Effects of CO and CO2 on the desulfurization of H2S using a ZnO sorbent:a density functional theory

• 作 者: LixiaLing[1]ZhongbeiZhao[2]BaojunWang[3]MaohongFan[4]RiguangZhang[3]
• 机 构: College of Chemistry and Chemical Engineering,Taiyuan University of Technology,Taiyuan 030024,Shanxi
• 出 处: 第八届国际分子模拟与信息技术应用学术会议
• 发表日期: 2016年期

　　The density functional theory(DFT)method has been performed to study the effects of CO and CO2 on the desulfurization of H2S over a ZnO sorbent.It shows that COS is inevitably formed on the ZnO(10-10)surface,which tends to be adsorbed onto the surface via a S–C bond binding with either a long or a short Zn–O bond.Potential energy profiles for the COS formation via reactions between H2S and CO,and H2S and CO2 on the ZnO(10-10)surface have been constructed.In the presence of CO,the dissociated active S of H2S reacting with CO leads to the formation of COS,and the activation energy of the ratedetermining step is 87.7 kJ mol-1.When CO2 is present,the linear CO2 is first transferred to active CO2 in a triplet state,and then combines with active S to form COS with the highest energy barrier of 142.4 kJ mol-1.Rate constants at different temperatures show that the formation of COS via the reaction of CO and H2S is easier than that of CO2 and H2S over the ZnO surface.