近年來，由於劇烈的氣候變遷以及石化燃料漸趨匱乏，產氫的相關的研究也獲得越來越多的關注。而光催化水解就是一種十分具有潛力的產氫方式。
本研究聚焦在將具有電漿增益效益的TiN/GaP 奈米線異質結構應用在光催化水解產氫。透過氣液固相 (vapor-liquid-solid) 法來合成GaP 奈米線，為了進一步增加GaP 奈米線的產氫量，加上TiN薄膜以形成異質結構。利用電子束蒸鍍，在GaP 奈米線上分別鍍上厚度為5奈米、10奈米、15奈米以及20奈米的TiN。藉由表面電漿共振 (surface plasmon resonance) 效應來優化光催化水解的效率。實驗結果顯示，當TiN的厚度為15奈米時會表現出最佳的增益效果，比起單純的GaP奈米，氫氣產量可提升約3.15倍。

The production of hydrogen has recently gained a great deal of interest owing to drastic climate change and the scarcity of fossil fuels. One promising method for producing hydrogen is through photocatalytic water splitting.
The present research focused on the plasmonic enhancement of photocatalytic water splitting with TiN/GaP nanowires heterostructures. GaP nanowires were synthesized through a vapor-liquid-solid (VLS) growth process. To further enhance the efficiency of hydrogen production, TiN was introduced. The heterostructures were fabricated by depositing a TiN film onto GaP nanowires using electron beam evaporation. GaP nanowires were coated with TiN of thicknesses 5 nm, 10 nm, 15 nm, and 20 nm. The surface plasmon resonance (SPR) effect was found to increase the efficiency of hydrogen production. The results demonstrated that photocatalysts with a TiN thickness of 15 nm on GaP NWs exhibited the optimal enhancement effect, leading to an increase of 3.15 times in hydrogen production compared to pure GaP nanowires.

[1] International Energy Agency. Net Zero by 2050. 2021.

[2] Qazi, U. Y. Future of Hydrogen as an Alternative Fuel for Next-Generation Industrial Applications; Challenges and Expected Opportunities. Energies 2022, 15, 4741.

[3] Nnabuife, S. G.; Ugbeh-Johnson, J.; Okeke, N. E.; Ogbonnaya, C. Present and Projected Developments in Hydrogen Production: A Technological Review⁎. Carbon Capture Science & Technology 2022, 3, 100042.

[4] Yousef, S. Hydrogen as a clean and sustainable energy for green future. Sustainable Technologies for Green Economy 2021, 1, 8-13.

[5] Uddin, M. N.; Nageshkar, V. V.; Asmatulu, R. Improving water-splitting efficiency of water electrolysis process via highly conductive nanomaterials at lower voltages. Energy, Ecology and Environment 2020, 5, 108-117.

[6] Kothari, R.; Buddhi, D.; Sawhney, R. L. Comparison of environmental and economic aspects of various hydrogen production methods. Renewable and Sustainable Energy Reviews 2008, 12, 553-563.

[7] Shaban, Y. A. Electrocatalysts for Photoelectrochemical Water Splitting. In Methods for Electrocatalysis: Advanced Materials and Allied Applications, Inamuddin, Boddula, R., Asiri, A. M. Eds.; Springer International Publishing, 2020, 353-374.

[8] Wu, Z.; Wang, W.; Cao, Y.; He, J.; Luo, Q.; Bhutto, W. A.; Li, S.; Kang, J. A beyond near-infrared response in a wide-bandgap ZnO/ZnSe coaxial nanowire solar cell by pseudomorphic layers. Journal of Materials Chemistry A 2014, 2, 14571-14576.

[9] Lai, G.-J.; Lyu, L.-M.; Huang, Y.-S.; Lee, G.-C.; Lu, M.-P.; Perng, T.-P.; Lu, M.-Y.; Chen, L.-J. Few-layer WS2–MoS2 in-plane heterostructures for efficient photocatalytic hydrogen evolution. Nano Energy 2021, 81, 105608.

[10] Feynman, R. There’s Plenty of Room at the Bottom,(talk at the 1959 Annual Meeting of the American Physical Society). Caltech’s Engineering and Science 1960, 23, 22-36.

[11] Alivisatos, A. P. Semiconductor Clusters, Nanocrystals, and Quantum Dots. Science 1996, 271, 933-937.

[12] Al Ghabban, A.; Al Zubaidi, A. B.; Jafar, M.; Fakhri, Z. Effect of Nano SiO2 and Nano CaCO3 on The Mechanical Properties, Durability and flowability of Concrete. IOP Conference Series: Materials Science and Engineering 2018, 454, 012016.

[13] Baig, N.; Kammakakam, I.; Falath, W. Nanomaterials: a review of synthesis methods, properties, recent progress, and challenges. Materials Advances 2021, 2, 1821-1871.

[14] McIntyre, P. C.; Fontcuberta i Morral, A. Semiconductor nanowires: to grow or not to grow? Materials Today Nano 2020, 9, 100058.

