Synthesis of Ordered Mesoporous CuO/CeO(2) Composite Frameworks as Anode Catalysts for Water Oxidation

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/CeO(2) composite frameworks with different contents of copper(II) oxide and demonstrate their activity for photocatalytic O(2) production via UV-Vis light-driven oxidation of water. Mesoporous CuO/CeO(2) materials have been successfully prepared by a nanocasting route, using mesoporous silica as a rigid template. X-ray diffraction, electron transmission microscopy and N(2) 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 CeO(2) lattice improved the photochemical properties. As a result, the CuO/CeO(2) composite catalyst containing ~38 wt % CuO reaches a high O(2) 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/CeO(2) counterpart (~1.3 µmol·h(−1)) and pure mesoporous CeO(2) (~1 µmol·h(−1)).