A Bruker D8 DaVinci powder
X-ray diffractometer was used for analysis of powders uniformly placed
on glass slides (Cu Kα, 0.0504°/s step). XPS was performed
on a Kratos Axis Ultra XPS (Al Kα) with samples mounted on carbon
tape. XPS peak analysis was performed using CasaXPS software (www.casaxps.com ). ICP–OES
(PerkinElmer Optima DV 7000) was used for bulk elemental analysis.
Samples were dissolved in a heated 5:1 mixture of concentrated H2SO4:HNO3 and diluted with 5% HNO3. Calibration standards were prepared from 1000 ppm commercial
ICP standards for Ti, Co, Cu (Alfa Aesar), and Ni (Fluka). UV–vis
DRS spectra were collected on a Cary 5000 Series spectrophotometer
(300–800 nm, 10 nm/s). Raw reflectance data were converted
to Kubelka–Munk units [F(R)], and band gaps were calculated using [F(R) × E]1/2 extrapolations
of linear regions of the curve. SEM images were collected on a Hitachi
S-4800 FE-SEM with an accelerating voltage of 1.3 kV. Samples were
mounted on aluminum stubs using carbon tape and were not coated prior
to analysis. BET surface area measurements were collected on a Quantachrome
NOVA 1200 using approximately 50 mg of solid sample.
X-ray diffractometer was used for analysis of powders uniformly placed
on glass slides (Cu Kα, 0.0504°/s step). XPS was performed
on a Kratos Axis Ultra XPS (Al Kα) with samples mounted on carbon
tape. XPS peak analysis was performed using CasaXPS software (
(PerkinElmer Optima DV 7000) was used for bulk elemental analysis.
Samples were dissolved in a heated 5:1 mixture of concentrated H2SO4:HNO3 and diluted with 5% HNO3. Calibration standards were prepared from 1000 ppm commercial
ICP standards for Ti, Co, Cu (Alfa Aesar), and Ni (Fluka). UV–vis
DRS spectra were collected on a Cary 5000 Series spectrophotometer
(300–800 nm, 10 nm/s). Raw reflectance data were converted
to Kubelka–Munk units [F(R)], and band gaps were calculated using [F(R) × E]1/2 extrapolations
of linear regions of the curve. SEM images were collected on a Hitachi
S-4800 FE-SEM with an accelerating voltage of 1.3 kV. Samples were
mounted on aluminum stubs using carbon tape and were not coated prior
to analysis. BET surface area measurements were collected on a Quantachrome
NOVA 1200 using approximately 50 mg of solid sample.