簡易檢索 / 詳目顯示

研究生: 廖怡婷
Liao, Yi-Ting
論文名稱: 摻雜金屬離子之二氧化鈦奈米顆粒及二氧化鈦/二氧化錫 奈米複合材料的合成與鑑定
Preparation and Characterization of Metal-Doped TiO2 Nanoparticles and TiO2-SnO2 Nanocomposites
指導教授: 楊家銘
Yang, Chia-Ming
口試委員:
學位類別: 碩士
Master
系所名稱: 理學院 - 化學系
Department of Chemistry
論文出版年: 2009
畢業學年度: 97
語文別: 中文
論文頁數: 121
中文關鍵詞: 光觸媒摻雜二氧化碳奈米顆粒
外文關鍵詞: photocatalysis, doping, TiO2, nanoparticle
相關次數: 點閱:2下載:0
分享至:
查詢本校圖書館目錄 查詢臺灣博碩士論文知識加值系統 勘誤回報
  • The first part of this thesis is the preparation and characterization of the metal-doped TiO2 nanoparticles. The preparation method was based on a nonaqueous sol-gel route using benzyl alcohol as solvent and titanium tetrachloride together with other metallic compound as metal precursors. The obtained metal-doped TiO2 materials were characterized by ICP-AES, XRD, TGA-DSC, UV-Vis, XPS and TEM. The results indicated that these materials were in the nanometer scale and were with highly crystalline and pure anatase phase. The tin-doped TiO2 and cobalt-doped TiO2 nanoparticles both showed higher photocatalytic activity as compared to undoped TiO2 nanoparticles. The second part of this thesis is the preparation and characterization of the TiO2/SnO2 nanocomposites. The nanocomposites were synthesized by a seed-mediated growth approach, using SnO2 nanocrystals as seeds and a mixture of TiCl4 and benzyl alcohol as a growth solution. The XRD and TEM characterizations indicated that the TiO2/SnO2 nanocomposites exhibited a flower-like morphology with uniform size, and the two metal oxides were with rutile and cassiterite phases, respectively.


