Ethylene Methoxycarbonylation over Heterogeneous Pt₁/MoS₂ Single-Atom Catalyst: Metal-Support Concerted Catalysis

Abstract

Ethylene methoxycarbonylation (EMC) to methyl propanoate (MP) is an industrially important reaction and commercially uses a homogeneous Pd-phosphine organometallic complex as the catalyst and corrosive strong acid as the promoter. In this work, we develop a Pt 1 /MoS 2 heterogeneous single-atom catalyst (SAC) which exhibits high activity, selectivity, and good recyclability for EMC reaction without need of any liquid acid. The production rate of MP achieves 0.35 g MP g cat −1 h −1 with MP selectivity of 91.1% at 1 MPa CO, 1 MPa C 2 H 4 , and 160 °C, which can be doubled at 2 MPa CO and corresponds to 320.1 mol MP mol Pt −1 h −1 , at least 1 order of magnitude higher than the earlier reported heterogeneous catalyst and even comparable to some of homogeneous catalyst. Advanced characterizations and DFT calculations reveal that all the Pt single atoms are located at the Mo vacancies along the Mo edge of the MoS 2 nanosheets, forming pocket-like Mo−S−Pt 1 −S−Mo ensembles with uniform and well-defined structure. Methanol is first adsorbed and dissociated on Mo sites, and the produced H spillovers to the adjacent Pt site forming Pt− H species which then activate ethylene, forming Pt-ethyl species. Meanwhile, CO adsorbed on the other Mo site reacts with the Ptethyl species, yielding propionyl species, and this carbonylation is the rate-determining step. The final methoxylation step proceeds via the nucleophilic attack of propionyl species by −OCH 3 affording the final product MP. Such a metal-support concerted catalysis enabled by the Mo−S−Pt 1 −S−Mo multisite ensemble opens a new avenue for SACs to promote the multimolecular reactions that prevail in homogeneous catalysis.

Probing Coordination Number of Single‐Atom Catalysts by d‐Band Center‐Regulated Luminescence

“…The calculated Pt L 3 -edge XANES spectra in Pt 1 /SiC-100, Pt 1 /SiC-140, and Pt 1 /SiC-200 were obtained based on previous studies. [49,50] The closed structures of these Pt-SACs were simulated by density functional theory (DFT) with PtÀ O CNs of 3, 4, and 5 (inset images in Figure 2f-h). The main features of the experimental data were well reproduced with the calculations (Figure 2f-h).…”

Co/SiO2 Catalyst for Methoxycarbonylation of Acetylene: On Catalytic Performance and Active Species

“…Ding and coworkers developed porous organic polymer-supported single-site Pd catalysts, in which the 2-pyridylphosphine ligand and p-toluenesulfonic acid were incorporated into the framework of the support [21,22], and the methoxycarbonylation reaction of acetylene was allowed to run in the absence of an extra acid promoter. However, this approach suffered from tedious procedures for the preparation of the support [23,24]. In addition, the high cost and low abundance of Pd compromised its efficiency.…”

Electrophoretic Microplate Protein Identification Based on Gold Staining of Molybdenum Disulfide Hydrogels

“…As an important member of the two-dimensional (2D) family, layered molybdenum disulfide (MoS 2 ) nanosheets have exhibited a series of unprecedented characteristics for diverse applications, such as transistors and electronic devices, − biosensors, , inorganic nanomedicine, − energy, − and catalysts. − The underlying properties of MoS 2 layers are considered for intriguing chemical reactions. For instance, exfoliated MoS 2 seeds served as heterostructural substrates, resulting in the anisotropic accumulation of Au atoms and the formation of chiral plasmonic nanodendritic structures .…”