Part 3: Hybrid Materials of Graphene and TMD and Their Applications
3.1 Introduction of hybrid materials of rGO/TMD for energy applications
3.1.2 Application of rGO/TMD for energy application
Lithium-ion batteries are one of the most promising rechargeable battery systems. The main issue is the aggregation and structural deterioration of nanostructured electrodes during the charge/discharge process at the lithium-insertion reaction. Graphene hybrids with the excellent conductivity and high surface areas have been employed as supporting materials to overcome these problems. Recently, the application of TMDs, especially MoS2, in LIBs has gained attention, and improved energy storage performance has been realized using hybrid nanostructured electrodes. MoS2 sheets have been combined with graphene nanosheets for improved conductivity and stability. Such hybrid materials can be obtained by the methods mentioned above. For example, the electrochemical performances of the MoS2/rGO composites to their robust composite structure as well as the synergistic effects between layered MoS2 and graphene have been demonstrated.2a Layered MoS2/rGO composites were synthesized by a hydrothermal method with subsequent annealing applied in a H2/N2 atmosphere at 800 °C for 2 h. The layered MoS2 is supported on the graphene surface, which then form MoS2/rGO composites. The MoS2/rGO materials exhibit a 3D architecture morphology consisting of curved nanosheets, which are attributed to the self-assembly of graphene hydrogel during the hydrothermal process. This structure, with a large exposed surface area possesses a short diffusion distance for the Li+ ions and a large electrode-electrolyte contact area for the flux of Li+ ions across the interface leading to an enhanced rate capability. In addition to the high specific capacity, the composites showed excellent cyclic stabilities.
A layered WS2/rGO composites prepared by a hydrothermal methods with an appropriated amount of CTAB surfactant showed a high specific capacity of 905 mAhg-1 at 100 mAg-1, excellent cycleability (average of 0.08 % capacity fading per cycle for 100 cycles), and rate performance (20% capacity reduction with a 50-fold increase in the current density from 100 mAg-1 to 5000 mAg-1).16 The efficient transport of electrons and Li through the composite can occur due to the curvature in the porous structure.
In addition, sodium ion batteries can be constructed using TMD/rGO hybrid materials. Layered
84
MoS2/rGO prepared by the vacuum filtration of a mixed solution of MoS2 and GO was evaluated as a counter electrode in a Na-ion battery. The electrode showed good Na cycling ability with a stable charge capacity of approximately 230 mAhg-1. Static uniaxial tensile tests performed on crumpled composite papers showed a high average strain to failure rate which reached approximately 2%. When applied as anodes in Na-ion batteries, WS2/rGO exhibited a high reversible sodium storage capacity of about 590 mAhg-1. Some examples of TMD-based hybrid electrodes for alkali metal batteries are listed in Table 3.1.1.
To date, Pt-group metals have been utilized as the most effective electrocatalysts for hydrogen evolution reactions in an acidic medium. However, their low abundance and high cost considerably limit the large-scale application of Pt-based catalysts.18 Recently, great efforts have been made to explore efficient non-noble catalysts. A few successful examples were shown, including MoS2,2b,19 MoSe2,20 WS2,7 WSe2,21 MoB,22 Mo2C,23 Ni2P,24 and Co0.6Mo1.4N2.25 Some layered TMDs, such as MoS2 and WS2 are well-known electrocatalysts and have drawn much attention due to their good catalytic properties for HER.2b,7 The excellent conductivity and large specific surface area of graphene make it an attractive matrix for the synthesis for hybrid materials for electrocatalytic reactions.10b Therefore, improved performance can be observed when using composites of rGO/TMD. The electrocatalyst for rGO/TMD will be discussed in section 3.2. Due to their low cost and good photostability, chalcogenide materials have been considered the suitable photocatalysts for environmental applications. Hybrid materials are important in photocatalysis, as a single-component catalyst may not be able simultaneously to meet the numerous requirements of high-performance photocatalysis (i.e., broad visible light adsorption, a large specific surface area, effective electron-hole pair generation and minimized charge carrier recombinations). Therefore, hybrid materials have been explored for photocatalysts. As examples, CdS functionalized graphene for visible-light-driven photocatalytic H2 production has been demonstrated. A high H2-production rate (1.12 mmol h-1) which is about 4.87 times that of pure CdS NPs, has been achieved.26 Yu et al. reported that a ZnSe Np- decorated N-doped graphene composite showed superior activity for the decomposition of methyl orange (MO) under visible-light irradiation. Hou et al. demonstrated a 2D porous g-C3N4
nanosheet/nitrogen-doped graphene/layered MoS2 (CNNS/NRGO/MoS2) ternary nanojunction. CNNS with a large surface area can absorb visible light, together with the layered MoS2, to enhance light absorption and generate more photoelectrons. The charge separation and transfer were improved at the CNNS/MoS2 interface, where the NRGO worked as an the electron mediator for shuttling electron- holes between CNNS and MoS2 sheets.12 Some of the recent trends are summarized in Table 3.1.1.
