Metal loading determines the stabilization pathway for Co2+ in titanate nanowires: ion exchange vs. cluster formation.
Co nanoparticles were produced and characterized on protonated titanate nanowires. Co deposits were obtained after low-temperature decomposition of Co2(CO)8 on titanate nanostructures. The carbonylation was carried out by vapor-phase adsorption in a fluidized bed reactor and the decarbonylation processes were followed by FT-IR spectroscopy and microbalance combined with temperature programmed reaction mass spectrometry. The band gap of Co-decorated titanate nanostructures determined by UV-VIS diffuse reflectance spectroscopy decreased sharply from 3.14 eV to 2.41 eV with increasing Co content up to 2 wt%. The Co-decorated titanate morphology was characterized by high-resolution transmission electron microscopy (HRTEM) and electron diffraction (ED). The chemical environment of Co deposition was studied by photoelectron spectroscopy (XPS). A certain amount of cobalt underwent an ion exchange process. Higher cobalt loadings led to the formation of nanosized-dispersed particles complexed to oxygen vacancies. The average sizes were found to be mostly between 2 and 6 nm. This size distribution and the measured band gap could be favorable regimes for some important low-temperature thermal- and photo-induced catalytic reactions.
Department of Applied and Environmental Chemistry, University of Szeged, Hungary.
D
D
Madarász
G
G
Pótári
A
A
Sápi
B
B
László
C
C
Csudai
A
A
Oszkó
Á
Á
Kukovecz
A
A
Erdőhelyi
Z
Z
Kónya
J
J
Kiss
D003035:Cobalt / Q000737:chemistry*; D007474:Ion Exchange; D007477:Ions / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D053770:Nanowires / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014025:Titanium / Q000737:chemistry*
D007477:Ions; D003035:Cobalt; D014025:Titanium