Open AccessStudy on the structural evolution of SiO2 extracted from Sidoarjo mud
Author(s) -
Devita Rachmat,
Doty Dewi Risanti
Publication year - 2019
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/588/1/012032
Subject(s) - materials science , tridymite , annealing (glass) , band gap , amorphous solid , analytical chemistry (journal) , triclinic crystal system , thermogravimetric analysis , phase (matter) , fourier transform infrared spectroscopy , transmittance , diffraction , cristobalite , mineralogy , crystallography , crystal structure , optics , chemistry , composite material , quartz , optoelectronics , organic chemistry , physics , chromatography
Sidoarjo mud is known to have a large amount of silica mineral i.e 44.8% with a purity of 88.4 to 95.7%. In this study, the annealing process in extracted silica was carried out for 5 hours to observe the structural changes at 800°C, 1000°C and 1150°C. Thermogravimetric analysis of extracted silica shows that glass temperature transition (Tg) occurs at onset temperature of 800°C and crystalline phase take places at above 1150°C. The results are confirmed by X-Ray Diffraction (XRD). It indicates that there is a transformation phase of amorphous SiO 2 to triclinic crystalline structure with increasing amount of tridymite phase as the temperature increases from 800°C up to 1150°C. The changes in SiO 2 phase structure are also confirmed by FTIR results that show a transmittance shift of Si-O bending band slightly to lower wavenumbers and increasing transmittance intensity of Si-O stretching bonds as the heating treatment temperature is increased. Based on the UV-Vis results, the optical band gap shows no dependencies on heat treatment temperature, whereas the Urbach energy is proportional to the increasing temperature, in which SiO 2 sample heated at 800°C has the lowest Urbach energy or the fewer defects. Urbach energy values of extracted silica are ranging from 7.91-17.33 eV. In accordance with Urbach energy, the DSSC with photoanode containing SiO 2 heated at 800°C shows the best performance with efficiency of 0.077 %.