Next Article in Journal
Experimental Research on Electromechanical Properties of Multiple Contact Surfaces Copper Bulks under Normal Cyclic Loading and Variable Temperature
Previous Article in Journal
Influence of PLLA/PCL/HA Scaffold Fiber Orientation on Mechanical Properties and Osteoblast Behavior
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:

CoS2/TiO2 Nanocomposites for Hydrogen Production under UV Irradiation

Faculty of Engineering and Science, Western Norway University of Applied Sciences, 5020 Bergen, Norway
Clean Energy Research Laboratory, Department of Physics, University of Jaffna, Jaffna 40000, Sri Lanka
Department of Natural Science, University of Agder, 4630 Kristiansand, Norway
Department of Chemistry, University of Jaffna, Jaffna 40000, Sri Lanka
Authors to whom correspondence should be addressed.
Materials 2019, 12(23), 3882;
Submission received: 22 October 2019 / Revised: 18 November 2019 / Accepted: 22 November 2019 / Published: 24 November 2019
(This article belongs to the Section Energy Materials)


Transition metal chalcogenides have intensively focused on photocatalytic hydrogen production for a decade due to their stronger edge and the quantum confinement effect. This work mainly focuses on synthesis and hydrogen production efficiencies of cobalt disulfide (CoS2)-embedded TiO2 nanocomposites. Materials are synthesized by using a hydrothermal approach and the hydrogen production efficiencies of pristine CoS2, TiO2 nanoparticles and CoS2/TiO2 nanocomposites are compared under UV irradiation. A higher amount of hydrogen production (2.55 mmol g−1) is obtained with 10 wt.% CoS2/TiO2 nanocomposite than pristineTiO2 nanoparticles, whereas no hydrogen production was observed with pristine CoS2 nanoparticles. This result unveils that the metal dichalcogenide–CoS2 acts as an effective co-catalyst and nanocrystalline TiO2 serves as an active site by effectively separating the photogenerated electron–hole pair. This study lays down a new approach for developing transition metal dichalcogenide materials with significant bandgaps that can effectively harness solar energy for hydrogen production.

Graphical Abstract

1. Introduction

Depletion of fossil fuel deserves utilization of hydrogen as a renewable energy source. It could be one of the promising energy sources alternative to fossil fuels in meeting the energy demand of the current world population. Currently, the major hydrogen production is from steam-methane reforming and thermal cracking of natural gas, and coal gasification, which cannot alleviate the emission of greenhouse gases [1]. Electrolysis is another method, which is being used to produce hydrogen. Electrochemical reduction of water [2,3,4] is an ecofriendly method and exhibits high-purity (99.999%) of hydrogen [5]; in addition, this is a key to many clean energy technologies. Although there have been several methods used to produce hydrogen, photocatalytic hydrogen generation have gained much attention these days. This technique integrates solar energy collection together with water splitting, therefore, it is a more cost-effective method compared with the water electrolysis process. Unfortunately, only a small percentage of hydrogen is produced from the photocatalytic method under solar extended irradiation. Therefore, the development of new materials for sustainable hydrogen production is necessary to overcome the detrimental environmental impacts. In the past decade, different photocatalyst materials, such as TiO2 [6,7,8], ZnO [9], CdS [10,11], WS2 [12,13], mixed oxides [14,15], perovskites [16,17], dye and metal doped oxide materials [18,19] have been used as phototcatalysts for environmental remediation and energy production, such as water splitting applications. In particular, catalysts contain noble metals, such as Pt have also been utilized in the state-of-the-art hydrogen evolution reaction. However, large scale hydrogen production is limited with these catalysts [20,21,22]. Among the materials studied, TiO2 has been considered as the golden standard due to its significant characteristics that include photochemical stability, low toxicity, relative affordability, and ease of preparation [23]. Although the bandgap energy of TiO2 necessitates the use of UV irradiation, composites of TiO2 with co-catalysts, such as transition metal chalcogenides (TMCs), enable the catalysts to absorb visible light abundant in solar irradiation [24]. In this regard, TMCs have gained much attention among the research community in the field of lithium ion batteries, solar cells and hydrogen evolution, due to their significant characteristic features that include indirect bandgaps, optoelectronic properties and stability [24]. In addition, nanodots (quantum dots)/nano structures of these metal chalcogenides show stronger edge effects, and the quantum confinement effect make them suitable to be utilized under solar simulated irradiation [24,25]. The transition metal chalcogenides can be synthesized by employing different techniques, such as one-pot wet chemical method [10], impregnation–sulfidation [11], simple microwave-assisted solvothermal process [26], ion exchange and precipitation methods [27], and hydrothermal method [28]. Several studies on bare transition metal chalcogenides (MoS2, NiS2, WS2, CdS and CoS) for the hydrogen evolution reaction (HER) and oxygen reduction reactions (ORR) are reported [29,30,31,32], however, most of these studies mainly focused on electrochemical water splitting. Co-catalysts, such as, reduced graphene oxides [33], metal oxides [34], dyes, for example, Porphyrin (Zn(II)-5,10,15,20-tetrakis(4-carboxyphenyl)-porphyrin (ZnTCPP)) [19], graphene [35], metals [36], and CdLa2S4 nanocrystals [37] were used to enhance the rate of HER. Inorganic crystals with desired properties can be used as excellent candidates for HER. It was reported that the first-row transition metal chalcogenides (MS2; where M = Fe, Co, Ni) exhibit excellent catalytic properties for HER due to their pyrite or marcasite structure, in which the metal atoms are octahedrally bonded to adjacent S atoms. Stability is an important criterion in the development of catalysts [30,38,39,40,41,42,43,44,45]. In this regard, computational modelling was also employed on these metal chalcogenide materials to evaluate their structural properties for photocatalytic water splitting and hydrogen production [46]. In particular, MoS2 has been utilized with other elements via adsorption or intercalation of a cation, such as Li for electrochemical water splitting [46]. In another modelling work, a comparative study was done between WS2 and MoS2 in electrocatalytic water splitting [12]; In an experimental study, Yuexiang Li et al. reported hydrogen production of 99 μmol h−1 with MoS2 loaded on the composites of reduced graphene oxide and CdS, and this was found to be over 20 times higher than the bare CdS. CoS2 doped with Mn [47] and Al [48] used for electrocatalytic HER [49].
Although all the reported work on TMC-embedded TiO2 mainly focused on the electrochemical water splitting and computer modelling, to the best of our knowledge, no experimental study on TMC-embedded TiO2 for heterogeneous hydrogen production over extended solar irradiation has been reported yet. This study focuses on the synthesis of CoS2 (metal chalcogenide)-embedded TiO2 nanocomposite, and the impact of doping CoS2 with TiO2 in hydrogen evolution under UV irradiation.

