Metal–Organic Frameworks Encaged Ru Single Atoms for Rapid Acetylene Harvest and Activation in Hydrochlorination
Yurui Fan, Zhisong Liu, Songyuan Sun, Wenjun Huang, Lei Ma, Zan Qu, Naiqiang Yan, Haomiao Xu
Abstract
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.