Copper-gallia interaction in Cu-Ga2O3-ZrO2 catalysts for methanol production from carbon oxide(s) hydrogenation

P. SANGUINETI; M. BALTANÁS; A. BONIVARDI

APPLIED CATALYSIS A-GENERAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 504 p. 476 - 481

0926-860X

The impact of the interaction between copper and gallia was studied over a selected set of supported (2 wt%) Cu on Ga2O3, ZrO2 and Ga2O3?ZrO2 catalysts, which were employed in the methanol synthesis from CO2 and CO mixtures. The higher initial rate of methanol production on the Cu/ZrO2 catalyst was accompanied by an activity loss of ∼35% after 5 h on stream. However, all the gallated catalysts were notoriously more stable (and selective) than copper on pure zirconia was. Temperature-programmed reduction in H2, X-ray photoelectron spectroscopy and infrared spectroscopy of adsorbed CO results proved that temperatures higher than 553 K are needed to completely reduced Cu2+ to metallic Cu particles in the gallia-containing catalysts, which was attributed to the formation of a CuGa2O4 nanospinel. The ternary Cu?Ga2O3?ZrO2 catalysts showed an intermediate behavior, quite dependent on the preparation protocol, which emphasizes the need for tuning the degree of Cu?oxides interactions. It is suggested that just a moderate copper?gallia interaction is beneficial in terms of both activity and selectivity but, also, that a detrimental loss of ?active? copper should be avoided.