Amplified visible light photocatalytic activity of mesoporous TiO2/ZnPc hybrid by cascade Mie light scattering

Abstract

We synthesize the anatase TiO2/zinc phthalocyanine (ZnPc) hybrids in various sizes (245-1188 nm) and examine the visible light photocatalytic activity of TiO2/ZnPc hybrids, in conjunction with their Mie light scattering ability. Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy show that ZnPc molecules are well-incorporated and dispersed on the surface of the TiO2, instead of being aggregates. From the field-emission scanning electron microscopy, dynamic light scattering, and nitrogen adsorption-desorption analysis, we confirm the formation of spherical TiO2/ZnPc hybrids in various sizes (245, 548, 798, 1188 nm in diameter), the large specific surface areas (up to 223.76 m(2)/g), and the mesoporous structures. The mesoporous TiO2/ZnPc hybrids show excellent photocatalytic efficiency (up to 89.93% after 90 min) toward the degradation of methylene blue under visible light irradiation, which is about 2 times of that of simple nanoparticular P25/ZnPc. Among the mesoporous TiO2/ZnPc hybrids, the hybrid with a size of 548 nm (P123-TiO2/ZnPc) exhibits the highest photocatalytic activity. The highest activity observed on P123-TiO2/ZnPc may be attributed to its efficient cascade Mie scattering effect under visible light irradiation. (C) 2016 Elsevier Inc. All rights reserved.