Role of the ceria promoter and carrier on the functionality of Cu-based catalysts

The effects of ZnO or CeO2 promoters and carrier composition (ZrxCe(1-x)O2, 0<=x<= 1) on the structure and CO2-hydrogenation functionality (TR, 453-513 K; PR, 3.0 MPa; GHSV, 8.8 N L g-1 h-1) of Cu/ZrO2 and Cu-ZnO catalysts respectively have been addressed. The influence of the reduction atmosphere (5 or 100% H2) on metal surface area (MSA) and activity pattern has been probed. ZnO acts as promoter of both structural and catalytic properties of the metal Cu phase, while the replacement of zirconia carrier with ceria depresses both surface area (SA) and MSA of the Cu-ZnO system. Higher surface methanol yields point out a remarkable promoting effect of ceria on the activity of the Cu-ZnO system, while unsystematic effects of the activation atmosphere on MSA and functionality of the various systems rely on the dual-site nature of the main reaction path involving metal and oxide sites at metal/oxide interface.