Preparation And Properties Of Mesoporous Ceria Nanoparticles

In the method for preparing mesoporous ceria nano-materials,high-temperature calcination is generally used.It is still challenging to prepare mesoporous CeO₂ composite nano-materials with good catalytic performance under mild conditions.Nitrophenols are one of the most common organic pollutants in industrial and agricultural waste waters.Nitrobenzene compounds are toxic substances due to its carcinogenic,mutagenic,and cyto-and embryotoxic effects in humans.Catalytic reduction of nitrobenzene compounds into aminobenzene compounds is one of the methods of nitrobenzene compounds causing water pollution.In this paper,mesoporous Cu₂O-CeO₂ and mesoporous Au-Cu₂O-CeO₂ composite nanomaterials were prepared under mild conditions using block copolymer as template.The structures of mesoporous Cu₂O-CeO₂ and mesoporous Au-Cu₂O-CeO₂ composite nanomaterials were characterized.It was successfully applied to the catalytic reduction of nitrophenols such as p-nitrophenol,o-nitrophenol and m-nitrophenol.Mesoporous CuO_x-CeO₂-TiO₂ nanoparticles were successfully prepared by coating TiO₂ with mesoporous Cu₂O-CeO₂ nanoparticles.?1?Mesoporous Cu₂O-CeO₂ nanoparticles were prepared under mild conditions.Spherical micelles of block copolymer P2VP-b-PEO in aqueous solution were used as structure directing agent and Ce?NO₃?₃/Cu?NO₃?₂ were used as an inorganic precursor.Cu²⁺and Ce³⁺were complexed on spherical micelles of P2VP-b-PEO through electrostatic interaction.Hydrated hydrazine acted as a reducing agent for Cu²⁺and an alkaline condition for Ce³⁺.It converts Ce³⁺to Ce?OH?₃,reducing Cu²⁺to Cu⁺and forming Cu?OH?.The formed Ce?OH?₃ and Cu₂O nanoparticles aggregated and assembled on spherical micelles to form mesoporous Cu₂O-CeO₂ nanoparticles.Ce?OH?₃ is converted to Ce?OH?₄ in the air.The mesoporous Cu₂O-CeO₂ nanoparticles showed good catalytic activity and catalytic stability in the catalytic reduction of p-nitrophenol.The experimental results show that the activity factor?K?for mesoporous Cu₂O-CeO₂ nanospheres with a Ce³⁺/Cu²⁺molar ratio of5/1 is 3006.6 s^-1g^-1,which is much higher than that reported values.The mesoporous Cu₂O-CeO₂ nanospheres catalyst still has a high activity after 10 cycles.This catalyst has potential applications in CO oxidation,reduction of other nitrophenolic pollutants.?2?Mesoporous Au-Cu₂O-CeO₂ nanoparticles were prepared under mild conditions.The spherical micelles of P2VP-b-PEO in water was used as a template,aqueous solution,chloroauric acid,Ce?NO₃?₃ and Cu?NO₃?₂ as inorganic precursor.[AuCl₄]^-,Cu²⁺and Ce³⁺were complexed on spherical micelles of P2VP-b-PEO.The[AuCl₄]^-and Cu²⁺and Ce³⁺were converted into Au,Cu₂O and Ce?OH?₃ with N₂H₄ and assembled into composite nanoparticles.Ce?OH?₃ is converted to CeO₂ in the air.Block copolymer removed by ethanol.The complete conversion of Ce?OH?₄ to CeO₂ crystals was obtained to obtain mesoporous Au-Cu₂O-CeO₂nanoparticles at 130?.Mesoporous Au-Cu₂O-CeO₂ nanoparticles have good catalytic performance in reduction of p-nitrophenol.?3?Mesoporous CuO_x-CeO₂-TiO₂ nanoparticles were prepared by TiO₂ coating on the mesoporous Cu₂O-CeO₂ spherical nanoparticles.Using TTIP as the inorganic precursor and using CTAB as a surfactant,TTIP was complexed with CTAB on the surface of the mesoporous CeO₂-Cu₂O nanoparticles,thus leaving TTIP on the mesoporous CeO₂-Cu₂O nanoparticles.By adjusting the amount of TTIP added,CuO_x-CeO₂-TiO₂ nanoparticles with mesoporous hollow structure with different content of TiO₂ were prepared.