Synthesis of hybrid Zn–Al–In mixed metal oxides/carbon nanotubes composite and enhanced visible-light-induced photocatalytic performance

Hybrid nanocomposite of Zn–Al–In mixed metal oxides (ZnAlIn-MMO) and multi-walled carbon nanotubes (CNTs) was synthesized effectively from composite precursor of ternary Zn–Al–In layered double hydroxide (ZnAlIn-LDH) and 1-pyrenebutyric acid-modified CNTs (P-CNTs). The structural, morphological and optical properties of the materials were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), low temperature nitrogen adsorption–desorption, Raman spectra, and UV–vis diffuse reflectance spectroscopy. The results indicated that ZnAlIn-LDH nanoparticles could be attached closely onto the surface of the P-CNTs through the interfacial interaction, thus resulting in the formation of the remarkably dispersed ZnAlIn-MMO nanoparticles on the surface of the modified nanotubes after calcination. Compared with pristine ZnAlIn-MMO, as-synthesized hybrid ZnAlIn-MMO/P-CNTs had smaller band gap of about 2.08 eV, characteristic of enhanced visible light absorption. Furthermore, ZnAlIn-MMO/P-CNTs exhibited excellent visible-light-induced photodegradation activity toward methylene blue, which was attributable to the efficient separation and transportation of the photogenerated charge carriers originating from the unique heterostructure of such nanocomposite. The present finding provides an approach to fabricate new types of visible-light-induced heteronanostructured photocatalysts.