Two-dimensional BP/β-AsP van der Waals heterostructures as promising photocatalyst for water splitting

Constructing two-dimensional (2D) van der Waals (vdW) heterostructures is becoming a promising way for photocatalytic water splitting to produce hydrogen. In this Letter, we perform a 2D vdW blue phosphorous/β-AsP (BP/β-AsP) heterostructure based on density functional theory calculations. The type II band alignment in the BP/β-AsP vdW heterostructure is beneficial for separating the photogenerated electrons and holes and suppressing their recombination. The BP/β-AsP heterostructure not only keeps a suitable band edge position for the water splitting reaction but also significantly improves the optical absorption in the visible and ultraviolet light region. Appropriate uniaxial strain can change the indirect bandgap of the BP/β-AsP heterostructure into a direct one. The present findings indicate that the BP/β-AsP heterostructure is a promising candidate for applications in photovoltaic devices and photocatalysis.