Mössbauer spectroscopy of frozen solutions as a stepwise control tool in preparation of biocompatible humic-stabilized feroxyhyte nanoparticles

Quasi-2D Co3O4 nanoflakes as an efficient gas sensor versus alcohol VOCs

“…The results are assembled in Table 1. 63 The full width at half maximum indicates a decrease of broadening in about 3 times with the rise of the annealing temperature what is especially pronounced for (311) plane in accordance with enhancing a crystal size. While the material deposited on electrode comprises agglomerated nanoflakes, we have further utilized TEM to observe the structure of single flakes that were drop-casted from isopropanol suspension of material picked from the electrode just after the deposition and following the annealing at 300 °C.…”

Key Roles of Size and Crystallinity of Nanosized Iron Hydr(oxides) Stabilized by Humic Substances in Iron Bioavailability to Plants

“…The photosynthetic activity of test-plants was measured at the seventh day of growing period using light response curves. 38 Rapid light curves (RLC) of chlorophyll fluorescence (nominally, apparent relative electron transport rate (rETR) vs amount of photosynthetically active radiation (PAR)) were recorded using an Imaging-PAM M-Series Chlorophyll Fluorometer (Heinz Walz GmbH, Germany) after preliminary dark adaptation of the plants for 1 h. RLCs were plotted using 12 actinic increasing light levels (4,14,24,59,204,334,414,504,604,714,834, and 964 μmol photons m −2 s −1 ). The RLCs were modeled using the following equation: 38…”

“…44 The distribution functions of the parameters calculated from δ'-FeOOH-HS spectra at the both temperatures are consistent with the data for feroxyhyte. 24,43 A lower value of the hyperfine magnetic field may be associated with the absence of the magnetic field saturation and the small particle size. Hence, it can be concluded that the δ'-FeOOH sample contains feroxyte NPs in the magnetically ordered crystalline state.…”

“…21 Our studies have shown substantial size reduction of feroxyhyte NPs from submicron sizes (300−400 nm) down to 20−30 nm in the presence of HS traces under conditions of rapid oxidations, and the formed NPs maintained crystalline character. 23,24 However, a use of high HS:Fe ratios and slow oxidation rates yielded highly amorphous iron-HS compounds represented by iron (hydr)oxides NPs with sizes from 5 to 20 nm. 25 Hence, the presence of HS in soils favors formation of iron (hydr)oxide particles which are much smaller in size and less crystalline as compared to those formed by the processes unaffected by HS.…”