Synthesis of ammonium and sulfate ion-functionalized titanium dioxide for photocatalytic applications

Abstract

Due to high band gap energy the optimum photocatalytic activities can only be achieved under UV light, thus limiting the practical application of TiO 2 . In this study, a method combining NH 4? /SO 4 2--functionalization technique and post-treatment was developed and successfully applied to synthesize photoactive TiO 2 samples which showed higher photocatalytic activity than the commercial P25 TiO 2 under visible light radiation. The results also showed that the addition of (NH 4 ) 2 SO 4 surface functionalization on TiO 2 increased the photocatalytic activity, which could be due to the combined effect of crystallinity and band gap energies. Moreover, the results showed that calcination temperature was inversely proportional to photocatalytic activity. The degradation efficiency for methylene blue under visible light was improved by *2 times from 10.7% for P25 nano Degussa TiO 2 to 20.2% for the synthesized sample. The band gap energies were also reduced from 3.7 to 3.4 eV (under UV-Vis direct transition mode) indicating a red shift towards higher wavelength.

Enhanced thermal conductivity of copper‐doped polyethylene glycol/urchin‐like porous titanium dioxide phase change materials for thermal energy storage

“…The peak at 842 cm −1 corresponds to the C–H deformation vibration (Figure A) . The characteristic absorptions at 3411 and 1621 cm −1 are attributed to the –OH vibrations of TiO 2 and water molecules . The peak at 559 cm −1 was denoted the Ti–O–Ti stretching vibration (Figure B) .…”

“…41 The characteristic absorptions at 3411 and 1621 cm −1 are attributed to the -OH vibrations of TiO 2 and water molecules. 43 The peak at 559 cm −1 was denoted the Ti-O-Ti stretching vibration ( Figure 5B). 44 Compared with the peaks of PEG and TiO 2 , the FT-IR spectra of PEG/TiO 2 porous composite PCMs clearly displayed the characteristic peaks of both PEG and TiO 2 , suggesting that the urchin-like porous TiO 2 sphere was filled with PEG polymer (Figures 5C and S5a-f).…”