Understanding the structure of Cu-doped MgAl2O4 for CO2 hydrogenation catalyst precursor using experimental and computational approaches

The combination of experiments and simulations revealed the structural and electronic origins of Cu-doped MgAl 2 O 4 spinel-type oxides, which we developed as the catalyst precursor for CO 2 -to-methanol hydrogenation. When the doping was high, elongated O–Cu octahedrally coordinated [CuO 6 ] el was confirmed in the spinel structure. As the amount decreased, [CuO 6 ] el was deformed to short O–Cu octahedrally coordinated [CuO 6 ] s . Simultaneously, O atoms surrounding Cu atoms became more negatively charged, and Cu nanoparticle with a size <10 nm was formed by H 2 reduction. The Cu nanoparticles derived from [CuO 6 ] s was highly selective to CO 2 -to-methanol hydrogenation. • Cu-doped MgAl 2 O 4 was developed for CO 2 -to-methanol hydrogenation. • H 2 reduction with low Cu doping yields Cu nanoparticles with size <10 nm. • The short O–Cu octahedrally coordinated [CuO 6 ] s was found as decreasing Cu loading. • DFT calculations revealed that the O atoms of [CuO 6 ] s are more negatively charged.