Quenching of Photoactivity in Phthalocyanine Copper(II)-Titanate Nanotube Hybrid Systems

Titanate nanotubes (TiNTs) were obtained by hydrothermal treatment of anatase powder in aqueous NaOH solution and then modified with 2,9,16,23-tertracarboxyl phthalocyanine copper(H) (CuPc). This hybrid organic inorganic nanoscopic system was characterized by X-ray diffraction, microscopy, and spectroscopy. Transmission electron microscopy (TEM) images of pure and modified TiNTs revealed multiwall structures with an average outer diameter of 9 nm and a length of several hundred nanometers. The tubular morphology of the TiNTs was covered with CuPc-film. The amount of CuPc adsorbed onto the TiNTs was quantified by electron paramagnetic resonance (EPR). Using the same technique and spin-trapping methodology, the photogeneration of reactive oxygen species (ROS) from the TiNTs was systematically investigated. A drastic quenching of photoactivity was observed in the CuPc/TiNT hybrid system. Electron transfer from excited CuPc states to the TiNT conduction band followed by electron recombination may be the cause of this quenching.

FAPESP[08/53576-9]

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)

FAPEMIG

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

CNPq

INCT in Bioanalytics (FAPESP)[08/57805-2]

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

INCT in Bioanalytics (CNPq)[573672/2008-3]

INCT in Bioanalytics (CNPq)

LME-LNLS[TEM-MSC 9005]

LME-LNLS

LME-LNLS

LME-LNLS[11338]