Photocatalytic behavior of α-Bi2Mo3O12 prepared by the Pechini method: degradation of organic dyes under visible-light irradiation

Abstract

Nanoparticles of α-Bi2Mo3O12 were prepared by the Pechini method. The process of formation of the bismuth molybdate was followed by simultaneous thermogravimetric and differential thermal analysis (TGA/DTA). Different samples of α-Bi2Mo3O12 were obtained at 400, 450, and 500 °C, and characterized by X-ray powder diffraction (XRD), nitrogen physisorption (BET), and scanning electron microscopy (SEM). When observed by SEM, the morphology of the sample obtained at the lowest temperature consisted of semi-spherical particles with an average diameter of 150 nm. On the other hand, the highest calcination temperature led to the formation of sintered particles of 500–600 nm. The photocatalytic activity of α-Bi2Mo3O12 was tested by photodegradation of the organic dyes rhodamine B (rhB) and indigo carmine (IC) under visible-light irradiation. The bismuth molybdate nanoparticles were able to bleach aqueous solutions of both organic dyes. The sample obtained at 400 °C was the best photocatalyst with half-lives, t1/2, of 108 and 154 min for rhB and IC, respectively.