Breaking structure sensitivity in CO2 hydrogenation by tuning metal-oxide interfaces in supported cobalt nanoparticles

A high dispersion of the active metal phase of transition metals on oxide supports is important when designing efficient heterogeneous catalysts. Besides nanoparticles, clusters and even single metal atoms can be attractive for a wide range of reactions. However, many industrially relevant catalytic transformations suffer from structure sensitivity, where reducing the size of the metal particles below a certain size substantially lowers catalytic performance. A case in point is the low activity of small cobalt nanoparticles in the hydrogenation of CO and CO2. Here we show how engineering of catalytic sites at the metal-oxide interface in cerium oxide-zirconium dioxide (ceria-zirconia)-supported cobalt can overcome this structure sensitivity. Few-atom cobalt clusters dispersed on 3 nm cobalt(II)-oxide particles stabilized by ceria-zirconia yielded a highly active CO2 methanation catalyst with a specific activity higher than that of larger particles under the same conditions.