Investigation of trimethylacetic acid adsorption on stoichiometric and oxygen-deficient CeO2(111) surfaces.

We studied the interactions between the carboxylate anchoring group from trimethylacetic acid (TMAA) and CeO2(111) surfaces as a function of oxygen stoichiometry using in situ X-ray photoelectron spectroscopy (XPS). The stoichiometric CeO2(111) surface was obtained by annealing the thin film under 2.0 × 10(-5) Torr of oxygen at ∼550 °C for 30 min.

Enzyme-free detection of hydrogen peroxide from cerium oxide nanoparticles immobilized on poly(4-vinylpyridine) self-assembled monolayers.

A simple enzyme-free spectrophotometric detection of hydrogen peroxide is demonstrated based on its colorimetric reaction with oxygen deficient cerium oxide nanoparticles (CNPs). This colorimetric sensitivity of CNPs towards HO increases significantly with decreasing crystallite size due to an increase in the surface area as well as the concentration of Ce on the surface. The origin of this colorimetric reaction was studied using DFT that suggests the adsorption of peroxide and oxygen molecules on ceria nanoparticles creates new states in the electronic structure leading to transitions absorbing in the visible region of the electromagnetic spectrum.