Recently, Zn x Zr1–x O2–x catalysts have attracted attention as next-generation CO2-to-methanol hydrogenation catalysts. In this study, we examined the effect of the Zn content on CO2-to-methanol hydrogenation over Zn x Zr1–x O2–x catalysts and determined the active-site structure through both calculations and experiments. When the Zn content was low, Zn x Zr1–x O2–x contained Zn clusters (isolated [ZnO a ] clusters and [Zn b O c ] oligomers). The presence of clusters indicates the formation of Zn–O–Zr sites. Interestingly, our calculations revealed that the Zn species in the clusters are easily exposed on the Zn x Zr1–x O2–x surface. This result is in line with the experimental results, suggesting that Zn species were unevenly distributed on the Zn x Zr1–x O2–x surface and deposited near the surface. The addition of excess Zn to ZrO2 led to the formation of both Zn-containing clusters and ZnO nanoparticles. During the reactions, the Zn–O–Zr sites derived from the clusters showed specific activity for CO2-to-methanol hydrogenation. Understanding the active-site structure will lead to the future development of Zn x Zr1–x O2–x catalysts.

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