Zhai Ziwei, Zhang Bofeng, Wang Yutong, Wang Li, Liu Sibao, Liu Guozhu
Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
Phys Chem Chem Phys. 2022 Oct 5;24(38):23236-23244. doi: 10.1039/d2cp03263e.
Nanocarbons are promising supports for Pt clusters applied in propane dehydrogenation (PDH), owing to their large surface areas and tunable chemical properties. The vacancies and oxygen-containing groups (OCGs) in nanocarbons can enhance catalytic performance by tailoring the coordination environment of Pt clusters. Herein, 46 nanocarbons with coexisting vacancies and OCGs were designed to support Pt clusters, of which the influences on PDH were revealed by density functional theory calculations. Nanocarbons with divacancies (V2) and CO edge groups were screened out as the most appropriate support for Pt clusters in PDH. Due to the V2, tetrahedral Pt clusters were distorted into three-layered configurations, contributing to enhanced binding strength and a favorable reactive pathway starting from the methylene group in propane. This changed the rate-determining step to the first C-H bond scission with a low energy barrier. The introduction of CO edge groups coexisting with V2 further improved the stabilization of Pt clusters, resulting from the increased electron transfer from Pt atoms to C atoms. The abilities to break C-H bonds and inhibit C-C bond cracking were also enhanced as compared to the nanocarbons with only V2. Therefore, this work provides references on the regulation of vacancies and OCGs in carbon-based catalysts.
由于具有大的表面积和可调节的化学性质，纳米碳是应用于丙烷脱氢（PDH）的铂簇的有前途的载体。纳米碳中的空位和含氧基团（OCGs）可以通过调整铂簇的配位环境来提高催化性能。在此，设计了46种同时存在空位和OCGs的纳米碳来负载铂簇，通过密度泛函理论计算揭示了它们对PDH的影响。筛选出具有双空位（V2）和CO边缘基团的纳米碳作为PDH中铂簇最合适的载体。由于V2的存在，四面体铂簇扭曲成三层结构，有助于增强结合强度，并形成从丙烷中亚甲基开始的有利反应途径。这将速率决定步骤改变为具有低能垒的第一个C-H键断裂。与仅具有V2的纳米碳相比，与V2共存的CO边缘基团的引入进一步提高了铂簇的稳定性，这是由于从铂原子到碳原子的电子转移增加所致。其断裂C-H键和抑制C-C键裂解的能力也得到了增强。因此，这项工作为碳基催化剂中空位和OCGs的调控提供了参考。
