Palladium and Ruthenium Dual‐Single‐Atom Sites on Porous Ionic Polymers for Acetylene Dialkoxycarbonylation: Synergetic Effects Stabilize the Active Site and Increase CO Adsorption

Abstract

Heterogeneous single‐metal‐site catalysts usually suffer from poor stability, thereby limiting industrial applications. Dual Pd1−Ru1 single‐atom‐sites supported on porous ionic polymers (Pd1−Ru1/PIPs) were constructed using a wetness impregnation method. The two isolated metal species in the form of a binuclear complex were immobilized on the cationic framework of PIPs through ionic bonds. Compared to the single Pd‐ or Ru‐site catalyst, the dual single‐atom system exhibits higher activity with 98 % acetylene conversion and near 100 % selectivity to dialkoxycarbonylation products, as well as better cycling stability for ten cycles without obvious decay. Based on DFT calculations, it was found that the single‐Ru site exhibited a strong CO adsorption energy of −1.6 eV, leading to an increase in the local CO concentration of the catalyst. Notably, the Pd1−Ru1/PIPs catalyst had a much lower energy barrier of 2.49 eV compared to 3.87 eV of Pd1/PIPs for the rate‐determining step. The synergetic effect between neighboring single sites Pd1 and Ru1 not only enhanced the overall activity, but also stabilized PdII active sites. The discovery of synergetic effects between single sites can deepen our understanding of single‐site catalysts at the molecular level.

High activity nitrogen-doped hollow carbon/silicon hollow spheres as encapsulated Pd–Fe nanoreactors for acetylene dialkoxycarbonylation

“…6d, the peak position at 2117 indicates the absorption peak of Pd d+ -CO, whereas at 2172, it denotes the absorption peak of Pd 2+ -CO. The addition of Fe induces a red-shift in Pd d+ -CO and a blue-shift in Pd 2+ -CO. [35][36][37][38] This suggests that the introduction of Fe enhances the catalyst's capacity to provide electron feedback to CO, implying electron transfer from Fe to Pd. Consequently, there is an increase in the degree of Pd-CRO feedback, strengthening the Pd-C bond while weakening the CRO bond.…”

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

“…One way is to immobilize the conventional homogeneous metal–ligand complex onto a solid support and thus heterogenize the whole catalysis system. − For example, Ding and co-workers developed a series of porous organic polymers (POP) that incorporate phosphine ligands into the framework, onto which an active metal species (e.g., Rh, Pd, etc.) was adsorbed and complexed with phosphine ligand, thus greatly improving the durability of the resultant catalyst in carbonylation reactions. − In spite of high efficiency, this approach suffers from difficulties and high cost in the synthesis of phosphine-containing POPs, which poses a high barrier for commercialization.…”

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

“…Reppe carbonylation reactions of acetylene (including hydrocarboxylation, alkoxycarbonylation, etc.) (Scheme 1) provide atom-economic and non-petroleum routes to produce acrylic acid (AA), methyl acrylate, and dimethyl succinate [1,2], which are raw materials and key intermediates that are widely used in the textile, leather finishing, and polymer industries, with a global demand of 10 million tons annually [3][4][5]. Various catalysts have been developed for the carbonylation reactions of acetylene, of which Ni-based catalysts are the original ones [6].…”