Active Sites on Zn_xZr_1–xO_2–x Solid Solution Catalysts for CO₂-to-Methanol Hydrogenation

Abstract

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.

Adsorption of CO2 on Amorphous and Crystalline Zirconia: A DFT and Experimental Study

“…101) surface is comparable to 1.06−1.69 J/m 2 in the previous DFT studies using the other DFT functionals. 10,28,36 The relative surface energies qualitatively agree with the previous calculations 28 and increase in the following order: (101) < (001) < (100) < (111) < (110).…”

“…We prepared Zn-doped ZrO2 as t-ZrO2 according to our previous work. 10 First, am-ZrO2 was impregnated with an aqueous solution of Zn nitrate (Fujifilm Wako), and then dried at 110 °C. Next, the obtained powder was calcined at 500 °C for 3 h. The Zn/(Zn+Zr) atomic ratio was 7%.…”

Realizing and Revealing Complex Isobutyl Alcohol Production over a Simple Cu–ZrO2 Catalyst

“…The adsorbed CO/CO 2 then reacts with the spillover of H atoms to form C -containing species on the ZrO 2 surface. Subsequently, formate species (HCOO*) are successively hydrogenated to methoxy species and finally to methanol. ,,− …”

Heterogeneous Cu Catalyst for CO₂-to-Methanol Hydrogenation Importance of Catalyst Precursor Structure

“…Based on this feature, Cu-doped MgAl2O4 can be regenerated. Our next challenge is to extend this Cu catalyst development guideline to the development of catalysts based on transition metals other than Cu, such as Zn 32) . Tested using methanol steam reforming which is the reverse reaction of CO 2 -to-methanol hydrogenation 30) .…”