Reflux Condensation Method Research Articles

Low temperature growth of CuS nanoparticles by reflux condensation method

We report a facile, low-temperature soft solution route to synthesize copper sulfide (CuS) nanomaterials with different morphologies by reflux condensation method. CuS nanomaterials were synthesized without the assistance of additional surfactant or templates, and the influence of key synthetic parameters namely solvent medium and sulfur source on the final structure of CuS was comprehensively investigated. XRD pattern of the synthesized products revealed the formation of hexagonal structure of covellite CuS. SEM analysis showed that the CuS products synthesized in water were ball-like microspheres and the products prepared in ethanol were spherical shaped CuS nanocrystals, but those synthesized in ethylenediamine were flower-like CuS hierarchical network consisting of self-assembled nanoflakes as primary building units. DRS exhibited the characteristics broadband absorption of CuS in near-IR region. The optical band gap of the CuS nanocrystals was in the range between 2.35 eV and 2.81 eV, exhibiting considerable blue shift due to quantum size effects. Electrical resistivity measurements confirmed the semiconducting nature of CuS. On the basis of experimental results, the plausible formation mechanism of different CuS nanostructures was put forward and discussed briefly.

Highly mesoporous α-Fe2O3 nanostructures: preparation, characterization and improved photocatalytic performance towards Rhodamine B (RhB)

Single-crystalline porous hematite nanorods and spindle-like nanostructures were successfully synthesized by a low temperature reflux condensation method. Two different iron sources, namely, FeCl3·6H2O and Fe(NO3)3·9H2O, were hydrolyzed in the presence of urea to selectively prepare nanorods and spindle-like nanostructures. Initially, the akagenite phase was obtained by refluxing the precursor for 12 h and then the as-prepared akagenite nanostructures were transformed to porous hematite nanostructures upon calcination at 300 °C for 1 h. The shape and the aspect ratio of the 12 h refluxed sample was retained even after calcination and this shows the topotactic transformation of the nanostructure. TEM and HRTEM investigations have shown the porous nature of the prepared sample. Brunauer–Emmett–Teller and Barret–Joyner–Halenda measurements have shown a large surface area and distribution of mesopores in the nanorods sample. The photocatalytic activity of the prepared nanostructures towards RhB has reflected this variation in the pore size distribution and specific surface area, by showing a higher activity for the nanorods sample. Magnetic studies by VSM have shown a weak ferromagnetic behaviour in both the samples due to shape anisotropy.