CO2 hydrogenation to methanol over Cu-In intermetallic catalysts: Effect of reduction temperature
2019
Shi, Zhisheng | Tan, Qingqing | Tian, Chao | Pan, Yu | Sun, Xuewei | Zhang, Jinxin | Wu, Dongfang
Cu-In intermetallic catalysts are prepared by controlled reduction of CuO-In₂O₃ with hydrogen. The effects of reduction temperature on the catalyst properties and CO₂ hydrogenation performance are studied. Three typical reduction steps are shown with increasing the reduction temperature. Especially, after 350 °C reduction, Cu₁₁In₉ appears and a Cu₁₁In₉-In₂O₃ intermetallic catalyst (CuIn-350) is obtained. It is shown that the formation of Cu₁₁In₉ modulates Cu electronic structure and improves H₂ adsorption strength. An interface exists between Cu₁₁In₉ and In₂O₃, illustrating that Cu₁₁In₉ interacts closely with In₂O₃ and thus affects CO₂ adsorption strength. It is also found that H₂ adsorption capacity is not a principal factor and that CH₃OH space-time yield is positively correlated with CO₂ adsorption capacity. Furthermore, Cu₁₁In₉-In₂O₃ interface can be seen as the catalytic sites and an interface-catalyzed mechanism is proposed. Due to medium H₂ adsorption, excellent CO₂ adsorption, numerous Cu₁₁In₉-In₂O₃ interfacial sites and excellent thermal stability, CuIn-350 gives a high CH₃OH space-time yield and is recommended for catalyzing CO₂ hydrogenation to CH₃OH.
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