2. Materials and Methods

2.1. Materials

Without further purification, titanium isopropoxide, 98+% (Sigma-Aldrich Norway AS, Oslo, Norway) was employed as the precursor for TiO2 preparation, Cobalt (II) nitrate hexahydrate, 99% pure (Sigma-Aldrich Norway AS) was utilized as the cobalt precursor, and Na2S2O3 (Sigma-Aldrich Norway AS) as sulfur source. PHARMCO-AAPER Ethyl alcohol (200 Proof; Absolute, anhydrous, Sigma-Aldrich Norway AS) was used as solvent and deionized water (resistivity >18 Ω·cm, Velp/AREC, VELP Scientifica Srl, Usmate (MB), Italy) was used to prepare the solution mixtures.

2.2. Methods

2.2.1. Synthesis

(1) Titanium dioxide
Nanocrystalline titanium dioxide material was prepared under hydrothermal condition using sol-gel technique. In a typical synthesis, 32.5 mL of ethanol was acidified with 0.3 mL concentrated HNO3 (Sigma-Aldrich, Oslo, Norway) in a Teflon liner and stirred at a constant speed (300 rpm, Velp/AREC, VELP Scientifica Srl,). 6.60 mL of titanium (iv) isopropoxide was added drop wise into it with continuous stirring, Finally, 3.0 mL of water was added to the above solution. Then, it was transferred into an autoclave (AUTOCLAVE-PTFE-0100, TECINSTRO, Maharashtra, India) and kept at 180 °C for 9 hours. The final material was heated at 500 °C for 3 h.
(2) CoS2 embedded TiO2 nanocomposite
118.24 mg of Co(NO3)2 and 192.72 mg of Na2S2O3 were added in to a 100 mL aqueous solution containing deionized water and ethanol in 2:1 ratio under constant stirring (300 rpm) for 30 min. Finally, required amount of TiO2 was dispersed into above solution and the resulting mixture was hydrothermally treated at 180 °C to prepare 10 wt.% of CoS2 embedded TiO2 material. Similar conditions were followed in the preparation of pristine CoS2 nanoparticles without adding titanium dioxide.

2.2.2. Characterization

Synthesized materials were subjected to different characterization techniques, such as Powder X-ray Diffraction (P-XRD, Ultima IV Rigaku, USA) Method, Diffuse Reflectance Spectra (DRS Cary 100 Bio UV–Visible spectrophotometer, Santa Clara, CA, USA) and Scanning Electron Microscopy (SEM, Oxford instrument, NanoAnalysis, Concord, MA, USA). P-XRD patterns were recorded on a Rigaku Ultima IV instrument (Scottsdale, AZ, USA) with Cu Kα radiation (λ = 1.5408 Å) at ambient temperature, under the following operating conditions; accelerating voltage of 40 kV; emission current of 44 mA; scanned range (2θ) between 20° and 80° with a step size of 0.02°, and a scan speed of 1°/min. DRS were acquired using a Cary 100 Bio UV–Visible spectrophotometer, and the SEM images were captured on an Oxford instrument.

