This study aims to synthesize Au/TiO2/Na2Ti6O13 composites to reduce the occurrence of recombination and increase photocatalytic activity in phenol degradation. Gold was used due to its high stability and strong surface plasmon resonance (SPR) properties which make it operate effectively in the visible light spectrum. The prepared composites were characterized using XRD, SEM, TEM, FTIR, and DRS. The results showed that the composite consisted of rutile TiO2 with a crystal size of 38–40 nm and Na2Ti6O13 with a crystal size of 25 nm. The gold in the composite has a crystallite size of 16–19 nm along with the percentage of gold added. Morphological analysis shows that the composite has the form of inhomogeneous spherical particles with gold spread among composites with sizes less than 20 nm. FTIR analysis showed the presence of Na–O and Ti–O–Ti bonds in the composite. The best composite was 3% Au/TiO2/Na2Ti6O13 which had high crystallinity, small particle size, and bandgap energy of 2.59 eV. Furthermore, it had an efficiency 205% better than without gold. After that, cost estimation is proposed as a large-scale application. This study describes the total cost, break-even analysis, and payback analysis for the commercialization needs of the designed photocatalytic catalyst.
Photocatalysis is a process of accelerating reactions that are assisted by energy from light irradiation. Titanium dioxide (TiO2) is one of the most widely developed photocatalysis materials, and is used because of its high catalytic activity, stability and very affordable. The most commonly used precursors of TiO2 are titanium butoxide (TBOT) and titanium tetraisopropoxide (TTIP). These variations in precursor can lead to phase difference in the formation of TiO2 crystals, which further improves its nature in the activity of photocatalysis. In this study, the sol-gel method was used to synthesize titanium dioxide nanoparticles from variations of TBOT and TTIP. Furthermore, the structure, crystallite size and band gap of TiO2 were determined by X-ray diffraction (XRD) and UV-vis reflectance spectroscopy (DRS). Subsequently, TiO2 photocatalytic activity was evaluated in phenol photodegradation as a contaminant model with UV irradiation. The results showed the structure synthesized from TBOT had a higher amount of anatase, higher crystallinity, smaller crystallite size, larger band gap, and better photocatalytic activity than those from TTIP. Furthermore, it was shown that TiO2 from TBOT had an efficiency of 147% greater than TiO2 P25 Degussa, while TiO2 from TTIP had 66% efficiency compared to TiO2 P25.
ZnAl LDH has been successfully prepared as single phase by urea as precipitant. Anion exchange is conducted for Ag(CN) 2 intercalation. After the LDH has been intercalated by Ag(CN) 2-, the anion is reduced into Ag(0) state. The structure of Ag-intercalated LDH was examined by synchrotron XRD. In the sample, the Ag(0) exists at closer position than center between hydroxide layers due to no coordinated H 2 O molecules. UV-vis spectra confirm the existence of surface plasmon resonance at around 380 nm. Finally, the LDH has been examined for its photocatalytic activity by phenol degradation in the aqueous solution with Xe light irradiation. The concentration of phenol is continuously decreased during photocatalyst process by the ZnAl/Ag LDH sample. The degradation rate of the sample is much better than those of the pure LDH and unreduced samples. In this case, phenol solution with the concentration of 20 mg/L can be degraded completely for 120 min.
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