Accelerating Surface Photoreactions Using MoS<sub>2</sub>–FeS<sub>2</sub> Nanoadsorbents: Photoreduction of Cr(VI) to Cr(III) and Photodegradation of Methylene Blue
Hossein Ashrafi, Fatemeh Rahnama, Morteza Akhond, Ghodratollah Absalan
Abstract
Nanocubic MoS2–FeS2, as a photocatalyst, was synthesized with high catalytic active edges and high specific surface areas with the capability of absorbing visible light. The results showed that the photocatalytic efficiency of nanocubic MoS2–FeS2 for adsorption/degradation of methylene blue (MB) as well as the reduction of Cr(VI) was high. The adsorption process was found to follow a kinetic model of a pseudo-second-order kind (Qe.cal = 464 mg g–1) along with an isotherm described by the Langmuir model with Qe.cal = 340 mg g–1. The photodegradation process was achieved by holes. It was found that the photodegradation rate constant of MB by MoS2–FeS2 (0.203 min–1) was about 22 times higher than that of MoS2 (0.0091 min–1). The percent apparent quantum yield for photoreduction of Cr(VI) to Cr(III) using MoS2–FeS2 (5.7%) was about 33 times higher than utilizing MoS2 (0.1709%). Therefore, the synergistically prolonged visible-light harvesting as well as the photocarrier diffusion length proved that MoS2–FeS2 nanotubes can effectively be utilized in environmental pollutant’s remediation.