First-principles investigations of electronic, optical, and photocatalytic properties of Au-adsorbed MoSi2N4 monolayer

The electronic, optical, and photocatalytic properties of Au-adsorbed MoSi2N4 systems are predicted by first-principles calculations. Electronic structure analysis shows that the band gap is reduced from 1.89 eV (intrinsic MoSi2N4) to 0 eV (MoSi2N4–9Au). Calculation results of density of states indicate that the valence band edge is mainly contributed by the Mo 4d state, whereas the conduction band edge is contributed by both the Mo 4d and Si 3p states. As the number of adsorbed Au atoms is increased, the absorption coefficient increases from 3.0 × 104 cm−1 to 5.6 × 104 cm−1, meaning that more photons can be absorbed. Indeed, Au-adsorbed MoSi2N4 monolayer shows greater potential for applications such as water splitting and CO2 reduction based on redox potential analysis. The Au-adsorbed MoSi2N4 structures can effectively change the properties of materials, offering great potential in different fields.