Visible light-responsive Fe-loaded TiO2 photocatalysts for total oxidation of acetaldehyde: Fundamental studies towards large-scale production and applications

Annealing Temperature-Dependent Effects of Fe-Loading on the Visible Light-Driven Photocatalytic Activity of Rutile TiO2 Nanoparticles and Their Applicability for Air Purification

“…The formation of acetic acid as an intermediate species on the surface of photocatalysts during the photocatalytic oxidation of acetaldehyde into CO 2 was previously reported [28][29][30]. The previous results indicated that the reaction rate of acetic acid oxidation into CO 2 was slower than that of acetic acid formation from acetaldehyde, which can result in the CO 2 selectivity being higher than 100% at longer reaction times [28][29][30].…”

“…For instance, in the presence of Fe-TiO 2 -375 samples, the concentration of gaseous CO 2 continued to increase even after 410 min when the acetaldehyde concentration in the reactor reached zero (Figure 2a,b). This phenomenon can occur when gaseous acetaldehyde is first removed by partial oxidation on the surface of a photocatalyst, and the partially oxidized species is later oxidized into CO 2 by a longer exposure to light [28][29][30]. The formation of acetic acid as an intermediate species on the surface of photocatalysts during the photocatalytic oxidation of acetaldehyde into CO 2 was previously reported [28][29][30].…”

“…However, rutile TiO 2 exhibits a smaller band gap (~3.0 eV) than anatase TiO 2 , which makes rutile TiO 2 a possible candidate base material for developing visible-light-responsive photocatalysts [25][26][27]. Recently, we demonstrated that the anatase-to-rutile phase transition of commercial TiO 2 particles (P25, Evonik), which originally consisted of both anatase and rutile phases in an 8:2 ratio, could enhance the photocatalytic activity regarding acetaldehyde oxidation under visible light irradiation [28]. The anatase-to-rutile transformation was achieved by thermal annealing at 750 • C, and the visible-light response of the rutile TiO 2 can be further enhanced by the small loading of Fe-oxide via the temperature-regulated chemical vapor deposition (tr-CVD) [28].…”

“…Recently, we demonstrated that the anatase-to-rutile phase transition of commercial TiO 2 particles (P25, Evonik), which originally consisted of both anatase and rutile phases in an 8:2 ratio, could enhance the photocatalytic activity regarding acetaldehyde oxidation under visible light irradiation [28]. The anatase-to-rutile transformation was achieved by thermal annealing at 750 • C, and the visible-light response of the rutile TiO 2 can be further enhanced by the small loading of Fe-oxide via the temperature-regulated chemical vapor deposition (tr-CVD) [28]. Previous results also showed that the amount of Fe-loading was an important factor in determining the photocatalytic activity of Fe-loaded rutile TiO 2 under visible light, since the formation of larger Fe-oxide particles on the surface of TiO 2 can facilitate the non-radiative recombination of light-induced electron-hole pairs [28].…”

“…The anatase-to-rutile transformation was achieved by thermal annealing at 750 • C, and the visible-light response of the rutile TiO 2 can be further enhanced by the small loading of Fe-oxide via the temperature-regulated chemical vapor deposition (tr-CVD) [28]. Previous results also showed that the amount of Fe-loading was an important factor in determining the photocatalytic activity of Fe-loaded rutile TiO 2 under visible light, since the formation of larger Fe-oxide particles on the surface of TiO 2 can facilitate the non-radiative recombination of light-induced electron-hole pairs [28].…”