ZnIn2S4 hybrid with MoS2: A non-noble metal photocatalyst with efficient photocatalytic activity for hydrogen evolution

    ZnIn2 S4 hybrid with MoS 2 : A non-noble metal photocatalyst with efficient photocatalytic activity for hydrogen evolution Ting Huang, Wei Chen, Tian-Yu Liu, Qing-Li Hao, Xiao-Heng Liu PII: DOI: Reference:

S0032-5910(17)30271-1 doi:10.1016/j.powtec.2017.03.054 PTEC 12459

To appear in:

Powder Technology

Received date: Revised date: Accepted date:

21 November 2016 15 January 2017 22 March 2017

Please cite this article as: Ting Huang, Wei Chen, Tian-Yu Liu, Qing-Li Hao, Xiao-Heng Liu, ZnIn2 S4 hybrid with MoS2 : A non-noble metal photocatalyst with efficient photocatalytic activity for hydrogen evolution, Powder Technology (2017), doi:10.1016/j.powtec.2017.03.054

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT ZnIn2S4 hybrid with MoS2: A non-noble metal photocatalyst with efficient photocatalytic activity for hydrogen evolution

1

IP

T

Ting Huang1, Wei Chen1, Tian-Yu Liu1, Qing-Li Hao1, Xiao-Heng Liu1,* Key Laboratory of Education Ministry for Soft Chemistry and Functional Materials, Nanjing

SC R

University of Science and Technology, Nanjing 210094, China Tel. 86-25-84315943

NU

Fax 86-25-84315054

MA

E-mail: [email protected]

Abstract

D

We report the synthesis of ternary zinc indium sulfide hybrid with few-layer MoS2 via

TE

a sequential two-step hydrothermal method. The products were characterized by TEM,

CE P

HR-TEM, XPS, XRD, and DRS. The visible-light induced photocatalytic activities for hydrogen evolution were also evaluated. The result showed that the nanohybrid with a loading amount of MoS2 at 0.5 wt% manifested a superior H2-production rate

AC

under visible-light irradiation(λ＞420nm). The enhanced photocatalytic activity is mainly attributed to the synergistic effect of enhanced specific surface area, effective electron–hole pair separation and boosted catalytic active sites. This work may contribute to the design and construction of non-noble metal photocatalyst.

Key words Zinc indium sulfide; Transition metal dichalcogenide; Photocatalytic water splitting

ACCEPTED MANUSCRIPT 1.Introduction

T

With the increasing emphasis recently on sustainable energy harvesting and

IP

conversion, H2 production from water splitting has gained mounting attention[1-3].

SC R

Since the discovery of photoelectrocatalytic water splitting by titania[4], great efforts have been devoted to the exploration of semiconductor photocatalysts.

NU

Except for TiO2, various semiconductors, including CdS[5-8], ZnO[9-11],

MA

Bi2WO6[12] have been intensively investigated. However, their application is restricted by their own intrinsic limitations, such as toxicity, wide band-gap and low

TE

D

efficiency caused by the rapid recombination of photo-generated electron–hole pairs. Given that, ZnIn2S4, a visible-light-responsive material with a bandgap of 2.0-2.2 eV,

CE P

has raised great concern due to its excellent illumination stability, visible-light

AC

responsive photocatalytic activity and low toxicity[13-15]. Many reports revealed that the ternary zinc indium sulfide shows excellent photocatalytic activity for pollutants degradation in water[16-19]. For example, Fang et al.[20] successfully synthesized well-defined micro ZnIn2S4 peony by a solventhermal method. The as-obtained ternary zinc indium sulfide exhibited excellent photocatalytic activity for the photodegradation of methylene blue. Chen’s group[21] compared the photocatalytic performance of Hexagonal ZnIn2S4 microspheres and Cubic ZnIn2S4 nanoparticles toward the degradation of different dyes. A detailed study on the physicochemical and

ACCEPTED MANUSCRIPT

IP

T

surface properties was conducted to explain for that.

SC R

Besides, ZnIn2S4 exhibits great potential in the field of photocatalytic water splitting[22-26]. For example, Chai and his co-workers[27] reported a facile template-

NU

free hydrothermal method to prepare ZnIn2S4 floriated microspheres and evaluate the

MA

photocatalytic activities for hydrogen production under visible-light irradiation. However, it should be noted that the application of pure ZnIn2S4 for hydrogen

TE

D

generation is still limited due to its relatively low efficiency under visible light irradiation.

