Recently, Zn_xZr_1–xO_2–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_xZr_1–xO_2–x catalysts and determined the active-site structure through both calculations and experiments. When the Zn content was low, Zn_xZr_1–xO_2–x contained Zn clusters (isolated [ZnO_a] clusters and [Zn_bO_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_xZr_1–xO_2–x surface. This result is in line with the experimental results, suggesting that Zn species were unevenly distributed on the Zn_xZr_1–xO_2–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_xZr_1–xO_2–x catalysts.

中文翻译：

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用于 CO2 制甲醇加氢的 ZnxZr1–xO2–x 固溶体催化剂上的活性位点

最近，Zn _x Zr _{1– x} O _{2– x}催化剂作为下一代CO ₂制甲醇加氢催化剂引起了人们的关注。在这项研究中，我们研究了 Zn 含量对Zn _x Zr _{1– x} O _{2– x催化剂上的 CO 2}加氢反应的影响，并通过计算和实验确定了活性位点结构。当 Zn 含量较低时，Zn _x Zr _{1– x} O _{2– x}包含 Zn 簇（孤立的 [ZnO _a ] 簇和 [Zn _b O_c ] 低聚物）。簇的存在表明形成了 Zn-O-Zr 位点。有趣的是，我们的计算表明簇中的 Zn 物种很容易暴露在 Zn _x Zr _{1– x} O _{2– x}表面上。这一结果与实验结果一致，表明 Zn 物种在 Zn _x Zr _{1- x} O _{2- x}表面上分布不均匀，并沉积在表面附近。_{向 ZrO 2}中添加过量的 Zn导致含 Zn 簇和 ZnO 纳米粒子的形成。在反应过程中，来自簇的 Zn-O-Zr 位点表现出对 CO _{2的比活性}甲醇加氢。了解活性位点结构将导致 Zn _x Zr _{1– x} O _{2– x}催化剂的未来发展。