Hernández Erendida, Bertin Virineya, Soto Jorge, Miralrio Alan, Castro Miguel
Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa , San Rafael Atlixco 186, Col. Vicentina, México, D.F. 09340, Mexico.
Departamento de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM) , Del. Coyoacán, 04510 México D.F., Mexico.
J Phys Chem A. 2018 Mar 1;122(8):2209-2220. doi: 10.1021/acs.jpca.7b11055. Epub 2018 Feb 21.
The search for a catalyst for the reduction of nitrous oxide (NO) is now imperative, as this molecule is a very dangerous pollutant. We found that the low-symmetry Pt cluster presents multiple reaction pathways for NO rupture, which are regioselective. This result was revealed by means of density functional theory calculations within the zero-order-regular approximation, ZORA, explicitly including relativistic effects. It is further proved that Pt is a competitive NO catalyst compared to sub-nanometric rhodium clusters, obtaining similar reaction barriers. The hot adsorption site, a tip atom of Pt, and the rotation of the NO molecule over the metallic cluster promote the formation of a frustrated bridge activated transition state, Pt-NO. This transition structure yields to spontaneous dissociation of NO without bridge formation. Along this catalytic process, rearrangements within the metal cluster take place, preserving its stability. Moreover, in addition to being important attributes of the Pt particle in the NO reduction, fluxionality and multiple reaction pathways may also prevent poisoning effects. Overall, this differs from reported results for more symmetric metal particles also used as catalysts.
由于一氧化二氮（NO）是一种极其危险的污染物，因此现在迫切需要寻找一种用于还原一氧化二氮的催化剂。我们发现，低对称性的铂簇呈现出多种NO裂解反应途径，这些途径具有区域选择性。这一结果是通过零级正则近似（ZORA）下的密度泛函理论计算揭示的，该计算明确包含了相对论效应。进一步证明，与亚纳米级铑簇相比，铂是一种具有竞争力的NO催化剂，具有相似的反应势垒。热吸附位点，即铂的一个尖端原子，以及NO分子在金属簇上的旋转促进了受挫桥活化过渡态Pt-NO的形成。这种过渡结构导致NO自发解离而不形成桥。在这个催化过程中，金属簇内部会发生重排，以保持其稳定性。此外，除了是铂颗粒在NO还原中的重要属性外，流动性和多种反应途径还可能防止中毒效应。总体而言，这与报道的同样用作催化剂的更对称金属颗粒的结果不同。