CE P

The loading of noble metal as cocatalyst on semiconductors could significantly enhance the H2 production efficiency in presence of sacrificial reagents[28-31]. In

AC

view of its high cost, active searches have been ongoing for low-cost alternatives based on earth-abundant elements[32, 33]. Amomg them, molybdenum disulfide(MoS2), a transition metal dichalcogenide (TMD) with layered structure, holds tremendous promise for clean energy generation[34-37]. The S atoms on exposed edges of MoS2 have strong bonds to H+ in the solution, which are easily reduced to H2 by electrons[38, 39]. Thus it has been considered as a promising candidate for next-generation substitute for noble metals. For example, Zong et al.[40] reported the synthesis of CdS/MoS2 composite with even higher photocatalytic H2 production rate than that of Pt/CdS. Zhou et al.[41] prepared MoS2 nanosheet coated TiO2 nanobelt heterostructure via a hydrothermal reaction with a high photocatalytic

ACCEPTED MANUSCRIPT hydrogen production rate even without the Pt co-catalyst. Zhao et al.[42] described the synthesis of MoS2–Cd0.5Zn0.5S as an efficient non-noble metal photocatalyst of H2

T

evolution from water under visible light irradiation. Xiang et al.[43] report a new

IP

composite material consisting of TiO2 nanocrystals grown in the presence of a layered

SC R

MoS2/graphene hybrid as a high-performance photocatalyst for H2 evolution. Based on the results aforementioned, we anticipated that the MoS2 could act as an efficient cocatalyst for water splitting.

NU

Herein, a two-step hydrothermal method was employed to synthesize the

MA

ZnIn2S4/MoS2 composite. Although during the past few years, various methods have been developed for the controllable synthesis of few-layer MoS2, including chemical

D

vapour deposition, mechanical exfoliation and liquid exfoliation. In consideration of

TE

the feasibility of operation and subsequent fabrication of zinc indium sulfide, a direct sonication in aqueous solution was applied to synthesize few-layer MoS2. The as-

CE P

obtained MoS2 with more exposed active edges was used as a non-noble metal cocatalyst for ZnIn2S4 to enhance the photocatalytic H2 production activity. The

AC

nanohybrid manifested a superior H2-production rate under visible-light irradiation(λ ＞420nm). We hope that this work may provide a new insight in the design and construction of non-noble metal photocatalyst for sustainable energy generation. 2. Experimental 2.1. Materials Indium nitrate hydrate (In(NO3)3･4.5H2O), Zinc nitrate hexahydrate (Zn(NO3)2･ 6H2O), thioacetamide (TAA), Sodium diethyldithiocarbamatre (NaDDTC) were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). Molybdenum chloride (MoCl5) were supplied by Aladdim Industrial Corporation.

ACCEPTED MANUSCRIPT Deionized(DI) water was used in all experiments. All chemicals were used without further purification.

T

2.2. Synthesis of few-layer MoS2

IP

In a typical synthesis of MoS2, 0.5 mmol of MoCl5 was dissolved into 20 mL of

SC R

ethanol. 15 ml aqueous solution containing 2.5mmol of NaDDTC were dropped into the above solution. The as-obtained homogenous solution was transferred into a 50mL PPL-lined autoclave and maintained at 200℃ for 24h. the black product was collected

NU

by centrifugation, washed five times by deionized water and ethanol, and dried in an

MA

oven overnight.

To prepare few-layer MoS2, a sonication method was applied. Typically, 20 mg of as-

D

prepared MoS2 and 100 mL water were added into a beaker and the beaker was

TE

immersed into a 800W ultrasonic machine for 4h. The as-obtained homogeneous suspension of MoS2 was directly used for the preparation of composite.

CE P

2.3.Synthesis of ZnIn2S4/MoS2

1mmol of Zn(NO3)2 and 1mmol of In(NO3)3 were dissloved into certain amount of the

AC

above mentioned homogeneous suspension. The weight addition ratio of MoS2 was selected as 0, 0.3%, 0.5%, 0.7%, 1%, 3%. Then, 15 mL water containing 2mmol of TAA was added dropwise under magnetic stirring. The obtained mixture was sealed into a Teflon-lined stainless autoclave and maintained at 120 ℃ for 12 h. After cooling to room temperature, the precipitate was centirfugated and washed with water and ethanol several times. Then the samples were dried in a oven at 60 ℃ overnight.

2.4.Characterization The morphology of ZnIn2S4/MoS2 were evaluated by transmission electron microscopy(TEM, JEOL-2100). The structure and crystal phase of the samples were

ACCEPTED MANUSCRIPT examined by X-ray diffraction(XRD, Bruker D8 Advance) with monochromated high-intensity Cu Kα radiation (λ=1.5418Å) operated at 40 kV and 40 mA. The

T

optical properties of the photocatalyst samples were measured using UV-vis diffuse

IP

reflectance spectroscopy (Shimadzu UV-2500) and BaSO4 was used as the reflectance

SC R

standard. The elemental compositions and chemical states of the as-prepared samples were analyzed by X-ray photoelectron spectra (XPS) on a Phi Quantera II SXM X-ray

exciting source.

