Influence of Zr on the performance of Cu/Zn/Al/Zr catalysts via hydrotalcite-like precursors for CO₂ hydrogenation to methanol
2013
Gao, Peng | Li, Feng | Zhan, Haijuan | Zhao, Ning | Xiao, Fukui | Wei, Wei | Zhong, Liangshu | Wang, Hui | Sun, Yuhan
A series of Cu/Zn/Al/Zr hydrotalcite-like precursors with Zr⁴⁺:(Al³⁺+Zr⁴⁺) from 0 to 0.7 were synthesized by a co-precipitation method. X-ray diffraction and thermogravimetric measurements demonstrated that the yield of the hydrotalcite-like phase decreases with increased Zr content. The Cu/Zn/Al/Zr mixed oxides were then obtained by calcination of the hydrotalcite-like precursors and tested for methanol synthesis from CO₂ hydrogenation. With increased Zr⁴⁺:(Al³⁺+Zr⁴⁺) atomic ratio, the exposed Cu surface area and dispersion of Cu first increase until Zr⁴⁺:(Al³⁺+Zr⁴⁺)=0.3 and then decrease. However, the total number of basic sites on catalysts increases continuously. It is also found that the CO₂ conversion is related to the exposed Cu surface area and the dispersion of Cu, while the CH₃OH selectivity is related to the distribution of basic sites on the catalyst surface. The incorporation of a suitable amount of Zr is beneficial for the production of methanol, and the best catalytic performance is obtained when the Zr⁴⁺:(Al³⁺+Zr⁴⁺) atomic ratio is 0.3.
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