Theoretical Study On The Structure And Photocatalytic Properties Of XP₃?X=Al,Bi? And BiMP₆?M=Al,Ga,In? Monolayers

The emergence of graphene in 2004 triggered a research boom for two-dimensional materials.Two-dimensional materials have many unusual advantages,such as unique electronic properties,optical properties,and mechanical properties.At the same time,two-dimensional materials have outstanding performance in emerging fields such as solar cells,solar photodetectors,integrated digital inverters,and photocatalysis.Due to the increasing energy crisis and environmental problems,it is urgent to find clean and renewable energy to replace fossil fuels.Under the sunlight,photocatalysis technology can use semiconductors to promote the gas produced by water,providing a new method for solving the energy crisis and environmental problems.Therefore,the hydrogen production technology of photocatalytic decomposition has attracted much attention.In the photocatalytic reaction,the photocatalyst is crucial,which is proportional to the three-dimensional material.The two-dimensional material has unique advantages in photocatalytic applications.The original two-dimensional material has an ultra-high specific scale,which can provide more catalytic reaction sites.Secondly,the two-dimensional material can reduce the migration distance of carriers,thereby reducing the recombination of photo-generated carriers and improving the photocatalysis.Therefore,two-dimensional materials of XP3?X=Al,Bi?and BiMP6?M=Al,Ga,In?were designed and studied,and their stability and good photocatalytic performance were confirmed by first-principle calculations.Mainly for the following two aspects:1.Based on first-principles calculations,it is confirmed that XP3 monolayer will be a highly efficient photocatalytic hydrolysis hydrogen production material,and is also expected to be used in photovoltaic devices.We have optimized the new members of the structures of two-dimensional triphosphide family-two-dimensional AlP3 and BiP3 monolayer with the space groups C2/m and P3m1,and the phonon scattering curve and molecular dynamics simulation images can also show that the AlP3 and Bi P3 monolayers of the two space groups after complete relaxation are stable.The previously reported narrow-band-gap triphosphide,AlP_3,and BiP₃ monolayers calculated by the hybrid functional method have appropriate band gap values,and we found that strain can effectively change the electronic and optical properties of XP3monolayers.Under the influence of appropriate strain,the AlP₃ monolayer band edge of the P3m1 structure can cross the redox potential of water,while the band edge of the two-dimensional P3m1 Bi P₃ of the intrinsic structure can meet the photocatalytic decomposition requirements,and it is still under small strain Satisfy.At the same time,the calculation of the deformation potential theory shows that the carrier mobility of the two monolayers can reach?10⁵ cm²V^-1s^-1,which is higher than that of other reported XP3 monolayer carrier mobility.Combined with the considerable light absorption coefficient,this provides favorable conditions for the use of XP3monolayer as a high-efficiency photocatalyst.2.Based on density functional theory,we studied photocatalytic properties of a series of hexaphosphide monolayer BiMP6?M=Al,Ga,In?,these hexaphosphide monolayers are derived from XP₃ monolayers.The phonon spectrum curve calculated under the CASTEP module in the materials studio software shows no virtual frequency,quantum molecular dynamics simulation,and work is calculated by first-principles.We studied the electronic properties,optical properties,and carrier mobility of the BiMP6 monolayer and the effects of strain.the study.It was found that the BiMP₆ single layer not only has higher carrier mobility(?10⁵ cm²V^-1s^-1),but also has a great difference in the mobility of electrons and offsets in different directions,showing an excellent probability of passing GW calculations show that the gap of Bi MP₆ monolayer increases through M atomic number and shows a regular decrease,and two BiMP₆ monolayers?M=Al,Ga?can be used for photocatalytic decomposition of hydrogen production,free of Gibbs Energy analysis further indicates that BiAlP6 is the most likely material for hydrogen evolution reaction in all considered monolayers.