氫氣是一種理想乾淨的能源，而利用水分解產氫的方法，能使環境不受到汙染。然而，電解水反應需要一高效率的觸媒來降低反應所需的能量，至今，最有效的產氫觸媒依然是鉑，因此，尋找便宜、地球含量高的產氫觸媒是必要的，而硫化鉬已被證明為優秀的產氫觸媒。

本實驗利用低溫常壓熱解的方法來合成非晶相硫化鉬觸媒在碳紙基材上，然而，在前驅液乾燥過程中，液滴濕潤動態行為會影響硫化鉬形成不同的形態，因此，本實驗重點在於結合基材的親疏水性以及溶劑的極性，調整溶劑分子間的內聚力與溶劑和基材之間的附著力，藉以控制硫化鉬最後形成的形態。

將前驅物溶劑二甲基甲醯胺(DMF)和水混合且基材為親水碳紙，此結果具有相對較強的附著力，能夠使硫化鉬包覆著親水碳紙纖維，降低電荷傳導阻抗，讓電流密度在-0.20 V vs. RHE的電壓下增加到43 mA/cm2。因此，利用DMF和水的混合溶劑與親水碳紙成對可以合成出優秀的硫化鉬產氫觸媒。

Hydrogen is an ideal clean energy, and using the method of water splitting for hydrogen evolution reaction (HER), can prevent the environment from pollution. However, water splitting needs highly efficient catalysts to lower the overpotential. Till today, the most efficient catalyst for HER is still Pt. Therefore, finding a cheap and earth abundant catalyst for HER is essential. Molybdenum sulfide has been proved to be an excellent catalyst for HER.

In this study, the low temperature within atmospheric pressure for thermo-decomposition method to produce amorphous molybdenum sulfide (MoSx) catalyst on carbon paper substrates. However, during the precursor solution drying process, the dynamics of liquid wetting behavior dominates the morphology of MoSx. As a result, here, pairing the substrate hydrophobicity and solvent polarity, the cohesive force between solvent molecules and adhesive force between solvent and carbon paper substrates can be tuned, and thus the MoSx morphology can be controlled.

Pairing hydrophilic carbon paper with DMF+H2O mixing solvent results in a relatively strong adhesive force, it can make the well wrapped MoSx on carbon paper fiber structure. It can lower the charge transfer resistance and boost the current density to 43 mA/cm2 at -0.20 V vs. RHE. Therefore, using DMF+H2O mixing solvent and pair hydrophilic carbon paper can prepare the excellent MoSx catalyst for HER.

1.Jaramillo, T. F.; Jørgensen, 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 (5834), 100-102.
2.Hinnemann, B.; Moses, P. G.; Bonde, J.; Jørgensen, K. P.; Nielsen, J. H.; Horch, S.; Chorkendorff, I.; Nørskov, J. K., Biomimetic hydrogen evolution: MoS2 nanoparticles as catalyst for hydrogen evolution. J. Am. Chem. Soc. 2005, 127 (15), 5308-5309.
3.Merki, D.; Fierro, S.; Vrubel, H.; Hu, X., Amorphous molybdenum sulfide films as catalysts for electrochemical hydrogen production in water. Chem. Sci. 2011, 2 (7), 1262-1267.
4.Morales-Guio, C. G.; Hu, X., Amorphous molybdenum sulfides as hydrogen evolution catalysts. Acc. Chem. Res. 2014, 47 (8), 2671-81.
5.Armaroli, N.; Balzani, V., The hydrogen issue. ChemSusChem 2011, 4 (1), 21-36.
6.Holladay, J. D.; Hu, J.; King, D. L.; Wang, Y., An overview of hydrogen production technologies. Catal. Today 2009, 139 (4), 244-260.
7.Palo, D. R.; Dagle, R. A.; Holladay, J. D., Methanol steam reforming for hydrogen production. Chem. Rev. 2007, 107 (10), 3992-4021.
8.Han, J. W.; Park, J. S.; Choi, M. S.; Lee, H., Uncoupling the size and support effects of Ni catalysts for dry reforming of methane. Appl. Catal. B-Environ 2017, 203, 625-632.
9.Zou, X.; Zhang, Y., Noble metal-free hydrogen evolution catalysts for water splitting. Chem. Soc. Rev. 2015, 44 (15), 5148-5180.
10.Kudo, A.; Miseki, Y., Heterogeneous photocatalyst materials for water splitting. Chem. Soc. Rev. 2009, 38 (1), 253-78.
11.Roeb, M.; Neises, M.; Säck, J. P.; Rietbrock, P.; Monnerie, N.; Dersch, J.; Schmitz, M.; Sattler, C., Operational strategy of a two-step thermochemical process for solar hydrogen production. Int. J. Hydrogen Energy 2009, 34 (10), 4537-4545.
