直接Z-型BAs/Ga_(2)SO范德华异质结光催化分解水研究

Study of direct Z-scheme BAs/Ga_(2)SO van der Waals heterojunction for photocatalytic overall water splitting

基于第一性原理计算,系统研究了BAs/Ga_(2)SO异质结的光催化分解水性能.结果表明:BAs/Ga_(2)SO异质结具有良好的热力学稳定性并表现出交错的能带排列方式,带隙值为0.73 eV,界面处存在从BAs指向Ga_(2)SO的内建电场使其形成了直接Z-型异质结,能够有效分离光生电子-空穴对.另外,异质结的带边位置可以跨越水的氧化还原电位,析氢反应发生在BAs侧而析氧反应发生在Ga_(2)SO侧.最后,基于吉布斯自由能变化计算,发现在有光照时,析氢和析氧反应在BAs/Ga_(2)SO异质结表面可自发进行.以上结果表明BAs/Ga_(2)SO异质结是有潜力的光催化分解水材料.

Based on the first-principles calculations,the photocatalytic water splitting performance of BAs/Ga_(2)SO heterostructure has been systematically studied.Results reveal that the BAs/Ga_(2)SO heterostructure exhibits good thermal stability and a staggered band alignment with a band gap of 0.73 eV.A built-in electric field pointing from BAs to Ga_(2)SO is established at the interface,resulting in a direct Z-scheme heterostructure,which can effectively separate the photogenerated electron-hole pairs.In addition,the band edge positions of the BAs/Ga_(2)SO heterostructure can span the redox potential of water,with hydrogen evolution reaction occurring on the BAs side and oxygen evolution reaction occurring on the Ga_(2)SO side.Finally,based on the calculation of Gibbs free energy change,it is found that hydrogen evolution and oxygen evolution reactions can spontaneously occur on the surface of BAs/Ga_(2)SO heterostructure under illumination.All above results indicate that the BAs/Ga_(2)SO heterostructure is a potential photocatalyst for water splitting.