Highly dispersed Ni nanoparticles confined in mesoporous SBA-15 for methane dry reforming with improved coke resistance and stability

Abstract

Methane dry reforming (DRM) is a promising route for sustainable syngas production, in which Ni-based catalysts face challenges of metal sintering and coke formation. In this work, highly dispersed Ni nanoparticles (NPs) embedded in the mesopores of SBA-15 were prepared using a simple solid-state impregnation (SSI) method. TEM and cross-section HRTEM results clearly indicated that ultra-small Ni NPs (3–4 nm) were orderly dispersed within the mesopores of the SBA-15 support. Compared with the conventional wetness impregnation (WI) method, the Ni/SBA-15 catalyst prepared by solid-state impregnation method possessed much better catalytic activity, stability, and coke resistance in DRM. In-situ DRIFTS and semi-in-situ XRD were used to elucidate the dispersion and encapsulation mechanism of Ni within the mesopores of SBA-15 during the sample preparation process. Specifically, WI formed large NiO particles, while SSI formed smaller NiO NPs with stronger interaction between metal and support (SIMS) via forming Ni-O-Si species which is beneficial for the DRM reactivity. This work establishes relationships among catalyst preparation, structure, and DRM performance, paving the way for general template-assisted methods to prepare nanometallic catalysts for various applications.