2.2.3. Photocatalytic Hydrogen Evolution

The photocatalytic experiments were carried out for pristine TiO2, CoS2 and CoS2/TiO2. Catalysts were suspended in a solution containing 1.5 mL of H2O and 0.5 mL of methanol as a scavenging agent. The suspension was degassed for 30 minutes with high-purity argon prior to irradiation. The suspensions were continuously stirred throughout the course of the experiment. A 300 W Xenon lamp (Oriel light source, Xenon arc lamp, Newport 1000W, CA, USA) with an appropriate filter was used as the source of UV radiation. The amount of H2 produced was measured by gas chromatography (SRI 8610 C, SRI instruments, Torrance, CA, USA) equipped with a molecular sieve column and a TCD (Thermal Conductivity detector), and the amount of hydrogen produced was quantified by using a calibration curve prepared previously.

3. Results and Discussion

3.1. Characterization of Materials

The powder XRD patterns of the pristine CoS2, TiO2, and 10 wt.% CoS2/TiO2 nanocomposites are shown in Figure 1. The peaks observed at the 2 theta values of 26.04°, 31.58°, 37.08°, 40.34°, 45.34° and 55.1° are due to (111), (200), (210), (211), (220) and (311) diffraction planes of CoS2 (PDF Card No.: 9007682). The peaks at 2θ of 25.50°, 37.76°, 48.10°, 53.88°, 55.84° and 62.90° due to the (101), (004), (200), (105), (211) and (204) diffraction planes confirm the formation of TiO2 anatase phase (JCPDS 21-1272) [50]. Combination of CoS2 and TiO2 peaks observed with the 10 wt.% CoS2/TiO2 nanocomposite confirms good impregnation of CoS2 on TiO2.
Scanning electron microscopic images of blank CoS2 (a,b), TiO2 (c,d) and 10 wt.% CoS2/TiO2 (e,f) are illustrated in Figure 2. It can clearly be seen from Figure 2a,b that the bare CoS2 shows an aggregation, which is surrounded by flake like structures. An irregular 3D block-like structure covered with spongy like particles was attained for TiO2 nanocomposite and is shown in Figure 2c, and the zoom in image (Figure 2d) clearly illustrates the aggregated particles which have spongy-like structures. The mixed composite, CoS2/TiO2 also exhibits the aggregation, in which the zoom in image (Figure 2f) shows the hexagonal rod like structure decorated with spongy like materials [51].
The bandgap energies for the pristine CoS2, TiO2 and 10 wt.% CoS2/TiO2 nanocomposite materials corresponding to the absorbance spectra of powder samples (Figure 3a), were estimated by using the Tauc plot (Figure 3b), which was transformed via the Kubelka–Munk function [52], [ F ( R ) E ] n vs. E, when n = 0.5, for a direct allowed transition ( K = F ( R ) ) . Estimates derived from the Tauc plots by extrapolating the steep portion of the plot in Figure 3b to the x-axis suggest that the bandgaps of the pristine CoS2 (2.5 eV), TiO2 (3.2 eV) and CoS2 embedded TiO2 nanocomposite (3.4 eV) materials lie in the range between 2.4 and 3.4 eV.

3.2. Hydrogen Evolution

The amount of hydrogen evolved in the presence of UV irradiation is tabulated and compared with what is reported in the literature in Table 1. Transition metal chalcogenides, including MoS2, NiS, SnS2, WS2, and CdS, have been extensively explored for photocatalytic water splitting [11,24,36,49], since they are usually inexpensive, stable, and easily prepared on a large scale for practical applications. To improve the efficiency of TMCs on hydrogen evolution elemental doping, heterojunctions, and nano structuring have been explored. In this regard, metal chalcogenides have been doped with other components, such as reduced graphene oxide, graphene, dyes, and TiO2 using different experimental conditions.
For example, Qun Wang et al. worked on MoS2 quantum dots-doped TiO2 for hydrogen evolution reaction in under different experimental condition, and the rate of hydrogen evolution was found to be 0.05 mmol cm−2 h−1 [24]. In another study, Youngjun Yuan et al. used ZnTCPP-MoS2 /TiO2 material for HER (Hydrogen Evolution Reaction), where 0.10 mmol h−1 of hydrogen evolved with 1.00 wt.% of MoS2 on TiO2 material [19]. In line with these studies, the results from our study on metal chalcogenide-TiO2 nanocomposites showed that 10 wt.% CoS2 embedded on TiO2 nanocomposites synthesized by hydrothermal method was the excellent candidate for the photocatalytic HER with better hydrogen evolution rate of 2.55 mmol g−1. Pristine CoS2 alone showed no activity towards hydrogen production even after 4 hours of irradiation, whereas the TiO2 materials exhibited 1.88 mmolg−1 of hydrogen under the same experimental conditions. The reason for this observation can be correlated with the bandgap energies of the materials. The CoS2/TiO2 materials with highest activity exhibit bandgap of 3.4 eV, whereas the pristine TiO2 exhibits bandgap of 3.2 eV. Under UV irradiation, the electron-hole pair formed on the nanocomposites was effectively separated due to the bandgap >3 eV. However, in the case of pristine CoS2 (Bandgap of 2.5 eV), it can be concluded that the faster recombination rate of photogenerated electrons and holes hinder the formation of hydrogen effectively, and, thus, there is no activity observed with this catalyst, but CoS2 nanoparticles act as a co-catalyst in the nanocomposite of CoS2/TiO2 materials to enhance the hydrogen production by exciting more electrons to the surface of titanium dioxide.

