Coking-resistant CeAlO3-Socketed Nickel Nanocatalysts for dry reforming of methane

Abstract

Nickel-based catalysts are regarded as the most promising candidates for industrial dry reforming of methane (DRM), yet severe coking and metal sintering impede their commercial viability. Herein, we report a CeAlO₃-socketed Ni nanocatalyst with extensive Ni-CeAlO₃ interfaces, demonstrating coke-free stability with no deactivation over 500 h test at 700 °C for a feed of CH₄/CO₂ = 1/1 (undiluted). The socket-structured catalyst was obtained via H₂-reduction-triggered Ni exsolution and simultaneous formation of CeAlO₃ from a Ce₁Al_0.95Ni_0.05O_x composite oxide. A socketed structure featuring extensive Ni-CeAlO₃ interface was achieved upon reduction at 750 °C, which essentially modulated the catalytic activation kinetics of both CO₂ and CH₄. In-situ diffused reflectance infrared Fourier transformed spectroscopy and isotope-labeling experiments were performed to gain insight into the interfacial catalysis, revealing that CO₂ was preferentially activated at the Ni-CeAlO₃ interface to form CO and O*, and CH₄ was subsequently oxidized by O* to form H₂ and another CO through formation of CH₃O* intermediates. Such tandem reaction pathway led to stoichiometric conversion of CO₂ and CH₄ molecules thereby imparting our catalyst to high coking resistance. Our findings shed light on the rational design of a valid Ni-based DRM catalyst with substantial potential for industrial application.