MA

2.5.Electrochemical measurement

NU

photoelectron spectrometer with a monochromatic Al Kα radiation (λ = 8.4 Å) as the

The photocurrent test of the samples were measured using an electrochemical

TE

D

analyzer(CHI600E Instruments) in a three-electrode system consisting of a working electrode, a platinum wire as a counter electrode, and a Ag/AgCl electrode (SCE) as a

CE P

reference electrode. The working electrode was prepared as follows: the catalyst ink

AC

was first prepared by dispersing 10 mg of products into 5 mL mixed solvents of water, isopropanol and Nafion (volume ratio as 40:20:1). Then 0.1 mL catalyst ink dispersions were dropped directly onto a cleaning FTO glass surface and placed in a vacuum oven to speed dry. The working electrodes were immersed in a supporting electrolyte solution of 0.5 M Na2SO4. The electrochemical impedance spectra (EIS) measurement was conducted in 0.1 M KCl solution containing 2.5 mM K3[Fe(CN)6]/K4[Fe(CN)6]. The amplitude was set at 5mV and frequency varied from 100000 Hz to 0.01 Hz. The working electrode was irradiated with a xenon lamp (300 W) with a 420 nm cut-off filter during the above measurement.

ACCEPTED MANUSCRIPT Mott–Schottky measurement was carried out in a solution containing 0.5 M Na2SO4. 2.6. Photocatalytic reaction test

IP

T

H2 evolution reactions were carried out in a closed gas-circulation system. In this

SC R

system, 50 mg catalyst was dispersed in 200 mL aqueous solution of Na2S 0.35 M /Na2SO3 0.25M. After removing air from the reaction system, the solution was

NU

irradiated by a 300 W xenon lamp (XL-300, Yirda) equipped with a 420 nm cut-off

MA

filter and the amount of H2 produced was measured by gas chromatography (GC-1690, Jiedao, TCD, Ar carrier).

D

3 Results and discussion

TE

The XRD pattern of the pure ZnIn2S4 and MoS2 loadings of 0.3, 0.5, 1 and 3wt% are

CE P

presented in Fig. 1. We denote the hybrid photocatalysts with different MoS2 catalyst loadings in mass as ZnIn2S4/MoS2-x(x=0.3, 0.5, 1 and 3). All peaks can be assigned to

AC

cubic phase of ZnIn2S4 (JCPDS 48-1778). The intense peaks at 27.846, 33.735 and 48.436 can be indexed to the (311), (400), (440) planes, respectively. No apparent peaks for MoS2 in ZnIn2S4/MoS2 can be observed due to the low loading amount and poor crystallinity of MoS2. The morphology and microstructures of ZnIn2S4/MoS2 hybrid were further investigated by transmission electron microscopy (TEM). As can be seen from Fig. 2(a) and (b), ZnIn2S4 nanoparticles were dispersed on the surface of MoS2 nanosheet to form a closely conjugated structure. The HR-TEM in Fig. 2(c) reveals that the composite sample possess distinct lattice fringes with an interplanar spacing of 0.321

ACCEPTED MANUSCRIPT and 0.615 nm, corresponding well to the (311) and (111) plane of cubic ZnIn2S4 phase, respectively. The interplanar spacing of 0.303 nm in Fig. 2(d) can be indexed to the

T

(222) plane as well.

IP

The valence states of the elements in pure ZnIn2S4 and ZnIn2S4/MoS2 are analyzed by

SC R

X-ray photoelectron spectroscopy (XPS). The binding energies obtained were corrected by referencing the C 1s line to 284.6 eV. As shown in Fig. 3(a) and (b), the peaks centered at 1020.4 and 1043.7 eV are attributed to Zn 2p3/2 and 2p1/2, while the

NU

peaks at 443.5 and 451.0 eV are attributed to In 3d5/2 and 3d3/2 of pure ZnIn2S4, which

MA

verify the existence of Zn2+ and In3+ in the sample. After the introduction of MoS2, a higher binding energy shift can be observed. The BE peaks of Zn 2p for

D

ZnIn2S4/MoS2 were observed at 1020.7 and 1043.9 eV, while the In 3d at 443.8 and

TE

451.3 eV. The binding energies of 160.2 eV for S 2p3/2 and 161.6 eV for S 2p1/2 can be assigned to S2-[44]. After hybridizing with MoS2 nanosheet, the binding energies

CE P

ascribed to Zn 2p, In 3d and S 2p are slightly shift towards high values, which suggest the strong interaction between zinc indium sulfide and MoS2 nanosheet. As we know,

AC

the electronegativity of Zn and In is lower than that of Mo (χZn= 1.65, χIn= 1.78, χMo = 2.16), thus the electron of ZnIn2S4 tend to transfer to more electronegative MoS2[45]. The XPS spectra of ZnIn2S4/MoS2 shows that the binding energies of Mo 3d3/2 and Mo 3d5/2 peaks are located at 230 and 227 eV, respectively, implying that Mo4+ exists in the sample. The values are similar to previous reports for MoS2[46]. The UV-vis diffuse reflectance spectroscopy(DRS) was carried out to investigate the optical absorption properties of the samples. As can be seen from Fig. 4(a), the pure ZnIn2S4 shows a wide absorption in visible region, which indicate that ZnIn2S4 is a visible light responsive photocatalyst,. The composites show a relatively enhanced absorption intensity compared to pure ZnIn2S4. With increasing the content of MoS2,

