Search query: Fabrication of MgFe2O4/MoS2 heterostructure nanowires for photoelectrochemical catalysis

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abstract: A novel one dimensional MgFe2O4/MoS2 heterostructure has been successfully designed and fabricated. The bare MgFe2O4 was obtained as uniform nanowires through electrospinning, and MoS2 thin film appeared on the surface of MgFe2O4 after further chemical vapor deposition. The structure of the MgFe2O4/MoS2 heterostructure was systematic investigated by X ray diffraction (XRD) high resolution transmission electron microscopy (HRTEM) X ray photoelectron spectrometry (XPS) and Raman spectra. According to electrochemical impedance spectroscopy (EIS) results, the MgFe2O4/MoS2 heterostructure showed a lower charge transfer resistance compared with bare MgFe2O4, which indicated that the MoS2 played an important role in the enhancement of electron/hole mobility. MgFe2O4/MoS2 heterostructure can efficiently degrade tetracycline (TC) since the superoxide free radical can be produced by sample under illumination due to the active species trapping and electron spin resonance (ESR) measurement, and the optimal photoelectrochemical degradation rate of TC can be achieved up to 92% (radiation intensity: 47 mW/cm(2) 2 h) Taking account of its unique semiconductor band gap structure, MgFe2O4/MoS2 can also be used as an photoelectrochemical anode for hydrogen production by water splitting, and the hydrogen production rate of MgFe2O4/MoS2 was 5.8 mmol/h*m(2) (radiation intensity: 47 mW/cm(2) which is about 1.7 times that of MgFe2O4.
author_names: Weiqiang Fan

Meng Li

Hongye Bai

Dongbo Xu

Chao Chen

Chunfa Li

Yilin Ge

Weidong Shi
title: Fabrication of MgFe2O4/MoS2 Heterostructure Nanowires for Photoelectrochemical Catalysis.
venue: Langmuir the ACS journal of surfaces and colloids
year: 2016

abstract: Abstract A novel heterostructure of PbO2 tipped Co3O4 nanowire arrays (NWs) is fabricated by the combination of hydrothermal synthesis and electrochemical deposition. The hydrothermal process is used to fabricate the Co3O4 nanowire arrays (NWs) on the Ti sheet substrates, and subsequently the PbO2 nanoparticles were preferentially adhered on the sharptip of Co3O4 NWs using an electrochemical deposition method. It is found that the as constructed PbO2/Co3O4 composites exhibit large electroactive areas, low charge transfer resistance, high efficiency regarding the generation of hydroxyl radicals. The photoelectrochemical (PEC) properties of as constructed PbO2/Co3O4 composites were evaluated by the decolorization of dye (reactive brilliant blue KN R) in aqueous solution. The PEC measurement indicated that as constructed PbO2/Co3O4 composites have higher PEC acitivity, better reproducibility and obvious photoelectric synergism, as compared with bare Co3O4 NWs. The promoted PEC ability for the PbO2/Co3O4 composites can be ascribed to the construction of heterointerface between PbO2 and Co3O4. The present work offered attractive perspectives for applications of the PbO2 tipped Co3O4 NWs in the photoanode regarding the treatment of refractory organic pollutant.
author_names: Xiao-Qing Wang

Qiong Wu

Hongchao Ma

Chun Ma

Zhihui Yu

Yinghuan Fu

Xiaoli Dong
title: Fabrication of PbO2 tipped Co3O4 nanowires for efficient photoelectrochemical decolorization of dye (reactive brilliant blue KN R) wastewater
venue: Solar Energy Materials and Solar Cells
year: 2019

abstract: We report a systematic and scalable single step growth of three dimensional hierarchical ZnO/ZnS heterojunction branched nanowires (3D ZnO/ZnS h b NWs) on a Si substrate using MOCVD for the first time and their application as photoanodes for photoelectrochemical water splitting (PEC WS) Vertically well aligned main trunk ZnO nanowires (MTr ZnO NWs) were grown on a low temperature ZnO buffer layer, which was followed by ZnS deposition. Subsequently, hierarchically branched ZnO nanowires (h b ZnO NWs) were grown on the side wall of the core shell heterostructure, which was further modified with a thin layer of ZnS for the growth of multiple ZnO NW branches. The PEC WS results revealed that the photo conversion efficiency achieved using MTr ZnO NWs and 3D ZnO/ZnS h b NWs was 0.03% and 0.46% at 0.5 V vs. RHE, respectively, which corresponds to 16 fold enhancement. The achieved improvements can be attributed to the enhanced photoabsorption, which is directly related to the augmented surface area. In addition, ZnS plays a significant role in promoting faster photogenerated carrier transport with high efficiency and visible light absorption by type II transition at the ZnO/ZnS interface. The novel growth approach that we followed to fabricate the photoanode opens a new avenue for the synthesis of multiple level hierarchical heterostructures that are beneficial for PEC WS devices.
author_names: Mostafa Afifi Hassan

