TOF‐SIMS studies of intercalated Gibbsite and Bayerite

TLDR: In this paper, a base-hydrolyzed solution of FeCl 3 was used to induce intercalation between the Al/O octahedral layers of the Gibbsite structure and the effects of modification were examined in the TOF-SIMS spectra.

Abstract: Surface studies of the oxides and hydroxides of aluminum by TOF-SIMS have raised the question of the origin of large fragment ions observed in these spectra at masses well beyond 2000 Daltons. The larger fragment ions, especially in the negative secondary ion spectra, are simple net singly charged (based on stoichiometry) combinations of Al, 0 and OH. To investigate the origin of these fragments, the layered aluminum hydroxide Gibbsite has been modified to induce changes in interlayer bonding. A base-hydrolyzed solution of FeCl 3 was used to induce intercalation between the Al/O octahedral layers of the Gibbsite structure and the effects of modification were examined in the TOF-SIMS spectra. The spectra of Fe-modified Gibbsite are dominated by two major families of (Al 2 O 3 ) x OH - and (Al 2 O 3 ) x AlO 2 - fragments, while those of the unmodified material exhibit additional intermediate fragments attributed to the sampling of multiple octahedral layers. The intercalation of Fe 2 O 3 also causes morphological and structural changes to the Gibbsite particles. Similar modification of another layered aluminum hydroxide, Bayerite, grown on metal surfaces, also removes these intermediate groups, but introduces new iron-based families of repeating fragments. These studies indicate the repeating fragments observed in the SIMS spectra are sensitive to modification of interlayer bonding in these structures.