Pyrocatalytic removal of Cr(VI) by MoS2 nanosheets under controlled thermal fluctuation

Traditionally, photocatalysts have been considered as effective tool to combat water pollution caused by Cr(VI) contamination. However, absence of sunlight in night and poor transmittance in the waste water restrict their wide-spread practical applications. Herein, two dimensional MoS₂ nanosheets have been employed as pyrocatalyst for round-o-clock utilization of natural temperature fluctuation and consequent reduction of Cr(VI). MoS₂ pyrocatalysts have been synthesized via facile hydrothermal technique and further characterized by XRD, XPS, SEM technique. The developed pyrocatalyst exhibits ∼95 % removal of 80 ppm Cr(VI) under thermal cycles between 20 ºC and 70 ºC. Moreover, the pyrocatalyst can effectively harness natural temperature variation for the catalytic reduction of Cr(VI) in just 30 days. The excited electrons generated during the temperature variation are identified as active species responsible for Cr(VI) reduction. The results and concept presented here may bring new possibilities for the removal of heavy metal ions in waste water treatment technology.