12.Manish, S.; Banerjee, R., Comparison of biohydrogen production processes. Int. J. Hydrogen Energy 2008, 33 (1), 279-286.
13.Bard, A. J.; Faulkner, L. R., Electrochemical Methods: Fundamentals and Applications. Wiley: 2000.
14.Liang, H.; Li, L.; Meng, F.; Dang, L.; Zhuo, J.; Forticaux, A.; Wang, Z.; Jin, S., Porous two-dimensional nanosheets converted from layered double hydroxides and their applications in electrocatalytic water splitting. Chem. Mater. 2015, 27 (16), 5702-5711.
15.Nagai, N.; Takeuchi, M.; Kimura, T.; Oka, T., Existence of optimum space between electrodes on hydrogen production by water electrolysis. Int. J. Hydrogen Energy 2003, 28 (1), 35-41.
16.Roy, A.; Watson, S.; Infield, D., Comparison of electrical energy efficiency of atmospheric and high-pressure electrolysers. Int. J. Hydrogen Energy 2006, 31 (14), 1964-1979.
17.Chen, Z.; Cummins, D.; Reinecke, B. N.; Clark, E.; Sunkara, M. K.; Jaramillo, T. F., Core-shell MoO3-MoS2 nanowires for hydrogen evolution: a functional design for electrocatalytic materials. Nano Lett. 2011, 11 (10), 4168-75.
18.Shinagawa, T.; Garcia-Esparza, A. T.; Takanabe, K., Insight on Tafel slopes from a microkinetic analysis of aqueous electrocatalysis for energy conversion. Sci. Rep. 2015, 5, 13801.
19.Quaino, P.; Juarez, F.; Santos, E.; Schmickler, W., Volcano plots in hydrogen electrocatalysis - uses and abuses. Beilstein J. Nanotechnol. 2014, 5, 846-54.
20.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. Hydrogen Energy 2013, 38 (28), 12302-12309.
21.Norskov, J. K.; Bligaard, T.; Rossmeisl, J.; Christensen, C. H., Towards the computational design of solid catalysts. Nat. Chem. 2009, 1 (1), 37-46.
22.Benck, J. D.; Hellstern, T. R.; Kibsgaard, J.; Chakthranont, P.; Jaramillo, T. F., Catalyzing the hydrogen evolution reaction (HER) with molybdenum sulfide nanomaterials. ACS Catalysis 2014, 4 (11), 3957-3971.
23.Zhang, K.; Kim, H. J.; Lee, J. T.; Chang, G. W.; Shi, X.; Kim, W.; Ma, M.; Kong, K. J.; Choi, J. M.; Song, M. S.; Park, J. H., Unconventional pore and defect generation in molybdenum disulfide: application in high-rate lithium-ion batteries and the hydrogen evolution reaction. ChemSusChem 2014, 7 (9), 2489-95.
24.Voiry, D.; Salehi, M.; Silva, R.; Fujita, T.; Chen, M.; Asefa, T.; Shenoy, V. B.; Eda, G.; Chhowalla, M., Conducting MoS(2) nanosheets as catalysts for hydrogen evolution reaction. Nano Lett. 2013, 13 (12), 6222-7.
25.Lukowski, M. A.; Daniel, A. S.; Meng, F.; Forticaux, A.; Li, L.; Jin, S., Enhanced hydrogen evolution catalysis from chemically exfoliated metallic MoS2 nanosheets. J. Am. Chem. Soc. 2013, 135 (28), 10274-7.
26.Bose, R.; Balasingam, S. K.; Shin, S.; Jin, Z.; Kwon, D. H.; Jun, Y.; Min, Y. S., Importance of hydrophilic pretreatment in the hydrothermal growth of amorphous molybdenum sulfide for hydrogen evolution catalysis. Langmuir 2015, 31 (18), 5220-7.
27.Wang, H.; Tsai, C.; Kong, D.; Chan, K.; Abild-Pedersen, F.; Nørskov, J. K.; Cui, Y., Transition-metal doped edge sites in vertically aligned MoS2 catalysts for enhanced hydrogen evolution. Nano Res. 2015, 8 (2), 566-575.
28.Tan, Y.; Liu, P.; Chen, L.; Cong, W.; Ito, Y.; Han, J.; Guo, X.; Tang, Z.; Fujita, T.; Hirata, A.; Chen, M. W., Monolayer MoS2 films supported by 3D nanoporous metals for high-efficiency electrocatalytic hydrogen production. Adv. Mater. 2014, 26 (47), 8023-8.
29.Han, G.-Q.; Liu, Y.-R.; Hu, W.-H.; Dong, B.; Li, X.; Shang, X.; Chai, Y.-M.; Liu, Y.-Q.; Liu, C.-G., Structure–function relationship of electrodeposited MoSx film in N, N-dimethyl-formamide/H2O mixture solvent as electrocatalyst for hydrogen evolution. Int. J. Hydrogen Energy 2016, 41 (3), 1635-1644.
