Adsorption of hydrogen gas on polymorphic zirconium dioxide surfaces

Abstract

Adsorption of hydrogen gas on polymorphic zirconium dioxide (ZrO2) surfaces including cubic, tetragonal and monoclinic phase denoted by c-ZrO2(111), t-ZrO2(101) and m-ZrO2(111), respectively has been investigated using the periodic density functional theory (DFT) calculation. The stabilities of perfect and oxygen vacancy defective ZrO2 surfaces are in orders: c-ZrO2(111) > t-ZrO2(101) > m-ZrO2(111) and [c-ZrO2(111)+VO] > [t-ZrO2(101)+VO] > [m-ZrO2(111)+VO], respectively. The abilities of hydrogen adsorption on perfect and oxygen vacancy defective ZrO2 surfaces are in orders: [c-ZrO2(111)+VO] (∆Eads = –4.13 eV) > [m-ZrO2(111)+VO] (∆Eads = –3.31 eV) > [t-ZrO2(101)+VO] (∆Eads = –2.91 eV) > c-ZrO2(111) (∆Eads = –1.89 eV) > m-ZrO2(111) (∆Eads = –1.67 eV) > t-ZrO2(101) (∆Eads = –0.27 eV). The lanthanide-doped c-ZrO2(111) surfaces were obtained and exhibit hydrogen adsorption stability. Hydrogen adsorption ability on Eu-[c-ZrO2(111)+VO] (∆Eads = –0.80 eV)is higher than on Ce-[c-ZrO2(101)] (∆Eads = –0.21 eV). The oxygen vacancy defective polymorphic ZrO2 surfaces exhibit a high potential for hydrogen-storage materials. The [t-ZrO2(101)+VO], [m-ZrO2(111)+VO] and m-ZrO2(111) surface types have been recommended as hydrogen-sensing materials via electrical resistance measurement.