The novel two-dimensional photocatalyst SnN₃ with enhanced visible-light absorption for overall water splitting

Herein, we proposed a novel excellent two-dimensional photocatalyst, the SnN₃ monolayer, using first-principles calculations. The stability of the SnN₃ monolayer was examined via formation energy, phonon spectroscopy and ab initio molecular dynamics simulations. The SnN₃ monolayer has an ultra-high optical absorption capacity of the order of 10⁵ cm^-1 in the visible region, which is 3, 4 and 10 times those of SnP₃, MoS₂ and g-C₃N₄ monolayers, respectively. Moreover, it has a higher carrier mobility, 769.19 cm² V^-1 s^-1, than the other monolayers; the available electrostatic potential of -5.02 eV and the appropriate band gap of 1.965 eV indicate its applicability as a catalyst for overall water splitting over a wide strain range. The electronic properties of the SnN₃ monolayer could also be engineered effectively by altering the external strain and electric field.