Redox Chemistry of Cu Colloids Probed by Adsorbed CO:  An in Situ Attenuated Total Reflection Fourier Transform Infrared Study

Abstract

The IR spectroscopic investigation of both the adsorption of carbon monoxide and the interaction of oxygen and CO on the surface of copper colloids is described for the first time. The copper colloids were produced by pyrolysis of [Cu(OCH(Me)CH(2)NMe(2))(2)] in hot n-hexadecylamine. Upon contact to synthetic air Cu/Cu(x)O core-shell particles are formed. The treatment of these particles with CO results in the reestablishment of pure Cu(0) particles. These results demonstrate that small molecules penetrate the ligand shell of the nanoparticles and reversibly adsorb at the surface without affecting the particle morphology and size distribution.

Selective photo-deposition of Cu onto the surface of monodisperse oleic acid capped TiO2nanorods probed by FT-IR CO-adsorption studies

“…HDA stabilsed CuO x @Cu core shell particles were formed by intentional oxidation and were reduced by dosing CO as well as reoxidation by dosing O 2 was possible without changing the particle size distribution. 16 From literature references it is known, that CO adsorbs at Cu supported at TiO 2 exhibiting several peaks for the different oxidation states of Cu:CO binding to Cu 21 @TiO 2 can be found at around 2150 cm À1 and above, depending on the sample, CO binding at a Cu 1 site was assigned to 2100-2150 cm À1 and finally for CO adsorbed at Cu 0 @TiO 2 peaks at 2100 cm À1 and below were reported. [21][22][23] All these data have been obtained for powder materials synthesized by co-precipitation/ calcination/reduction protocols and/or aqueous salt impregnation recipes using simple inorganic salt precursors for copper, the agglomerated titania support being of course completely insoluble in organic media in contrast to our case here.…”

Ligand‐Capped Pt Nanocrystals as Oxide‐Supported Catalysts: FTIR Spectroscopic Investigations of the Adsorption and Oxidation of CO

“…[12,13] In colloidal solution, it was also shown that CO can penetrate the ligand shell of Cu nanocrystals capped with hexadecylamine. [14] In a study of propene hydrogenation by relatively large (ca. 9 nm) polyacrylate-capped Pt nanoparticles supported on alumina, increased activity was observed when the polymer shell was removed by pretreatment.…”

Ligandenstabilisierte Pt‐Nanokristalle als Katalysatoren auf einem Oxidträger: FT‐IR‐spektroskopische Untersuchungen zur Adsorption und Oxidation von CO

“…[12,13] Auch kann CO in kolloidaler Lösung die Ligandenhülle von mit Hexadecylamin umgebenen Cu-Nanokristallen durchdringen. [14] In einer Studie zur Propenhydrierung durch relativ große (ca. 9 nm), mit Polyacrylaten bedeckte Pt-Nanopartikel, die auf einem Aluminiumoxidträger fixiert waren, wurde eine Zunahme der Aktivität beobachtet, wenn die Polymerhülle zuvor entfernt worden war.…”