  Considering the rapid development of experimental techniques for fabricating
2D materials in recent years, various monolayers are expected to be
experimentally realized in the near future. Motivated by the recent research
activities focused on the honeycomb arsenene monolayers, stability and carrier
mobility of non-honeycomb and porous allotropic arsenene are determined using
first principles calculations. In addition to five honeycomb structures of
arsenene, a total of eight other structures are considered in this study. An
extensive analysis comprising energetics, phonon spectra and mechanical
properties confirms that these structures are energetically and dynamically
stable. All these structures are semiconductors with a broad range of band gap
varying from ~1 eV to ~2.5 eV. Significantly, these monolayer allotropes
possess anisotropic carrier mobilities as high as several hundred
cm^{2}V^{-1}s^{-1} which is comparable with the well-known 2D materials such as
black phosphorene and monolayer MoS_{2}. Combining such broad band gaps and
superior carrier mobilities, these monolayer allotropes can be promising
candidates for the superior performance of the next generation nanoscale
devices. We further explore these monolayer allotropes for photocatalytic water
splitting and find that arsenene monolayers have potential for usage as visible
light driven photocatalytic water splitting.