85
Figure 3.1.1. (a) 2D hybrid- nanosheets can be prepared through vacuum filtration of mixed solution with exfoliated MoS2 and GO sheets.11 (b) Tri-hybrid materials of Mo2N, Mo2C, and MoS2 catalysts supported on CNT–RGO hybrid.13
(a) (b)
86
Table 3.1.1. Recent trend of two-dimensional hybrid materials based on graphene
Reference Materials Structure Method Application
ACS Nano 2014, 8, 1759
MoS2/rGO 2D
Vacuum filtration with acid-treated MoS2 flakes and
GO
Sodium-ion battery
Adv. Energy. Mater.
2013, 3, 839
MoS2/N-doped
graphene 2D Hydrothermal
method Lithium storage J. Solid State Sci.
Technol.
2013, 2, M3034
MoS2/rGO 2D
Vacuum filtration with MoS2 and
GO sheets
Li-ion battery
Int. J. Hydrogen. Energ.
2013, 38, 14027
MoS2/rGO 2D Hydrothermal
method Supercapacitor J. Phys. Chem. C
2012, 116, 25415
MoS2/rGO 2D Hydrothermal
method Photocatalyst J. Am. Chem. Soc.
2011, 133, 7296
MoS2/rGO 0D-2D Solvothermal
method Electrocatalyst Nanoscale
2013, 5, 9562
MoS2/rGO 2D Hydrothermal
method Mg battery
Adv. Energy. Mater.
2014,
DOI:10.1002/aenm.201300775
MoSx-compound
CNT-graphene 0D-2D Liquid phase reaction
Quantum-dot- sensitized solar
cells J. Mater. Chem. A
2014, 2, 360
MoSe2/rGO 2D Hydrothermal
method Electrocatalyst Crys. Res. Technol.
2014, 49, 204
MoSe2/rGO 2D Hydrothermal
method
Oil-based additives
87 Chem. Comm. 2014,
DOI:10.1039/C4CC00840E
WS2/rGO 2D Hydrothermal
method
Sodium-ion battery Nanoscale
2013, 5, 7890
WS2/rGO 2D Hydrothermal
method Li+ storage
88 3.1.3 References
1. Chhowalla, M.; Shin, H. S.; Eda, G.; Li, L.-J.; Loh, K. P.; Zhang, H. The chemistry of two- dimensional layered transition metal dichalcogenide nanosheets. Nat. chem 2013, 5, 263-275.
2. (a) Chang, K.; Chen, W. L-Cysteine-assisted synthesis of layered MoS2/graphene composites with excellent electrochemical performances for lithium ion batteries. ACS Nano 2011, 5, 4720-4728; (b) 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.
3. Rout, C. S.; Kim, B.-H.; Xu, X.; Yang, J.; Jeong, H. Y.; Odkhuu, D.; Park, N.; Cho, J.; Shin, H.
S. Synthesis and characterization of patronite form of vanadium sulfide on graphitic layer. J.
Am. Chem. Soc. 2013, 135, 8720-8725.