Aadil Waseem

Muhammad Ali Johar

Indrajit V Bagal

Jun-Seok Ha

Sang-Wan Ryu
title: Single step fabrication of 3D hierarchical ZnO/ZnS heterojunction branched nanowires by MOCVD for enhanced photoelectrochemical water splitting
year: 2020

abstract: Abstract The nickel SiC nanowires composite electrode with high photoelectrocatalytic activity for water splitting in alkaline solution was fabricated via constant current electrodeposition. Compared with pristine SiC nanowires, this photocathode with a three dimensional porous structure produced a current density of 32.4 mA cm 2 at 1.4 V vs. Ag/AgCl. The enhanced performance was ascribed to efficient photogenerated carriers separation resulting from the heterostructure interface of Ni metal and SiC semiconductor. Moreover, this photocathode showed high stability in KOH solution over 600s' continuous reaction, which suggests a promising application in alkaline conditions for photocatalysis and PEC water splitting.
author_names: Min Jiang

Zhaoxiang Liu

Lijuan Ding

Jianjun Chen
title: Facile fabrication and efficient photoelectrochemical water splitting activity of electrodeposited nickel/SiC nanowires composite electrode
year: 2017

abstract: Abstract Branched heterostructures play an important role in solar energy harvesting through an efficient separation of photogenerated charges as well as enhancement in catalytic reaction sites. Here we report the CuO/Cu2O nanoflake/nanowire heterostructure with the enhanced surface area directly grown on Cu foil through scalable process steps ensuring easy large scale fabrication. A hydrothermal treatment on Cu2O nanowires, obtained through anodization of Cu foil and argon annealing, leads to a partial conversion of Cu2O into CuO nanoflakes resulting in a heterostructure with a highly enhanced surface area facilitating a higher semiconductor electrolyte interface. Brief annealing at 250 degC for 5 min on the sample results in a photocurrent density of 1.9 mA/cm2 (at 0.3 V vs. Ag/AgCl under AM1.5G illumination) which is about an order of magnitude higher than the Cu2O nanowires. Further, CuO/Cu2O shell/core heterostructure is fabricated through direct annealing of Cu2O nanowires to understand the effect of highly enhanced surface area over the charge separation due to heterostructure. A comparative study on both heterostructures by photocurrent, electrochemical impedance, and Mott Schottky measurements reveals that although CuO/Cu2O heterojunction helps in charge separation, however, the enhanced surface area obtained through nanoflake morphology has a dominating effect in deciding high photocurrent density.
author_names: Subish John

Somnath Chanda Roy
title: CuO/Cu2O nanoflake/nanowire heterostructure photocathode with enhanced surface area for photoelectrochemical solar energy conversion
year: 2020

abstract: Abstract A photoelectrochemical immunosensor was developed by incorporating graphene quantum dots (GQDs) and highly oriented silicon nanowires (SiNWs) for the determination of microcystin LR (MC LR) in water samples. The GQDs/SiNWs heterostructure was employed for signal transduction and biocompatible nanoscaffold for antibody (Ab) immobilization. The results showed that the fabricated GQDs/SiNWs electrode exhibited better photoelectrochemical performance than that of SiNWs. The specific recognition of MC LR affected the optoelectronic properties of the Ab/GQDs/SiNWs electrode, leading to the photocurrent decreases. In the linear range from 0.1 mg L 1 to 10 mg L 1 the photocurrent decrease was proportional to the concentration of microcystin LR and the linear regression equation was Y 59.67 6.08 X with a limit of detection of 0.055 mg L 1 The immunosensor possessed good sensitivity, selectivity and acceptable reusability for the determination of microcystin LR, which was successfully applied in determining MC LR in real water samples.
author_names: Junping Tian

Huimin Zhao

Xie Quan

Yao-Shan Zhang

Hongtao Yu

Shuo Chen
title: Fabrication of graphene quantum dots/silicon nanowires nanohybrids for photoelectrochemical detection of microcystin LR
year: 2014

abstract: Hierarchical one dimensional CdS nanowires (NWs)/CdSe core shell heterostructure have been synthesized through a simple wet chemical approach. The formation of CdS NWs/CdSe core shell has been confirmed by structural, morphological and optical analysis. Fascinatingly, an optimum number of CdSe nanoparticles loaded over CdS NWs boosts the device efficiency five times than a bare CdS NW structure. The effect of increasing the CdSe SILAR cycles over CdS induces red shift in the absorption wavelength along with quenching, which leads to the negative shift of the conduction band, and hence, increases the electron lifetime, as analyzed by photoluminescence, external quantum efficiency and Mott Schottky studies. Interestingly, a discrepancy has been found in the device performance with an increase in the SILAR cycles beyond the optimum condition. The reason behind this fact has been investigated through different comprehensive photoelectrochemical characterization and discussed herein.
author_names: Sutripto Majumder

