A transient isotopic study for investigating important design parameters of NiCo/Ce0.75Zr0.25O2-δ catalyst for the dry reforming of methane

The effects of metal loading and particle size of NiCo alloy deposited on Ce0.75Zr0.25O2-δ carrier on the carbon reaction paths of dry reforming of methane at 750 °C with respect to the observed long-term activity profiles was elucidated. Small NiCo nanoparticles (7.8 nm) showed progressive deactivation as opposed to the larger ones (43 nm) which exhibited self-regeneration. Towards this goal, appropriate transient kinetic isotopic experiments (use of 18O2 and 13CO2) and other catalyst characterization studies (transient isothermal reduction, XPS, HAADF-STEM-EDX) were conducted. This work paves the way for the design of highly active and coke-resistant reducible metal oxides-supported NiCo. [Display omitted] •DRM activity vs TOS profile at 750 °C strongly depends on NiCo alloy particle size.•CH4 decomposition rates (per NiCo alloy particle) at 750 °C are significantly higher on large than small NiCo particles.•Higher rates of carbon removal by lattice oxygen than by O-s derived from CO2 activation on large NiCo particles.•Surface coverage of active carbon formed in DRM is significantly lower on small than large NiCo particles.•TOFCO (s−1) of the CO2 activation route in the DRM at 750 °C decreases with increasing NiCo particle size (7.8 vs 43 nm).