New Insights from Microcalorimetry on the FeO_x/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.

Electrolyte-less design of PEC cells for solar fuels: Prospects and open issues in the development of cells and related catalytic electrodes

“…Fig. 6 reports a scheme of the assembled electrodes-membrane element of the EL-PEC solar cell, with a picture of the assembly from the electrocatalyst side anda HAADF-STEM (high-angle annular dark field scanning transmission electron microscopy) image for Fe/CNT catalyst (a) with a zoom (b) on the small particles present on the external surface of carbon nanotube (by HRTEM -high resolution transmission electron microscopy) [163]. Fig.…”

“…The presence of N functionalities on the CNT, particularly quaternary graphitic N species, allows changing significantly the heat of chemisorption of CO 2 [163].…”

Engineering in direct synthesis of hydrogen peroxide: targets, reactors and guidelines for operational conditions

“…44,92,113,120,125,126 Palladium as the only metal supported can lead to other conclusions. 42,127,128,134,135 As reported earlier, the research in recent years focused on the oxidation state of Pd, which is a crucial parameter along with the PdAu or Pd-Pt alloying and the support for the metals. The oxidation state of Pd in the bimetallic catalysts (or in the monometallic ones) can be related to the initial formation of H 2 O 2 , but also its sequential hydrogenation.…”

Higher Alcohol Synthesis Over Rh Catalysts: Conditioning of Rh/N-CNTs by Co and Mn Entrapped in the Support

“…Several studies indicated that CNTs are more efficient supports for higher alcohol synthesis [8,[17][18][19][20] than conventional metal oxides such as Al 2 O 3 [21], and SiO 2 [5,9,22]. On the other hand, N-doping of nanocarbons is known to efficiently increase the dispersion of noble metal nanoparticles [17,[23][24][25].…”