title: Rapid water disinfection using vertically aligned MoS2nanofilms and visible light.
abstract: Solar energy is readily available in most climates and can be used for water purification. However, solar disinfection of drinking water mostly relies on ultraviolet light, which represents only 4% of the total solar energy, and this leads to a slow treatment speed. Therefore, the development of new materials that can harvest visible light for water disinfection, and so speed up solar water purification, is highly desirable. Here we show that few-layered vertically aligned MoS2(FLV-MoS2) films can be used to harvest the whole spectrum of visible light (∼50% of solar energy) and achieve highly efficient water disinfection. The bandgap of MoS2was increased from 1.3 to 1.55 eV by decreasing the domain size, which allowed the FLV-MoS2to generate reactive oxygen species (ROS) for bacterial inactivation in the water. The FLV-MoS2showed a ∼15 times better log inactivation efficiency of the indicator bacteria compared with that of bulk MoS2, and a much faster inactivation of bacteria under both visible light and sunlight illumination compared with the widely used TiO2. Moreover, by using a 5 nm copper film on top of the FLV-MoS2as a catalyst to facilitate electron-hole pair separation and promote the generation of ROS, the disinfection rate was increased a further sixfold. With our approach, we achieved water disinfection of >99.999% inactivation of bacteria in 20 min with a small amount of material (1.6 mg l-1) under simulated visible light.
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Chong
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Desheng
authors.initials: D
authors.lastname: Kong
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Po-Chun
authors.initials: PC
authors.lastname: Hsu
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Yuan
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Hyun-Wook
authors.identifier: 0000-0001-9074-1619
authors.initials: HW
authors.lastname: Lee
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Yayuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Haotian
authors.identifier: 0000-0002-3552-8978
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Shuang
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Kai
authors.initials: K
authors.lastname: Yan
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Dingchang
authors.initials: D
authors.lastname: Lin
authors.affiliation: Department of Civil and Environmental Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Maraccini
authors.affiliation: Department of Civil and Environmental Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Kimberly M
authors.initials: KM
authors.lastname: Parker
authors.affiliation: Department of Civil and Environmental Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Alexandria B
authors.initials: AB
authors.lastname: Boehm
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.|Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94305, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Cui
mesh_terms: D002384:Catalysis; D003300:Copper / Q000737:chemistry; D004203:Disinfection / Q000295:instrumentation / Q000379:methods; D004220:Disulfides / Q000737:chemistry*; D004867:Equipment Design; D006046:Gold / Q000737:chemistry; D008027:Light; D008982:Molybdenum / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D056951:Photoelectron Spectroscopy; D017382:Reactive Oxygen Species; D014871:Water Microbiology; D018508:Water Purification / Q000295:instrumentation* / Q000379:methods*
chemical_list: D004220:Disulfides; D017382:Reactive Oxygen Species; D006046:Gold; D003300:Copper; D008982:Molybdenum; C082964:molybdenum disulfide