The mechanical, electronic and photocatalytic properties of two novel BCN monolayer

We predicted two novel BCN monolayers with fantastic mechanical properties and high photocatalytic activity for overall water splitting. Both BCN-1 and BCN-2 monolayers demonstrate excellent mechanical flexibility under tensile strain. The electronic structure calculation suggests that both the BCN-1 and BCN-2 monolayer are indirect bandgap semiconductors, with bandgaps of 3.56 and 2.76 eV, respectively. The BCN-2 monolayer meets the strict electronic structure requirements for ideal photocatalytic overall water splitting. The drastically different mobility of electron and hole may significantly reduce the charge-carrier recombination rate, and thus increase the photocatalytic activity. Additionally, the BCN-2 monolayer exhibits a high solar-to-hydrogen efficiency of similar to 14% for photocatalytic water splitting under - 5% compressive strain. Hence, the proposed BCN-2 monolayer is a promising candidate for semiconductor photocatalysts, while the BCN-1 shows potential as a material for nanomechanical devices.