[15] Wagner, a. R.; Ellis, s. W. Vapor‐liquid‐solid mechanism of single crystal growth. Applied physics letters 1964, 4, 89-90.

[16] Lin, J.-S.; Chen, C.-C.; Diau, E. W.-G.; Liu, T.-F. Fabrication and characterization of eutectic gold–silicon (Au–Si) nanowires. Journal of Materials Processing Technology 2008, 206, 425-430.

[17] Zayats, A. V.; Smolyaninov, I. I.; Maradudin, A. A. Nano-optics of surface plasmon polaritons. Physics Reports 2005, 408, 131-314.

[18] Zhang, J.; Zhang, L.; Xu, W. Surface plasmon polaritons: physics and applications. Journal of Physics D: Applied Physics 2012, 45, 113001.

[19] Willets, K. A.; Duyne, R. P. V. Localized Surface Plasmon Resonance Spectroscopy and Sensing. Annual Review of Physical Chemistry 2007, 58, 267-297.

[20] Zhang, X.; Zhao, J.; Whitney, A. V.; Elam, J. W.; Van Duyne, R. P. Ultrastable Substrates for Surface-Enhanced Raman Spectroscopy:  Al2O3 Overlayers Fabricated by Atomic Layer Deposition Yield Improved Anthrax Biomarker Detection. Journal of the American Chemical Society 2006, 128, 10304-10309.

[21] Ding, X.; Liow, C. H.; Zhang, M.; Huang, R.; Li, C.; Shen, H.; Liu, M.; Zou, Y.; Gao, N.; Zhang, Z.; et al. Surface Plasmon Resonance Enhanced Light Absorption and Photothermal Therapy in the Second Near-Infrared Window. Journal of the American Chemical Society 2014, 136, 15684-15693.

[22] Chen, Y.-C.; Huang, Y.-S.; Huang, H.; Su, P.-J.; Perng, T.-P.; Chen, L.-J. Photocatalytic enhancement of hydrogen production in water splitting under simulated solar light by band gap engineering and localized surface plasmon resonance of ZnxCd1-xS nanowires decorated by Au nanoparticles. Nano Energy 2020, 67, 104225.

[23] Liu, Z.; Hou, W.; Pavaskar, P.; Aykol, M.; Cronin, S. B. Plasmon Resonant Enhancement of Photocatalytic Water Splitting Under Visible Illumination. Nano Letters 2011, 11, 1111-1116.

[24] Kochuveedu, S. T.; Jang, Y. H.; Kim, D. H. A study on the mechanism for the interaction of light with noble metal-metal oxide semiconductor nanostructures for various photophysical applications. Chemical Society Reviews 2013, 42, 8467-8493.

[25] Linic, S.; Christopher, P.; Ingram, D. B. Plasmonic-metal nanostructures for efficient conversion of solar to chemical energy. Nature Materials 2011, 10, 911-921.

[26] Cushing, S. K.; Li, J.; Meng, F.; Senty, T. R.; Suri, S.; Zhi, M.; Li, M.; Bristow, A. D.; Wu, N. Photocatalytic Activity Enhanced by Plasmonic Resonant Energy Transfer from Metal to Semiconductor. Journal of the American Chemical Society 2012, 134, 15033-15041.

[27] Li, J.; Cushing, S. K.; Meng, F.; Senty, T. R.; Bristow, A. D.; Wu, N. Plasmon-induced resonance energy transfer for solar energy conversion. Nature Photonics 2015, 9, 601-607.

[28] Christopher, P.; Ingram, D. B.; Linic, S. Enhancing Photochemical Activity of Semiconductor Nanoparticles with Optically Active Ag Nanostructures: Photochemistry Mediated by Ag Surface Plasmons. The Journal of Physical Chemistry C 2010, 114, 9173-9177.

[29] Gao, J.; Zhan, Q.; Sarangan, A. M. High-index low-loss gallium phosphide thin films fabricated by radio frequency magnetron sputtering. Thin Solid Films 2011, 519, 5424-5428.

[30] Sun, J.; Liu, C.; Yang, P. Surfactant-Free, Large-Scale, Solution–Liquid–Solid Growth of Gallium Phosphide Nanowires and Their Use for Visible-Light-Driven Hydrogen Production from Water Reduction. Journal of the American Chemical Society 2011, 133, 19306-19309.

[31] Assali, S.; Zardo, I.; Plissard, S.; Kriegner, D.; Verheijen, M. A.; Bauer, G.; Meijerink, A.; Belabbes, A.; Bechstedt, F.; Haverkort, J. E. M.; et al. Direct Band Gap Wurtzite Gallium Phosphide Nanowires. Nano Letters 2013, 13, 1559-1563.

[32] Kudo, A.; Miseki, Y. Heterogeneous photocatalyst materials for water splitting. Chemical Society Reviews 2009, 38, 253-278.

