A water splitting photocatalysis: Blue phosphorus/g-GeC van der Waals heterostructure

A boom of vertical heterostructures (HTSs) with atomically clean interfaces excited the scientists' enthusiasm in materials science and device engineering. In this letter, we perform the blue phosphorus (BlueP)/graphene-like GeC (g-GeC) HTS by DFT calculations. Direct bandgap for the g-GeC is beneficial for applications in photoelectronics. The energy levels of both water oxidation and reduction are within the bandgaps of the HTS and two separate monolayers, predicting their significant capacity for water splitting reactions. A type-II band alignment is presented for the BlueP/g-GeC HTS, ascribing to the efficient separation of the photogenerated electron-hole pairs. Modulated band edges are obtained by tailoring pH values to achieve the control of photocatalytic properties. Enhanced optical absorption in the visible region is observed for the HTS compared with others' work. These findings suggest that BlueP/g-GeC vdW HTS has promising potential in the field of photovoltaics and photocatalysis.