Defect-Engineering MoS₂/borophene/WS 2 Sandwich Heterostructures Enhanced the HER Catalytic Activity and Improve Water Splitting Efficiency

Abstract

To enhance the stability of borophene and improve its catalytic activity for HER, we proposed a MoS 2 /borophene/WS 2 sandwich-structure and systematically examined the impact of defect morphology on its catalytic performance. We carried out an in-depth investigation into the impact of five intrinsic-defects on HER catalytic activity in the contact surface of MoS 2 /borophene/WS 2 heterojunction. To assess the HER catalytic performance of heterojunction, we calculated dissociation-energy-barriers of water molecules on MoS₂/borophene/WS₂ heterojunction with sulfur vacancies and systematically analyzed the energy barriers with three potential dissociation pathways. Results demonstrate that MoS₂/borophene/WS₂ sandwich-structure substantially improves the stability of 2D-borophene structure. Notably, MoS₂/borophene/WS₂ heterojunction with S-vacancies exhibits superior catalytic performance, as evidenced by its calculated ΔG H* is only -0.01eV. This value is considerably lower than those of Pt and borophene/WS₂ heterojunction, highlighting its enhanced catalytic efficiency. In particular, owing to the synergistic effect between borophene and defective WS₂, the dissociation energy of water molecules is significantly reduced to 0.71eV.Consequently, we propose that this MoS₂/boronene/WS₂ heterojunction not only demonstrates superior HER catalytic activity but also effectively lowers the energy barrier for water dissociation in alkaline or neutral conditions. This advancement provides critical support for facilitating the practical application of borophene as an efficient HER catalyst.