Green synthesis of β-CoMoO4 nanowires catalyst for organic dye photodegradation

Abstract

This paper presents a simple and low-cost one-step synthesis method of cobalt molybdates. Several structural, optical and catalytic characterization techniques are used in synergy to highlight the properties of the synthesized material. EDX, FTIR, and X-ray diffraction analysis confirmed the formation of the pure β-CoMoO4 phase. The obtained β-CoMoO4 particles are polydisperse with quasi-agglomerated nanowires shape and the diameters are estimated in the range (115 ± 22) nm by atomic force microscopy (AFM). In addition, the band gap energy, Eg = 2.81 eV, shows that β-CoMoO4 nanowires can absorb in the near-UV visible range and therefore act as a photocatalyst. A photocatalytic activity against methylene blue (MB) degradation of up to 52 % was observed under visible light irradiation. As a result, a pseudo-first-order kinetic rate constant of MB photodegradation, in the presence of β-CoMoO4 nanowires, was estimated to be 0.013 min−1. The photodegradation efficiency of the synthesized material could be mainly related to the positions of the conduction (ECB = 0.23 eV) and valence (EVB = 3.04 eV) potential energies, which are favorable to the generation of reactive oxygen species (ROS). Moreover, the sample was recovered from the solution by a simple centrifugation and reused three times without significant loss in photocatalytic activity. We experimentally prove that the synthesized nanowires show strong photodegradation efficiency and photocatalytic stability for three consecutive cycles.