Alcohol reactivity is strongly affected by the OH groups. Here, we report the effect of the number and positions of OH groups on the adsorption of C3 molecules on close-packed transition metal surfaces through an ab initio method.
Experimental and theoretical studies have suggested the use of strain effects to design efficient catalysts for direct alcohol fuel cells. However, our atomistic understanding of the adsorption of alcohols on strained transition-metal (TM) catalysts is still far from satisfactory. Here, we report an ab initio investigation based on density functional theory within the van der Waals D3 correction to explore the adsorption properties of methanol, ethanol and glycerol on Pt3Ni(111) alloys under different conditions. For that, we selected five TM substrates, namely, (i) Ni(111), (ii) Pt12Ni4/Pt12Ni4/Ni(111) (compressive strain), (iii) Pt16/Pt8Ni8/Pt3Ni(111) (without strain), (iv) Pt16/Pt8Ni8/Pt(111) (tensile strain) and (v) Pt(111). As expected, the physical and chemical properties of the Pt3Ni thin-layers are affected by the strain induced by the underlayer TM substrate, and hence, we can tune the adsorption properties of alcohols. In general, the magnitude of the alcohol adsorption energy increases in the following order Pt16/Pt8Ni8/Pt3Ni(111) < Pt16/Pt8Ni8/Pt(111) < Pt12Ni4/Pt12Ni4/Ni(111), which correlates with the d-band center and the effective charge on the adsorption sites, i.e., the coulombic contribution plays an important role in the adsorption. Structural and electronic density analyses indicate that, upon adsorption, the O-H and C-H bonds weaken and their breaking should be the first steps in the decomposition of alcohols. From the Bader charge analysis, we found that the TM atom directly below the bonding O loses charge to neighboring atoms, which polarizes the surface and changes the substrate work function. Although a significant enhancement of energetic and structural properties was found, the addition of the D3 correction does not change our qualitative results except for improving the dependence of the adsorption energy with the alcohol size.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.