4. Conclusions

Pristine CoS2 and TiO2, and CoS2/TiO2 nanocomposites were successfully synthesized via a hydrothermal method using titanium(iv)isopropoxide, Co(NO3)2 and Na2S2O3 as precursors. The mixed COS2/TiO2 nanocomposite exhibits a high hydrogen production value of 2.55 mmol g−1, whereas the pristine CoS2 material was found to be inactive due to its very low bandgap energy. The TiO2 material shows an intermediate hydrogen production of 1.88 mmol g−1. In summary, the hydrogen production seems to depend on the band gap energy of the catalysts, and the CoS2 may assist to effectively separate the electron-hole pair forms in the mixed nanocomposite, and thus, results in a higher value of hydrogen production.

Author Contributions

Conceptualization, Y.S, and S.S.; methodology, S.S. and Y.S.; software, S.S., and Y.S.; validation, S.S., A.A.C., D.V., P.R. and Y.S.; formal analysis, S.S. and Y.S.; investigation, S.S. and S.R.; resources, Y.S., P.R., and D.V.; data curation, S.S. and Y.S.; writing—original draft preparation, S.S.; writing—review and editing, Y.S., D.V., P.R., and A.A.C.; visualization, S.S.; supervision, A.A.C., D.V., P.R., and Y.S.; project administration, P.R. and D.V.; funding acquisition, P.R. and D.V.


This research was funded by Capacity Building and Establishment of a Research Consortium (CBERC) project, grant number LKA-3182-HRNCET and Higher Education and Research collaboration on Nanomaterials for Clean Energy Technologies (HRNCET) project, and grant number NORPART/2016/10237.


Authors would like to acknowledge Aravind Baride (University of South Dakota), who assisted with the SEM analysis. Y.S would like to thank Ranjit Koodali (University of South Dakota) for allowing her to utilize his lab to do the hydrogen evolution measurements.

Conflicts of Interest

The authors declare no conflict of interest.


