Combined Methane Cracking for H₂ Production with CO₂ Utilization for Catalyst Regeneration Using Dual Functional Nanostructured Particles

A two-stage chemical looping approach is demonstrated for sustainable hydrogen production through methane decomposition (CH₄ → C + 2H₂) combined with cyclic catalyst regeneration via the reverse Boudouard reaction (C + CO₂ → 2CO). A Ni-based spherical nanoparticle cluster, fabricated using a continuous aerosol-based synthetic approach, is developed for effective cyclic catalysis of the above two chemical reactions. A sufficiently high CO₂ conversion rate for catalyst regeneration (in terms of TOFCO2, 36.09 h^–1) and a stably high yield of hydrogen (in terms of STYH2, 5.19 mmol g_cat^–1 min^–1) are achievable using the 10Ni–1Ce/5Al sample. The outstanding performance of 10Ni–1Ce/5Al is attributed to the incorporation of CeO₂ as a promoter, which possesses a high redox ability that enhances catalytic activity. Additionally, the synergistic effect between nickel and ceria on the two-stage chemical looping is of crucial importance, where CeO₂ promotes CO₂ capture and Ni catalyzes CO₂ dissociation at the Ni–CeO₂ interface. CeO₂-incorporated samples generating whisker carbon after methane pyrolysis demonstrate better activity for cyclic catalyst regeneration. The novelty of the work stands on developing a high-performance dual functional nanostructured catalyst using an aerosol-based synthetic route. This approach creates a massive amount of active interface, by which the two-stage reactions can be promoted under a remarkably low temperature (e.g., 600 °C). The proposed dual functional catalyst material and catalytic pathway demonstrate significant advances for effective hydrogen production combined with cyclic catalyst regeneration via CO₂ utilization, offering an eco-friendly pathway for industrial applications.