CO2 hydrogenation to Methanol and Dimethyl Ether by Pd-Pd2Ga catalysts supported over Ga2O3 polymorphs.

O. OYOLA; MIGUEL ANGEL BALTANAS; N. CARDONA-MARTÍNEZ

Journal of CO2 Utilization

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 9 p. 8 - 15

2212-9820

The production of methanol and dimethyl ether (DME) via CO2hydrogenation was studied using Pd catalysts supported on α-Ga2O3, α-β-Ga2O3 and β-Ga2O3 polymorphs. The formation of a Pd2Ga intermetalliccompound was observed using XRD and XPS. The catalytic activity improveswith an increase in the content of the Pd2Ga intermetallic compound. Thecontent of Pd2Ga on Pd/Ga2O3 depends on the Ga2O3 crystalline phase ofthe catalyst. A slight catalytic deactivation was observed for allsamples studied. The Pd/α-β-Ga2O3 catalyst displayed the largestdeactivation. The deactivation appears to be caused by a loss of basicsites. The selectivity to dimethyl ether is not dependent on the Pd2Gacontent, but depends on the catalyst acidity. This assertion was testedby adding niobia to the catalysts, thus increasing the DME selectivityfrom 0 to 53 %. The content of Pd2Ga over Pd/Ga2O3 catalysts wasidentified to be a crucial parameter for CO2 hydrogenation to methanol.