ACCEPTED MANUSCRIPT the hierarchical composites showed enhanced absorption intensity in the visible light region, and it was consistent with that the color of the samples changed from yellow

T

to gray when more black MoS2 was introduced into the system. The Tauc plot of

IP

pristine ZnIn2S4 was shown in Fig. 4(b). The bandgap of pure ZnIn2S4 was estimated

literaturally reported value[47]. Photocatalytic Activity of Photocatalysts

SC R

by kubelka-Munk function and determined at 2.2 eV, which is in accordance with the

NU

The photocatalytic H2 production activities of ZnIn2S4 with different MoS2 contents

MA

were evaluated under visible light illumination (λ＞420nm). As shown in Fig. 5(a), The pure ZnIn2S4 shows a very low rate of H2 evolution (ca. 26 µmol･h-1) in an

D

aqueous solution with Na2S 0.35 M/Na2SO3 0.25 M as sacrificial electron donor. This

TE

may be ascribed to the rapid recombination between CB electrons and VB holes of

CE P

ZnIn2S4. With the increase of the amount of MoS2,the rate of H2 evolution is increased and reaches a maximum when the loading amount of MoS2 reached about 0.5%. The total yield of H2 exhibit four-time higher than pure ZnIn2S4, which

AC

demonstrates it is quite effective to employ MoS2 as cocatalyst for improving efficiency of ZnIn2S4 photocatalytic activity. Further increases in the MoS2 content lead to a gradual reduction of the H2 generation rate. When the MoS2 content reaches 3%, the photo-catalytic activity was found to be dramatically decreased. This might be due to the less exposed active sites of ZnIn2S4 resulting from the excess MoS2 shielding. Besides, it is considerable that the irradiation intensity passing through the solution decreased when the samples get darker. To evaluate its photostability, five recycling tests were carried out, as illustrated in Fig. 5(b). The rate of H2 production is relatively steady, without an apparent decrease after five cycling runs.

ACCEPTED MANUSCRIPT Fig. 6(a) compares the photocurrent response of pure ZnIn2S4 and ZnIn2S4/MoS2 composites. Under visible-light illumination, the photocurrent response of the ZnIn2S4

T

electrode was very weak. The average photocurrent density is ca. 0.05 μA･cm−2 for

IP

the three light-on and light-off cycles. An enhanced photocurrent response for the

SC R

ZnIn2S4/MoS2-0.3 electrode was observed under the similar experimental conditions and the photocurrent density reaches ca. 0.1μA･cm−2. The transient photocurrent

NU

response was reached about 7 times as high as that of ZnIn2S4 after loading 0.5 wt%

MA

of MoS2, indicating that the heterojunction between ZnIn2S4 and MoS2 can accelerate the charge separation.

Electrochemical impedance spectra (EIS) under visible light irradiation is also

TE

D

conducted to study the charge transfer at the semiconductor/electrolyte interface. As can be seen in Fig. 6(b), pure ZnIn2S4 shows a bigger radius than the ZnIn2S4/MoS2

CE P

composite in the middle-frequency region. When the loading amount of MoS2 was at 0.5%, the composite exhibits the smallest semicircle, which indicates the fastest

AC

interfacial electron transfer. Thus we come to the conclusion that the introduction of MoS2 can facilitate the transfer of photogenerated charge carriers and MoS2 is an effective cocatalyst for photocatalytic hydrogen generation.

Mechanism The tentative electron transfer and hydrogen production mechanism in the ZnIn2S4/MoS2 composites are proposed in Fig. 7. The CB position of ZnIn2S4 were estimated by Mott–Schottky analysis. As shown in Fig. S2, the conduction band potential of pure ZnIn2S4 are determined at -1.003 V (vs NHE).

ACCEPTED MANUSCRIPT Since the band gap of ZnIn2S4 is calculated at 2.2 V according to the UV-vis diffuse reflectance spectroscopy, the valence band potential is finally determined at 1.197 V.

T

Under visible-light irradiation(λ＞420nm), ZnIn2S4 nanoparticles are excited to

IP

generate electrons and holes. The generated electrons are easily transferred to

SC R

conduction band (CB), leaving photo-generated holes in the valence band (VB). However, the photocatalytic activity of pure ZnIn2S4 was lower because of the rapid

NU

recombination of photo-generated electrons and holes. In the case of ZnIn2S4/MoS2 composites, the excited electrons from the CB of ZnIn2S4 may transfer to the MoS2

MA

nanosheets because of the low Fermi energy level of MoS2 (ca. −0.1 V)[48-50]. As demonstrated by the TEM image in Figure 2, ZnIn2S4 deposited on the surface of

D

MoS2 sheets contributes to the photo-generated electrons transfer from CB of ZnIn2S4

TE

to MoS2. The S atoms on exposed edges of MoS2 have strong bonds to H+ in the

CE P

solution, which are easily reduced to H2 by electrons. Thus MoS2 may act as an efficient cocatalyst in the system. The holes that remained on the VB of ZnIn2S4 nanoparticles are consumed by the Na2S and Na2SO3 in the solution.

