Ni/Silicalite-1 coating being coated on SiC foam: A tailor-made monolith catalyst for syngas production using a combined methane reforming process

Abstract

Silicalite-1 zeolite coating was coated on the honeycomb-like monolithic SiC foam via hydrothermal synthesis method. The as-made Silicalite-1-coated SiC (S-1/SiC) was used as catalyst support to prepare a novel supported Ni monolith catalyst (Ni/S-1/SiC) by impregnation method. The Ni/S-1/SiC monolith catalyst was characterized by X-ray diffraction (XRD), N2 physical adsorption, scanning electron microscope (SEM), thermogravimetry (TG), etc. The analysis results of XRD and SEM disclosed that Silicalite-1 coating successfully grew in situ on the SiC surface under the employed hydrothermal conditions. The Ni/S-1/SiC monolith catalyst was employed for syngas production in a combined reforming reaction consisting of CO2 dry reforming of methane (CDRM) and partial oxidation of CH4 (POM). Activity results indicated that the Ni/S-1/SiC monolith catalyst exhibited better catalytic activity than Silicalite-1 supported Ni catalyst (Ni/S-1) and SiC supported Ni (Ni/SiC) catalyst. The Silicalite-1 coating on the Ni/S-1/SiC catalyst combined the SiC support and Ni-based species tightly, leading to the enhanced catalytic performance of Ni/S-1/SiC catalyst. The stability test indicated that the Ni/S-1/SiC monolith catalyst also presented excellent stability and strong resistance to carbon deposition, which was attributed to the high heat conductivity of SiC, the presence of Silicalite-1 being coated on SiC as well as the combined reforming reaction of CDRM-POM. Furthermore, the H2/CO molar ratio of syngas generated in the combined CDRM-POM reaction over Ni/S-1/SiC catalyst could be tuned facilely by adjusting the proportion of O2 coexisting in feed gas.