Accelerating Surface Photoreactions Using MoS-FeS Nanoadsorbents: Photoreduction of Cr(VI) to Cr(III) and Photodegradation of Methylene Blue.

Nanocubic MoS-FeS, 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 MoS-FeS 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 ( = 464 mg g) along with an isotherm described by the Langmuir model with = 340 mg g. The photodegradation process was achieved by holes. It was found that the photodegradation rate constant of MB by MoS-FeS (0.203 min) was about 22 times higher than that of MoS (0.0091 min). The percent apparent quantum yield for photoreduction of Cr(VI) to Cr(III) using MoS-FeS (5.7%) was about 33 times higher than utilizing MoS (0.1709%). Therefore, the synergistically prolonged visible-light harvesting as well as the photocarrier diffusion length proved that MoS-FeS nanotubes can effectively be utilized in environmental pollutant's remediation.