AC

4.Conclusion

We have successfully constructed ZnIn2S4/MoS2 composites via a two-step hydrothermal method. Our results showed that there exists an optimum loading amount of MoS2 (∼0.5wt%) for the best photocatalytic response of ZnIn2S4. The introduction of MoS2 can efficiently promotes the electron–hole separation and lengthen the charge lifetime in the process of photocatalytic reaction. The composite holds tremendous promise for clean energy generation.

Acknowledgements

ACCEPTED MANUSCRIPT The authors are grateful for the financial support from the Natural Science Foundation of China (Grant no.51572126). The work was supported by the program for Science

AC

CE P

TE

D

MA

NU

SC R

IP

T

and Technology Innovative Research Team in Universities of Jiangsu Province.

ACCEPTED MANUSCRIPT Reference [1] X.-J. Lv, W.-F. Fu, H.-X. Chang, H. Zhang, J.-S. Cheng, G.-J. Zhang, Y. Song,

T

C.-Y. Hu, J.-H. Li, Hydrogen evolution from water using semiconductor

IP

nanoparticle/graphene composite photocatalysts without noble metals, J. Mater.

SC R

Chem., 22 (2012) 1539-1546.

[2] A. Kudo, Y. Miseki, Heterogeneous photocatalyst materials for water splitting, Chemical Society reviews, 38 (2009) 253-278.

NU

[3] T.M. Gür, S.F. Bent, F.B. Prinz, Nanostructuring Materials for Solar-to-Hydrogen

MA

Conversion, The Journal of Physical Chemistry C, 118 (2014) 21301-21315. [4] A. Fujishima,K. Honda, Electrochemical photolysis of water at a semiconductor

D

electrode, Nature, 238(1972) 37–39

TE

[5] Q. Li, B. Guo, J. Yu, J. Ran, B. Zhang, H. Yan, J.R. Gong, Highly efficient visible-light-driven photocatalytic hydrogen production of CdS-cluster-decorated

10884.

CE P

graphene nanosheets, Journal of the American Chemical Society, 133 (2011) 10878-

AC

[6] W. Chen, G.-R. Duan, T.-Y. Liu, Z.-M. Jia, X.-H. Liu, S.-M. Chen, X.-J. Yang, Synthesis of homogeneous one-dimensional Ni x Cd1−x S nanorods with enhanced visible-light response by ethanediamine-assisted decomposition of complex precursors, Journal of Materials Science, 50 (2015) 3920-3928. [7]L. Wang, H. Chen, L. Xiao, J. Huang, CuS/ZnS hexagonal plates with enhanced hydrogen evolution activity under visible light irradiation, Powder Technology, 288 (2016) 103-108. [8]A. Hernández-Gordillo, A.G. Romero, F. Tzompantzi, R. Gómez, New nanostructured CdS fibers for the photocatalytic reduction of 4-nitrophenol, Powder Technology, 250 (2013) 97-102.

ACCEPTED MANUSCRIPT [9] X. Liu, M. Afzaal, K. Ramasamy, P. O’Brien, J. Akhtar, Synthesis of ZnO Hexagonal Single-Crystal Slices with Predominant (0001) and (0001) Facets by

T

Poly(ethylene glycol)-Assisted Chemical Bath Deposition, Journal of the American

IP

Chemical Society, 131 (2009) 15106-15107.

SC R

[10]J. Xie, Y. Li, W. Zhao, L. Bian, Y. Wei, Simple fabrication and photocatalytic activity of ZnO particles with different morphologies, Powder Technology, 207 (2011) 140-144.

NU

[11]J. Wang, J. Yang, X. Li, B. Feng, B. Wei, D. Wang, H. Zhai, H. Song, Effect of

MA

surfactant on the morphology of ZnO nanopowders and their application for photodegradation of rhodamine B, Powder Technology, 286 (2015) 269-275.

D

[12] W. Chen, T.-Y. Liu, T. Huang, X.-H. Liu, J.-W. Zhu, G.-R. Duan, X.-J. Yang, In

TE

situ fabrication of novel Z-scheme Bi2WO6 quantum dots/g-C3N4 ultrathin nanosheets heterostructures with improved photocatalytic activity, Applied Surface

CE P

Science, 355 (2015) 379-387.

