Coating-free TiO₂@β-SiC alveolar foams as a ready-to-use composite photocatalyst with tunable adsorption properties for water treatment

Abstract

Coating-free TiO2@β-SiC photocatalytic composite foams gathering within a ready-to-use shell/core alveolar medium the TiO2 photocatalyst and the β-SiC foam structure were prepared via a multi-step shape memory synthesis (SMS) replica method.

Porous Silicon Carbide (SiC): A Chance for Improving Catalysts or Just Another Active-Phase Carrier?

“…Even if the kinetics is lower for the supported photocatalysts with respect to TiO 2 powder suspension, β-SiC support allows conduction of the photodegradation in continuous operational mode for several cycles without the need for any filtration step to separate the catalyst from treated water, thus opening to the large scale development of the process. Other than extending the applicability of their composite to the removal of natural organic matter (NOM) in treated water, as a further step forward, Robert’s group recently reported the direct synthesis of TiO 2 -β-SiC composites prepared by a shape-memory replica method. , In particular, they incorporated TiO 2 powders directly in the slurry used for the transformation of polyurethane foams in the corresponding carbides, avoiding any successive step for TiO 2 immobilization on SiC. Even if the as-prepared materials result in being slightly less efficient in Diuron mineralization with respect to the classical TiO 2 -supported β-SiC, they benefit in higher stability with a negligible titania release in water.…”

“…Other than extending the applicability of their composite to the removal of natural organic matter (NOM) in treated water, 663 as a further step forward, Robert's group recently reported the direct synthesis of TiO 2 -β-SiC composites prepared by a shape-memory replica method. 664,665 In particular, they incorporated TiO 2 powders directly in the slurry used for the transformation of polyurethane foams in the corresponding carbides, avoiding any successive step for TiO 2 immobilization on SiC. Even if the as-prepared materials result in being slightly less efficient in Diuron mineralization with respect to the classical TiO 2 -supported β-SiC, they benefit in higher stability with a negligible titania release in water.…”

Ti-Modified LaFeO3/β-SiC Alveolar Foams as Immobilized Dual Catalysts with Combined Photo-Fenton and Photocatalytic Activity

“…While β-SiC foams have received strong interest for immobilizing titania photocatalysts [17][18][19][20][21][22][23] , to date only scarce works have reported on their use -and more globally on the use of alveolar foams -as support for Fenton-like catalysts. For example, magnetite powder onto Ni and FeCrAl 24 , BiFeO3/Ni 25 , sludge carbon/SiC 26 , ferrisilicate/SiC 27 or Fe-ZSM-5/SiC 28 have been reported as dark-Fenton foam catalysts for CWPO.…”

“…Self-bonded (binder-free) β-SiC foams prepared via the shape memory synthesis (SMS) replica method stand out in comparison to polymer, metallic, and other ceramic foams such as cordierite, alumina, or zirconia, , thanks to good characteristics such as high thermal/chemical stability, which allows them to withstand severe conditions, and high density of oxygenated surface groups, thereby favoring the anchorage of catalysts. , Although β-SiC foams have received strong interest for immobilizing titania photocatalysts, − to date only scarce works have reported on their useand more globally on the use of alveolar foamsas a support for Fenton-like catalysts. For example, magnetite powder onto Ni and FeCrAl, BiFeO 3 /Ni, sludge carbon/SiC, ferrisilicate/SiC, or Fe-ZSM-5/SiC have been reported as dark-Fenton foam catalysts for CWPO.…”

Solar hydrogen production from ethanol-water vapours over metal/TiO2 photocatalysts supported on β-SiC alveolar foams

“…Open-cell alveolar foams have attracted significant interest as supports for immobilizing photocatalysts because of their ability of acting as an active static mixer while working at an ultralow pressure drop and maintaining a better light transmission than packed-bed supports [12,13]. Self-bonded β-SiC foams stand out compared to polymer, metallic, and other ceramic foams [14,15] in terms of thermal/chemical stability, allowing them to withstand harsh conditions for catalyst immobilization or for the reaction of application, and of density of oxygenated surface groups for catalyst anchorage, since their surface consists of an amorphous SiO 2 overlayer, formed upon thermal treatment and characterized by a high density of hydrophilic hydroxyl groups [16].…”