Optical and photocatalytic studies of the novel 2D penta-M4P4X2Y2 (M=Pd, Pt; X/=Y--S, Se, Te) Janus monolayers

In this article we report novel penta-like M4P4X2Y2 (M = Pd, Pt; X/=Y--S, Se, Te) Janus monolayers. The structural stability of the monolayers is double checked by using the phonon spectra and AIMD simulations. After confirming the thermodynamic stability of the monolayers, their structural, mechanical, electronic, and optical properties are systematically explored using the density functional theory (DFT). The calculated results demonstrate indirect bandgap for these monolayers, ranging from 1.57 to 2.58 eV. Furthermore, the photocatalytic investigations show that M4P4X2Y2 Janus monolayers exhibit the capability of oxidizing H2O/O2 to O2, while reducing H+ to H2. These findings strongly indicate the potential of M4P4X2Y2 monolayers as photocatalysts for water splitting reaction.