Metal-Organic Frameworks Encaged Ru Single Atoms for Rapid Acetylene Harvest and Activation in Hydrochlorination.

Ruthenium (Ru)-based catalysts have been candidates in hydrochlorination for vinyl chloride monomer (VCM) production, yet they are limited by efficient acetylene (C 2 H 2 ) utilization. The strong adsorption performance of HCl can deactivate Ru active sites which resulted in weak C 2 H 2 adsorption and slow activation kinetics. Herein, we designed a channel that employed metal-organic framework (MOF)-encaged Ru single atoms to achieve rapid adsorption and activation of C 2 H 2 . Low-Ru (∼0.5 wt %) single-atom catalysts (named Ru-NC@MIL) were assembled by hydrogen-bonding nanotraps (the H-C≡C-H δ+ ···O δ- interactions between C 2 H 2 and carboxylate groups/furan rings). Results confirmed that C 2 H 2 could easily enter the encapsulation channels in an optimal mode perpendicular to the channel with a potential energy of 42.3 kJ/mol. The harvested C 2 H 2 molecules can be quickly passed to Ru-N 4 active sites for activation by stretching the length of carbon-carbon triple bonds (C≡C) to 1.212 Å. Such a strategy guaranteed >99% C 2 H 2 conversion efficiency and >99% VCM selectivity. Moreover, a stable long-term (>150 h) catalysis with high efficiency (∼0.85 kg vcm /h/kg cat. ) and a low deactivation constant (0.001 h -1 ) was also achieved. This work provides an innovative strategy for precise C 2 H 2 adsorption and activation and guidance for designing multi-functional Ru-based catalysts.