4. Cao, A.; Liu, Z.; Chu, S.; Wu, M.; Ye, Z.; Cai, Z.; Chang, Y.; Wang, S.; Gong, Q.; Liu, Y. A facile one-step method to produce graphene–CdS quantum dot nanocomposites as promising optoelectronic materials. Adv. Mater. 2010, 22, 103-106.
5. Kim, Y.-T.; Han, J. H.; Hong, B. H.; Kwon, Y.-U. Electrochemical synthesis of CdSe quantum- dot arrays on a graphene basal plane using mesoporous silica thin-film templates. Adv. Mater.
2010, 22, 515-518.
6. Katsukis, G.; Malig, J.; Schulz-Drost, C.; Leubner, S.; Jux, N.; Guldi, D. M. Toward combining graphene and QDs: assembling CdTe QDs to exfoliated graphite and nanographene in water.
ACS Nano 2012, 6, 1915-1924.
7. Yang, J.; Voiry, D.; Ahn, S. J.; Kang, D.; Kim, A. Y.; Chhowalla, M.; Shin, H. S. Two‐
dimensional hybrid nanosheets of tungsten disulfide and reduced graphene oxide as Catalysts for enhanced hydrogen evolution. Angew. Chem. Int. Ed. 2013, 52, 13751-13754.
8. Manga, K. K.; Wang, J.; Lin, M.; Zhang, J.; Nesladek, M.; Nalla, V.; Ji, W.; Loh, K. P. High- performance broadband photodetector using solution-processible PbSe–TiO2–graphene hybrids. Adv. Mater. 2012, 24, 1697-1702.
9. Zhang, Y.; Zhang, N.; Tang, Z.-R.; Xu, Y.-J. Graphene transforms wide band gap ZnS to a visible light photocatalyst. The new role of graphene as a macromolecular photosensitizer. ACS Nano 2012, 6, 9777-9789.
10. (a) Xiang, Q.; Yu, J.; Jaroniec, M. Synergetic effect of MoS2 and graphene as cocatalysts for enhanced photocatalytic H2 production activity of TiO2 nanoparticles. J. Am. Chem. Soc. 2012, 134, 6575-6578; (b) Min, S.; Lu, G. Sites for high efficient photocatalytic hydrogen evolution on a limited-layered MoS2 cocatalyst confined on graphene sheets―The role of graphene. J.
Phys. Chem. C 2012, 116, 25415-25424; (c) Huang, K.-J.; Wang, L.; Liu, Y.-J.; Liu, Y.-M.;
89
Wang, H.-B.; Gan, T.; Wang, L.-L. Layered MoS2–graphene composites for supercapacitor applications with enhanced capacitive performance. Int. J. Hydrogen Energ. 2013, 38, 14027- 14034.
11. (a) David, L.; Bhandavat, R.; Singh, G. MoS2/graphene composite paper for sodium-ion battery electrodes. ACS Nano 2014, 8, 1759-1770; (b) Hu, Y.; Li, X.; Lushington, A.; Cai, M.; Geng, D.; Banis, M. N.; Li, R.; Sun, X. Fabrication of MoS2-graphene nanocomposites by layer-by- layer manipulation for high-performance lithium ion battery anodes. ECS J. Solid State Sci.
Technol. 2013, 2, M3034-M3039.
12. Hou, Y.; Wen, Z.; Cui, S.; Guo, X.; Chen, J. Constructing 2D porous graphitic C3N4
nanosheets/nitrogen-doped graphene/layered MoS2 ternary nanojunction with enhanced photoelectrochemical activity. Adv. Mater. 2013, 25, 6291-6297.
13. Seol, M.; Youn, D. H.; Kim, J. Y.; Jang, J.-W.; Choi, M.; Lee, J. S.; Yong, K. Mo- compound/CNT-graphene composites as efficient catalytic electrodes for quantum-dot- sensitized solar cells. Adv. Energy. Mater. 2014, 4, DOI:10.1002/aenm.201300775
14. (a) Tang, H.; Dou, K.; Kaun, C.-C.; Kuang, Q.; Yang, S. MoSe2 nanosheets and their graphene hybrids: synthesis, characterization and hydrogen evolution reaction studies. J. Mater. Chem.
