Mo-based catalysts based on B-modified two-dimensional carbon-rich conjugate frameworks for efficient nitrogen reduction reaction

Abstract

Under environmental conditions, electrochemical nitrogen reduction reaction (NRR), which has the advantages of low energy consumption, zero CO2 emissions, green and sustainability, is considered to be an alternative to the Haber-Bosch method for ammonia synthesis. However, the practical application of NRR is hindered by the poor N2 adsorption capacity, low NH3 synthesis efficiency, and poor selectivity of the catalyst. In this paper, from a theoretical point of view, we design a Mo-based catalyst with multiple active sites based on B-modified 2D CCFs. The B atom has a similar N2 activation mechanism to transition metal atoms in that their empty orbitals (sp3, d orbitals) can accept lone pairs of electrons of nitrogen and feedback electrons to the anti-bond orbitals of the NˆN bond. Moreover, the addition of the B atom leads to new orbital hybridization and charge distribution, which strengthens the N2 adsorption capacity and reduces the energy change, thereby improving the NRR catalytic activity. After a series of analyses, it is concluded that MoZr-BPc CCF catalyst has the best NRR activity with the minimum limiting potential of −0.36 V, the overpotential of 0.20 V, and FENRR of 100%, and it can well inhibit the HER extremely. The synergistic effect of non-metallic and metal atoms provides a new idea for the rational design of NRR electrocatalysts and lays a theoretical foundation for the widespread use of NRR in practical applications.