酸改性CoPd/TiO2催化CH4-CO2直接合成C2含氧化合物

采用酸处理方法对CoPd/TiO₂催化剂进行改性，并将酸改性催化剂用于温和条件下CH₄-CO₂梯阶转化直接合成C₂含氧化合物（乙酸和乙醇）的反应。在150～300℃考察了浸酸方式和不同种类酸处理对催化剂活性和选择性的影响。采用X射线衍射（XRD）、X射线光电子能谱（XPS）、NH₃程序升温脱附（NH₃-TPD）和N₂吸附对催化剂进行了表征。结果表明，酸改性明显提高了CoPd/TiO₂上C₂含氧化合物的生成速率和选择性。浸酸方式对催化剂性能和结构有显著影响，先用酸浸渍载体然后再浸渍活性金属所得催化剂具有更高的活性。在H₃PO₄、HNO₃和HCl中，H₃PO₄浸渍的催化剂活性最佳，在150℃时C₂含氧化合物（乙酸和乙醇）的生成速率为3365 μg/(g·h)，选择性达到91%。

Direct synthesis of C2-oxygenates from CH4 and CO2 over acid-modified CoPd/TiO2 catalyst

CoPd/TiO₂catalysts modified by acids were used to catalyze the step-wise reaction of CH₄ and CO₂ to directly synthesize C₂-oxygenates（acetic acid and ethanol） under mildness conditions. The effect of the different introducing manners of acid and treatment of different acids on the activity and selectivity of catalysts was investigated at temperature between 150℃ and 300℃. All Catalysts were characterized by XRD, TPD, XPS, NH₃-TPD and N₂ adsorption. The formation rate and selectivity of C₂-oxygenates was markedly improved by acid modification. The performance and structure of catalysts were obviously affected by introducing manner of acid. High activity was observed on the catalyst which was prepared by first treating the TiO₂ support with acids then immobilizing Co and Pd. In the case of the treatment of H₃PO₄, HNO₃and HCl, the best activity was attained on the catalyst modified by H₃PO₄. The highest formation rate of C₂-oxygenates (acetic acid and ethanol) reached 3365μg/(g·h), while the highest selectivity of C₂-oxygenates was 91% at 150℃.