  1. Kudo, A.; Miseki, Y. Heterogeneous photocatalyst materials for water splitting. Chem. Soc. Rev. 2009, 38, 253–278. [Google Scholar] [CrossRef] [PubMed]
  2. Cook, T.R.; Dogutan, D.K.; Reece, S.Y.; Surendranath, Y.; Teets, T.S.; Nocera, D.G. Solar Energy Supply and Storage for the Legacy and Nonlegacy Worlds. Chem. Rev. 2010, 110, 6474–6502. [Google Scholar] [CrossRef] [PubMed]
  3. Walter, M.G.; Warren, E.L.; Mckone, J.R.; Boettcher, S.W.; Mi, Q.; Santori, E.A.; Lewis, N.S. Solar Water Splitting Cells. Chem. Rev. 2010, 110, 6446–6473. [Google Scholar] [CrossRef] [PubMed]
  4. Lewis, N.S.; Nocera, D.G. Powering the planet: Chemical challenges in solar energy utilization. Proc. Natl. Acad. Sci. USA 2006, 103, 15729–15735. [Google Scholar] [CrossRef] [PubMed]
  5. Shiva Kumar, S.; Himabindu, V. Hydrogen production by PEM water electrolysis—A review. Mater. Sci. Energy Technol. 2019, 2, 442–454. [Google Scholar] [CrossRef]
  6. Yin, Y.; Jin, Z.; Hou, F. Enhanced solar water-splitting efficiency using core/sheath heterostructure CdS/TiO2 nanotube arrays. Nanotechnology 2007, 18, 495608. [Google Scholar] [CrossRef]
  7. Kim, S.B.; Hong, S.C. Kinetic study for photocatalytic degradation of volatile organic compounds in air using thin film TiO2 photocatalyst. Appl. Catal. B Environ. 2002, 35, 305–315. [Google Scholar] [CrossRef]
  8. Matthews, R.W. Photooxidative degradation of coloured organics in water using supported catalysts. TiO2 on sand. Water Res. 1991, 25, 1169–1176. [Google Scholar] [CrossRef]
  9. Chakrabarti, S.; Dutta, B.K. Photocatalytic degradation of model textile dyes in wastewater using ZnO as semiconductor catalyst. J. Hazard. Mater. 2004, 112, 269–278. [Google Scholar] [CrossRef]
  10. Chen, J.; Wu, X.J.; Yin, L.; Li, B.; Hong, X.; Fan, Z.; Chen, B.; Xue, C.; Zhang, H. One-pot synthesis of CdS nanocrystals hybridized with single-layer transition-metal dichalcogenide nanosheets for efficient photocatalytic hydrogen evolution. Angew. Chem. Int. Ed. 2015, 54, 1210–1214. [Google Scholar] [CrossRef] [PubMed]
  11. Zong, X.; Han, J.; Ma, G.; Yan, H.; Wu, G.; Li, C. Photocatalytic H2 evolution on CdS loaded with WS2 as cocatalyst under visible light irradiation. J. Phys. Chem. C 2011, 115, 12202–12208. [Google Scholar] [CrossRef]
  12. Chen, T.Y.; Chang, Y.H.; Hsu, C.L.; Wei, K.H.; Chiang, C.Y.; Li, L.J. Comparative study on MoS2 and WS2 for electrocatalytic water splitting. Int. J. Hydrog. Energy 2013, 38, 12302–12309. [Google Scholar] [CrossRef]
  13. Feng, C.; Huang, L.; Guo, Z.; Liu, H. Synthesis of tungsten disulfide (WS2) nanoflakes for lithium ion battery application. Electrochem. Commun. 2007, 9, 119–122. [Google Scholar] [CrossRef]
  14. Pirashanthan, A.; Murugathas, T.; Robertson, N.; Ravirajan, P.; Velauthapillai, D. A Quarterthiophene-Based Dye as an Efficient. Polymers 2019, 11, 1752. [Google Scholar] [CrossRef] [PubMed]
  15. Mugunthan, E.; Saidutta, M.B.; Jagadeeshbabu, P.E. Photocatalytic degradation of diclofenac using TiO2–SnO2 mixed oxide catalysts. Environ. Technol. (UK) 2019, 40, 929–941. [Google Scholar] [CrossRef]
  16. Kim, H.G.; Hwang, D.W.; Kim, J.; Kim, Y.G.; Lee, J.S. Highly donor-doped (110) layered perovskite materials as novel photocatalysts for overall water splitting. Chem. Commun. 1999, 2, 1077–1078. [Google Scholar] [CrossRef]
  17. Kanazawa, T.; Nozawa, S.; Lu, D.; Maeda, K. Structure and Photocatalytic Activity of PdCrOx Cocatalyst on SrTiO3 for Overall Water Splitting. Catalysts 2019, 9, 59. [Google Scholar] [CrossRef]
  18. Jafari, T.; Moharreri, E.; Amin, A.S.; Miao, R.; Song, W.; Suib, S.L. Photocatalytic water splitting—The untamed dream: A review of recent advances. Molecules 2016, 21, 900. [Google Scholar] [CrossRef]
  19. Yuan, Y.; Lu, H.; Ji, Z.; Zhong, J.; Ding, M.; Chen, D.; Li, Y.; Tu, W.; Cao, D.; Yu, Z.; et al. Enhanced visible-light-induced hydrogen evolution from water in a noble-metal-free system catalyzed by ZnTCPP-MoSTiO2 assembly. Chem. Eng. J. 2015, 275, 8–16. [Google Scholar] [CrossRef]
