Novel core-shell SnIn4S8@Bi2MoO6 heterojunction with highly-enhanced photocatalytic activity for visible light-driven Cr (VI) reduction

摘要

The photocatalytic reduction of toxic soluble Cr (VI) heavy metal pollutant to lower toxicity Cr (III) is a green and promising approach for environmental remediation. In this study, a novel core-shell SnIn4S8@Bi2MoO6 heter-ojunction (SIS/BMO) photocatalyst was successfully fabricated via encapsulating Bi2MoO6 nanosheets on the surface of flower-like SnIn4S8 microsphere. The Cr (VI) reduction under visible light illumination was evaluated to demonstrate the photocatalytic performance of the samples. Results show that the optimized SIS/BMO-35 % sample exhibit the best Cr (VI) reduction ability with the apparent rate constant of k = 0.117 min(-1), which is 5.85 and 3.44 times higher than that of SnIn4S8 and Bi2MoO6, respectively. Detailed analyses illustrate the principal reason for the improvement of SIS/BMO photocatalytic activity is the efficient charge transfer and separation, which was proved via the transient photocurrent response, electrochemical impedance spectra, photoluminescence spectrum and fluorescence lifetime. Moreover, the photo-stability of the SIS/BMO sample was significantly enhanced for the protection of Bi2MoO6 shell.

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