Built-in electric field-assisted W-C3/X-C3 van der Waals heterogeneous single-atom catalysts for enhanced electrocatalytic nitrogen reduction

Electrocatalytic nitrogen reduction reaction (eNRR) is considered an alternative approach to the Haber-Bosch process for green ammonia synthesis. However, developing NRR electrocatalysts with high activity and selectivity remains a great challenge. Here, we designed a new type of van der Waals heterogeneous single -atom catalysts (vdW-SACs): W-C3/X-C3 (X = TM, Be, B, C, N, O, P, S, and Cl). By means of large-scale density functional theory (DFT) calculations, we built up the full profile of the stability, NRR activity, and selectivity of these vdW-SACs. Five structures exhibit lower overpotential for NRR than the previously reported monolayer W1C3. A volcano-shaped relationship between & UDelta;G*N and UL was obtained, and particularly, the W-C3/P-C3 locates right on the peak of the volcano with the highest activity. The built-in electric field induced by the asymmetric active sites (W and P) adjusts the binding strength between reactants and catalysts surface and achieves the lowest overpotential. The electronic structure analysis discloses that the high degree of pd hybridization between W 5d orbitals and N2 & pi;* antibonding orbitals in W-C3/P-C3 promotes the activation of intermediates. These new insights may open up opportunities for exploring advanced electrocatalysts for NRR and beyond by regulating the built-in electric field of vdW-SACs.

Automated summary

This study presents a new design of van der Waals heterogeneous single-atom catalysts (vdW-SACs) for electrocatalytic nitrogen reduction reaction (eNRR). Large-scale density functional theory (DFT) calculations were employed to investigate the stability, NRR activity, and selectivity of these vdW-SACs. It was found that the W-C3/P-C3 catalyst exhibits the highest activity with the lowest overpotential due to the asymmetric active sites and the pd hybridization between W 5d orbitals and N2 π* antibonding orbitals. This research provides new insights for the development of advanced electrocatalysts for NRR and beyond.