[13] S. Yang, L. Li, W. Yuan, Z. Xia, Enhanced visible light photocatalytic activity of

AC

ZnIn2S4 modified by semiconductors, Dalton transactions, 44 (2015) 6374-6383. [14] J. Song, T. Jiang, G. Ji, W. Zhang, X. Cheng, W. Weng, L. Zhu, X. Xu, Visiblelight-driven dye degradation using a floriated ZnIn2S4/AgIn5S8heteromicrosphere catalyst, RSC Adv., 5 (2015) 95943-95952. [15] W. Chen, T.-Y. Liu, T. Huang, X.-H. Liu, J.-W. Zhu, G.-R. Duan, X.-J. Yang, One-pot hydrothermal route to synthesize the ZnIn2S4/g-C3N4 composites with enhanced photocatalytic activity, Journal of Materials Science, 50 (2015) 8142-8152. [16] L. Ye, J. Fu, Z. Xu, R. Yuan, Z. Li, Facile one-pot solvothermal method to synthesize sheet-on-sheet reduced graphene oxide (RGO)/ZnIn2S4 nanocomposites

ACCEPTED MANUSCRIPT with superior photocatalytic performance, ACS applied materials & interfaces, 6 (2014) 3483-3490.

T

[17] W.K. Jo, J.Y. Lee, T.S. Natarajan, Fabrication of hierarchically structured novel

IP

redox-mediator-free ZnIn2S4 marigold flower/Bi2WO6 flower-like direct Z-scheme

SC R

nanocomposite photocatalysts with superior visible light photocatalytic efficiency, Physical chemistry chemical physics : PCCP, 18 (2015) 1000-1016. [18] S. Peng, L. Li, Y. Wu, L. Jia, L. Tian, M. Srinivasan, S. Ramakrishna, Q. Yan,

NU

S.G. Mhaisalkar, Size- and shape-controlled synthesis of ZnIn2S4 nanocrystals with

MA

high photocatalytic performance, CrystEngComm, 15 (2013) 1922. [19] L. Yuan, M.-Q. Yang, Y.-J. Xu, A low-temperature and one-step method for

D

fabricating ZnIn2S4–GR nanocomposites with enhanced visible light photoactivity,

TE

Journal of Materials Chemistry A, 2 (2014) 14401. [20] F. Fang, L. Chen, Y.-B. Chen, L.-M. Wu, Synthesis and Photocatalysis of

CE P

ZnIn2S4 Nano/Micropeony, The Journal of Physical Chemistry C, 114 (2010) 23932397.

AC

[21] Y. Chen, R. Huang, D. Chen, Y. Wang, W. Liu, X. Li, Z. Li, Exploring the different photocatalytic performance for dye degradations over hexagonal ZnIn2S4 microspheres and cubic ZnIn2S4 nanoparticles, ACS applied materials & interfaces, 4 (2012) 2273-2279. [22] Z. Mei, S. Ouyang, D.M. Tang, T. Kako, D. Golberg, J. Ye, An ion-exchange route for the synthesis of hierarchical In2S3/ZnIn2S4 bulk composite and its photocatalytic activity under visible-light irradiation, Dalton transactions, 42 (2013) 2687-2690.

ACCEPTED MANUSCRIPT [23] J. Hou, C. Yang, H. Cheng, Z. Wang, S. Jiao, H. Zhu, Ternary 3D architectures of CdS QDs/graphene/ZnIn2S4 heterostructures for efficient photocatalytic H2

T

production, Physical chemistry chemical physics : PCCP, 15 (2013) 15660-15668.

IP

[24] Z. Lei, W. You, M. Liu, G. Zhou, T. Takata, M. Hara, K. Domen, C. Li,

SC R

Photocatalytic water reduction under visible light on a novel ZnIn2S4 catalyst synthesized by hydrothermal method, Chemical communications, (2003) 2142. [25] J. Zhou, G. Tian, Y. Chen, X. Meng, Y. Shi, X. Cao, K. Pan, H. Fu, In situ

NU

controlled growth of ZnIn2S4 nanosheets on reduced graphene oxide for enhanced

MA

photocatalytic hydrogen production performance, Chemical communications, 49 (2013) 2237-2239.

D

[26] M.A. Mahadik, P.S. Shinde, M. Cho, J.S. Jang, Fabrication of a ternary

TE

CdS/ZnIn2S4/TiO2heterojunction for enhancing photoelectrochemical performance: effect of cascading electron–hole transfer, J. Mater. Chem. A, 3 (2015) 23597-23606.

CE P

[27] B. Chai, T. Peng, P. Zeng, X. Zhang, X. Liu, Template-Free Hydrothermal Synthesis of ZnIn2S4Floriated Microsphere as an Efficient Photocatalyst for

AC

H2Production under Visible-Light Irradiation, The Journal of Physical Chemistry C, 115 (2011) 6149-6155. [28] G. Xi, J. Ye, Q. Ma, N. Su, H. Bai, C. Wang, In situ growth of metal particles on 3D urchin-like WO3 nanostructures, Journal of the American Chemical Society, 134 (2012) 6508-6511. [29] K. Wu, Z. Chen, H. Lv, H. Zhu, C.L. Hill, T. Lian, Hole removal rate limits photodriven H2 generation efficiency in CdS-Pt and CdSe/CdS-Pt semiconductor nanorod-metal tip heterostructures, Journal of the American Chemical Society, 136 (2014) 7708-7716.

