H2在WO3表面解离吸附反应的第一性原理研究

采用第一性原理方法对H2在WO3表面的解离吸附反应进行了研究.首先通过清洁表面模型的计算,证明了c(2×2)重构表面是最稳定的WO3(001)表面构型;进而研究了4种可能的H2解离吸附模型,结果表明最可能的吸附反应为两个氢原子吸附在表面O1c原子上,氢原子被氧化在表面形成水,同时伴随着产生一个表面氧空位.态密度结果表明氢的吸附导致体系能带下移,导带部分填充电子,从而阐明了实验中WO3吸附H2后电导率上升的微观机理.

First-Principles Study of H2 Dissociative Adsorption Reactions on WO3 Surfaces

The reaction mechanism of H 2 dissociative adsorption on WO 3 surfaces was studied by a first-principles method.Calculations for the clean surface indicated that the c(2×2)reconstruction was the most stable surface geometry.Four H 2 dissociative adsorption models were investigated.The optimal configuration was for two H atoms adsorbed at the terminal O 1c site,followed by water formation and an oxygen vacancy on the surface.The density of states(DOS)results revealed that H 2 dissociative adsorption led to partial filling of the conduction band,which accounted for the increase of WO 3 electrical conductivity upon H 2 exposure.