A 2014, 2, 360-364; (b) Li, H.; Chen, L.; Zhang, Y.; Ji, X.; Chen, S.; Song, H.; Li, C.; Tang, H.
Synthesis of MoSe2/reduced graphene oxide composites with improved tribological properties for oil-based additives. Crys. Res. Tech. 2014, 49, 204-211.
15. Su, D.; Dou, S.; Wang, G. WS2@graphene nanocomposites as anode materials for Na-ion batteries with enhanced electrochemical performances. Chem. Commun. 2014, 50, 4192-4195.
16. Chen, D.; Ji, G.; Ding, B.; Ma, Y.; Qu, B.; Chen, W.; Lee, J. Y. In situ nitrogenated graphene- few-layer WS2 composites for fast and reversible Li+ storage. Nanoscale 2013, 5, 7890-7896.
17. Chen, P.; Xiao, T.-Y.; Li, H.-H.; Yang, J.-J.; Wang, Z.; Yao, H.-B.; Yu, S.-H. Nitrogen-doped graphene/ZnSe nanocomposites: hydrothermal synthesis and their enhanced electrochemical and photocatalytic activities. ACS Nano 2011, 6, 712-719.
18. Zheng, Y.; Jiao, Y.; Ge, L.; Jaroniec, M.; Qiao, S. Z. Two-step boron and nitrogen doping in graphene for enhanced synergistic catalysis. Angew. Chem. Int. Ed. 2013, 52, 3110-3116.
19. (a) Hinnemann, B.; Moses, P. G.; Bonde, J. ; Jorgensen, K. P.; Nielsen, J. H.; Horch, S.;
Chorkendorff, I.; Norskov, J. K. Biomimetic hydrogen evolution: MoS2 Nanoparticles as catalyst for hydrogen evolution. J. Am. Chem. Soc. 2005, 127, 5308-5309. (b) Jaramillo, T. F.;
Jorgensen, K. P.; Bonde, J.; Nielsen, J. H.; Horch, S.; Chorkendorff, I. Identification of active edge sites for electrochemical H2 evolution from MoS2 nanocatalysts. Science 2007, 317, 100- 102.
90
20. 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.
21. Wang, H.; Kong, D.; Johanes, P.; Cha, J. J.; Zheng, G.; Yan, K.; Liu, N.; Cui, Y. MoSe2 and WSe2 nanofilms with vertically aligned molecular layers on curved and rough surfaces. Nano Lett. 2013, 13, 3426−3433.
22. Vrubel, H.; Hu, X. Growth and activation of an amorphous molybdenum sulfide hydrogen evolving catalyst. ACS Catal. 2013, 3, 2002−2011.
23. Chen, W. F.; Wang, C. H.; Sasaki, K.; Marinkovic, N.; Xu, W.;Muckerman, J. T.; Zhu, Y.; Adzic, R. R. Highly active and durable nanostructured molybdenum carbide electrocatalysis for hydrogen production. Energy Environ. Sci. 2013, 6, 943−951.
24. Popczun, E. J.; McKone, J. R.; Read, C. G.; Biacchi, A. J.; Wiltrout, A. M.; Lewis, N. S.;
Schaak, R. E. Nanostructured nickel phosphide as an electrocatalyst for the hydrogen evolution reaction. J. Am. Chem. Soc. 2013, 135, 9267−9270.
25. Cao, B.; Veith, G. M.; Neuefeind, J. C.; Adzic, R. R.; Khalifah, P. G. Mixed close-packed cobalt molybdenum nitrides as non-noble metal electrocatalysts for the hhydrogen evolution reaction.
J. Am. Chem. Soc. 2013, 135, 19186−19192.
26. Li, Q.; Guo, B.; Yu, J.; Ran, J.; Zhang, B.; Yan, H.; Gong, J. R. Highly efficient visible-light driven photocatalytic hydrogen production CdS-cluster-decorated graphene nanosheets. ACS Nano, 2011, 133, 10878-10884.
91