30.Merki, D.; Hu, X., Recent developments of molybdenum and tungsten sulfides as hydrogen evolution catalysts. Energy Environ. Sci. 2011, 4 (10), 3878.
31.Liu, K. K.; Zhang, W.; Lee, Y. H.; Lin, Y. C.; Chang, M. T.; Su, C. Y.; Chang, C. S.; Li, H.; Shi, Y.; Zhang, H.; Lai, C. S.; Li, L. J., Growth of large-area and highly crystalline MoS2 thin layers on insulating substrates. Nano Lett. 2012, 12 (3), 1538-44.
32.Benck, J. D.; Chen, Z.; Kuritzky, L. Y.; Forman, A. J.; Jaramillo, T. F., Amorphous molybdenum sulfide catalysts for electrochemical hydrogen production: insights into the origin of their catalytic activity. ACS Catalysis 2012, 2 (9), 1916-1923.
33.Wang, T.; Liu, L.; Zhu, Z.; Papakonstantinou, P.; Hu, J.; Liu, H.; Li, M., Enhanced electrocatalytic activity for hydrogen evolution reaction from self-assembled monodispersed molybdenum sulfidenanoparticles on an Au electrode. Energy Environ. Sci. 2013, 6 (2), 625-633.
34.Lee, S. C.; Benck, J. D.; Tsai, C.; Park, J.; Koh, A. L.; Abild-Pedersen, F.; Jaramillo, T. F.; Sinclair, R., Chemical and phase evolution of amorphous molybdenum sulfide catalysts for electrochemical hydrogen production. ACS Nano 2016, 10 (1), 624-32.
35.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 (19), 7296-9.
36.Behranginia, A.; Asadi, M.; Liu, C.; Yasaei, P.; Kumar, B.; Phillips, P.; Foroozan, T.; Waranius, J. C.; Kim, K.; Abiade, J.; Klie, R. F.; Curtiss, L. A.; Salehi-Khojin, A., Highly efficient hydrogen evolution reaction using crystalline layered three-dimensional molybdenum disulfides grown on graphene film. Chem. Mater. 2016, 28 (2), 549-555.
37.Deng, J.; Ren, P.; Deng, D.; Yu, L.; Yang, F.; Bao, X., Highly active and durable non-precious-metal catalysts encapsulated in carbon nanotubes for hydrogen evolution reaction. Energy Environ. Sci. 2014, 7 (6), 1919.
38.Laursen, A. B.; Kegnæs, S.; Dahl, S.; Chorkendorff, I., Molybdenum sulfides—efficient and viable materials for electro - and photoelectrocatalytic hydrogen evolution. Energy Environ. Sci. 2012, 5 (2), 5577.
39.Yan, Y.; Ge, X.; Liu, Z.; Wang, J. Y.; Lee, J. M.; Wang, X., Facile synthesis of low crystalline MoS2 nanosheet-coated CNTs for enhanced hydrogen evolution reaction. Nanoscale 2013, 5 (17), 7768-71.
40.Wang, H.; Lu, Z.; Kong, D.; Sun, J.; Hymel, T. M.; Cui, Y., Electrochemical tuning of MoS2 nanoparticles on three-dimensional substrate for efficient hydrogen evolution. ACS Nano 2014, 8 (5), 4940-4947.
41.Hsu, C.-L.; Chang, Y.-H.; Chen, T.-Y.; Tseng, C.-C.; Wei, K.-H.; Li, L.-J., Enhancing the electrocatalytic water splitting efficiency for amorphous MoSx. Int. J. Hydrogen Energy 2014, 39 (10), 4788-4793.
42.Laursen, A. B.; Vesborg, P. C.; Chorkendorff, I., A high-porosity carbon molybdenum sulphide composite with enhanced electrochemical hydrogen evolution and stability. Chem. Commun. 2013, 49 (43), 4965-4967.
43.Bonde, J.; Moses, P. G.; Jaramillo, T. F.; Norskov, J. K.; Chorkendorff, I., Hydrogen evolution on nano-particulate transition metal sulfides. Faraday Discuss. 2008, 140, 219-231.
44.Lv, X.-J.; She, G.-W.; Zhou, S.-X.; Li, Y.-M., Highly efficient electrocatalytic hydrogen production by nickel promoted molybdenum sulfide microspheres catalysts. RSC Adv. 2013, 3 (44), 21231.
45.Sun, X.; Dai, J.; Guo, Y.; Wu, C.; Hu, F.; Zhao, J.; Zeng, X.; Xie, Y., Semimetallic molybdenum disulfide ultrathin nanosheets as an efficient electrocatalyst for hydrogen evolution. Nanoscale 2014, 6 (14), 8359.
