Boosting oxygen vacancy formation and Ni dispersion by Ce0.9Y0.1O2 nanorod: Efficient water and hydrocarbon activation

Abstract

Ni-based higher hydrocarbon steam reforming (SR) catalyst usually encounters low water dissociation rate and carbon deposition-induced inactivity and instability. Herein, we report a Ni–Ce0.9Y0.1O2-nanorod (Ni–CYO–NR) with a MgSiO3 postcoating that exhibits a TOF and conversion of 0.18·s−1 and 95% at 700 ℃ and carbon deposition amount and deactivation rate constant 2 orders of magnitude lower than those of Ni–Ce0.9Y0.1O2-nanoparticle (Ni–CYO–NP). Characterization results suggested that Ni–CYO–NR has a higher oxygen vacancy concentration and Ni dispersion than Ni–Ce0.9Zr0.1O2–NR and Ni–CYO–NP because of its CYO(110) nature. DFT calculations revealed that CYO(110) has the lowest formation energy of oxygen vacancies and energy barrier for H2O dissociation relative to CZO(110) and CYO(111). Additionally, MgSiO3 postcoating inhibited the deep sintering of Ni, which in turn suppressed carbon formation. This demonstrates that the superior n-dodecane SR performance of MgSi–Ni–CYO–NR can be attributed to the enhanced and stabilized O–H, C–C, and C–H bond dissociation and carbon formation resistance and removal.