Penta-SiAsP Monolayer: A Highly Stable Pentagonal Ternary Material with Photocatalytic Potential for Overall Water Splitting

Currently, photocatalysts that can effectively promote overall water splitting and regulate hydrogen or oxygen release reactions using certain means remain a research hotspot. Based on first principles calculations, we theoretically predict a two-dimensional material called penta-SiAsP with a pentagonal structure. The phonon spectrum, formation energy, binding energy, and ab initio molecular dynamics calculations demonstrate that penta-SiAsP has stability. Under a certain range of electric field applied, the bandgap can still remain unchanged. Even under a certain biaxial strain, penta-SiAsP can still meet the requirements for overall water splitting in different pH ranges with respect to the band edge. Besides, tensile strain can effectively improve the light absorption performance of penta-SiAsP. Under pH 0 and pH 14 conditions, penta-SiAsP can spontaneously undergo photocatalytic water splitting. When pH 7, additional voltages of 0.79 and 0.76 V are required for hydrogen and oxygen evolution reactions. Penta-SiAsP exhibits resistance to photoinduced corrosion. The products of hydrogen and oxygen can be quickly separated from the photocatalyst. This study predicts a novel two-dimensional material with a ternary pentagonal structure and finds that it has potential for application in the field of photocatalysis, further expanding the research field of the pentagonal structured two-dimensional material family.