species • Exsolution-derived catalysts exhibited superior coke resistance and structural stability under long-term DRM reaction. • Controlled Ni and Co metal loading sequence effectively improved catalytic performance.