Superior catalytic activity for dry reforming of methane: Ni-incorporated in silica supports by framework ligands

Abstract

The dry reforming of methane (DRM) presents a promising approach to converting greenhouse gases into valuable syngas. However, catalyst deactivation due to sintering and carbon deposition remains a significant challenge. For stable DRM catalysts, this study introduces Ni-incorporated into ligand-controlled silica (NILS) catalysts through precise control of silica frameworks. The NILS series catalysts were synthesized by a combined sol-gel and re-precipitation method, in which catalyst structure, properties and performance controlled by silica framework precursors containing C1 to C4 carbon chains (tetramethyl orthosilicate (C1, TMOS), tetraethyl orthosilicate (C2, TEOS), tetrapropyl orthosilicate (C3, TPOS) and tetrabutyl orthosilicate (C4, TBOS). The most complex ligand (C4) enhanced catalyst properties by three key mechanisms: (1) uniform nano-sized nickel clusters formed through slower sol-gel reactions, (2) increased surface hydroxyl groups promoting metal-support interactions and (3) development of bimodal pore structures facilitating efficient mass transport. The TBOSderived catalyst (NILS-B) achieved exceptional stability, maintaining 95% CH4 and 97% CO2 conversions over 40 h at 800 degrees C without deactivation. This performance is attributed to synergistic effects of nano-sized Ni clusters, hydroxylated Ni species, and optimized pore structure. This study provides fundamental understanding of framework ligand effects and demonstrates a practical approach for designing stable Ni-SiO2 catalysts through simple one-pot synthesis without complex modifications or additional promoters.