Asymmetrical radial strain energy strategy of M–N–SWCNT single atom catalysts for highly efficient hydrogen evolution: A high-throughput DFT study

Abstract

Single-atom catalysts (SAC) with highly active and stable yet low-cost are widely used in hydrogen evolution reaction (HER). In this study, the strategy of combining the asymmetrical radial strain and high-throughput screening based on DFT calculations was employed to accelerate the discovery of SAC for HER under acidic conditions. Through evaluating various factors including thermodynamics stability, electrochemical stability, asymmetrical radial strain, and HER activity, the M–N–SWCNT (M = Ge, Sn, In, Pb, Bi, Sb and Fe) were identified as potentially highly active HER electrocatalysts. Fe-N-SWCNT with the asymmetrical radial strain of (−6.40%, 5.99%) exhibited the best HER performance with ΔGH* of 0.04 eV and TOF of 14.99 s−1. Increasing strain energy in M–N–SWCNT catalysts enhances electron density distribution and energy release of the HER mechanism, leading to higher HER activity. Incorporating p-block metals in M–N–SWCNT improves HER activity and stability due to p-π conjugated effect, supporting their use in HER. The analysis of active sites and catalytic activity demonstrates the importance of the second-nearest neighbor effect in M–N–SWCNT. This study provides valuable insights into the design and optimization of M–N–SWCNT SAC for efficient HER under acidic conditions, highlights the potential applications of p-block metals in HER.