Superior photocatalytic and electrochemical activity of the MoSe2 modified ZIF-67 for the reduction and detection of Cr (VI)

The removal and detection of heavy metals from wastewater have proven to be challenging due to the limitations of the materials and technologies. Therefore, in this work, we have synthesized novel Z-scheme-based MoSe2-modified ZIF-67 by a two-step method and tested it for environmental safety by electrochemical detection and photocatalytic reduction of carcinogenic heavy metal pollutant (hexavalent chromium (Cr (VI)). The nanosheets and polyhedrons-like morphology of MoSe2 and ZIF-67 were confirmed using Field emission scanning electron microscope (FESEM) and High-resolution transmission electron microscope (HRTEM), respectively. The nanocomposite exhibited superior activity for photocatalytic reduction (similar to 89% within 30 min) towards Cr (VI) along with the detection (LOD-0.01 mu M) with high stability. The superior activity of the MZ67 nanocomposite is attributed to enhanced recombination time (4.65 ns) with respect to pristine ZIF-67 (1.21 ns) as observed from time-correlated single photon counting (TCSPC) studies. The scavenger test and electron paramagnetic resonance (EPR) studies confirmed the Z-scheme of the nanocomposite. The electrochemical sensing for Cr (VI) combined with the photocatalytic reduction, tends to provide a trustworthy tool for wastewater management.

Automated summary

In this study, a novel Z-scheme-based MoSe2-modified ZIF-67 nanocomposite was synthesized and tested for environmental safety through electrochemical detection and photocatalytic reduction of hexavalent chromium. The nanocomposite showed superior photocatalytic reduction activity and high stability, and the enhanced recombination time and Z-scheme of the nanocomposite were confirmed. The combination of electrochemical sensing and photocatalytic reduction of Cr (VI) provides a reliable tool for wastewater management.