4 research outputs found
Sustainable Chemical Synthesis for Phosphorus-Doping of TiO<sub>2</sub> Nanoparticles by Upcycling Human Urine and Impact of Doping on Energy Applications
Recently,
there has been significant research interest toward sustainable
chemical synthesis and processing of nanomaterials. Human urine, a
pollutant, requires energy intensive processing steps prior to releasing
into rivers and oceans. Upcyling urine has been proposed and practiced
as a sustainable process in the past. Doping is one of the foremost
processes to elevate the functionality of nanomaterials depending
on the applications it is sought for. Phosphorus doping in to TiO<sub>2</sub> nanomaterials has been of research interest over a decade
now, that has been chiefly done using acidic precursors. Here we demonstrate,
upcycling urine, a sustainable process for phosphorus doping into
TiO<sub>2</sub> lattice. Upon doping the changes in morphology, surface
chemistry and band gap is studied in detail and compared with undoped
TiO<sub>2</sub> that is prepared using deionized water instead of
urine. X-ray photoelectron spectroscopy confirmed that the P was replacing
Ti in the lattice and exists in P<sup>5+</sup> state with a quantified
concentration of 2.5–3 at %. P-doped nanoparticles were almost
50% smaller in size with a lower concentration of surface −OH
groups and a band gap increase of 0.3 eV. Finally, impact of these
changes on energy devices such as dye-sensitized solar cells and li-ion
batteries has been investigated. It is confirmed that P-doping induced
surface chemical and band gap changes in TiO<sub>2</sub> affected
the solar cell characteristics negatively, while the smaller particle
size and possibly wider surface channels improved Li-ion battery performance