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CaTi2O5 was selectively prepared by a solvothermal process without template and surfactant. The phase of the as-prepared samples was determined by X-ray diffraction (XRD). The microstructure was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results found that pH values had a crucial effect on the crystal phase and shape evolution of the samples. CaTi2O5 sample prepared at pH of 5.2 shows high efficient light harvesting, large surface area and crystallinity. Moreover, CaTi2O5 shuttle-like sample shows good photocatalytic activity against methyl orange due to its longer and thinner shuttle-like morphology and high crystallinity, enhanced light harvesting and large surface area. The photocatalytic rate of CaTi2O5 shuttle-like structure reaches 0.1988 min−1 for 25-min methyl orange degradation under the ultraviolet light irradiation and displays an excellent photostability with a degradation efficiency of 0.1952 min−1 after four cycles.

As a new black ceramic pigment, encapsulated carbon black pigment has been prepared by a sol–gel-spraying method. The obtained pigment sintered at 900 °C for 2 h in air has a deep black hue (L* = 19), indicating carbon black can be fully covered. In the pigment, a dense coating layer on carbon black is formed due to the fast transformation from sol into gel by rapid extraction of solvent. The transparent silica phase spaces out the fine crystalline (zirconia or zircon), which permits to display the color of carbon black. This preparation method provides a way to prepare the encapsulated pigments. It will provide more colorful ceramic pigment applied in ceramic decoration by encapsulating.