  20. Gasteiger, H.A.; Shao-horn, Y.; Sheng, W.; Gasteiger, H.A.; Shao-horn, Y. Hydrogen Oxidation and Evolution Reaction Hydrogen Oxidation and Evolution Reaction Kinetics on Platinum: Acid vs Alkaline Electrolytes. J. Electrochem. Soc. 2010, 157, B1529–B1536. [Google Scholar]
  21. Greeley, J.; Nørskov, J.K.; Kibler, L.A.; El-aziz, A.M.; Kolb, D.M. Hydrogen Evolution Over Bimetallic Systems: Understanding the Trends. Chem. Phys. Chem. 2006, 7, 1032–1035. [Google Scholar] [CrossRef] [PubMed]
  22. Schuldiner, S. Hydrogen Overvoltage on Bright Platinum. J. Electrochem. Soc. 1952, 99, 488–494. [Google Scholar] [CrossRef]
  23. Hamidi, F. TiO2 -based Photocatalytic Cementitious Composites: Materials, Properties, Influential Parameters, and Assessment Techniques. Nanomaterials 2019, 9, 1444. [Google Scholar] [CrossRef] [PubMed]
  24. Wang, Q.; Huang, J.; Sun, H.; Ng, Y.H.; Zhang, K.Q.; Lai, Y. MoS2 Quantum Dots@TiO2 Nanotube Arrays: An Extended-Spectrum-Driven Photocatalyst for Solar Hydrogen Evolution. Chem. Sus. Chem. 2018, 11, 1708–1721. [Google Scholar] [CrossRef]
  25. Zheng, L.; Zhang, W.; Xiao, X. Preparation of titanium dioxide/tungsten disulfide composite photocatalysts with enhanced photocatalytic activity under visible light. Korean J. Chem. Eng. 2016, 33, 107–113. [Google Scholar] [CrossRef]
  26. Liu, H.; Su, Y.; Chen, P.; Wang, Y. Microwave-assisted solvothermal synthesis of 3D carnation-like SnS 2 nanostructures with high visible light photocatalytic activity. J. Mol. Catal. A Chem. 2013, 378, 285–292. [Google Scholar] [CrossRef]
  27. Nezamzadeh-Ejhieh, A.; Moeinirad, S. Heterogeneous photocatalytic degradation of furfural using NiS-clinoptilolite zeolite. Desalination 2011, 273, 248–257. [Google Scholar] [CrossRef]
  28. Huerta-Flores, A.M.; Torres-Martínez, L.M.; Moctezuma, E.; Singh, A.P.; Wickman, B. Green synthesis of earth-abundant metal sulfides (FeS2, CuS, and NiS2) and their use as visible-light active photocatalysts for H2 generation and dye removal. J. Mater. Sci. Mater. Electron. 2018, 29, 11613–11626. [Google Scholar] [CrossRef]
  29. Fang, W.; Liu, D.; Lu, Q.; Sun, X.; Asiri, A.M. Nickel promoted cobalt disulfide nanowire array supported on carbon cloth: An efficient and stable bifunctional electrocatalyst for full water splitting. Electrochem. Commun. 2016, 63, 60–64. [Google Scholar] [CrossRef]
  30. Desheng, K.; Cha, J.J.; Wang, H.-T.; Hye, R.L.; Yi, C. First-row transition metal dichalcogenide catalysts for hydrogen evolution reaction. Energy Environ. Sci. 2013, 6, 3553–3558. [Google Scholar]
  31. Susac, D.; Zhu, L.; Teo, M.; Sode, A.; Wong, K.C.; Wong, P.C.; Parsons, R.R.; Bizzotto, D.; Mitchell, K.A.R.; Campbell, S.A. Characterization of FeS2 -Based Thin Films as Model Catalysts for the Oxygen Reduction Reaction. J. Phys. Chem. C 2007, 111, 18715–18723. [Google Scholar] [CrossRef]
  32. Feng, Y.; He, T.; Alonso-vante, N. Electrochimica Acta Oxygen reduction reaction on carbon-supported CoSe2 nanoparticles in an acidic medium. Electrochim. Acta 2009, 54, 5252–5256. [Google Scholar] [CrossRef]
  33. Li, Y.; Wang, H.; Xie, L.; Liang, Y.; Hong, G.; Dai, H. MoS2 nanoparticles grown on graphene: An advanced catalyst for the hydrogen evolution reaction. J. Am. Chem. Soc. 2011, 133, 7296–7299. [Google Scholar] [CrossRef] [Green Version]
  34. Khan, Z.; Chetia, T.R.; Vardhaman, A.K.; Barpuzary, D.; Sastri, C.V.; Qureshi, M. Visible light assisted photocatalytic hydrogen generation and organic dye degradation by CdS-metal oxide hybrids in presence of graphene oxide. RSC Adv. 2012, 2, 12122–12128. [Google Scholar] [CrossRef]
  35. Chang, K.; Mei, Z.; Wang, T.; Kang, Q.; Ouyang, S.; Ye, J. MoS2/graphene cocatalyst for efficient photocatalytic H2 evolution under visible light irradiation. ACS Nano 2014, 8, 7078–7087. [Google Scholar] [CrossRef]
