Regulating the spin state of single-atom doped covalent triazine frameworks for efficient nitrogen fixation

作者：Fang, Lei; Gou, Gaozhang; Shang, Jin; Liu, Mingxian; Gu, Qinfen; Li, Liangchun^*

来源：Journal of Colloid and Interface Science, 2022, 627: 931-941.

DOI：10.1016/j.jcis.2022.07.090

• Covalent triazine frameworks
• Nitrogen reduction reaction
• Single-atom coordination
• High-throughput screening
• Two-state reactivity

Covalent triazine frameworks (CTFs), served as a versatile platform, can form expedient metal-N single -atom coordination sites as promising catalytic centers. To seek out excellent candidate catalysts of M/ CTFs (M = Transition metal) for nitrogen reduction reaction (NRR), a "five-step " strategy involving spin states has been established for hierarchical high-throughput screening and reveals strong coordination ability of the CTFs, outstanding conductivity of the M/CTFs, effective adsorption and activation of N2* attributed to the electron transfer and orbital hybridization between the M/CTFs and N2*. Among the potential candidates, the Cr/CTF is screened out to be an excellent one for nitrogen fixation, which can not only inhibit hydrogen evolution reaction (HER) greatly but also has good thermodynamic stability (Eb =-4.40 eV), narrow band gap (Eg = 0.03 eV), moderate adsorption energy (Ea =-0.84 eV), large acti-vation energy (DGN2* =-0.71 eV) and a theoretical Faradaic efficiency of 100%. The spin state has been confirmed to be an important descriptor of catalytic activity and the two-state reactivity (TSR) is validated to exist in the NRR. Reaction mechanism with different spin states of Cr/CTF has been demon-strated to give a great impact on the nitrogen fixation, providing solid theoretical support for the design of more efficient NRR catalysts.

• 单位
  同济大学