ACCEPTED MANUSCRIPT [30] T. Liu, W. Chen, T. Huang, G. Duan, X. Yang, X. Liu, Titania-on-gold nanoarchitectures for visible-light-driven hydrogen evolution from water splitting,

T

Journal of Materials Science, 51 (2016) 6987-6997.

IP

[31] G. He, M. Qian, X. Sun, Q. Chen, X. Wang, H. Chen, Graphene sheets-based

SC R

Ag@Ag3PO4 heterostructure for enhanced photocatalytic activity and stability under visible light, Powder Technology, 246 (2013) 278-283.

[32] A. Wang, X. Li, Y. Zhao, W. Wu, J. Chen, H. Meng, Preparation and

NU

characterizations of Cu2O/reduced graphene oxide nanocomposites with high photo-

MA

catalytic performances, Powder Technology, 261 (2014) 42-48. [33] Y.J. Zhang, L.C. Liu, D.P. Chen, Synthesis of CdS/bentonite nanocomposite

D

powders for H2 production by photocatalytic decomposition of water, Powder

TE

Technology, 241 (2013) 7-11.

[34] J.D. Benck, Z. Chen, L.Y. Kuritzky, A.J. Forman, T.F. Jaramillo, Amorphous

CE P

Molybdenum Sulfide Catalysts for Electrochemical Hydrogen Production: Insights into the Origin of their Catalytic Activity, ACS Catalysis, 2 (2012) 1916-1923.

AC

[35] J.D. Benck, T.R. Hellstern, J. Kibsgaard, P. Chakthranont, T.F. Jaramillo, Catalyzing the Hydrogen Evolution Reaction (HER) with Molybdenum Sulfide Nanomaterials, ACS Catalysis, (2014) 3957-3971. [36] J. Xie, J. Zhang, S. Li, F. Grote, X. Zhang, H. Zhang, R. Wang, Y. Lei, B. Pan, Y. Xie, Controllable disorder engineering in oxygen-incorporated MoS2 ultrathin nanosheets for efficient hydrogen evolution, Journal of the American Chemical Society, 135 (2013) 17881-17888. [37] J. Kibsgaard, Z. Chen, B.N. Reinecke, T.F. Jaramillo, Engineering the surface structure of MoS2 to preferentially expose active edge sites for electrocatalysis, Nature materials, 11 (2012) 963-969.

ACCEPTED MANUSCRIPT [38] B. Hinnemann, P.G. Moses, J. Bonde, K.P. Jørgensen, J.H. Nielsen, S. Horch, I. Chorkendorff, J.K. Nørskov, Biomimetic Hydrogen Evolution:  MoS2 Nanoparticles

T

as Catalyst for Hydrogen Evolution, Journal of the American Chemical Society, 127

IP

(2005) 5308-5309.

SC R

[39] H.I. Karunadasa, E. Montalvo, Y. Sun, M. Majda, J.R. Long, C.J. Chang, A molecular MoS(2) edge site mimic for catalytic hydrogen generation, Science, 335 (2012) 698-702.

NU

[40] X. Zong, H. Yan, G. Wu, G. Ma, F. Wen, L. Wang, C. Li, Enhancement of

MA

Photocatalytic H2 Evolution on CdS by Loading MoS2 as Cocatalyst under Visible Light Irradiation, Journal of the American Chemical Society, 130 (2008) 7176-7177.

D

[41] W. Zhou, Z. Yin, Y. Du, X. Huang, Z. Zeng, Z. Fan, H. Liu, J. Wang, H. Zhang,

TE

Synthesis of few-layer MoS2 nanosheet-coated TiO2 nanobelt heterostructures for enhanced photocatalytic activities, Small, 9 (2013) 140-147.

CE P

[42] S. Zhao, J. Huang, Q. Huo, X. Zhou, W. Tu, A non-noble metal MoS2– Cd0.5Zn0.5S photocatalyst with efficient activity for high H2evolution under visible

AC

light irradiation, J. Mater. Chem. A, 4 (2016) 193-199. [43] Q. Xiang, J. Yu, M. Jaroniec, Synergetic effect of MoS2 and graphene as cocatalysts for enhanced photocatalytic H2 production activity of TiO2 nanoparticles, Journal of the American Chemical Society, 134 (2012) 6575-6578. [44] W. Chen, T. Huang, Y.X. Hua, T.Y. Liu, X.H. Liu, S.M. Chen, Hierarchical CdIn2S4 microspheres wrapped by mesoporous g-C3N4 ultrathin nanosheets with enhanced visible light driven photocatalytic reduction activity, J Hazard Mater, 320 (2016) 529-538.

ACCEPTED MANUSCRIPT [45] L. Wei, Y. Chen, Y. Lin, H. Wu, R. Yuan, Z. Li, MoS2 as non-noble-metal cocatalyst for photocatalytic hydrogen evolution over hexagonal ZnIn2S4 under visible

T

light irradiations, Applied Catalysis B: Environmental, 144 (2014) 521-527.

