  We propose a novel excellent two-dimensional photocatalyst SnN3 monolayer
using first-principles calculations. The stability of SnN3 monolayer have been
examined via formation energy, phonon spectrum and ab initio molecular dynamics
calculations. Large optical absorption capacity plays significant role in the
enhancement of photocatalytic splitting of water. The SnN3 monolayer have
ultra-high optical absorption capacity in visible region, which is as three and
four times as that of SnP3 and MoS2 monolayer, respectively. Available
potential and appropriate band positions indicating the ability of overall
water splitting even in a wide strain range. Electronic properties of SnN3
monolayer can also be engineered effectively via the external strain, such as
the conversion from in-direct band gap to direct band gap. The applied electric
field splits the energy levels due to Stark effect, resulting in states
accumulation and smaller gap width
