Preserved in a Shell: High‐Performance Graphene‐Confined Ruthenium Nanoparticles in Acetylene Hydrochlorination

Abstract

The potential implementation of ruthenium‐based catalysts in polyvinyl chloride production via acetylene hydrochlorination is hindered by their inferior activity and stability compared to gold‐based systems, despite their 4‐fold lower price. Combining in‐depth characterization and kinetic analysis we reveal the superior activity of ruthenium nanoparticles with an optimal size of 1.5 nm hosted on nitrogen‐doped carbon (NC) and identify their deactivation modes: 1) nanoparticle redispersion into inactive single atoms and 2) coke formation at the metal sites. Tuning the density of the NC carrier enables a catalytic encapsulation of the ruthenium nanoparticles into single layer graphene shells at 1073 K that prevent the undesired metal redispersion. Finally, we show that feeding O2 during acetylene hydrochlorination limits coke formation over the nanodesigned ruthenium catalyst, while the graphene layer is preserved, resulting in a stability increase of 20 times, thus rivalling the performance of gold‐based systems.

2D and 3D Ruthenium Nanoparticle Covalent Assemblies for Phenyl Acetylene Hydrogenation

“…Although we have not performed STEM-HAADF analyses to confirm that possibility, this phenomenon has already been reported for Ru/C catalysts. [47] These results highlight the good stability of the covalent assemblies prepared as already reported in our previous studies. [15a]…”

“…Although we have not performed STEM‐HAADF analyses to confirm that possibility, this phenomenon has already been reported for Ru/C catalysts. [ 47 ]…”

Nanostructuring unlocks high performance of platinum single-atom catalysts for stable vinyl chloride production

“… 9 , 22 – 24 Interestingly, the opposite particle-size dependency was found for ruthenium catalysts, underlining the importance of careful nanostructuring of the active site. 25 Despite promising initial activity, both metal-based catalysts suffer from deactivation, mainly due to reduction of the active metal sites and agglomeration ( i.e ., on non-functionalised carbon supports), or fouling ( i.e ., on functionalised carbon supports). 9 , 17 , 23 , 25 In order to improve the catalyst stability, several strategies, some of which have reached pilot plant testing, 20 , 26 have been developed, based on employing organic ligands containing soft donor atoms ( e.g .…”

“… 25 Despite promising initial activity, both metal-based catalysts suffer from deactivation, mainly due to reduction of the active metal sites and agglomeration ( i.e ., on non-functionalised carbon supports), or fouling ( i.e ., on functionalised carbon supports). 9 , 17 , 23 , 25 In order to improve the catalyst stability, several strategies, some of which have reached pilot plant testing, 20 , 26 have been developed, based on employing organic ligands containing soft donor atoms ( e.g . thiosulfate, thiocyanate, thiourea, and cyanides to stabilise cationic Au), 20 , 26 ionic liquids, 21 additional metals and/or promoters, 16 , 17 , 27 and functionalised supports ( i.e ., N, S, P, B-doped carbons or carbon-metal oxide mixtures).…”

Synthetic Organic Transformations of Transition‐Metal Nanoparticles as Propitious Catalysts: A Review

“…Ramirez and co-workers described well-defined rutheniumbased catalysts in the production of polyvinyl chloride via the addition of HCl to acetylene. [49] The active catalyst was prepared by ruthenium NP doping on to polyaniline-derived nitrogendoped carbon (NC) and activated carbon (AC). The metal loading was determined by ICP-OES (1 wt%.)…”