  36. Yan, C.; Xue, X.; Zhang, W.; Li, X.; Liu, J.; Yang, S.; Hu, Y.; Chen, R.; Yan, Y.; Zhu, G.; et al. Well-designed Te/SnS2/Ag artificial nanoleaves for enabling and enhancing visible-light driven overall splitting of pure water. Nano Energy 2017, 39, 539–545. [Google Scholar] [CrossRef]
  37. Yuan, Y.P.; Cao, S.W.; Yin, L.S.; Xu, L.; Xue, C. NiS2 Co-catalyst decoration on CdLa2S4 nanocrystals for efficient photocatalytic hydrogen generation under visible light irradiation. Int. J. Hydrog. Energy 2013, 38, 7218–7223. [Google Scholar] [CrossRef]
  38. Chen, W.; Sasaki, K.; Ma, C.; Frenkel, A.I.; Marinkovic, N.; Muckerman, J.T.; Zhu, Y.; Adzic, R.R. Hydrogen-Evolution Catalysts Based on Non-Nobel Metal Nickel–Molybdenum Nitride Nanosheets. Angew. Chem. Int. Ed. 2012, 51, 6131–6135. [Google Scholar] [CrossRef]
  39. Chen, W.-F.; Wang, C.-H.; Sasaki, K.; Marinkovic, N.; Xu, W.-Q.; Muckerman, J.; Zhu, Y.-M.; Adzic, R.R. Nanostructured Molybdenum Carbide as Pt-free Catalysts for Hydrogen Evolution. Electrochem. Soc. 2012, 1817. Available online: (accessed on 22 October 2019).
  40. Vrubel, H.; Hu, X. Molybdenum Boride and Carbide Catalyze Hydrogen Evolution in both Acidic and Basic Solutions. Angew. Chem. Int. Ed. 2012, 12703–12706. [Google Scholar] [CrossRef] [Green Version]
  41. Wang, H.; Kong, D.; Johanes, P.; Cha, J.J.; Zheng, G.; Yan, K.; Liu, N. MoSe2 and WSe2 Nano fi lms with Vertically Aligned Molecular Layers on Curved and Rough Surfaces. Nano Lett. 2013, 13, 3426–3433. [Google Scholar] [CrossRef]
  42. Kong, D.; Wang, H.; Cha, J.J.; Pasta, M.; Koski, K.J.; Yao, J.; Cui, Y. Synthesis of MoS2 and MoSe2 Films with Vertically Aligned Layers. Nano Lett. 2013, 13, 1341–1347. [Google Scholar] [CrossRef]
  43. Merki, D.; Vrubel, H.; Rovelli, L.; Fierro, S.; Hu, X. Fe, Co, and Ni ions promote the catalytic activity of amorphous molybdenum sulfide films for hydrogen evolution. Chem. Sci. 2012, 3, 2515–2525. [Google Scholar] [CrossRef] [Green Version]
  44. Environ, E. Hydrogen evolution catalyzed by MoS3 and MoS2 particle. Energy Environ. Sci. 2012, 5, 6136–6144. [Google Scholar]
  45. Merki, D.; Fierro, S.; Vrubel, H.; Hu, X. Amorphous molybdenum sulfide films as catalysts for electrochemical hydrogen production in water. Chem. Sci. 2011, 2, 1262–1267. [Google Scholar] [CrossRef] [Green Version]
  46. Wu, L.; Dzade, N.Y.; Yu, M.; Mezari, B.; van Hoof, A.J.F.; Friedrich, H.; de Leeuw, N.H.; Hensen, E.J.M.; Hofmann, J.P. Unraveling the Role of Lithium in Enhancing the Hydrogen Evolution Activity of MoS2: Intercalation versus Adsorption. ACS Energy Lett. 2019, 4, 1733–1740. [Google Scholar] [CrossRef] [Green Version]
  47. Zhang, J.; Liu, Y.; Sun, C.; Xi, P.; Peng, S.; Gao, D.; Xue, D. Accelerated Hydrogen Evolution Reaction in CoS2 by Transition-Metal Doping. ACS Energy Lett. 2018, 3, 779–786. [Google Scholar] [CrossRef]
  48. Wang, M.; Zhang, W.; Zhang, F.; Zhang, Z.; Tang, B.; Li, J.; Wang, X. Theoretical Expectation and Experimental Implementation of in Situ Al-Doped CoS2 Nanowires on Dealloying-Derived Nanoporous Intermetallic Substrate as an Efficient Electrocatalyst for Boosting Hydrogen Production. ACS Catal. 2019, 9, 1489–1502. [Google Scholar] [CrossRef]
  49. Li, Y.; Wang, H.; Peng, S. Tunable photodeposition of MoS2 onto a composite of reduced graphene oxide and CdS for synergic photocatalytic hydrogen generation. J. Phys. Chem. C 2014, 118, 19842–19848. [Google Scholar] [CrossRef]
  50. Xing, J.; Li, Y.H.; Jiang, H.B.; Wang, Y.; Yang, H.G. The size and valence state effect of Pt on photocatalytic H2 evolution over platinized TiO2 photocatalyst. Int. J. Hydrog. Energy 2014, 39, 1237–1242. [Google Scholar] [CrossRef]
  51. Raut, P.; Li, S.; Chen, Y.M.; Zhu, Y.; Jana, S.C. Strong and Flexible Composite Solid Polymer Electrolyte Membranes for Li-Ion Batteries. ACS Omega 2019, 4–10. [Google Scholar] [CrossRef] [PubMed]
