The influence of La incorporation on the performance of the CuxCeyLa1-(+)O2-δ catalysts for CO2 hydrogenation to methanol

• La incorporation into Cu–Ce for CO 2 hydrogenation to methanol. • La promoted the formation of smaller ceria crystallites. • Oxygen vacancy-rich Cu x /Ce y La 1-( x + y ) O 2 -δ active domains were formed. The effect of La incorporation on the catalytic performance of Cu–CeO 2 for CO 2 hydrogenation to methanol was investigated. The increase of the CeO 2 lattice constant and shift in the F 2g band from Raman spectroscopy confirmed La incorporation into the CeO 2 lattice. The La atomic percent of ≤ 19 % was the upper limit for the amount of La incorporated fully into the CeO 2 lattice without any phase segregation. XPS results of Cu 0.25 Ce 0.56 La 0.19 O 2-δ assumed to have full La incorporation, showed a maximum concentration of oxygen vacancies that facilitated CO 2 adsorption and conversion to methanol. The lattice fringes from HRTEM and lattice expansion confirmed that Cu was located on the catalyst surface for the synthesized catalysts. Cu 0.25 Ce 0.56 La 0.19 O 2-δ showed an improvement in the methanol space-time yield when the temperature was increased from 260 °C to 280 °C, in contrast to the catalysts with excess La on the surface. The descriptors for the methanol production were the availability of oxygen vacancies and the metal-metal oxide interaction (Cu–Ce x La 1−x O 2-δ and Cu–La 2 O 2 CO 3 ). The smaller metallic Cu crystallite size for Cu 0.25 Ce 0.19 La 0.56 O 2-δ suggested increased interactions between Cu 0 and the Ce x La 1−x O 2-δ support, which was conducive for methanol formation. The highest performance of Cu 0.25 Ce 0.56 La 0.19 O 2-δ at a higher temperature of 280 °C and pressure of 50 bar with a methanol space-time yield of 55.2 g CH3OH .kg catal .h −1 was attributed to the excellent thermal stability of the formed Ce x La 1−x O 2-δ solid solution support interacting with Cu which prevented sintering.