Enhancing the catalytic hydrogen evolution reaction (HER) of the defective borophene@Pt/Pd/MoS2 heterojunction

Borophene (B) is a promising two dimensional (2D) material because of the excellent carrier mobility, large specific surface area and very light mass. However, many problems (overactive borophene chemistry and difficulty) have limited it's further applications. To improve the catalytic hydrogen evolution reaction properties, here, we apply ab-initio calculations to study the structural stability of two defective borophene (χ3 and β12)/MoS2 heterojunction as a hydrogen evolution reaction (HER) catalyst. In particular, we further explore the influence noble metals (Pt and Pd) on the catalytic properties of borophene(χ3 and β12)/MoS2 heterojunction. The calculated results show that the involvement of MoS2 not only improves the structural stability of the defective borophene@MoS2 but also further improves the catalytic ability of the borophene@MoS2. In particular, the calculated hydrogen adsorption Gibbs free energy (ΔG) of the χ3/MoS2-III heterojunction is only −0.0004 eV, which is an ideal catalyst for HER. Furthermore, the calculated Gibbs free energy (ΔG) of borophene (β12)/Pd@MoS2-II is 0.0007 eV because of the strong localized hybridization between Pd and the borophene (β12)/MoS2-II. Therefore, we believe that the Pd-doping can effectively improve the catalytic properties of the borophene (β12)/Pd@MoS2 as a hydrogen evolution reaction (HER) catalyst.