Tatyana Yu. Kardash

On the effect of Cu on the activity of carbon supported Ni nanoparticles for hydrogen electrode reactions in alkaline medium

Effects of adding varied amounts of copper to carbon-supported nickel particles on their structure, composition and electrocatalytic activity for the hydrogen oxidation and evolution reactions in alkaline medium have been explored. Ni1-xCux/C catalysts were prepared by the incipient wetness impregnation. Comprehensive characterization of the catalysts included X-ray powder diffraction, X-ray photoelectron spectroscopic, transmission electron microscopic and cyclic voltammetric analyses, while atomistic Monte Carlo simulations have been undertaken to obtain further insights into the structure of the bimetallic NiCu nanoparticles. We found that compared to monometallic Ni, NiCu nanoparticles show lower propensity towards oxidation under ambient conditions. Furthermore, we report that adding Cu allows increasing the surface-weighted electrocatalytic activity, and the specific surface area of Ni1-xCux/C electrodes, both contributing to a ca four-fold enhancement of the mass-weighted activity. The nature of the synergistic interactions between Ni and Cu is proposed on the basis of the analysis of experimental data and Monte Carlo structural modelling results.

Direct CO2 capture from ambient air by K2CO3/alumina composite sorbent for synthesis of renewable methane

Abstract A composite sorbent was synthesized by impregnating cylindrical granules of mesoporous γ-Al2O3 with an aqueous solution of K2CO3. Three fractions of the composite with the

Transformation of a Pt-CeO2 Mechanical Mixture of Pulsed-Laser-Ablated Nanoparticles to a Highly Active Catalyst for Carbon Monoxide Oxidation

The pulsed laser ablation (PLA) in alcohol and water media was employed to prepare Pt and CeO2 PLA‐nanoparticles of different sizes and degrees of defectiveness. Interactions of metallic platinum and ceria particles were studied using the thermal activation of Pt–CeO2 mechanical mixtures in the CO+O2 reaction medium or O2 atmosphere. The thermal activation resulted in oxidized Pt2+/Pt4+ states of platinum in the surface solid solutions PtCeOx and/or PtOx clusters. Catalysts formed after calcination of the PLA‐ablated Pt–CeO2 mixtures in oxygen at 450–600 °C revealed CO conversion at very low temperatures up to 70 % depending on the conditions of PLA particles preparation and thermal activation of Pt–CeO2 mechanical mixture.

The influence of CuO dispersion on catalytic properties in the CO oxidation: a comparative studies in two types of catalytic reactors

The catalytic properties of copper(II) oxide powders were studied in the CO oxidation reaction by using plug‐flow and flow‐circulation reactors. Data obtained from different catalytic experiments were in good agreement with each other. The specific catalytic rate [molecules cm−2 s−1] increased by a factor of approximately four if the surface area of the CuO powder was reduced from 90 to 8 m2 g−1. A further decrease in the CuO surface area to 1 m2 g−1 resulted in the decrease of the specific CO oxidation rate by more than 20‐fold. These results indicate that CO oxidation is sensitive to the structure of the copper(II) oxide catalyst. The structural sensitivity of CuO powders was discussed in terms of its defect structure and particle morphology.