Monatomic Ti doped on defective monolayer boron nitride as an electrocatalyst for the synthesis of ammonia: A DFT study

Abstract

Due to its high efficiency, safety and environmental friendliness, electro catalytic nitrogen reduction reaction (NRR) is expected to replace the traditional process. However, due to the high energy of NN, the design of effective electrocatalyst for activation and adsorption of nitrogen molecules has become a research hotspot. Single atom doped on defective two-dimensional (2D) materials is expected to increase the adsorption activity of N2 and reduce the energy barrier of the NRR rate-determining step. In this paper, we constructed Ti atom doped Stone-Wales defect type and N defect type boron nitride (BN) 2D materials (Ti-VSW-BN and Ti-VN-BN) and used DFT to study the structural properties, charges transfer and thermodynamic stability of the new materials. The results show that Ti doping can improve the stability of defective BN 2D materials, and compared with the pristine BN, the band gap is reduced from 5.117 eV to 0.828 eV and 1.192 eV, respectively. By studying Gibbs free energy of the reaction path, it is shown that defective BN 2D materials can effectively enhance efficiency of NRR. Especially for Ti-VN-BN, energy barrier in the rate-determining step of the overall reaction can be reduced from 1.20 eV (pristine BN) to 0.96 eV. It shows that defective BN 2D material has the potential to become a new catalyst for the electrocatalytic ammonia synthesis.