The feasibility of SiI₂ monolayer as the candidate for photocatalytic water splitting for hydrogen generation under the irradiation of the solar light is explored. The geometrical structure, the electronic and optical properties, the mobility of carrier and strain engineering of the monolayer are investigated based on the first-principles calculations. The results demonstrate SiI₂ monolayer possesses an indirect gap of 2.33 eV (HSE06), and both the band edge and the bandgap match the redox potential conditions of the water splitting for hydrogen generation. There is an obvious optical absorption in the visible light and near-ultraviolet region and can be enhanced by the compressive strain. Moreover, the mobility of the electron is significantly different from that of the hole, implicating that the effective spatial charge separation is expectable and the ratio of the recombination of the photogenerated charge pairs is low. The primary adsorption site of the water molecule is identified. The Gibbs free energy and the adsorption energies are calculated to demonstrate the H₂ generation from the water molecule splitting on the monolayer. All the considered properties support that SiI₂ monolayer can be achieved as a promising candidate for the photocatalytic water splitting for hydrogen production under the irradiation of the solar light.

探讨了SiI ₂单层作为光催化水分解在太阳光照射下产生氢的可行性。基于第一性原理计算，研究了单层的几何结构，电子和光学性质，载流子迁移率和应变工程。结果表明SiI ₂单层具有2.33 eV（HSE06）的间接间隙，并且能带边缘和能带隙都与水分解产生氢的氧化还原电势条件相匹配。在可见光和近紫外线区域有明显的光吸收，并且可以通过压缩应变来增强。此外，电子的迁移率与空穴的迁移率显着不同，这意味着可以期望有效的空间电荷分离，并且光生电荷对的复合比率低。确定了水分子的主要吸附位点。计算吉布斯自由能和吸附能以证明由单分子层上分裂的水分子产生H ₂。所有考虑的特性均支持SiI可以实现_2个单层作为光催化水分解的有希望的候选物，以在太阳光的照射下制氢。