Hexagonal 2H-MoSe2 broad spectrum active photocatalyst for Cr(VI) reduction.

Haipeng Chu,Baibai Liu,Xinjuan Liu,Can Li,Guang Zhu,Junying Liu,Changqing Sun,Huigang Du,Jianwei Li,Wenyan Lei

doi:10.1038/srep35304

Abstract

To make full use of the solar energy, exploring broad spectrum active photocatalysts has become one of the core issues for photocatalysis. Here we report a novel hexagonal 2H-MoSe2 photocatalyst with ultraviolet (UV)-visible-near infrared (NIR) light response for the first time. The results indicate that the MoSe2 displays excellent photo-absorption and photocatalytic activity in the reduction of Cr(VI) under UV and visible even NIR light irradiation. MoSe2 synthesized at pH value of 2 achieves the highest Cr(VI) reduction rates of 99%, 91% and 100% under UV, visible and NIR light irradiation, respectively, which should be attributed to its comparatively higher light absorption, efficient charge separation and transfer as well as relatively large number of surface active sites. The excellent broad spectrum active photocatalytic activity makes the MoSe2 to be a promising photocatalyst for the effective utilization of solar energy.

Highlights

Agrowing number of contaminations such as heavy metal ions and organic chemical compounds in natural water have become a serious threat to environment and human health
The diffraction patterns of as-prepared MoSe2 samples show that all the peaks can be indexed to (002), (102) and (110) crystal planes of the hexagonal 2H-MoSe2 phase with space group P63/mmc (JCPDS: 29–0914)[37]
It can be observed that the X-ray diffraction (XRD) patterns of as-prepared MoSe2 samples show relatively broader diffraction peaks compared with MoSe2 bulk, indicating that the as-prepared products are somewhat amorphous and have short range structural order[38]

Summary

Introduction

Agrowing number of contaminations such as heavy metal ions and organic chemical compounds in natural water have become a serious threat to environment and human health. It is highly toxic to most organisms when its concentration is above 0.05 mg l−1, and can cause the lung-cancer, chromeulcer, perforation of nasal septum and kidney-damage Various techniques, such as adsorption, biosorption, electrocoagulation, ion exchange, membrane filtration, have been reported to remove the Cr(VI) from wastewater[1,2]. Transition metal dichalcogenides (TMDs) have attracted great interests due to their intriguing properties and potential applications in hydrogen evolution[29], lithium/sodium batteries[30], and photocatalysis[31,32,33,34] Among these TMDs, MoSe2 with a narrow band gap of ~1.4 eV can harvest the solar energy in a very broad spectral region and has been employed as an efficient photocatalyst under UV, visible and NIR light irradiation[35]. The photocatalytic mechanism was studied in terms of a series of characterization and controlled experiments using hole scavengers

Methods

Results

Conclusion