GeN3 monolayer: A promising 2D high-efficiency photo- hydrolytic catalyst with High carrier mobility transport anisotropy

[Display omitted] •A novel two-dimensional photocatalyst GeN3 monolayer is determined.•GeN3 monolayer has extremely high carrier mobility with anisotropy, which boost the separation of electron-hole pairs.•The GeN3 monolayer shows strong light absorption coefficients (up to 105 cm−1) in the visible regions.•The GeN3 monolayer exhibits high solar-to-hydrogen efficiency (12.96 %).•The band gap of the GeN3 monolayer could be engineered from indirect to direct under external strain and electric field. The investigations of two-dimensional photocatalysts are promising subjects in clean and renewable energy. Herein, we proposed a novel two-dimensional GeN3 monolayer. The stability of GeN3 monolayer was examined via formation energy, phonon calculations and ab initio molecular dynamics simulations. Excellent photocatalytic properties are revealed: (a) GeN3 monolayer is a semiconductor with appropriate band gap of 1.962 eV that the valence and conduction bands straddle the redox potential of water. (b) GeN3 monolayer has extremely high carrier mobility with anisotropic character (its electron mobility is 1.55 × 104 cm2 V−1 s−1 along the armchair direction, whereas the hole mobility reaches 1.6 × 103 cm2 V−1 s−1 along the zigzag direction), which boost the separation of electron-hole pairs. (c) The GeN3 monolayer shows strong light absorption coefficients (up to 105 cm−1) in the visible regions, leading to high solar-to-hydrogen efficiency (12.63 %). (d) Furthermore, the band gap of the GeN3 monolayer could be engineered from indirect to direct under external strain and electric field. This work discloses a novel 2D GeN3 monolayer whose fascinating properties make it a promising photocatalyst for hydrolyzing to produce hydrogen.