All-solid-state MoS2/WO3 photoelectrodes as high-efficiency catalysts for reductive/sorptive/recycling of hexavalent chromium

作者：Chen, Zhenglin; Cao, Wenjing; Luo, Yan; Yang, Lixia^*; Jin, Yuyan; Zheng, Lingyi; Wei, Zhihui

来源：Ceramics International, 2023, 49(13): 21433-21442.

DOI：10.1016/j.ceramint.2023.03.272

• Cr(VI)
• Photoelectrocatalytic (PEC)
• MoS2
• WO3
• Recovered
• Adsorption

Photoelectrocatalysis (PEC) is an effective approach to eliminate carcinogen hexavalent chromium (Cr(VI)) in wastewater, in which high-performance catalysts are crucial. Herein, controlled growth of thin molybdenum disulphide (MoS2) nanosheets on self-supported tungsten trioxide (WO3) created an all-solid-state MoS2/WO3 heterojunction serving as electrode and catalyst simultaneously for removing Cr(VI). Countless small and thin MoS2 nanoflakes build in a huge and porous interface for harvesting lights and adsorbing chromium species. And the highly conductive WO3 substrate facilitates the transfer of those photoexcited-electron and therefore suppresses the recombination between electrons and holes. Furthermore, assisted by bias potential, electron streams from external circuit render an electron-rich interface at the MoS2/WO3 cathode, accelerating the Cr(VI) reduction by PEC. At -1.2 V, the PEC reduction efficiency of Cr(VI) reaches 100% within 30 min, surpassing the pristine WO3 by 2.7 times. The generated Cr(III) ions can be immobilized on the porous MoS2/WO3 cathode through electrostatic attraction, enabling removal of total chromium. More importantly, the Cr(III) anchored to the catalyst can be effortlessly recovered by eluting with clean water, which also refreshes the MoS2/WO3 cathode. This study provides a new approach to fabricating photoelectrodes for sustainable PEC reduction and treatment of Cr(VI) containing wastewater.

• 单位
  南昌航空大学