[33] Wilson, D. J.; Schneider, K.; Hönl, S.; Anderson, M.; Baumgartner, Y.; Czornomaz, L.; Kippenberg, T. J.; Seidler, P. Integrated gallium phosphide nonlinear photonics. Nature Photonics 2020, 14, 57-62.

[34] Patsalas, P.; Kalfagiannis, N.; Kassavetis, S. Optical Properties and Plasmonic Performance of Titanium Nitride. Materials 2015, 8, 3128-3154.

[35] Naik, G. V.; Schroeder, J. L.; Ni, X.; Kildishev, A. V.; Sands, T. D.; Boltasseva, A. Titanium nitride as a plasmonic material for visible and near-infrared wavelengths. Opt. Mater. Express 2012, 2, 478-489.

[36] Naldoni, A.; Guler, U.; Wang, Z.; Marelli, M.; Malara, F.; Meng, X.; Besteiro, L. V.; Govorov, A. O.; Kildishev, A. V.; Boltasseva, A.; et al. Broadband Hot-Electron Collection for Solar Water Splitting with Plasmonic Titanium Nitride. Advanced Optical Materials 2017, 5, 1601031.

[37] Yu, S.; Zeng, Q.; Oganov, A. R.; Frapper, G.; Zhang, L. Phase stability, chemical bonding and mechanical properties of titanium nitrides: a first-principles study. Physical Chemistry Chemical Physics 2015, 17, 11763-11769.

[38] Liu, Y.-T.; Lu, M.-Y.; Perng, T.-P.; Chen, L.-J. Plasmonic enhancement of hydrogen production by water splitting with CdS nanowires protected by metallic TiN overlayers as highly efficient photocatalysts. Nano Energy 2021, 89, 106407.

[39] Yee, K. Numerical solution of initial boundary value problems involving Maxwell's equations in isotropic media. IEEE Transactions on antennas and propagation 1966, 14, 302-307.

[40] Lee, S.; Wen, W.; Cheek, Q.; Maldonado, S. Comparison of GaP nanowires grown from Au and Sn vapor-liquid-solid catalysts as photoelectrode materials. Journal of Crystal Growth 2018, 482, 36-43.

[41] Johansson, J.; Karlsson, L. S.; Patrik T. Svensson, C.; Mårtensson, T.; Wacaser, B. A.; Deppert, K.; Samuelson, L.; Seifert, W. Structural properties of 〈111〉B -oriented III–V nanowires. Nature Materials 2006, 5, 574-580.

[42] Shi, W.; Zheng, Y.; Wang, N.; Lee, C.; Lee, S. Synthesis and microstructure of gallium phosphide nanowires. Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena 2001, 19, 1115-1118.

[43] Lin, T.; Cong, X.; Lin, M.-L.; Liu, X.-L.; Tan, P.-H. The phonon confinement effect in two-dimensional nanocrystals of black phosphorus with anisotropic phonon dispersions. Nanoscale 2018, 10, 8704-8711.

[44] Ryzhkov, N. V.; Ledovich, O.; Eggert, L.; Bund, A.; Paszuk, A.; Hannappel, T.; Klyukin, K.; Alexandrov, V.; Skorb, E. V. Layer-By-Layer Polyelectrolyte Assembly for the Protection of GaP Surfaces from Photocorrosion. ACS Applied Nano Materials 2021, 4, 425-431.

[45] Tan, T.; Potter, M. FDTD Discrete Planewave (FDTD-DPW) Formulation for a Perfectly Matched Source in TFSF Simulations. IEEE Transactions on Antennas and Propagation 2010, 58, 2641-2648.

[46] Berenger, J. Perfectly matched layer for the FDTD solution of wave-structure interaction problems. IEEE Transactions on Antennas and Propagation 1996, 44, 110-117.

[47] Li, X.; Yan, X.; Zhao, Z.; Mohamed, M. S.; Wang, J.; Zhu, X. FDTD simulation on transmittance of silica microsphere thin films with varying embedding in an optical adhesive. Optik 2021, 241, 166997.

[48] Gajaria, T. K.; Roondhe, B.; Dabhi, S. D.; Śpiewak, P.; Kurzydłowski, K. J.; Jha, P. K. Hydrogen evolution reaction electrocatalysis trends of confined gallium phosphide with substitutional defects. International Journal of Hydrogen Energy 2020, 45, 23928-23936.

[49] Kudo, A. Z-scheme photocatalyst systems for water splitting under visible light irradiation. MRS bulletin 2011, 36, 32-38.

[50] Maeda, K. Z-Scheme Water Splitting Using Two Different Semiconductor Photocatalysts. ACS Catalysis 2013, 3, 1486-1503.

[51] Van Dang, H.; Wang, Y. H.; Wu, J. C. Z-scheme photocatalyst Pt/GaP-TiO2-SiO2: Rh for the separated H2 evolution from photocatalytic seawater splitting. Applied Catalysis B: Environmental 2021, 296, 120339.