Stabilizing Catalytic Performance in Dry Reforming of Methane via Surface-Engineered Intermetallic Carbide Nanoparticles

Intermetallic Ni₃ZnC_0.7 catalysts were synthesized and demonstrated for the stable low-temperature CO₂ reforming of methane. Annealing of silica-supported Ni₃Zn nanoparticles with CO₂/CH₄ formed an intermetallic ordered Ni₃ZnC_0.7 phase with interstitial subsurface carbon atoms, and Ni^δ--Zn^δ+ paired active sites. The intermetallic carbide exhibited exceptional 160 h stability with negligible deactivation, contrasted with severe deactivation in the monometallic Ni catalyst due to coking. The critical roles of carbon diffusion, local structural and electronic modulation, and intermetallic bonding in stabilizing the optimal surface structure in intermetallic carbide nanocatalysts were revealed through in situ XPS, HS-LEIS, XAS, neutron PDF analysis, and performance testing. The controlled synthesis of these intermetallic carbide nanoparticles provides insights into designing the next generation of high performing nanocatalysts.