Montserrat Domínguez

Fast and efficient hydrogen generation catalyzed by cobalt talc nanolayers dispersed in silica aerogel

Cobalt talc nanolayers dispersed in silica aerogel constitute an active nanocomposited material with outstanding catalytic properties for the generation of hydrogen by ethanol steam reforming at low temperature. Delamination of talc particles into individual nanolayers of ca. 1.8 nm thick readily occurs under the reforming conditions, which results in a strong enhancement of the exposed catalytic active area. The presence of aerogel assures the immobilization of the talc nanolayers resulting from the delamination while maintaining an excellent mass transfer of products and reactants to the surface of the talc nanolayers. A fast and reversible surface activation for the steam reforming of ethanol occurs at 580–590 K under the reforming conditions. Magnetic characterization and in situ X-ray photoelectron spectroscopy (XPS) show the non-reversible formation of metal cobalt ensembles during activation, which escape HRTEM detection. This material appears as a good candidate for on-board hydrogen generation from ethanol–water mixtures for mobile and portable fuel cell applications.

Simultaneous in situ generation of hydrogen peroxide and Fenton reaction over Pd–Fe catalysts

High mineralization degree of organic compounds can be achieved by a novel environmentally-friendly full heterogeneous Pd-Fe catalytic system, which involves in situ generation of hydrogen peroxide from formic acid and oxygen, and oxidation of organic compounds by Fenton process in a one-pot reaction.

Selective liquid phase benzyl alcohol oxidation over Cu-loaded LaFeO3 perovskite

Copper loaded LaMO3 (M = Mn, Fe and Co) perovskites have been synthesized by a single-step solution combustion method. These materials have been investigated for liquid phase oxidation of benzyl alcohol using tertiary butyl hydrogen peroxide (TBHP) as oxidant in air at 80 °C under ambient pressure. Among these, the 10 at% Cu-loaded LaFeO3 has shown the best activity i.e., ∼99% conversion with complete benzaldehyde selectivity. The formation of perovskite phase was confirmed from XRD and the presence of Cu2+ was confirmed by XPS analysis. The higher activity of the combustion synthesized catalyst has been ascribed to the presence of a poorly defined surface structure containing an amorphous CuO phase wrapping the LaFeO3 particle, as evidenced from the HRTEM analysis. The catalyst recycling tests have shown a negligible loss of activity in the consecutive cycles.

Single step combustion synthesized Cu/Ce0.8Zr0.2O2 for methanol steam reforming: Structural insights from in situ XPS and HRTEM studies

Abstract Single step combustion synthesized Cu (5–15 at.-%)/Ce0.8Zr0.2O2 materials containing highly dispersed copper have been assessed for methanol steam reforming (MSR). The activity patterns suggest Cu (10 at.-%)/Ce0.80Zr0.20O2 as the most active formulation, converting ~51% methanol at 300 °C at a gas hourly space velocity of 40,000 h-1 (W/F = 0.09 s). The in situ XPS experiments carried over the most active sample show a sharp falloff of Cu-surface concentration from a considerably high value of 26% before to 7.4% after the in situ MSR tests and it is associated with the complete reduction of oxidized Cu-species (Cu2+) to metallic copper (Cu0). These findings point to the sintering of copper during MSR which is attributed to be responsible for the deactivation observed with time on stream. Interestingly, the MSR activity is shown to be regenerated nearly completely through an intermediate in situ oxidation step in the consecutive cycles of methanol reforming.

Oxidation by H 2 O(g) in the presence of H 2 (g) of UO 2 doped with Pd nanoparticles

This is a post-peer-review, pre-copyedit version of an article published in Journal of Radioanalytical and Nuclear Chemistry. The final authenticated version is available online at: http://dx.doi.org/10.1007/s10967-018-6217-2.AbstractThis work studies the influence of epsilon particles and metallic precipitates, simulated through the deposition of Pd nanoparticles on non-irradiated UO2, on the oxidation of the spent nuclear fuel (SNF). The presence of Pd nanoparticles favored the reduction by hydrogen of oxidized uranium phases located on the UO2 surface, decreased the oxidation of the UO2 by H2O in the absence of hydrogen, and, in the presence of hydrogen and water vapor, no oxidation of the UO2 by water was detected, contrasting experiments without Pd nanoparticles.

Transforming a Compact Disk into a Simple and Cheap Photocatalytic Nanoreactor

A commercial compact disk has been converted into an effective photocatalytic nanoreactor by depositing a catalyst layer inside the nanochannels by means of an electrophoretic method. The resultant device has been tested for water splitting, obtaining a high yield of hydrogen at an unbeatable low cost.