  52. Sun, J.; Wang, H.; Zhang, Y.; Zheng, Y.; Xu, Z.; Liu, R. Structure and luminescent properties of electrodeposited Eu3 +-doped CaF2 thin films. Thin Solid Film. 2014, 562, 478–484. [Google Scholar] [CrossRef]
  53. Liu, E.; Chen, J.; Ma, Y.; Feng, J.; Jia, J.; Fan, J.; Hu, X. Fabrication of 2D SnS2 /g-C3N4 heterojunction with enhanced H2 evolution during photocatalytic water splitting. J. Colloid Interface Sci. 2018, 524, 313–324. [Google Scholar] [CrossRef] [PubMed]
  54. Yu, J.; Xu, C.Y.; Ma, F.X.; Hu, S.P.; Zhang, Y.W.; Zhen, L. Monodisperse SnS2 nanosheets for high-performance photocatalytic hydrogen generation. ACS Appl. Mater. Interfaces 2014, 6, 22370–22377. [Google Scholar] [CrossRef] [PubMed]
  55. Kong, C.; Min, S.; Lu, G. Dye-sensitized NiSx catalyst decorated on graphene for highly efficient reduction of water to hydrogen under visible light irradiation. ACS Catal. 2014, 4, 2763–2769. [Google Scholar] [CrossRef]
Figure 1. XRD patterns of the pristine CoS2, TiO2, and 10 wt.% CoS2/TiO2 nanocomposite.
Figure 1. XRD patterns of the pristine CoS2, TiO2, and 10 wt.% CoS2/TiO2 nanocomposite.
Materials 12 03882 g001
Figure 2. SEM images of the CoS2 (a,b), TiO2 (c,d), and 10 wt.% CoS2/TiO2 (e,f) nanocomposite.
Figure 2. SEM images of the CoS2 (a,b), TiO2 (c,d), and 10 wt.% CoS2/TiO2 (e,f) nanocomposite.
Materials 12 03882 g002
Figure 3. (a) Absorbance from diffuse reflectance spectra and (b) Tauc plots of pristine CoS2, TiO2 and 10 wt.% CoS2/TiO2 nanocomposite.
Figure 3. (a) Absorbance from diffuse reflectance spectra and (b) Tauc plots of pristine CoS2, TiO2 and 10 wt.% CoS2/TiO2 nanocomposite.
Materials 12 03882 g003
Table 1. Amount of hydrogen evolved with different transition metal Chalcogenides: A comparison.
Table 1. Amount of hydrogen evolved with different transition metal Chalcogenides: A comparison.
MaterialSynthesis MethodRate of Hydrogen EvolutionSacrificial AgentReference
2D SnS2/g-C3N4
(5 wt.% SnS2/g-C3N4)
Hydrothermal method0.97 mmol h−1 g−110 vol% TEOA and 3 wt.% H2Pt2Cl6·6H2OEnzhou Liu et al., 2018 [53]
Te/SnS2/AgHydrothermal method0.33 mmol h−1-Changzeng Yan et al., 2017[36]
SnS2 NanosheetsSolvothermal1.06 mmol h−1 g−10.1 M Na2S
0.1M Na2S2O3
Jing yu et al., 2014[54]
CdS/ WS2Impregnation-sulfidation0.42 mmol h−1Latic acid solutionZong et al., 2011[11]
Dye-Sensitized NiSx/ graphene
(in EY/G)
Insitu chemical deposition method0.04 mmol h−1-Chao Kong et al., 2014[55]
Dye-Sensitized NiSx/ graphene
(in EY/NiSx/G)
Insitu chemical deposition method0.34 mmol h−1-Chao Kong et al., 2014[55]
MoS2/ RGO and CdS
(pH11-MoS2/rGO 1.5/CdS)
Photoreduction method0.10 mmol h−110 vol.% Latic acid solutionYuexiang Li et al., 2014 [49]
MoS2/GrapheneHydrothermal1.80 mmol h−1Na2S-Na2S2O3 solutionChang et al., 2014[35]
MoS2 quantum dots/TiO2 nanotube arraysElectrodeposition0.07 mmol cm−2 h−1
0.05 mmol cm−2 h−1
0.02 mmoL cm−2 h−1
-Qun Wang et al., 2018[24]
(1.00 wt.% MoS2 on TiO2)
Hydrothermal0.10 mmol h−10.2 M triethanolamine (TEOA) aqueousYoungjun Yuan et al., 2015[19]
10 wt.% CoS2/TiO2Hydrothermal2.55 mmol g−1MethanolThis work

Share and Cite

MDPI and ACS Style

Shanmugaratnam, S.; Velauthapillai, D.; Ravirajan, P.; Christy, A.A.; Shivatharsiny, Y. CoS2/TiO2 Nanocomposites for Hydrogen Production under UV Irradiation. Materials 2019, 12, 3882.

AMA Style

Shanmugaratnam S, Velauthapillai D, Ravirajan P, Christy AA, Shivatharsiny Y. CoS2/TiO2 Nanocomposites for Hydrogen Production under UV Irradiation. Materials. 2019; 12(23):3882.

Chicago/Turabian Style

Shanmugaratnam, Sivagowri, Dhayalan Velauthapillai, Punniamoorthy Ravirajan, Alfred Antony Christy, and Yohi Shivatharsiny. 2019. "CoS2/TiO2 Nanocomposites for Hydrogen Production under UV Irradiation" Materials 12, no. 23: 3882.

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop