Chinese Journal of Catalysis ›› 2022, Vol. 43 ›› Issue (4): 1139-1147.DOI: 10.1016/S1872-2067(21)63950-5

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Synergistic interaction of Nb atoms anchored on g-C3N4 and H+promoting high-efficiency nitrogen reduction reaction

Shaokang Yang, Chaonan Zhang, Dewei Rao*(), Xiaohong Yan   

  1. School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, China
  • Received:2021-09-09 Accepted:2021-09-09 Online:2022-03-05 Published:2022-03-01
  • Contact: Dewei Rao
  • Supported by:
    National Natural Science Foundation of China(51801075);National Natural Science Foundation of China(91750112)

Abstract:

Nowadays catalytic nitrogen reduction reaction (NRR) by electrochemistry has attracted much attention because of its key role in producing the basic chemical product ammonia with low energy consumption. A stable and environmentally-friendly single- or multi-atom catalyst with good performance in activity and selectivity is highly desired for NRR. From density functional theory calculations, the NRR mechanisms catalyzed by Nb monomer, dimer, trimer and tetramer anchored on graphitic carbon nitride (Nbx@g-C3N4, x = 1, 2, 3, 4) have been deeply explored. It has been found that Nb3@g-C3N4 exhibits the best catalytic ability among the four catalysts with the introduction of H+. A more stable intermediate (*NH2+*H) can be found to reduce the huge free energy barrier of forming *NH3 from *NH2 directly in a multi-atom system. By analyzing the density of states and projected crystal orbital Hamilton population, a synergistic effect among Nb atoms and the adsorbed H+is responsible for reducing the overpotential of NRR. Furthermore, the competitive hydrogen evolution reaction is suppressed effectively. This work introduces a new insight in the reaction pathway in multi-atoms for developing high-efficiency NRR catalysts.

Key words: Catalysis, N2 fixation, Nitrogen reaction, H+absorption, Selectivity