Regulating the coordination environment of Ru single-atom catalysts and unravelling the reaction path of acetylene hydrochlorination

In this work, DFT calculations were used firstly to simulate the nitrogen coordinated metal single-atom catalysts (M-Nx SACs, M = Hg, Cu, Au, and Ru) to predict their catalytic activities in acetylene hydrochlorination. The DFT results showed that Ru-Nx SACs had the best catalytic performance among the four catalysts, and Ru-Nx SACs could effectively inhibit the reduction of ruthenium cation. To verify the DFT results, Ru-Nx SACs were fabricated by pyrolyzing MOFs in-situ spatially confined metal precursors. The N coordination environment could be controlled by changing the pyrolysis temperature. Catalytic performance tests indicated that low N coordination number (Ru-N2, Ru-N3) exhibited excellent catalytic activity and stability compared to RuCl3 catalyst. DFT calculations further revealed that Ru-N2 and Ru-N3 had a tendency to activate HCl at the first step of reaction, whereas Ru-N4 tended to activate C2H2. These findings will serve as a reference for the design and control of metal active sites.& COPY; 2022 Institute of Process Engineering, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communi-cations Co., Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

DFT calculations were used to predict the catalytic activities of metal single-atom catalysts with nitrogen coordination in acetylene hydrochlorination. The results showed that Ru-Nx SACs had the best catalytic performance. Ru-Nx SACs were fabricated by pyrolyzing MOFs with in-situ spatially confined metal precursors, and the N coordination environment was controlled by changing the pyrolysis temperature. Catalytic performance tests indicated that low N coordination number (Ru-N2, Ru-N3) showed excellent activity and stability. DFT calculations further revealed the preference of Ru-N2 and Ru-N3 for activating HCl and Ru-N4 for activating C2H2. These findings provide a reference for the design and control of metal active sites.