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-N x SACs, M = Hg, Cu, Au, and Ru) to predict their catalytic activities in acetylene hydrochlorination. The DFT results showed that Ru-N x SACs had the best catalytic performance among the four catalysts, and Ru-N x SACs could effectively inhibit the reduction of ruthenium cation. To verify the DFT results, Ru-N x 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–N 2 , Ru–N 3 ) exhibited excellent catalytic activity and stability compared to RuCl 3 catalyst. DFT calculations further revealed that Ru–N 2 and Ru–N 3 had a tendency to activate HCl at the first step of reaction, whereas Ru–N 4 tended to activate C 2 H 2 . These findings will serve as a reference for the design and control of metal active sites. We have controllably constructed Ru-Nx SACs with different N coordination environment, which was conducive to the structure-performance relationship study and exhibited enhanced catalytic performance compared with traditional carbon-supported RuCl 3 catalyst. This work provided a reference for the design and control of metal active sites. • DFT calculations were used to simulate activity of M-N x SACs (M = Hg, Cu, Au, Ru). • Ru-N x SACs were fabricated via an in situ spatially confined Ru atoms using ZIF-8. • The N environment of Ru-N x SACs could be regulated by changing pyrolysis temperature. • Ru–N 2 and Ru–N 3 SACs exhibited outstanding C 2 H 2 conversion and stability. • Ru–N 2 and Ru–N 3 tended to activate HCl first whereas Ru–N 4 tended to activate C 2 H 2 .