Design of active and stable NiCeO sub(2)ZrO sub(2)MgAl sub(2)O sub(4) dry reforming catalysts

An active and stable NiCeO sub(2)ZrO sub(2)MgAl sub(2)O sub(4) catalyst for dry reforming in severe coking conditions (CO sub(2)/CH sub(4) = 1.1, GHSV = 32,000 h[super]-1, 670 [deg]C and 1.5 bar) was developed by combining conventional and combinatorial research strategies using high-throughput experimentation. A D-optimal design was applied to setup statistically verified models for catalytic activity (X sub(C)H sub(4),X sub(C)O sub(2)), selectivity (H sub(2)/CO molar ratio) and stability (coke resistance) as function of the selected input factors, viz. the amount of active element and amount of promoters. The importance of selecting the proper objective function R and appropriate unit to express the amount of coke deposited are discussed in detail. Via the most reliable objective function R an optimal catalyst composition area is obtained, where catalysts combine high activity with a long service lifetime. It was recognized that stable dry reforming occurs only with a subtle balance of the catalyst composition. Best dry reforming performances are achieved with catalyst compositions having low Ni (2 wt%), ZrO sub(2) (1 wt%) and high CeO sub(2) (3 wt%) content.