ASEE Postdoctoral Research Associate, Naval Research Laboratory, Materials Science and Technology Division, Washington, DC 20375, USA.
Naval Research Laboratory, Chemistry Division, Washington, DC 20375, USA.
Molecules. 2017 Sep 20;22(9):1579. doi: 10.3390/molecules22091579.
Iron-based CO₂ catalysts have shown promise as a viable route to the production of olefins from CO₂ and H₂ gas. However, these catalysts can suffer from low conversion and high methane selectivity, as well as being particularly vulnerable to water produced during the reaction. In an effort to improve both the activity and durability of iron-based catalysts on an alumina support, copper (10-30%) has been added to the catalyst matrix. In this paper, the effects of copper addition on the catalyst activity and morphology are examined. The addition of 10% copper significantly increases the CO₂ conversion, and decreases methane and carbon monoxide selectivity, without significantly altering the crystallinity and structure of the catalyst itself. The FeCu/K catalysts form an inverse spinel crystal phase that is independent of copper content and a metallic phase that increases in abundance with copper loading (>10% Cu). At higher loadings, copper separates from the iron oxide phase and produces metallic copper as shown by SEM-EDS. An addition of copper appears to increase the rate of the Fischer-Tropsch reaction step, as shown by modeling of the chemical kinetics and the inter- and intra-particle transport of mass and energy.
铁基 CO₂ 催化剂作为一种从 CO₂ 和 H₂ 气体生产烯烃的可行途径已经显示出了前景。然而，这些催化剂可能存在转化率低、甲烷选择性高的问题，并且对反应过程中产生的水特别敏感。为了提高氧化铝负载的铁基催化剂的活性和稳定性，在催化剂基质中添加了铜（10-30%）。在本文中，研究了铜添加对催化剂活性和形貌的影响。添加 10%的铜可显著提高 CO₂ 的转化率，降低甲烷和一氧化碳的选择性，而不会显著改变催化剂本身的结晶度和结构。FeCu/K 催化剂形成了一种独立于铜含量的反尖晶石晶体相和一种随铜负载量（>10%Cu）增加的金属相。在更高的负载量下，铜与氧化铁相分离，生成金属铜，这一点通过 SEM-EDS 可以看出。铜的添加似乎增加了费托合成反应步骤的速率，这可以通过化学动力学的建模以及质量和能量的内、颗粒间输运来证明。
