Combinatorial discovery of new autoreduction catalysts for the CO2 reforming of methane

High-throughput synthesis and screening techniques were used in the search for and optimization of new autoreduction catalysts for the CO2 reforming of methane. Diverse libraries had been synthesized via three different modified sol–gel methods using a synthesis robot and library design software. The catalyst libraries were screened for catalytic activity and stability in a simple high-throughput reactor system at 600 °C connected to a micro-gas chromatograph for product analysis. During generations 1 and 2, more than 5000 highly diverse mixed oxides were tested for potential catalytic activity. Ni10Ce90Ox demonstrated effective activity and stability among nonprecious metal catalysts without a prereduction step. In a conventional study, two advantages (i.e., rapid startup operation and high coking resistance) of Ni10Ce90Ox were noted relative to the well-known Ni/Al2O3, but deactivation was recognized. To reduce deactivation of Ni10Ce90Ox, catalyst libraries with additional dopants were prepared and examined during generations 3 and 4. Among these, (Al5, Al15, Zr15)Ni10Ce90−yOx, in which metal nitrate was used as a dopant precursor, and (Al15, Zr5, Zr15)Ni10Ce90−yOx, in which metal alkoxide was used, exhibited comparable activity and strongly reduced deactivation compared with Ni10Ce90Ox. Good performance of the best new catalysts, particularly Al15Ni10Ce75Ox, in which aluminium alkoxide was used as a dopant precursor, and Zr15Ni10Ce75Ox, in which zirconium dinitrate oxide was used, was found in high-throughput studies and confirmed in conventional experiments.