Babasaheb R Sankapal
title: Facile fabrication of CdS/CdSe core shell nanowire heterostructure for solar cell applications
year: 2017

abstract: A core shell structure, formed in a nanostructured photoanode, is an effective strategy to achieve high solar to hydrogen conversion efficiency. In this study, we present a facile and simple synthesis of a unique vertically aligned ZnO/ZnS core shell heterostructure nanowires (NWs) on a Si substrate. Well aligned ZnO NWs were grown on Si (100) substrates on a low temperature ZnO buffer layer by metal organic chemical vapor deposition. The ZnO NWs were then coated with various thicknesses of ZnS shell layers using atomic layer deposition. The structural characterizations exhibit the well developed ZnO/ZnS core shell NWs heterostructure. The as prepared ZnO/ZnS core shell NWs was applied as photoanode for photoelectrochemical (PEC) water splitting. This unique ZnO/ZnS core shell NWs photoanode shows photocurrent density of 1.21 mA cm 2, which is 8.5 times higher than bare ZnO NWs. The PEC performance and the applied bias photon to current conversion efficiency of ZnO/ZnS core shell NWs photoanode are further improved with the optimized ZnS shell. The type II band alignment of the heterostructure photoanode is the key factor for their excellent PEC performance. Importantly, this type of core shell NWs heterostructure provides useful insights into novel electrode design and fabrication based on earth abundant materials for low cost solar fuel generation.
author_names: Mostafa Afifi Hassan

Muhammad Ali Johar

Aadil Waseem

Indrajit V Bagal

Jun-Seok Ha

Sang-Wan Ryu
title: Type II ZnO/ZnS core shell nanowires: Earth abundant photoanode for solar driven photoelectrochemical water splitting.
venue: Optics express
year: 2019

abstract: Abstract We report the fabrication of hybrid Si nanowires g C3N4 nanosheets based photocathode using metal assisted chemical etching and facile liquid exfoliated process. The g C3N4 nanosheets on Si nanowires form hybrid heterojunction photocathode, which exhibits an enhanced photon induced water reduction activity enabling higher photocurrent density of 22 mA cm 2 with applied bias photocurrent conversion efficiency of 4.3% under visible light irradiation. The onset potential of cathodic photocurrent is positively shifted from 41 to 420 mV vs. RHE with the short circuit current density, Jsc of 0.50 mA cm 2 owing to superior charge transport in hybrid photocathode as compared to pristine Si nanowires for hydrogen evolving reaction at pH~7. The electrochemical impedance spectroscopy measurement elucidates the interface layer of g C3N4 nanosheets form hybrid heterojunction with Si nanowires that result significant increment in solar water reduction activity owing to low charge transferred resistance with high life time of excited electrons in conduction band. This strategy may open to design a new low cost stable hybrid heterostructure photocathode for solar induced water reduction.
author_names: S Gopalakrishnan

Gopalkrishna M Bhalerao

Kulandaivel Jeganathan
title: g C3N4 nanosheets functionalized silicon nanowires hybrid photocathode for efficient visible light induced photoelectrochemical water reduction
venue: Journal of Power Sources
year: 2019

abstract: Abstract One dimensional heterostructured nanomaterials represent key building blocks for nanotechnologies due to a large number of applications such as electronics, catalysis, drug delivery, and energy storage and conversion devices. Electrospinning has been considered a straightforward and versatile method to prepare inorganic nanowires, but the heterostructured nanowires have been only fabricated by using dual nozzle or by introducing additional encapsulating step. Here we report one step fabrication of surface decorated inorganic nanowires via single nozzle electrospinning. Although the electrospinning precursor uses one mixed solution containing nickel salt, ceria nanoparticles, and polyvinylpyrrolidine (PVP) the nanowires show a core/shell like shape. The surface decorated nanowires consist of nickel shell and ceria core, which exhibits 95.52% of methane conversion at 600 degC whereas conventional particle type catalysts have only 60% at the same temperature in steam reforming.
author_names: Jin Goo Lee

Ok Sung Jeon

Jae-ha Myung

Yong-gun Shul
title: One step fabrication of surface decorated inorganic nanowires via single nozzle electrospinning
year: 2018