The Adsorption Behavior Of Co, O, Oh On Pt-Vased Alloys And B₁₂N₁₂ For Hydrogen Stor-Ge: A Density Functional Theory Study

In this work, the adsorption behaviors of CO, O, and OH on the surfaceof Pt based alloys have been systematically investigated by using firstprinciples calculations based on density functional theory, providing atheoretical investigation for the design and application of electrode catalyst inproton exchange membrane fuel cell. In addition, the hydrogen storageproperty of Li decorated B₁₂N₁₂cage has also been studied. The mainconclusions can be summarized as follows:（1）The adsorption energy and configuration of CO on the surfaces of Pt（111）, Ni（111）, and six kinds of Pt/Ni alloys （namely, Pt₃Ni （111）, PtNi （111）,PtNi₃（111）, Pt（111） skin Pt₃Ni, subsurface, surface） have been calculated.The results show thatthe CO adsorption ability on different surfaces mentionedabove has the order of the sequence subsurface<Pt（111） skin Pt₃Ni<Pt₃Ni（111）<PtNi（111）<Pt（111）<PtNi₃（111）<Ni（111）<surface.Therefore, the Pt/Ni alloywith subsurface structure has a good tolerance to CO.（2） The adsorption behavior of O and OH on the surfaces of Pt （111）, Ni（111）, and six kinds of Pt/Ni alloys have been studied, including the d band center （ε d）, local density of states （LDOS）, and stability （U）. The resultsindicate that there is a linear dependence betweenε dand adsorption energy,and the subsurface alloy possesses the weakest O and OH adsorption strength,which can be explained directly from theε dshift away from Fermi level byanalyzing LDOS. Moreover, in case of O atom adsorption and without O atomadsorption, subsurface is the most stable one.（3） The adsorption behavior of O on the catalyst surface of3d transitionmetals （M=Co, Cr, Fe, Ni, Mn, Ti, V and Sc） doped Pt₃M（111）, Pt（111） skinPt3M, and Pt（111） subsurface have been investigated.The results show that theadsorp tion strength of O displays in the order of Pt（111） subsurface<Pt（111）skin P_t3M<Pt₃M（111）, except Cr and V.（4） Hydrogen storage behavior inside of B₁₂N₁₂cage and outside LiB₁₂N₁₂have been investigated. Inside the B₁₂N₁₂cage, the adsorbed hydrogen prefersto remain the molecular form and the B₁₂N₁₂cage could adsorb five H2molecules. It is found that B₁₂N₁₂cage could adsorb three Li atoms. Ourresults show that the total maximum hydrogen storage capacity of theLi3B₁₂N₁₂cage is9.1wt.%.