Insight into active sites of Pd-Au/TiO2 catalysts in hydrogen peroxide synthesis directly from H2 and O2
Insight into active sites of Pd-Au/TiO2 catalysts in hydrogen peroxide synthesis directly from H2 and O2
复制标题
深入了解直接从 H2 和 O2 合成过氧化氢中 Pd-Au/TiO2 催化剂的活性位点
DOI：
10.1016/j.jcat.2013.11.008
复制
发表时间：
2014-03-01
影响因子：
7.3
通讯作者：
Han, Yi-Fan
中科院分区：
文献类型：
--
作者：
Ouyang, Like;Da, Guo-jin;Han, Yi-Fan
系统地研究了直接从 H-2 和 O-2 合成 H2O2 以及该系统在各种 Pd-Au/TiO2 催化剂上的副反应。研究了 Pd/Au 比例对 H2O2 合成和随后的 H2O2 加氢的影响。使用多种技术对催化剂进行表征，包括透射电子显微镜 (TEM)、CO 吸附原位漫反射红外傅里叶变换光谱 (CO-DRIFTS)、X 射线光电子能谱 (XPS) 和 H-2/O-2 程序升温解吸 (H-2-/O-2-TPD)。通过对这些光谱和反应动力学的详细分析，详细阐述了 Pd 与 Au 合金化时各种活性位点的新见解。被 Au 原子包围的 Pd 单体可能是形成 H2O2 的主要活性位点。此外，Pd 整体被认为比单体 Pd 位点对 H2O2 氢化更活跃； H-2 过度氧化成 H2O 可能发生在 Au 和 TiO2 之间的界面处。 (C) 2013 Elsevier Inc. 保留所有权利。
H2O2 synthesis directly from H-2 and O-2 and side reactions in this system over a variety of Pd-Au/TiO2 catalysts have been studied systemically. The effects of Pd/Au ratio on H2O2 synthesis and subsequent H2O2 hydrogenation were investigated. The catalysts were characterized using multiple techniques including transmission electron microscopy (TEM), in situ diffuse reflectance infrared Fourier transform spectroscopy of CO adsorption (CO-DRIFTS), X-rays photoelectron spectroscopy (XPS), and temperature-programmed desorption of H-2/O-2 (H-2-/O-2-TPD). By detailed analysis of these spectroscopies and the kinetics of this reaction, new insights into various active sites of Pd upon alloying with Au were elaborated. Pd monomer surrounded by Au atoms could be the primary active site for H2O2 formation. In addition, Pd ensembles were assumed to be more active for H2O2 hydrogenation than monomeric Pd sites; the over-oxidation of H-2 to H2O likely occurred at the interface between Au and TiO2. (C) 2013 Elsevier Inc. All rights reserved.