Liu Daoru, Jiang Feifei, Zhang Qinghua, Huang Wei-Hsiang, Zheng Yanping, Chen Mingshu, Wu Liming, Qin Ruixuan, Wang Mingzhi, Zhang Shiyi, Chen Limin, Yan Keyou, Zhou Linan, Zhao Yun, Gu Lin, Chen Guangxu
School of Environment and Energy, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, South China University of Technology, Guangzhou 510006, China.
Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
ACS Nano. 2024 Dec 24;18(51):34671-34682. doi: 10.1021/acsnano.4c10030. Epub 2024 Dec 11.
Bimetallic Pt-based catalysts, for example, PtZn and PtSn catalysts, have gained significant attention for addressing the poor stability and low selectivity of pristine Pt catalysts over propane dehydrogenation (PDH). However, the structures of the active sites and the corresponding catalytic mechanism of PDH are still elusive. Here, we demonstrate a spatially confined Pt-ZnO@RUB-15 catalyst (where "" is the mole ratio of Zn/Pt and RUB-15 is a layered silica), which exhibited high catalytic activity, ultrahigh selectivity (>99%), and resistance to coking at 550 °C for PDH. Significantly different from the preliminary studies over the PtZn catalysts, through the assistance of quasi- X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (CO-FTIR), X-ray absorption spectroscopy (XAS), and CO titration, we discovered that the active sites for PDH were the Pt-ZnO interfaces, characterized by a structure of Pt-Zn-O-Si. Density functional theory (DFT) calculations showed that Pt atoms positioned at Pt-ZnO interfaces with coordinatively unsaturated ZnO sites facilitate the C-H bond breaking of propane while concurrently suppressing deep dehydrogenation processes. This study suggests that engineering the interfaces of Pt-metal oxides under spatially confined conditions holds promise for developing highly efficient Pt-based catalysts for light alkane dehydrogenation.
例如，双金属铂基催化剂PtZn和PtSn催化剂，在解决原始铂催化剂在丙烷脱氢（PDH）反应中稳定性差和选择性低的问题方面受到了广泛关注。然而，活性位点的结构以及相应的PDH催化机理仍然不清楚。在这里，我们展示了一种空间受限的Pt-ZnO@RUB-15催化剂（其中 是Zn/Pt的摩尔比，RUB-15是一种层状二氧化硅），该催化剂在550℃下对PDH表现出高催化活性、超高选择性（>99%）和抗结焦性能。与对PtZn催化剂的初步研究显著不同，通过准X射线光电子能谱（XPS）、傅里叶变换红外光谱（CO-FTIR）、X射线吸收光谱（XAS）和CO滴定的辅助，我们发现PDH的活性位点是Pt-ZnO界面，其特征结构为Pt-Zn-O-Si。密度泛函理论（DFT）计算表明，位于具有配位不饱和ZnO位点的Pt-ZnO界面处的Pt原子有利于丙烷C-H键的断裂，同时抑制深度脱氢过程。这项研究表明，在空间受限条件下设计Pt-金属氧化物的界面有望开发出用于轻质烷烃脱氢的高效铂基催化剂。
