Carbon dioxide (CO2) is an abundant carbon resource and a notorious greenhouse gas. Conversion of CO2 into useful chemicals is of great importance in both fundamental research and industrial application. CO2 reforming of methane into syngas and CO2 hydrogenation into methane are two of most promising technologies in CO2 conversion, both of which require feasible catalysts. Ni catalysts are most widely investigated candidates. The prime bottleneck of Ni catalysts in both technologies lies in rapid deactivation due to carbon deposition and/or metal sintering. Recently, a number of studies have demonstrated that nanostructured catalysts would deliver exceptional activity and stability. Herein, several nanostructured Ni catalysts have been designed for CO2 reforming of methane and CO2 methanation, respectively. First, nanoconfined Ni catalysts have been synthesized via the electrospinning technique for CO2 reforming of methane. Compared with the conventionally impregnated Ni/SiO2 catalyst, the SiO2 nanofibre confined Ni catalyst exhibited improved metal dispersion and enhanced metal-support interaction, leading to higher activity and better stability. Moreover, Al2O3 nanofibre confined Ni catalyst with superior reforming performance can be synthesized via electrospinning as well, reflecting the versatility of this technique. Second, SiC supported Ni catalysts with improved reforming activity have been accomplished via surface functionalizations. Moreover, a nanocomposite Ni/CeO2-CDC-SiC catalyst consisting of Ni-CeO2 interfaces on a nanoporous carbide-derived carbon (CDC) layer over SiC support was designed with improved coke resistance and better stability. Third, an Al2O3-coated SiC, Al2O3@SiC was designed via the evaporation-induced self-assembly (EISA) method to serve as a nanocomposite support for Ni catalysts in CO2 methanation. The Ni/Al2O3@SiC catalyst exhibited excellent initial activity and superior long-term stability in CO2 methanation due to high metal dispersion and proper physiochemical properties. Our work highlights the significance of the nanostructures and provides guideline for synthesis of novel catalysts for CO2 conversion.

Nanostructured catalysts for carbon dioxide conversion

255th National Meeting (2018)

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