IP

[46] U. Maitra, U. Gupta, M. De, R. Datta, A. Govindaraj, C.N. Rao, Highly effective

SC R

visible-light-induced H(2) generation by single-layer 1T-MoS(2) and a nanocomposite of few-layer 2H-MoS(2) with heavily nitrogenated graphene, Angewandte Chemie, 52 (2013) 13057-13061.

NU

[47] W. Chen, T.-Y. Liu, T. Huang, X.-H. Liu, X.-J. Yang, Novel mesoporous P-

MA

doped graphitic carbon nitride nanosheets coupled with ZnIn2S4 nanosheets as efficient visible light driven heterostructures with remarkably enhanced photoreduction activity, Nanoscale, 8 (2016) 3711-3719.

TE

D

[48] Y. Lu, D. Wang, P. Yang, Y. Du, C. Lu, Coupling ZnxCd1−xS nanoparticles with graphene-like MoS2: superior interfacial contact, low overpotential and

CE P

enhanced photocatalytic activity under visible-light irradiation, Catalysis Science & Technology, 4 (2014) 2650.

AC

[49] M. Liu, F. Li, Z. Sun, L. Ma, L. Xu, Y. Wang, Noble-metal-free photocatalysts MoS2–graphene/CdS mixed nanoparticles/nanorods morphology with high visible light efficiency for H2evolution, Chemical communications, 50 (2014) 11004. [50] Y. Min, G. He, Q. Xu, Y. Chen, Dual-functional MoS2 sheet-modified CdS branch-like heterostructures with enhanced photostability and photocatalytic activity, Journal of Materials Chemistry A, 2 (2014) 2578.

MA

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

AC

CE P

TE

D

Fig. 1.XRD patterns of synthesized ZnIn2S4 and ZnIn2S4/MoS2 hybrids.

CE P

TE

D

MA

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

Fig. 2.(a)TEM images of ZnIn2S4/MoS2 hybrid, (b)a magnified TEM image of

AC

ZnIn2S4/MoS2 hybrid, (c)and (d)HR-TEM image of ZnIn2S4/MoS2 hybrid.

TE

D

MA

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

CE P

Fig. 3.High resolution XPS spectra of (a)Zn 2p, (b)In 3d, (c)S 2p and (d)Mo 3d for

AC

the obtained samples.

SC R

IP

T

ACCEPTED MANUSCRIPT

NU

Fig. 4.(a) UV–Vis diffuse reflectance spectra of as-prepared photocatalysts, (b) Plot

AC

CE P

TE

D

MA

of (αhν)2 vs photo energy (hν) for pure ZnIn2S4 sample.

SC R

IP

T

ACCEPTED MANUSCRIPT

Fig. 5.(a)Average H2 production rate during five hours of ZnIn2S4 and ZnIn2S4/MoS2

NU

composites under visible light irradiation (λ≥420nm), (b)Cycling runs for the photocatalytic hydrogen generation of ZnIn2S4/MoS2-0.5 under visible light

AC

CE P

TE

D

MA

irradiation.

SC R

IP

T

ACCEPTED MANUSCRIPT

Fig. 6.(a)Photocurrent-time curves of ZnIn2S4 and ZnIn2S4/MoS2 composite,

AC

CE P

TE

D

MA

NU

(b)Electrochemical impedance spectra (EIS) of ZnIn2S4 and ZnIn2S4/MoS2 composite.

MA

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

D

Fig. 7.Schematic illustration of the potential and band positions of the ZnIn2S4/MoS2

AC

CE P

TE

composite.

ACCEPTED MANUSCRIPT Abstract We report the synthesis of ternary zinc indium sulfide hybrid with few-layer MoS2 via

T

a sequential two-step hydrothermal method. The products were characterized by TEM,

IP

HR-TEM, XPS, XRD, and DRS. The visible-light induced photocatalytic activities

SC R

for hydrogen evolution were also evaluated. The result showed that the nanohybrid with a loading amount of MoS2 at 0.5 wt% manifested a superior H2-production rate

NU

under visible-light irradiation(λ＞420nm). The enhanced photocatalytic activity is mainly attributed to the synergistic effect of enhanced specific surface area, effective

MA

electron–hole pair separation and boosted catalytic active sites. This work may

AC

CE P

TE

D

contribute to the design and construction of non-noble metal photocatalyst.

ACCEPTED MANUSCRIPT

AC

CE P

TE

D

MA

NU

SC R

IP

T

GRAPHICAL ABSTRACT

ACCEPTED MANUSCRIPT HIGHTLIGHT 1. A two-step hydrothermal method was applied to synthesize

T

ZnIn2S4/MoS2 composite.

IP

2. The few-layer MoS2 nanosheet was obtained via a ultrasonic method.

SC R

3. MoS2 replaced noble metals as an efficient cocatalyst for hydrogen generation.

NU

4. The composite shows enhanced H2 generation rate under visible light

MA

irradiation.

5. This work may contribute to the construction of noble-metal free

AC

CE P

TE

D

photocatalysts.