Oxidation of Supported Nickel Nanoparticles at Low Exposure to O2: Charging Effects and Selective Surface Activity

Abstract

The oxidation of Ni nanoparticles supported on highly oriented pyrolytic graphite was investigated under conditions of low exposure to oxygen by methods of scanning tunneling microscopy and spectroscopy. It was found that charge transfer effects at the Ni-C interface influenced the surface activity of the nanoparticles. The O2 dissociation and the Ni oxidation were shown to occur only at the top of the nanoparticle, while the border of the Ni-C interface was the less preferable area for these processes. The O2 dissociation was inhibited, and atomic oxygen diffusion was suppressed in the given nanosystem, due to the decrease in holes concentration.

Less and Less Noble: Local Adsorption Properties of Supported Au, Ni, and Pt Nanoparticles

“…A region is formed along the perimeter where the nanoparticle retains the former electronic structure of the metallic type. The experiment completely reproduces the results of our previous work, where we assumed that this locality of oxide formation is due to the excessive charge of the nanoparticle and its influence on oxygen diffusion [27]. However, several factors are most likely to work here, as in the case of gold.…”

“…This was proven in experiments with N2O, which dissociates at room temperature on platinum nanoparticles and is quickly followed by stable Pt-O formation. In the case of nickel nanoparticles, we did not manage to observe any intermediate forms of oxygen adsorption against the background of oxide formation [27].…”

“…For hydrogen adsorption on gold nanoparticles, these stages are quickly followed by chemisorption [17,18]. The same takes place for oxygen adsorption on nickel nanoparticles, which leads to oxide formation [27]. Only in the case of oxygen adsorption on platinum nanoparticles did we manage to observe some chaotic changes of the VAC curves.…”

Comparison activity of pure and chromium-doped nickel oxide nanoparticles for the selective removal of dyes from water

“…Among these different types of semiconductors, nickel oxide (NiO), this oxide exists in a deformed form because of the existence of excess oxygen atoms, and this leads to the formation of holes among the neighbouring ions of Ni 2+ ions, thus lead to the oxidation of nickel ions from (Ni 2+ to Ni 3+ ). Generally, changes in the color of this oxide result from this process 28 . In heterogeneous photocatalytic systems, nickel oxide can be employed singly or in combination with a supported co-catalyst.…”

Reduction of copper oxides by carbon monoxide at an applied potential

“…35 Recent experimental studies have demonstrated the influence of an external constant electric field (or the applied potential, which is equivalent to the electric field) to various types of reactions: the processes of hydrogen reduction of oxidized platinum, 36 hydrogen chemisorption on gold nanoparticle surfaces, 37,38 decomposition of ammonia on organoboron nanoparticles 39 and platinum nanoparticles, 40 and hydrogenation of ethylene on a nanostructured platinum coating. 41 The premise of the presented study was work, 42 which established the influence of an external electric field on the processes of reduction of an oxidized copper nanoparticles surface interacting with carbon monoxide by the methods of scanning tunneling microscopy and spectroscopy.…”