Effective catalytic steam reforming of naphthalene over Ni-modified ZSM-5 via one-pot hydrothermal synthesis

Abstract

Ni-modified ZSM-5 catalysts are prepared by a one-pot hydrothermal synthesis method and applied to the steam reforming of naphthalene as a tar model compound. The effects of the reaction temperature, silica-alumina ratio (Si/Al) and metal content on the catalytic performance for reforming naphthalene are investigated. Characterization results indicate that the Ni-modified ZSM-5 catalysts maintain the original MFI structure of ZSM-5 and a portion of Ni is successfully introduced into the zeolite structure. When the reaction temperature is 800 °C, the conversion efficiency of naphthalene achieves 91.5% with a high yield (6.75%) of hydrogen. Zeolite catalysts with higher Si/Al ratios improve the conversion of naphthalene to syngas, demonstrating their better catalytic activity. An appropriate active metal content (2.4 wt%) contributes to the catalytic performance of the catalyst owing to the strong metal-support interaction, resulting in resistance to sintering and carbon deposition. The reaction mechanism involved in the catalytic reforming of naphthalene is proposed. The application of a novel one-pot hydrothermal synthesis method greatly promoted the catalytic activity of Ni@ZSM-5, which provided an appropriate and universal approach for the improvement and optimization of tar reforming catalysts.