Surface Reactivity and Surface Characterization of the Layered β(III)-CoOOH Material: an Experimental and Computational Study

Abstract

In this article, we focused on the comprehension of the surface reactivity of layered β­(III)-cobalt oxyhydroxide, β­(III)-CoOOH, by implementing a multiscale study associating both experimental, surface characterization by X-ray photoemission spectroscopy (XPS) and scanning electron microscopy and first-principles calculations. The surface reactivity and the chemical properties of the surface are key factors in the charge-storage mechanism, and β­(III)-CoOOH presents interesting characteristics to be used as pseudo-capacitive electrode materials in supercapacitors thanks to its large surface specific area (∼100 m2/gs) and its high electronic conductivity (10–3 to 1 S cm–1). The surface reactivity (basic and redox character) of the synthesized compounds, which consists in aggregates of particles with 60–100 nm length, has been explored from the adsorption of SO2 molecules followed by XPS analyses. A kinetic study of the reactivity allowed us to identify three steps in the adsorption mechanism of our β­(III)-CoOOH samples. The coupling of XPS and computational results allows us to establish a link between the surface reactivity in the identified domains, the formation of sulfate and sulfite species, and the cobalt Co3+ and Co4+ species of the active sites along with the underlying electronic processes.

Two [Co(bipy)3]3+-Templated Silver Halobismuthate Hybrids: Syntheses, Structures, Photocurrent Responses, and Theoretical Studies

“…As shown in Figure b, the high-resolution Co 2p spectrum presented two single peaks with the binding energies at 782.4 and 797.3 eV, corresponding to the Co 2p 3/2 and Co 2p 1/2 states, respectively. This is the characteristic signal of the Co 3+ species, whose binding energy values are well close to the data from the literature, such as [Co­(en) 3 ]­V 3 O 9 ·H 2 O, β-CoOOH, Tb­(DMF) 4 (H 2 O) 3 Co­(CN) 6 ·H 2 O, and [Co­(NH 3 ) 6 ]­C1 3 . − In addition, the satellite peaks at about 786.0 and 803.0 eV can hardly be observed, which further excludes the possibility of the Co 2+ species in compound 1 . , Figure c displays two components occurring at 367.9 and 373.9 eV that can be attributed to characteristic signals from the Ag + species. These binding energies are normal and compared well with those of some silver-containing metal halides (e.g., [Fe­(phen) 3 ]­AgPb 2 I 7 and [Fe­(phen) 3 ] 2 Ag 3 Pb 2 I 11 ) .…”

Two Silver Halobismuthate Hybrids Decorated by Photosensitive Metal Complexes: Syntheses, Structures, Photoelectric Properties, and Theoretical Studies

“…For compound 1 , the high-resolution Co 2p spectrum contains two distinct peaks, with the binding energies centered at 782.4 and 797.4 eV, respectively (Figure b). These are characteristic signals from the Co 3+ species, whose binding energy values compare well with the results found in [Co(bipy) 3 ] 2 Ag 4 Bi 2 Br 16 , [Co(en) 3 ]V 3 O 9 ·H 2 O, [Co(NH 3 ) 6 ]Cl 3 , and β-CoOOH. ,− The doublet of 367.9 and 374.0 eV in compound 1 may correspond to the Ag 3d 5/2 and 3d 3/2 states, which blue shifts by about 0.1 and 0.2 eV compared to compound 2 (Figure c). A similar situation also occurs in the case of the high-resolution Bi 4f pattern, indicating the different electron cloud densities existing in compounds 1 and 2 .…”

Controlled Nanostructuration of Cobalt Oxyhydroxide Electrode Material for Hybrid Supercapacitors

“…The presence of ionic liquid tethered to the final cobalt oxyhydroxides was detected by X-ray photoelectron spectroscopy and confirmed by infrared analyses (Supplementary Figure S2). Indeed, the β3-pH14 and β3-pH↗ survey spectra (Figure 5) presented signatures of cobalt, oxygen and sodium elements (with Co 2p, O 1s and Na 1s core peaks) assigned to β3 cobalt oxyhydroxide [46]. C 1s core peak is related to adventitious carbon and Cl 2p to synthesis residue.…”