课题组近期研究发现，以MnO_x为催化剂载体，采用浸渍法制得的纳米xCo/MnO 催化剂对CO₂加氢反应有良好的催化作用。xCo/MnO催化剂表面的中等碱性位是主要的CO₂吸附位，而MnO_x载体表面具有的大量中等碱性位，可增强xCo/MnO催化剂对CO₂分子的吸附能力。通过改变Co物种在催化剂表面的负载量，可实现对xCo/MnO催化剂表面碱性位和加氢活性位数量的有效调控，进而改善xCo/MnO催化剂对CO₂分子的吸附、活化和加氢性能。此外，发现在制备的xCo/MnO催化剂中形成了Mn_1-yCo_yO 固溶体，有利于促进金属Co纳米颗粒在MnO表面的分散和xCo/MnO催化剂表面氧缺陷位的生成。12Co/MnO催化剂上的CO₂吸附量达到了1.76 mmol/g，使催化剂具有优越的CO₂吸附和活化能力，并使其具有良好的CO₂加氢性能。在常压和420 °C条件下，所制12Co/MnO催化剂的CO₂转化率和CH₄选择性分别达到了57.5%和78.8%。在12Co/MnO催化剂上进行的10次CO₂加氢循环测试中，CO₂转化率也始终保持在最初的57.5%，CH₄选择性保持在70.0%以上。

 Sheng Miao (苗盛), Shuang Chen, Jia Zeng, Zhenqiong Gou, Chuan Huang*, Xiang Wang, Guilin Zhou*. Synergistic effects between Mn and Co species in CO₂ hydrogenation over xCo/MnO catalysts [J]. Fuel, 2024, 362: 130853.

https://doi.org/10.1016/j.fuel.2023.130853

      In this paper, the xCo/MnO catalysts for CO₂ hydrogenation reaction were prepared by the impregnation method using MnO_x as the catalyst support. The effects of the Co loading on the CO₂ hydrogenation performances of the prepared xCo/MnO catalysts were investigated. The active Co⁰ species on the xCo/MnO catalysts surface are the main active centers for the CO₂ hydrogenation reaction, and the medium basic sites on the xCo/MnO catalysts are the main CO₂ adsorption sites. The MnO_x support possesses a large number of medium basic sites, which enhance the CO₂ molecules adsorption ability of the xCo/MnO catalysts. An effective regulation of the basic and hydrogenation active site numbers on the xCo/MnO catalysts surface can be achieved by changing the Co loading amount, which in turn can affect the CO₂ molecules adsorption, activation and hydrogenation abilities of the xCo/MnO catalysts. Moreover, the Mn_1-yCo_yO solid solution was found to be formed in the prepared xCo/MnO catalysts, which is conducive to the dispersion of metal Co nanoparticles on the MnO surface and the generation of oxygen-deficient sites. The CO₂ desorption amount on the 12Co/MnO catalyst reached 1.76 mmol/g, which provided the catalyst with strong CO₂ adsorption and activation abilities, enabling it to exhibit great CO₂ hydrogenation performance. Under the conditions of atmosphere and 420 ℃, the CO₂ conversion and CH₄ selectivity on the prepared 12Co/MnO catalyst reached 57.5% and 78.8%, separately. Furthermore, the CO₂ conversion was able to consistently remain at the initial 57.5%, and the CH₄ selectivity was maintained above 70% in the 10 times CO₂ hydrogenation cycle tests on the 12Co/MnO catalyst.