Direct Z-scheme MS2/Si2PAs (M = Zr, Hf) heterostructures for efficient water splitting: A first-principles study

Designing direct Z-scheme heterostructure is an effective strategy to enhance redox ability, greatly raising the attention of photocatalysis in recent years. Here, we design 24 diverse vertical MS2/Si2PAs (M = Zr, Hf) heterostructures with different stacking configurations. Four kinds of heterostructures with different interlayer contacts are taken as examples to investigate the geometry, stability, and electronic properties, as well as the photocatalytic mechanism based on the first-principles calculations. We find that the competitiveness of MS2/Si2PAs (M = Zr, Hf) heterostructures is attributed to their excellent visible light absorption (∼2 × 105 cm−1), ultrafast carrier migration (∼13 587.28 cm2 V−1 s−1), and high solar-to-hydrogen efficiency (10.02%), indicating that this kind of system can be as a promising candidate in the field of semiconductor photocatalysis.