title: Synthesis of Ordered Mesoporous CuO/CeO₂ Composite Frameworks as Anode Catalysts for Water Oxidation.
abstract: Cerium-rich metal oxide materials have recently emerged as promising candidates for the photocatalytic oxygen evolution reaction (OER). In this article, we report the synthesis of ordered mesoporous CuO/CeO₂ composite frameworks with different contents of copper(II) oxide and demonstrate their activity for photocatalytic O₂ production via UV-Vis light-driven oxidation of water. Mesoporous CuO/CeO₂ materials have been successfully prepared by a nanocasting route, using mesoporous silica as a rigid template. X-ray diffraction, electron transmission microscopy and N₂ porosimetry characterization of the as-prepared products reveal a mesoporous structure composed of parallel arranged nanorods, with a large surface area and a narrow pore size distribution. The molecular structure and optical properties of the composite materials were investigated with Raman and UV-Vis/NIR diffuse reflectance spectroscopy. Catalytic results indicated that incorporation of CuO clusters in the CeO₂ lattice improved the photochemical properties. As a result, the CuO/CeO₂ composite catalyst containing ~38 wt % CuO reaches a high O₂ evolution rate of ~19.6 µmol·h-1(or 392 µmol·h-1·g-1) with an apparent quantum efficiency of 17.6% at λ = 365 ± 10 nm. This OER activity compares favorably with that obtained from the non-porous CuO/CeO₂ counterpart (~1.3 µmol·h-1) and pure mesoporous CeO₂ (~1 µmol·h-1).
authors.affiliation: Department of Materials Science and Technology, University of Crete, Vassilika Vouton, Heraklion 71003, Greece. vassiamark@gmail.com.
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Markoulaki Ι
authors.affiliation: Department of Materials Science and Technology, University of Crete, Vassilika Vouton, Heraklion 71003, Greece. jpapadas@gmail.com.
authors.forename: Ioannis T
authors.initials: IT
authors.lastname: Papadas
authors.affiliation: Department of Materials Science and Technology, University of Crete, Vassilika Vouton, Heraklion 71003, Greece. gkornarakis@materials.uoc.gr.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Kornarakis
authors.affiliation: Department of Materials Science and Technology, University of Crete, Vassilika Vouton, Heraklion 71003, Greece. garmatas@materials.uoc.gr.
authors.forename: Gerasimos S
authors.initials: GS
authors.lastname: Armatas
keywords: cerium oxide; mesoporous materials; nanocasting; nanostructured; water oxidation