Progress in the Synthesis of Catalyst Supports: Synergistic Effects of Nanocomposites for Attaining Long-Term Stable Activity in CH4–CO2Dry Reforming

To attain sustained activity and stability in CH 4 –CO 2 dry reforming (CCDR), two nanocomposite materials comprising silicon carbide or alumina and ceria–zirconia were introduced to support cobalt–nickel (CoNi) catalysts. Following the sequential impregnation-ultrasonication–deposition precipitation procedure, catalysts were systematically characterized and their performances were tested at 1.2 bar and 750 °C, where undiluted CH 4 –CO 2 (ratio = 1:1) streams simulating biogas and the real industrial conditions were fed into a continuous flow reactor. For CCDR reactions conducted at a weight hourly space velocity (WHSV) of 12 L/(g cat h), good activity and stability were shown for both catalysts. Carbon content as low as 0.3 wt % and high conversions (70%–78% and 78%–88% for CH 4 and CO 2, respectively) were recorded over 23 h and 550 h tests. Interestingly, by increasing the WHSV value to an order of magnitude higher, i.e., at 120 L/(g cat h) with all other conditions held constant, a 6 h short-term test showed remarkably high conversions near equilibrium values, implying that the reactions still occurred within the thermodynamic regime, despite a reduced 10-fold mass of catalyst bed. This infers that not all active sites available on the catalyst surface were fully exploited. Compared to previous catalyst performances, the progress made in this work is ascribed to the synergistic effects from selected support materials that contributed remarkable redox properties, high surface area, mechanical and thermal stability to the catalysts.