title: New insights from microcalorimetry on the FeOx/CNT-based electrocatalysts active in the conversion of CO2 to fuels.
abstract: Fe oxide nanoparticles show enhanced electrocatalytic performance in the reduction of CO(2) to isopropanol when deposited on an N-functionalized carbon nanotube (CNT) support rather than on a pristine or oxidized CNT support. XRD and high-resolution TEM were used to investigate the nanostructure of the electrocatalysts, and CO(2) adsorptive microcalorimetry was used to study the chemical nature of the interaction of CO(2) with the surface sites. Although the particles always present the same Fe(3)O(4) phase, their structural anisotropy and size inhomogeneity are consequences of the preparation method of the carbon surface. Two types of chemisorption sites have been determined by using microcalorimetry: irreversible sites (280 kJ mol(-1)) at the uncoordinated sites of the facets and reversible sites (120 kJ mol(-1)) at the hydrated oxide surface of the small nanoparticles. N-Functionalization of the carbon support is advantageous, as it causes the formation of small nanoparticles, which are highly populated by reversible chemisorbing sites. These characteristic features correlate with a higher electrocatalytic performance.
authors.affiliation: Fritz-Haber-Institut der Max-Planck Gesellschaft, Abteilung Anorganische Chemie, Berlin, Germany. arrigo@fhi-berlin.mpg.de
authors.forename: Rosa
authors.initials: R
authors.lastname: Arrigo
authors.forename: Manfred E
authors.initials: ME
authors.lastname: Schuster
authors.forename: Sabine
authors.initials: S
authors.lastname: Wrabetz
authors.forename: Frank
authors.initials: F
authors.lastname: Girgsdies
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Tessonnier
authors.forename: Gabriele
authors.initials: G
authors.lastname: Centi
authors.forename: Siglinda
authors.initials: S
authors.lastname: Perathoner
authors.forename: Dang Sheng
authors.initials: DS
authors.lastname: Su
authors.forename: Robert
authors.initials: R
authors.lastname: Schlögl
mesh_terms: D019840:2-Propanol / Q000138:chemical synthesis*; D002151:Calorimetry / Q000379:methods; D002245:Carbon Dioxide / Q000737:chemistry*; D002384:Catalysis; D005290:Ferric Compounds / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D037742:Nanotubes, Carbon / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D005290:Ferric Compounds; D037742:Nanotubes, Carbon; D002245:Carbon Dioxide; C000499:ferric oxide; D019840:2-Propanol