Preparation of Ag/TiO₂ composite foams via Pickering emulsion for bactericide and photocatalysis

This research aims to prepare macroporous Ag/TiO₂ composite foams via particle-stabilized Pickering emulsion for bactericidal and photocatalytic activities. The Ag/TiO₂ particles used for preparing the composite foams consisted of Ag core surrounded by mesoporous TiO₂ shell. By selective adsorption of nonionic 1-hexadecylamine molecules on the Ag/TiO₂ particles, an initially hydrophilic surface was tuned to partly hydrophobic with contact angle of ∼80°. Stable foams were then prepared by a simple mechanical frothing of aqueous suspensions consisting of the hydrophobic Ag/TiO₂ particles as the filler phase, followed then by calcination to obtain the macroporous Ag/TiO₂ foams. The composite foams impart photo-degradation capability against methylene-blue dye in water under ultraviolet irradiation. The composite foams also render a synergistic antimicrobial activity against Escherichia coli, in which the bactericidal efficiency reached 99% under dark conditions in 3 h.