Photocatalytic oxidation of n-octanol in aerated supercritical CO2 on hydrophobic TiO2

Synthesis of TiO2 Photocatalysts in Supercritical CO2 via a Non-hydrolytic Route

“…Photocatalysis of 1-Octanol in scCO 2 . Previous study indicated that moisture in the reaction vessel may result in aggregates and precipitates of hydrophilic TiO 2 from scCO 2 , so the reactions were carried out under very dry conditions. The reaction cell was dried in an oven at 60 °C overnight before being used.…”

“…CO 2 and O 2 were passed through a moisture trap before entering the reaction vessel. Photocatalytic oxidations of 1-octanol in aerated scCO 2 on calcined TiO 2 −Ac, calcined TiO 2 −Fac, and commercial T805 TiO 2 produced the oxidation products (1-octanal and octanoic acid) previously reported. , For comparison, all photocatalytic experiments were carried out under completely identical conditions. Figure shows the dependence of the photocatalytic oxidative conversion of 1-octanol on reaction time upon band gap irradiation of each photocatalyst suspended in aerated scCO 2 .…”

“…The latter vessel was also used for observations of the solubilities of various titanium(IV) precursors in scCO 2 . Details of construction and operation of this high-pressure vessel have been described previously. , …”

“…After each sampling, CO 2 was added to the reaction vessel to maintain the desired reaction pressure, and the GC line was flashed with compressed air or nitrogen to remove any residue of the reactant or products in the sampling system. Further experimental details about such photocatalysis experiments have been described previously. , …”

“…Details of construction and operation of this highpressure vessel have been described previously. 22,23 Characterization. Fourier transform infrared (FTIR) spectra were measured using a Nicolet 510P FTIR spectrometer for samples dispersed in a KBr pellet.…”