Kim Nagyeong, Lim Seulgi, Kwon Seungdon, Choi Yuyeol, Lee Ji-Woong, Na Kyungsu
Department of Chemistry, Chonnam National University, Gwangju 61186, Korea.
Department of Chemistry, University of Copenhagen, 2100 Copenhagen, Denmark.
Nanomaterials (Basel). 2021 Nov 21;11(11):3146. doi: 10.3390/nano11113146.
The strong metal-support interaction (SMSI) between the three components in Au/CeO-Mg(OH) can be controlled by the relative composition of CeO and Mg(OH) and by the calcination temperature for the direct oxidative esterification of methacrolein (MACR) with methanol to methyl methacrylate (MMA). The composition ratio of CeO and Mg(OH) in the catalyst affects the catalytic performance dramatically. An Au/CeO catalyst without Mg(OH) esterified MACR to a hemiacetal species without MMA production, which confirmed that Mg(OH) is a prerequisite for successful oxidative esterification. When Au/Mg(OH) was used without CeO, the direct oxidative esterification of MACR was successful and produced MMA, the desired product. However, the MMA selectivity was much lower (72.5%) than that with Au/CeO-Mg(OH) catalysts, which have an MMA selectivity of 93.9-99.8%, depending on the relative composition of CeO and Mg(OH). In addition, depending on the calcination temperature, the crystallinity of the CeO-Mg(OH) and the surface acidity/basicity can be remarkably changed. Consequently, the Au-nanoparticle-supported catalysts exhibited different MACR conversions and MMA selectivities. The catalytic behavior can be explained by the different metal-support interactions between the three components depending on the composition ratio of CeO and Mg(OH) and the calcination temperature. These differences were evidenced by X-ray diffraction, X-ray photoelectron spectroscopy, and CO temperature-programmed desorption. The present study provides new insights into the design of SMSI-induced supported metal catalysts for the development of multifunctional heterogeneous catalysts.
Au/CeO-Mg(OH) 中三种组分之间的强金属-载体相互作用（SMSI）可通过 CeO 和 Mg(OH) 的相对组成以及用于甲基丙烯醛（MACR）与甲醇直接氧化酯化制甲基丙烯酸甲酯（MMA）的煅烧温度来控制。催化剂中 CeO 和 Mg(OH) 的组成比显著影响催化性能。不含 Mg(OH) 的 Au/CeO 催化剂将 MACR 酯化为半缩醛物种，未生成 MMA，这证实了 Mg(OH) 是成功进行氧化酯化的前提条件。当使用不含 CeO 的 Au/Mg(OH) 时，MACR 的直接氧化酯化成功并生成了所需产物 MMA。然而，MMA 的选择性远低于 Au/CeO-Mg(OH) 催化剂（72.5%），后者的 MMA 选择性根据 CeO 和 Mg(OH) 的相对组成在 93.9% - 99.8% 之间。此外，根据煅烧温度的不同，CeO-Mg(OH) 的结晶度以及表面酸度/碱度会发生显著变化。因此，负载金纳米颗粒的催化剂表现出不同的 MACR 转化率和 MMA 选择性。这种催化行为可以通过取决于 CeO 和 Mg(OH) 的组成比以及煅烧温度的三种组分之间不同的金属-载体相互作用来解释。X 射线衍射、X 射线光电子能谱和 CO 程序升温脱附证明了这些差异。本研究为设计用于开发多功能非均相催化剂的 SMSI 诱导负载型金属催化剂提供了新的见解。