    中文摘要 I Abstract II 目錄 III 圖目錄 VII 表目錄 XI 第一章 緒論 1 1-1 半導體光觸媒 2 1-2 二氧化鈦 3 1-3 二氧化鈦奈米顆粒的合成 6 1-3-1 水溶液溶膠-凝膠法 7 1-3-2 非水溶液溶膠-凝膠法 10 1-3-3 晶種促進生長法 13 1-4 二氧化鈦的缺陷 14 1-5 二氧化鈦的摻雜 16 1-6 光催化原理 19 1-6-1 二氧化鈦的光催化動力學機制 21 1-7 研究動機 26 第二章 實驗部分 28 2-1 實驗藥品 28 2-2 油浴加熱法及微波加熱法 28 2-2-1 油浴加熱法 28 2-2-2 微波加熱法 29 2-3 二氧化鈦與二氧化錫奈米顆粒的合成 29 2-3-1 二氧化鈦奈米顆粒的合成 30 2-3-2 二氧化錫奈米顆粒的合成 31 2-4 摻雜金屬離子之二氧化鈦奈米顆粒的合成 32 2-4-1 以油浴法合成摻雜錫之二氧化鈦奈米顆粒 32 2-4-2 以微波加熱法合成摻雜金屬離子之二氧化鈦奈米顆粒 33 2-5 二氧化鈦/二氧化錫奈米奈米結構的合成 35 2-5-1 二氧化鈦/二氧化錫奈米奈米結構的合成 35 2-6-1 光催化活性測試的溶液配置 36 2-6-2 光催化活性測試的實驗裝置 36 2-6-3 4-NPL的吸附測試 37 2-6-4 光降解4-NPL活性測試 37 2-7 實驗儀器鑑定 38 2-7-1 使用分析儀器清單 38 2-7-2 X光粉末繞射儀 39 2-7-3 熱分析儀 41 2-7-4 穿透式電子顯微鏡 41 2-7-5 紫外光-可見光光譜儀 44 2-7-6 高解析電子能譜儀 46 2-7-7 電子順磁共振光譜儀 48 2-7-8 感應耦合電漿原子發射光譜分析 49 第三章 結果與討論 51 3-1 以油浴法合成摻雜錫之二氧化鈦奈米顆粒 51 3-1-1 PXRD的鑑定 52 3-1-2 UV-Vis吸收光譜鑑定 58 3-1-3 XPS光譜鑑定 59 3-1-4 TGA-DSC鑑定以及相轉變現象 67 3-1-5 TEM鑑定 76 3-1-6 摻雜錫之二氧化鈦樣品結構鑑定總結 78 3-1-7 摻雜錫之二氧化鈦的光催化活性 80 3-2-1 以微波加熱法合成摻雜鐵之二氧化鈦奈米顆粒 84 3-2-1-1 PXRD鑑定 84 3-2-1-2 EPR鑑定 86 3-2-1-3 UV-Vis光譜鑑定 88 3-2-1-4 TGA-DSC鑑定 90 3-2-2 以微波加熱法合成摻雜鈷之二氧化鈦奈米顆粒 93 3-2-2-1 PXRD鑑定 93 3-2-2-2 TGA-DSC鑑定 95 3-2-2-3 UV-Vis光譜鑑定 99 3-2-3 金屬離子摻雜之二氧化鈦奈米顆粒的光催化活性 102 3-3 晶種促進生長法合成二氧化鈦/二氧化錫奈米奈米結構 106 3-3-1 二氧化鈦/二氧化錫奈米奈米結構的製備方式與命名列表 106 3-3-2 PXRD鑑定 106 3-3-3 TEM的鑑定 110 3-3-4 二氧化鈦/二氧化錫奈米奈米結構的光催化活性 112 第四章 結論 113 參考文獻 115 圖目錄 圖1-1 半導體材料能階圖 2 圖1-2 anatase 與 rutile的晶型結構 3 圖1-3 anatase轉變為rutile之相轉變機制示意圖 6 圖1-4 溶膠-凝膠法中控制最終產物形貌的多種步驟 8 圖1-5 非水溶液溶膠-凝膠法之縮合反應 11 圖1-6 乙醯丙酮鐵與苯甲醇的反應機制 13 圖1-7 二氧化鈦的晶格缺陷示意圖 15 圖1-8 二氧化鈦的本質缺陷能階圖 16 圖1-9 摻雜金屬離子於二氧化鈦之能階圖 18 圖1-10 半導體材料光生電子電洞對的反應途徑 20 圖1-11 二氧化鈦的光化學反應動力學 24 圖1-12 活性自由基產生的機制示意圖 25 圖2-1 