46.Wang, H.; Lu, Z.; Xu, S.; Kong, D.; Cha, J. J.; Zheng, G.; Hsu, P. C.; Yan, K.; Bradshaw, D.; Prinz, F. B.; Cui, Y., Electrochemical tuning of vertically aligned MoS2 nanofilms and its application in improving hydrogen evolution reaction. Proc. Natl. Acad. Sci. U. S. A. 2013, 110 (49), 19701-6.
47.Xie, J.; Zhang, J.; Li, S.; Grote, F.; Zhang, X.; Zhang, H.; Wang, R.; Lei, Y.; Pan, B.; Xie, Y., Controllable disorder engineering in oxygen-incorporated MoS2 ultrathin nanosheets for efficient hydrogen evolution. J. Am. Chem. Soc. 2013, 135 (47), 17881-8.
48.Zhou, W.; Hou, D.; Sang, Y.; Yao, S.; Zhou, J.; Li, G.; Li, L.; Liu, H.; Chen, S., MoO2 nanobelts@nitrogen self-doped MoS2 nanosheets as effective electrocatalysts for hydrogen evolution reaction. J. Mater. Chem. A 2014, 2 (29), 11358.
49.Chang, Y. H.; Wu, F. Y.; Chen, T. Y.; Hsu, C. L.; Chen, C. H.; Wiryo, F.; Wei, K. H.; Chiang, C. Y.; Li, L. J., Three-dimensional molybdenum sulfide sponges for electrocatalytic water splitting. Small 2014, 10 (5), 895-900.
50.Marshall, S. J.; Bayne, S. C.; Baier, R.; Tomsia, A. P.; Marshall, G. W., A review of adhesion science. Dent. Mater. 2010, 26 (2), e11-6.
51.von Fraunhofer, J. A., Adhesion and cohesion. Int. J. Dent. 2012, 2012, 951324.
52.Rotenberg, B.; Patel, A. J.; Chandler, D., Molecular explanation for why talc surfaces can be both hydrophilic and hydrophobic. J. Am. Chem. Soc. 2011, 133 (50), 20521-7.
53.Giovambattista, N.; Debenedetti, P. G.; Rossky, P. J., Enhanced surface hydrophobicity by coupling of surface polarity and topography. Proc. Natl. Acad. Sci. U. S. A. 2009, 106 (36), 15181-15185.
54.Baldan, A., Adhesively-bonded joints and repairs in metallic alloys, polymers and composite materials: adhesives, adhesion theories and surface pretreatment. J. Mater. Sci. 2004, 39 (1), 1-49.
55.Crick, C. R.; Parkin, I. P., Preparation and characterisation of super-hydrophobic surfaces. Chem. Eur. J. 2010, 16 (12), 3568-3588.
56.Pittoni, P. G.; Lin, C. H.; Yu, T. S.; Lin, S. Y., On the uniqueness of the receding contact angle: effects of substrate roughness and humidity on evaporation of water drops. Langmuir 2014, 30 (31), 9346-54.
57.Giannuzzi, L. A.; University, N. C. S., Introduction to Focused Ion Beams: Instrumentation, Theory, Techniques and Practice. Springer US: 2006.
58.Volkert, C. A.; Minor, A. M., Focused ion beam microscopy and micromachining. MRS Bull. 2007, 32 (05), 389-399.
59.Rigort, A.; Plitzko, J. M., Cryo-focused-ion-beam applications in structural biology. Arch. Biochem. Biophys. 2015, 581, 122-30.
60.Ooi, L., Principles of X-ray Crystallography. OUP Oxford: 2010.
61.van der Heide, P., X-ray Photoelectron Spectroscopy: An introduction to Principles and Practices. Wiley: 2011.
62.Kibel, M., X-ray photoelectron spectroscopy. Springer: 2003.
63.Pittoni, P. G.; Chang, C.-C.; Yu, T.-S.; Lin, S.-Y., Evaporation of water drops on polymer surfaces: pinning, depinning and dynamics of the triple line. Colloids Surf. A 2013, 432, 89-98.
64.Skoog, D. A.; Holler, F. J.; Crouch, S. R., Principles of Instrumental Analysis. Thomson Brooks/Cole: 2007.
65.Chang, Y. H.; Lin, C. T.; Chen, T. Y.; Hsu, C. L.; Lee, Y. H.; Zhang, W.; Wei, K. H.; Li, L. J., Highly efficient electrocatalytic hydrogen production by MoS(x) grown on graphene-protected 3D Ni foams. Adv. Mater. 2013, 25 (5), 756-60.
66.Lin, T.-S.; Zeng, Y.-H.; Tsay, R.-Y.; Lin, S.-Y., Roughness-induced strong pinning for drops evaporating from polymeric surfaces. J. Taiwan Inst. Chem. Eng. 2016, 62, 54-59.