Soft-template-carbonization route to highly textured mesoporous carbon–TiO2 inverse opals for efficient photocatalytic and photoelectrochemical applications

Abstract

Hierarchically organized mesoporous carbon–TiO₂ inverse opal nanostructures were synthesized by complementary colloid and block copolymer (BCP) self-assembly, where the triblock copolymer P123 acts simultaneously as the template and the carbon source. Highly ordered mesoporous inverse opal nanostructures with a nano-textured surface morphology and multiple-length scale nanopores provide increased light-activated surface area and scattering effects, leading to enhanced photoabsorption efficiency and the transport of matter. UV-vis absorption, X-ray photoelectron spectroscopy and Mott–Schottky measurement studies show that incorporation of carbon moieties into TiO₂via direct conversion of BCPs creates a new energy level above the valence band of TiO₂, resulting in an effective decrease in the band gap. A significantly enhanced visible light photocatalytic activity was demonstrated for the mesoporous carbon–TiO₂ inverse opals in terms of the degradation of p-nitrophenol (∼79%) and photoelectrochemical water splitting (∼0.087%).