微波合成儀及合成反應瓶 29 圖2-2 布拉格繞射示意圖 39 圖2-3 TEM影像系統繞射模式與影像模式 42 圖2-4 二氧化鈦樣品的UV-Vis吸收光譜圖 45 圖2-5 能隙的計算方法 46 圖2-6 X光入射激發光電子示意圖 47 圖2-7 電子能階分裂與施加磁場強度關係圖 48 圖3-1 摻雜錫之二氧化鈦、二氧化錫、二氧化鈦的PXRD圖 52 圖3-2 摻雜錫之二氧化鈦樣品之錫含量圖 55 圖3-3 摻雜錫之二氧化鈦樣品粒徑大小 56 圖3-4 摻雜錫之二氧化鈦樣品的UV-Vis吸收光譜 58 圖3-5 XPS光譜 61 圖3-6 XPS光譜 62 圖3-7 電子雲密度分佈示意圖,灰色色塊表示為電子雲密度 63 圖3-8 XPS光譜 67 圖3-9 TGA curve 69 圖3-10 DSC curve 69 圖3-11 燒結摻雜錫之二氧化鈦樣品之PXRD圖 72 圖3-12 燒結摻雜錫之二氧化鈦樣品於700℃之rutile含量與錫含量關係圖 74 圖3-13 燒結摻雜錫之二氧化鈦樣品於700℃之PXRD圖 76 圖3-14 Sn4TB-01的TEM圖 77 圖3-15 Sn4TB-01燒結至500℃的TEM圖 78 圖3-16 摻雜錫之二氧化鈦樣品可能形成的結構示意圖 79 圖3-17 催化劑在無光環境下對4-NPL的吸附實驗 81 圖3-18 光降解4-NPL的濃度與時間的關係圖,以及ln(C0/C) vs.時間的線性關係圖 82 圖3-19 催化劑在全光照射下對4-NPL的降解反應速率常數 83 圖3-20 摻雜鐵之二氧化鈦與純二氧化鈦的PXRD圖 85 圖3-21 Fe2TA-w之EPR光譜 87 圖3-22 摻雜鐵之二氧化鈦與純二氧化鈦的UV-Vis.吸收光譜 89 圖3-23 TGA curve 91 圖3-24 DSC curve 91 圖3-25 摻雜鈷之二氧化鈦與純二氧化鈦的PXRD圖 94 圖3-26 TGA curve 96 圖3-27 DSC curve 96 圖3-28 燒結摻雜鈷之二氧化鈦樣品至700℃之PXRD圖 99 圖3-29 摻雜鈷之二氧化鈦與純二氧化鈦的UV-Vis吸收光譜 100 圖3-30 Co3TC-w顏色變化以及UV-Vis吸收光譜圖 101 圖3-31 催化劑在全光照射下對4-NPL的降解反應速率常數 104 圖3-32 摻雜金屬離子之二氧化鈦樣品於黑暗中以及可見光下對4-NPL之濃度變化與時間關係圖 105 圖3-33 二氧化鈦/二氧化錫奈米結構之PXRD圖 107 圖3-34 燒結二氧化鈦/二氧化錫奈米結構500℃之PXRD圖 109 圖3-35 樣品TS-0.24-syn之TEM圖 110 圖3-36 樣品TS-0.24-syn之TEM圖以及EDX 111 圖3-37 光降解4-NPL的濃度與時間的關係圖 112 表目錄 表1-1 Anatase晶型與Rutile晶型的物理性質 4 表3-1 摻雜錫之二氧化鈦樣品製備條件列表 51 表3-2 摻雜錫之二氧化鈦樣品的結構、成分分析結果列表 53 表3-3 錫的含量 66 表3-4 TGA熱重損失數據 70 表3-5 摻雜錫之二氧化鈦粒徑列表 74 表3-6 摻雜鐵之二氧化鈦樣品製備條件列表 84 表3-7 摻雜鐵之二氧化鈦樣品的結構、成分分析結果列表 85 表3-8 TGA熱重損失數據 92 表3-9 摻雜鈷之二氧化鈦樣品製備條件列表 93 表3-10 摻雜鈷之二氧化鈦樣品的結構、成分分析結果列表 94 表3-11 TGA熱重損失數據 97 表3-12 金屬摻雜之二氧化鈦樣品的結構、組成成分分析結果列表 102 表3-13 合成樣品的製備條件列表 106 表3-14 合成樣品的結構以及粒徑大小列表 107 表3-15 晶格常數列表 108

