E-carbon antenna-assembled TiO2 nanotubes for sensitization of photocatalytic reaction exemplified by enhanced oxidation of nitrobenzene

Abstract

In this paper, E-carbon nanotubes were electrochemically assembled into binary TiO2 NTs. The assembled E-carbon nanotube, a nanoantenna for the sensitization of photocatalysis, enables trapping and transferring channels of mass and charge for uniformity and extension of the binary surface of the two-layer TiO2 NTs in the microstructure. Also, the E-carbon nanoantenna is electrojunctionally functionalized for an efficient charge separationone dominated by the photocatalytic process, determined by the effective photocapacitance. The E-carbon nanoantenna exhibited a superior adsorptive capacity to the reactive molecular adsorption—one key photocatalytic process—by increasing the mass transfer. Moreover, cyclic voltammetry of the assembled binary TiO2 NTs covered a large integrated area of the capacitance under UV-light. This characteristic indicated that super-photocapacitance exists in the catalytic system via light irradiation. In light of principles of photovoltage and photocatalysis, the NT features can generate a photovoltage by accelerating the charge separation, prolonging the charge lifetime and decreasing the charge recombination. It is necessary to promote the photocatalysis, as results, that the charges can be moved to the target substances on the surface of TiO2 NTs more quickly, which can greatly alter the photocatalytic process. Raised from the total sensitization, the photocatalysis was significantly enhanced by the exquisitely coupled catalyst system in the efficient NB oxidation increase of 24.5% compared to the unassembled one.