Promoting Cu/ZnO x Interface Formation and Zn-H-Zn Activation in Industrial CuZnAl Catalysts via ZrO2 Doping for Methanol Synthesis

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Abstract Although industrial Cu/ZnO/Al2O3 catalysts are highly promising for methanol synthesis from CO2 hydrogenation, identifying the nature of the surface active structure and establishing a quantitative structure-activity relationship remain elusive. Herein, through integrated qualitative, titration, and isothermal adsorption characterizations, we elucidate how Zr species promotion tailors the electronic and structural properties of Cu/ZnOx interfacial sites—the primary active sites. A substantial methanol STY of 0.813 g gcat–1 h–1 is achieved over the Cu/ZnO/Al2O3-2Zr catalyst at 503 K and 3 MPa with an H2/CO2 ratio of 4 and a GHSV of 40,000 mL gcat–1 h–1, a 23.9% leap over the pristine benchmark. Mechanistically, a linear dependence of CO2 conversion on the density of Cu/ZnOx interfacial sites is established, which originates from the improved dispersion of both ZnO and Cu induced by moderate ZrO2 incorporation. Electronic analyses reveal that Zr species acts as an electron donor to ZnOx, enriching its electron density. This electronic modulation facilitates H2 dissociation and the surface Zn-H-Zn species formation even at low temperature, selectively driving the intermediate hydrogenation to methanol. In situ spectroscopies identify a sequential HCOO* → CH3O* hydrogenation pathway for methanol synthesis. Ultimately, this work establishes a definitive quantitative structure-activity relationship, paving a clear path for designing advanced industrial methanol catalysts.

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