    1. Kudo, A. and Miseki, Y. Chemical Society Reviews, 2009. 38(1): p. 253-278.
    2. Bak, T., et al., International Journal of Hydrogen Energy, 2002. 27(10): p. 991-1022.
    3. Fujishima, A. and K. Honda, Nature, 1972. 238(5358): p. 37-38.
    4. Ni, M., et al., Renewable & Sustainable Energy Reviews, 2007. 11(3): p. 401-425.
    5. Rajeshwar, K., Journal of Applied Electrochemistry, 2007. 37(7): p. 765-787.
    6. Gratzel, M., Nature, 2001. 414(6861): p. 338-344.
    7. Hoffmann, M.R., et al., Chemical Reviews, 1995. 95(1): p. 69-96.
    8. Herrmann, J.M., Catalysis Today, 1999. 53(1): p. 115-129.
    9. Linsebigler, A.L., G.Q. Lu, and J.T. Yates, Chemical Reviews, 1995. 95(3): p. 735-758.
    10. Mills, A., R.H. Davies, and D. Worsley, Chemical Society Reviews, 1993. 22(6): p. 417-425.
    11. Hu, J.S., et al., Angewandte Chemie-International Edition, 2005. 44(8): p. 1269-1273.
    12. Wang, X.W., et al., Chemical Communications, 2009(23): p. 3452-3454.
    13. Weinhardt, L., et al., Journal of Physical Chemistry C, 2008. 112(8): p. 3078-3082.
    14. Zhang, S.C., et al., Journal of Solid State Chemistry, 2007. 180(4): p. 1456-1463.
    15. Zhao, Z.G. and M. Miyauchi, Angewandte Chemie-International Edition, 2008. 47(37): p. 7051-7055.
    16. Cozzoli, P.D., et al., Journal of the American Chemical Society, 2004. 126(12): p. 3868-3879.
    17. Cozzoli, P.D., et al., Small, 2006. 2(3): p. 413-421.
    18. Kitano, M., et al., Applied Catalysis A-General, 2007. 325(1): p. 1-14.
    19. Diebold, U., Surface Science Reports, 2003. 48: p. 53-229.
    20. Bouzoubaa, A., et al., Surface Science, 2005. 583(1): p. 107-117.
    21. Zhang, J., et al., Journal of Physical Chemistry C, 2009. 113(5): p. 1698-1704.
    22. Zhang, H.Z. and J.F. Banfield, Journal of Physical Chemistry B, 2000. 104(15): p. 3481-3487.
    23. Zhang, J., et al., Journal of Physical Chemistry B, 2006. 110(2): p. 927-935.
    24. Zhang, H.Z. and J.F. Banfield, Journal of Materials Chemistry, 1998. 8(9): p. 2073-2076.
    25. Ovenstone, J. and K. Yanagisawa, Chemistry of Materials, 1999. 11(10): p. 2770-2774.
    26. Cushing, B.L., V.L. Kolesnichenko, and C.J. O'Connor, Chemical Reviews, 2004. 104: p. 3893-3946.
    27. Bradley, D.C., Chemical Reviews, 1989. 89(6): p. 1317-1322.
    28. Hench, L.L. and J.K. West, 1990. 90(1): p. 33-72.
    29. Lee, G.R. and J.A. Crayston, 1993. 5(6): p. 434-442.
    30. Lu, Z.L., E. Lindner, and H.A. Mayer, Chemical Reviews, 2002. 102(10): p. 3543-3577.
    31. Mehrotra, R.C. and A. Singh, Chemical Society Reviews, 1996. 25(1): p. 1-13.
    32. Pierre, A.C. and G.M. Pajonk, Chemical Reviews, 2002. 102(11): p. 4243-4265.
    33. Schwarz, J.A., C. Contescu, and A. Contescu, Chemical Reviews, 1995. 95(3): p. 477-510.
    34. Wight, A.P. and M.E. Davis, Chemical Reviews, 2002. 102(10): p. 3589-3613.
    35. Niederberger, M. and G. Garnweitner, Chemistry-A European Journal, 2006. 12(28): p. 7282-7302.
    36. Burnside, S.D., et al., Chemistry of Materials, 1998. 10(9): p. 2419-2425.
    37. Yanagisawa, K. and Ovenstone J., Journal of Physical Chemistry B, 1999. 103(37): p. 7781-7787.
    38. Yin, H.B., et al., Journal of Materials Chemistry, 2002. 12(2): p. 378-383.
    39. Cheng, H.M., et al., Chemistry of Materials, 1995. 7(4): p. 663-671.
    40. Wang, C.C. and J.Y. Ying, Chemistry of Materials, 1999. 11(11): p. 3113-3120.
    41. Zhang, H.Z., M. Finnegan, and J.F. Banfield, Nano Letters, 2001. 1(2): p. 81-85.
    42. Niederberger, M., Accounts of Chemical Research, 2007. 40: p. 793-800.
    43. Ba, J.H., et al., Advanced Materials, 2005. 17(20): p. 2509-2515.
