Design And Research Of Two-dimensional Photo-water Splitting Materials Based On Density Functional Theory

In the confront of resource shortage and environmental pollution,it is urgent to develop new clean energy.For the past few years,hydrogen can be produced by photocatalytic decomposition of water by solar energy,which has become a hot research topic for scientists all over the world.With the maturity of theoretical calculation method and the improvement of accuracy,more and more people use theoretical calculation to predict whether some two-dimensional materials have the potential of photolysis of water.In this paper,several novel two-dimensional semiconductor materials have been designed by first-principles calculations,we have been systematically studied their stabilities,electronic structures,optical properties,and catalytic activities for photohydrolysis of water,the primary contents of this paper are as follows:There are six materials in the Al XY(X,Y = S,Se,Te)system,including two categories,one of them is a material with symmetrical structure including Al S,Al Se,and Al Te.Another is a material with asymmetric structure,including Al SSe,Al STe and Al Se Te.These two-dimensional materials have excellent dynamic stabilities and adjustable electrical properties.What's more,it's worth noting that Al SSe,Al STe and Al Se Te have a very strong dipole moment which can break the condition that the minimum energy required for redox reaction of water(1.23 e V).In addition,these materials have excellent optical absorption properties and could be expected to become new photocatalytic water decomposition materials.CX(X = S,Se)as a new two-dimensional semiconductor material with blue phosphorus structure is predicted by calculation.The results show that the twodimensional CS and CSe materials have good kinetic,thermodynamic and mechanical stabilities.And these CX materials have appropriate band gaps,strong visible light absorption capacities and high carrier mobilities.Not only can make full use of solar energy,but also can effectively reduce the composite of electrons and holes,improve the activity of photocatalytic decomposition of water.In addition,we also found that the electrical and photocatalytic properties of CS and CSe materials can be further adjusted by applying stress.Therefore,theoretical studies show that single-layer CS and CSe have great potential in the field of photocatalytic decomposition of water.