Catalytic properties of borophene/MoS2 heterojunctions for hydrogen evolution reaction under different stacking conditions

Abstract

Borophene and MoS₂ are promising two-dimensional functional materials because of their advantageous high specific surface areas. However, due to their instability and inert surface factors, they do not perform well in the hydrogen evolution reaction as the catalyst. To solve these problems, heterostructures combine the advantages of each component to achieve a synergistic performance. Therefore, we constructed borophene/MoS₂ heterojunctions to investigate their catalytic hydrogen evolution reaction performances. Using different stacking methods, four borophene/MoS₂ heterojunction models were designed. The results show that borophene@S2/MoS₂ has the best catalytic hydrogen precipitation performance. This borophene@S2/MoS₂ has a hydrogen adsorption Gibbs free energy of −0.024 eV, which is better than that of the commercial noble metal platinum. In particular, this borophene@S2/MoS₂ has a better exchange current and overpotential. Essentially, the better catalytic performance of borophene@S2/MoS₂ is related to three factors. First, the heterojunction enhances the electron transport capacity of borophene@S2/MoS₂. Second, the structure after hydrogen adsorption further promotes the conductivity of the catalyst and facilitates the catalytic hydrogen precipitation reaction. Third, the unique stacking gives the hydrogenated borophene@S2/MoS₂ a special electron distribution. Finally, it was found that borophene@S2/MoS₂ has an intense photoresponse in the ultraviolet light range and has potential in photocatalysis.