    44. Bilecka, I., I. Djerdj, and M. Niederberger, Chemical Communications, 2008(7): p. 886-888.
    45. Garnweitner, G. and M. Niederberger, Journal of the American Ceramic Society, 2006. 89(6): p. 1801-1808.
    46. Niederberger, M., M.H. Bartl, and G.D. Stucky, Chemistry of Materials, 2002. 14(10): p. 4364-4370.
    47. Pinna, N. and M. Niederberger,. Angewandte Chemie-International Edition, 2008. 47(29): p. 5292-5304.
    48. In, M. and C. Sanchez, Journal of Physical Chemistry B, 2005. 109(50): p. 23870-23878.
    49. Mann, S., et al., 1997. 9(11): p. 2300-2310.
    50. Brown, K.R. and M.J. Natan, Langmuir, 1998. 14(4): p. 726-728.
    51. Yu, H., et al., Journal of the American Chemical Society, 2001. 123(37): p. 9198-9199.
    52. Jana, N.R., L. Gearheart, and C.J. Murphy, Advanced Materials, 2001. 13(18): p. 1389-1393.
    53. Sun, S. and H. Zeng, Journal of the American Chemical Society 2002. 124(28): p. 8204-8205.
    54. Jana, N.R., L. Gearheart, and C.J. Murphy, Chemistry of Materials, 2001. 13(7): p. 2313-2322.
    55. Nikoobakht, B. and M.A. El-Sayed, Chemistry of Materials, 2003. 15(10): p. 1957-1962.
    56. Si, S., et al., Chemistry of Materials, 2004. 16(18): p. 3489-3496.
    57. Umar, A.A. and M. Oyama, Crystal Growth & Design, 2007. 7(12): p. 2404-2409.
    58. Wang, D.B., et al., Journal of Colloid and Interface Science, 2003. 261(2): p. 565-568.
    59. Nowotny, M.K., et al., Journal of Physical Chemistry C, 2008. 112(14): p. 5275-5300.
    60. Ba, J., et al., Small, 2007. 3(2): p. 310-317.
    61. Zhang, H.Y., et al., Journal of Physical Chemistry C, 2008. 112(23): p. 8604-8608.
    62. Clavel, G., et al., Advanced Functional Materials, 2007. 17: p. 3159-3169.
    63. Bryan, J.D., et al., Journal of the American Chemical Society, 2004. 126(37): p. 11640-11647.
    64. Chong, S.V., et al., Solid State Communications, 2008. 148(7-8): p. 345-349.
    65. Dietl, T., et al., Science, 2000. 287(5455): p. 1019-1022.
    66. Serpone, N., Journal of Physical Chemistry B, 2006. 110(48): p. 24287-24293.
    67. Serpone, N., et al., Langmuir, 1994. 10(3): p. 643-652.
    68. Xie, T.H., X. Sun, and J. Lin, Journal of Physical Chemistry C, 2008. 112(26): p. 9753-9759.
    69. Lin, W.Y. and H. Frei, Journal of the American Chemical Society, 2005. 127(6): p. 1610-1611.
    70. Nakamura, R., et al., Journal of the American Chemical Society, 2007. 129: p. 9596-9597.
    71. Choi, W.Y., A. Termin, and M.R. Hoffmann, Journal of Physical Chemistry, 1994. 98(51): p. 13669-13679.
    72. Ikeda, T., et al., Journal of Physical Chemistry C, 2008. 112(4): p. 1167-1173.
    73. Liu, H., A. Imanishi, and Y. Nakato, Journal of Physical Chemistry C, 2007. 111(24): p. 8603-8610.
    74. Niederberger, M., et al., Angewandte Chemie-International Edition, 2004. 43(17): p. 2270-2273.
    75. Zhang, L.Z., et al., Chemistry-an Asian Journal, 2008. 3(4): p. 746-752.
    76. Niederberger, M., et al., Journal of the American Chemical Society, 2004. 126(29): p. 9120-9126.
    77. Zhang, L.Z., et al., Advanced Materials, 2007. 19(16): p. 2083-2086.
    78. Clavel, G., et al., European Journal of Inorganic Chemistry, 2008(6): p. 863-868.
    79. Wang, X.F., et al., Advanced Materials, 2006. 18(18): p. 2476-2480.
    80. Sijakovic-Vujicic, N., et al., Journal of Sol-Gel Science and Technology, 2004. 30(1): p. 5-19.
    81. Chen, D.W. and A.K. Ray, Water Research, 1998. 32(11): p. 3223-3234.
    82. Priya, M.H. and G. Madras, Industrial & Engineering Chemistry Research, 2006. 45(2): p. 482-486.
    83. Sivalingam, G., M.H. Priya, and G. Madras,. Applied Catalysis B-Environmental, 2004. 51(1): p. 67-76.
