Recently, Deng Dehui, a researcher of the Special Zone Group for 2D Materials and Energy Transformation of Small Molecules in the State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics and Chinese Academy of Sciences , Use the distance between single rhodium atoms to adjust the electronic structure and catalytic activity of sulfur atoms in the two-dimensional MoS2 plane, so as to achieve high-efficiency electrocatalytic hydrogen evolution (HER) performance. This work provides a new idea for the in-depth understanding of the catalytic activity regulation mechanism of two-dimensional MoS2 restricted single-atom and the design of a new type of highly efficient electrolyzed hydrogen evolution catalyst for water evolution.
MoS2 is a typical two-dimensional transition metal chalcogenide compound. Its edge structure has moderate hydrogen adsorption strength and shows good HER activity. Therefore, it is widely regarded as a potential non-noble metal HER catalyst that can replace precious metal Pt . However, a large number of S atoms in the MoS2 plane are inert to the HER reaction, and the number of edge active sites is very limited. Therefore, developing a method that can effectively stimulate and optimize the in-plane S activity of MoS2 is important to increase the number of catalytically active sites of MoS2 and improve its catalytic HER activity, but it is extremely challenging.
The Deng Dehui team has long focused on the study of surface interface control of two-dimensional catalytic materials, and was the first in the world to propose and implement metal heteroatoms in the MoS2 lattice-limited domain to stimulate the catalytic activity of S atoms in its plane (Energy Environ. Sci., 2015, 8 , 1594; Nat. Nanotechnol., 2016, 11, 218; Nat. Commun., 2017, 8, 14430; Nano Energy, 2019, 61, 611; Chem. Rev., 2019, 119, 1806). This strategy can effectively improve the performance of MoS2 catalytic HER. However, how to accurately control and optimize the in-plane sulfur activity is still a key issue to be solved urgently. The team ’s latest research shows that the synergistic effect of the distance between the single-atom Rh in the restricted region of the MoS2 lattice can effectively regulate and optimize the reactivity of the in-plane S atom, thereby significantly increasing its HER catalytic activity. The research team changed the average distance between Rh atoms by controlling the concentration of Rh atoms, and found that there is a peculiar "volcanic curve" relationship between Rh atom spacing and HER activity. When the mass fraction of Rh atoms in the MoS2 lattice reaches a moderate 4.8%, the HER reaction activity of the catalyst reaches the highest level, and a current density of 10 mA cm-2 requires only 67 mV overpotential. This activity exceeds the catalytic activity of most reported MoS2-based materials in acidic systems, and is close to that of commercial 40% Pt / C catalysts. At the same time, density functional theory (DFT) calculations found that the MoS2 lattice-bounded Rh atoms stimulated the activity of Rh neighboring S atoms, and the "volcanic curve" also appeared between the Rh atom spacing and the S atom ’s free energy of hydrogen adsorption "Relationship, that is, when the restricted Rh atom spacing is moderate, the adsorption energy of hydrogen in the in-plane S atom active site is optimal (closer to 0 eV), reaching the highest HER catalytic activity. This work reveals the mechanism of the regulation and optimization of the synergistic effect of the distance between MoS2 restricted Rh single atoms on the in-plane S atom electronic structure and catalytic activity, which provides a reference for the design and optimization of new MoS2-based catalysts.
Relevant research results were published in "Angel. Chem. Int. Ed." The above work was supported by the National Ministry of Science and Technology Key R & D Program Project, National Natural Science Foundation Basic Science Center Major Project, Chinese Academy of Sciences Frontier Science Key Research Project, Chinese Academy of Sciences Clean Energy Innovation Research Institute Cooperation Fund Project, Ministry of Education Energy Materials Chemistry Collaborative Innovation Center ) Funding.
The influence of the synergistic effect of the distance of two-dimensional MoS2 restricted Rh atoms on HER activity
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