Reduction-driven Ni-exsolution toward a coking-resistance Ni-PrAlO3 catalyst for methane dry reforming

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Dry methane reforming (DRM) presents a promising solution for managing large-scale CO 2 emissions, yet developing coking- and sintering-resistant Ni-based catalysts remains an ongoing challenge. Herein, we report a reduction-driven exsolution of Ni nanoparticles from PrAlNiO x composite oxides that established an extensive Ni-PrAlO 3 redox interface in the resulting catalysts, thereby conferring high resistance to coking and Ni-sintering in the DRM reaction. An outstanding catalyst featuring Ni nanoparticles socketed within PrAlO 3 was obtained from the Pr 0.95 Al 1 Ni 0.05 O x composite oxide after calcination at 700 °C, followed by Ni exsolution driven by H 2 -reduction at 750 °C. This catalyst showed coking-free stability, maintaining CH 4 and CO 2 conversions at ∼44% and ∼ 54% over 100 h at 700 °C, using a feed of CH 4 /CO 2 = 1/1 (undiluted) and a GHSV of 15 L g cat −1 h −1 . Isotope-labeling and CH 4 /CO 2 feed-ratio ramping experiments were conducted to gain insight into the interfacial catalysis, revealing that CO 2 was preferentially activated at the Ni-PrAlO 3 interface to form CO and O*, and CH 4 was subsequently oxidized by O* to form H 2 and another CO. Such tandem reaction pathway led to stoichiometric conversion of CO 2 and CH 4 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.