CO inhibition in the CO 2 hydrogenation increasing methanol selectivity is promoted by dopping ZnO with Ga3+ in copper based catalysts. [Display omitted] • CO is strongly inhibited in Ga3+ doped Cu/ZnO sample. • Ga3+-doped in ZnO is a more effective promoter than the ZnGa 2 O 4 phase. • Copper-gallium interfaces favour the stabilization of surface Cu+/δ+. • Cu0 surface species are covered by reduced ZnO x on the most selective sample. A detailed understanding of the interactions among the active components in gallium promoted Cu/ZnO catalysts, depending on the speciation of the gallium, are reported using in situ/operando spectroscopic studies, and their effect in the CO 2 hydrogenation to methanol unraveled. In this contribution, the promoting effect of Ga3+-doped in the wurtzite ZnO lattice of a Cu/ZnO/Ga 2 O 3 catalyst is compared to that of a zinc gallate (ZnGa 2 O 4) phase. Remarkably, a strong inhibition of CO formation, together with an enhanced methanol formation, are observed in the Ga3+-doped ZnO sample, specifically at conditions where the competitive reverse water gas shift reaction predominates. The catalytic performance has been correlated with the microstructure of the catalyst where a surface enrichment with reduced ZnO x species, together with the stabilization of positive charged copper species and an increase in the amount of surface basic sites for CO 2 adsorption are observed on the most selective sample. [ABSTRACT FROM AUTHOR]