A study investigates the promotion of ZnZrOx catalysts with various hydrogenation metals (Re, Co, Au, Ni, Rh, Ag, Ir, Ru, Pt, Pd, and Cu) to enhance methanol synthesis from CO2. Cu is identified as the most effective promoter, doubling methanol productivity. Operando X-ray absorption, infrared, and electron paramagnetic resonance spectroscopy, along with density functional theory simulations, reveal that Cu0 species form Zn-rich low-nuclearity CuZn clusters on ZrO2 surfaces, correlating with oxygen vacancy formation. Mechanistic studies show that these clusters promote rapid hydrogenation of formate to methanol while suppressing CO production, highlighting the potential of low-nuclearity metal ensembles in CO2-based methanol synthesis. ZnZrOx catalysts are cost-effective and earth-abundant for CO2 hydrogenation to methanol, with the ability to suppress CO formation via the reverse water-gas shift reaction. Flame spray pyrolysis (FSP) produces materials with higher methanol space-time yield compared to coprecipitated systems. Despite similar catalytic ensembles, FSP maximizes surface area and forms isolated Zn2+ species on ZrO2 lattice, enhancing performance. The unique architecture of FSP catalysts promotes surface oxygen vacancies, key components of active ensembles favoring methanol formation. Metal promotion enhances hydrogen splitting ability and overall performance of oxide catalysts in CO2 to methanol conversion. Coprecipitated ZnZrOx catalysts benefit from small quantities of hydrogenation metals, with palladium recognized as the most effective. However, applying this strategy to flame-made ZnZrOx systems is challenging due to limited knowledge of promotional effects. The effects of a given metal depend on its identity and speciation, influenced by synthesis approach, promoter content, catalyst reconstruction, and oxide structure. In this study, flame-made ZnZrOx catalysts are systematically promoted by relevant hydrogenation metals (0.5 mol% Re, Co, Au, Ni, Rh, Ag, Ir, Ru, Pt, Pd, and Cu) for CO2 hydrogenation to methanol. Standardized synthesis and evaluation, along with in-depth characterization, reveal copper as the most effective promoter for ZnZrOx, leading to the largest performance improvement. Cu-promoted ZnZrOx catalysts are an earth-abundant and cost-effective alternative to conventional palladium promotion and are compositionally distinct from traditional Cu-ZnO-ZrO2 systems. Detailed microscopy, kinetic, stability, operando spectroscopy analyses, and theoretical simulations are applied to understand copper promotion. Specifically, the speciation under reaction conditions and its effect on oxygen vacancy formation, the architecture of active ensembles, and reactivity are investigated. The study provides valuable insights into ZnZrOx promotion by differentA study investigates the promotion of ZnZrOx catalysts with various hydrogenation metals (Re, Co, Au, Ni, Rh, Ag, Ir, Ru, Pt, Pd, and Cu) to enhance methanol synthesis from CO2. Cu is identified as the most effective promoter, doubling methanol productivity. Operando X-ray absorption, infrared, and electron paramagnetic resonance spectroscopy, along with density functional theory simulations, reveal that Cu0 species form Zn-rich low-nuclearity CuZn clusters on ZrO2 surfaces, correlating with oxygen vacancy formation. Mechanistic studies show that these clusters promote rapid hydrogenation of formate to methanol while suppressing CO production, highlighting the potential of low-nuclearity metal ensembles in CO2-based methanol synthesis. ZnZrOx catalysts are cost-effective and earth-abundant for CO2 hydrogenation to methanol, with the ability to suppress CO formation via the reverse water-gas shift reaction. Flame spray pyrolysis (FSP) produces materials with higher methanol space-time yield compared to coprecipitated systems. Despite similar catalytic ensembles, FSP maximizes surface area and forms isolated Zn2+ species on ZrO2 lattice, enhancing performance. The unique architecture of FSP catalysts promotes surface oxygen vacancies, key components of active ensembles favoring methanol formation. Metal promotion enhances hydrogen splitting ability and overall performance of oxide catalysts in CO2 to methanol conversion. Coprecipitated ZnZrOx catalysts benefit from small quantities of hydrogenation metals, with palladium recognized as the most effective. However, applying this strategy to flame-made ZnZrOx systems is challenging due to limited knowledge of promotional effects. The effects of a given metal depend on its identity and speciation, influenced by synthesis approach, promoter content, catalyst reconstruction, and oxide structure. In this study, flame-made ZnZrOx catalysts are systematically promoted by relevant hydrogenation metals (0.5 mol% Re, Co, Au, Ni, Rh, Ag, Ir, Ru, Pt, Pd, and Cu) for CO2 hydrogenation to methanol. Standardized synthesis and evaluation, along with in-depth characterization, reveal copper as the most effective promoter for ZnZrOx, leading to the largest performance improvement. Cu-promoted ZnZrOx catalysts are an earth-abundant and cost-effective alternative to conventional palladium promotion and are compositionally distinct from traditional Cu-ZnO-ZrO2 systems. Detailed microscopy, kinetic, stability, operando spectroscopy analyses, and theoretical simulations are applied to understand copper promotion. Specifically, the speciation under reaction conditions and its effect on oxygen vacancy formation, the architecture of active ensembles, and reactivity are investigated. The study provides valuable insights into ZnZrOx promotion by different