title: An attempt to correlate surface physics with chemical properties: molecular beam and Kelvin probe investigations of Ce1-xZrxO2thin films.
abstract: What is the correlation between physical properties of the surfaces (such as surface potential, electronic nature of the surface), and chemical and catalysis properties (such as chemisorption, sticking probability of surface)? An attempt has been made to explore any correlation that might exist between the physical and chemical properties of thin film surfaces. Kelvin probe microscopy (KPM) and the molecular beam (MB) methods were employed to carry out the surface potential, and oxygen adsorption and oxygen storage capacity (OSC) measurements on Ce1-xZrxO2thin films. A sol-gel synthesis procedure and spin-coating deposition method have been applied to make continuous nanocrystalline Ce1-xZrxO2(x = 0-1) (CZ) thin films with uniform thickness (35-50 nm); however, surface roughness and porosity inherently changes with CZ composition. MB studies of O2adsorption on CZ reveal high OSC for Ce0.9Zr0.1O2, which also exhibits highly porous and significantly rough surface characteristics. The surface potential observed from KPM studies varied between 30 and 80 mV, with Ce-rich compositions exhibiting the highest surface potential. Surface potential shows large changes after reduction or oxidation of the CZ film demonstrating the influence of Ce3+/Ce4+on surface potential, which is also a key to catalytic activity for ceria-based catalysts. The surface potential measured from KPM and the OSC measured from MB vary linearly and they depend on the Ce3+/Ce4+ratio. More and detailed studies are suggested to arrive at a correlation between the physical and chemical properties of the surfaces.
authors.affiliation: Catalysis Division, National Chemical Laboratory, Dr Homi Bhabha Road, Pune 411 008, India. cs.gopinath@ncl.res.in and Center of Excellence on Surface Science, National Chemical Laboratory, Dr Homi Bhabha Road, Pune 411 008, India.
authors.forename: Sadhu K
authors.initials: SK
authors.lastname: Kolekar
authors.affiliation: Catalysis Division, National Chemical Laboratory, Dr Homi Bhabha Road, Pune 411 008, India. cs.gopinath@ncl.res.in and Center of Excellence on Surface Science, National Chemical Laboratory, Dr Homi Bhabha Road, Pune 411 008, India.
authors.forename: Anjani
authors.initials: A
authors.lastname: Dubey
authors.affiliation: Department of Applied Physics, Defence Institute of Advanced Technology, Pune 411025, India.
authors.forename: Kalyani S
authors.initials: KS
authors.lastname: Date
authors.affiliation: Department of Applied Physics, Defence Institute of Advanced Technology, Pune 411025, India.
authors.forename: Suwarna
authors.initials: S
authors.lastname: Datar
authors.affiliation: Catalysis Division, National Chemical Laboratory, Dr Homi Bhabha Road, Pune 411 008, India. cs.gopinath@ncl.res.in and Center of Excellence on Surface Science, National Chemical Laboratory, Dr Homi Bhabha Road, Pune 411 008, India.
authors.forename: Chinnakonda S
authors.initials: CS
authors.lastname: Gopinath