Gallego Mario, Corma Avelino, Boronat Mercedes
Instituto de Tecnología Química, Universitat Politècnica de València - Consejo Superior de Investigaciones Científicas, Av de los Naranjos s/n, 46022 Valencia, Spain.
Phys Chem Chem Phys. 2024 Feb 14;26(7):5914-5921. doi: 10.1039/d3cp05802f.
The partial oxidation of methane to methanol catalyzed by Cu-exchanged zeolites involves at present a three-step procedure that requires changing reaction conditions along the catalytic cycle. In this work we present an alternative catalytic cycle for selective methane conversion to methanol using as active species small Cu clusters supported on CHA zeolite. Periodic DFT calculations show that molecular O is easily activated on Cu clusters producing bi-coordinated O atoms able to dissociate homolytically a CH bond from CH and to react with the radical-like non-adsorbed methyl intermediate formed producing methanol, while competitive overoxidation to CO is energetically disfavored. The present mechanistic study opens a new avenue to design catalytic materials based on their ability to stabilize radical species.
由铜交换沸石催化的甲烷部分氧化制甲醇目前涉及一个三步过程，该过程需要在催化循环中改变反应条件。在这项工作中，我们提出了一种用于将甲烷选择性转化为甲醇的替代催化循环，使用负载在CHA沸石上的小铜簇作为活性物种。周期性密度泛函理论计算表明，分子氧在铜簇上易于活化，生成双配位氧原子，该氧原子能够从甲烷中均裂解离出一个碳氢键，并与形成的类自由基非吸附甲基中间体反应生成甲醇，而竞争性过度氧化生成一氧化碳在能量上是不利的。目前的机理研究为基于稳定自由基物种能力来设计催化材料开辟了一条新途径。
