Heterostructured Ceramic Powders for Photocatalytic Hydrogen Production: Nanostructured TiO2 Shells Surrounding Microcrystalline (Ba,Sr)TiO3 Cores

Heterostructured photocatalysts were prepared to have nanostructured (ns) TiO2 shells surrounding microcrystalline (mc) cores of (Ba,Sr)TiO3. The as-prepared heterostructures were annealed between 400°C and 600°C to improve crystallinity and core-shell interfacial bonding. X-ray diffraction, electron microscopy, and gas adsorption measurements demonstrated that 50 nm thick shells composed of nanocrystalline and nanoporous TiO2 surrounded mc-cores such that the heterostructured particles had surface areas of 50–100 m/g. The mc-(Ba, Sr)TiO3/ns-TiO2 core-shell photocatalysts annealed at 600°C had slightly reduced surface areas, but had the highest rates of photochemical hydrogen production from water/methanol solutions, rates much greater than those for ns-TiO2 or mc-(Ba,Sr) TiO3 alone. Such heterostructured powders represent a new strategy for the design of efficient photocatalysts and the use of nanostructured catalytic coatings.