    84. Tian, M., et al., Journal of Physical Chemistry C, 2008. 112(3): p. 825-831.
    85. Elder, S.H., et al., Journal of the American Chemical Society, 2000. 122(21): p. 5138-5146.
    86. Cao, Y.A., et al., New Journal of Chemistry, 2004. 28(2): p. 218-222.
    87. Fresno, F., et al., Journal of Photochemistry and Photobiology A-Chemistry, 2005. 173(1): p. 13-20.
    88. Fresno, F., et al., Physical Chemistry Chemical Physics, 2006. 8(20): p. 2421-2430.
    89. Jing, L.Q., et al., Applied Catalysis B-Environmental, 2006. 62(3-4): p. 282-291.
    90. Mahanty, S., S. Roy, and S. Sen, Journal of Crystal Growth, 2004. 261(1): p. 77-81.
    91. Oliveira, M.M., D.C. Schnitzler, and A.J.G. Zarbin, Chemistry of Materials, 2003. 15(9): p. 1903-1909.
    92. Sayilkan, F., et al., Materials Research Bulletin, 2008. 43(1): p. 127-134.
    93. Sayilkan, H., Applied Catalysis a-General, 2007. 319: p. 230-236.
    94. Schnitzler, D.C., et al., Chemistry of Materials, 2003. 15(24): p. 4658-4665.
    95. Li, J. and H.C. Zeng, Journal of the American Chemical Society, 2007. 129(51): p. 15839-15847.
    96. Lin, J., et al., Journal of Catalysis, 1999. 183(2): p. 368-372.
    97. Uchiyama, H. and H. Imai, Chemical Communications, 2005(48): p. 6014-6016.
    98. Long, R., Y. Dai, and B. Huang, Journal of Physical Chemistry C, 2009. 113(2): p. 650-653.
    99. Chen, D.L. and L. Gao, Journal of Colloid and Interface Science, 2004. 279(1): p. 137-142.
    100. Yu, J.G., S.W. Liu, and M.H. Zhou,. Journal of Physical Chemistry C, 2008. 112(6): p. 2050-2057.
    101. Fresno, F., et al., Applied Catalysis B-Environmental, 2005. 55(3): p. 159-167.
    102. Shi, Z.M., et al., Journal of Non-Crystalline Solids, 2007. 353(22-23): p. 2171-2178.
    103. Li, J.X., et al., Applied Catalysis B-Environmental, 2009. 85(3-4): p. 162-170.
    104. Zhu, J.F., et al., Journal of Photochemistry and Photobiology A-Chemistry, 2006. 180(1-2): p. 196-204.
    105. Zhou, M.H., J.G. Yu, and B. Cheng, Journal of Hazardous Materials, 2006. 137(3): p. 1838-1847.
    106. Zhu, J.F., et al., Journal of Molecular Catalysis a-Chemical, 2004. 216(1): p. 35-43.
    107. Li, X.Y., P.L. Yue, and C. Kutal, New Journal of Chemistry, 2003. 27(8): p. 1264-1269.
    108. Hung, W.C., et al., Applied Surface Science, 2008. 255(5): p. 2205-2213.
    109. Cong, Y., et al., Journal of Physical Chemistry C, 2007. 111(28): p. 10618-10623.
    110. Yu, J.G., et al., Materials Chemistry and Physics, 2006. 95(2-3): p. 193-196.
    111. Gratzel, M. and R.F. Howe, Journal of Physical Chemistry, 1990. 94(6): p. 2566-2572.
    112. Nagaveni, K., M.S. Hegde, and G. Madras, Journal of Physical Chemistry B, 2004. 108(52): p. 20204-20212.
    113. Galindo, S., Physical Review B, 1984. 29(11): p. 6369.
    114. Abazovic, N.D., et al., Journal of the American Ceramic Society, 2009. 92(4): p. 894-896.
    115. Amadelli, R., et al., International Journal of Photoenergy, 2008: P. 1-9.
    116. Lommens, P., et al.,. Chemistry of Materials, 2007. 19(23): p. 5576-5583.
    117. Rao, C.N.R. and F.L. Deepak, Journal of Materials Chemistry, 2005. 15: p. 573-578.
    118. Radovanovic, P.V., et al., Journal of the American Chemical Society, 2002. 124(51): p. 15192-15193.
    119. Schwartz, D.A., et al., Journal of the American Chemical Society, 2003. 125: p. 13205-13218.
    120. Huang, W.P., et al., Chemical Communications, 2000(15): p. 1415-1416.
    121. Wu, M.M., et al., Chemistry of Materials, 2002. 14(5): p. 1974-1980.

    無法下載圖示 全文公開日期 本全文未授權公開 (校內網路)
    全文公開日期 本全文未授權公開 (校外網路)

    QR CODE