催化学报 ›› 2021, Vol. 42 ›› Issue (5): 694-709.DOI: 10.1016/S1872-2067(20)63699-3
刘晓艳a,b, 蓝国钧a,*(), 李振清a, 钱丽华a, 刘健b,c, 李瑛a,#()
收稿日期:
2020-05-27
接受日期:
2020-05-27
出版日期:
2021-05-18
发布日期:
2021-01-29
通讯作者:
蓝国钧,李瑛
基金资助:
Xiaoyan Liua,b, Guojun Lana,*(), Zhenqing Lia, Lihua Qiana, Jian Liub,c, Ying Lia,#()
Received:
2020-05-27
Accepted:
2020-05-27
Online:
2021-05-18
Published:
2021-01-29
Contact:
Guojun Lan,Ying Li
About author:
# Tel: +86-571-88320766; Fax: +86-571-88320259; E-mail: liying@zjut.edu.cnSupported by:
摘要:
生物质是天然的可再生能源和资源, 具有来源广泛、储量丰富、价格低廉的优点以及可转化为高附加值化学品的多功能性, 因此作为传统化石能源替代材料受到广泛关注和研究. 将生物质通过催化转化为平台化合物再进一步利用是生物质利用的重要途径, 其中催化加氢是常用的反应之一. 由于绝大多数生物质平台化合物分子中都含氧元素, 其加氢过程中会不可避免的产生水, 同时水作为绿色环保, 价廉易得的溶剂, 可以溶解绝大多数生物质平台化合物, 因此选择水做溶剂具有重要意义. 负载型纳米金属催化剂(如Au、Rh、Pt、Pd、Ru、Cu和Co等)在生物质水相加氢反应中具有广泛的应用, 但其在水相反应条件下(通常为高温、高压、强酸性等苛刻条件)容易在反应过程中发生纳米金属粒子的团聚、流失以及载体的坍塌、结构转变等引起失活. 因此, 发展可以在水相体系中稳定的金属多相催化剂对生物质资源化利用非常必要.
本文首先综述了溶剂水对反应的影响以及负载型金属催化剂在水相体系中的失活类型与机理, 内容包括: (1)溶剂水对催化剂及催化加氢反应的积极作用, 包含提高转化率和影响产物选择性; (2)溶剂水引起催化剂失活的原因, 如引起金属纳米粒子发生团聚、氧化、流失以及载体发生溶解、坍塌、结构转变等. 从负载型金属催化剂的失活机理入手, 分别从提高金属纳米粒子的稳定性和载体的稳定性两个方向综述了提高负载型金属催化剂稳定性的普适性策略, 内容包括: (1)通过界面限域策略增强金属-载体相互作用的方式提高金属纳米粒子在载体上的稳定性, 包括有机基团配位、杂原子配位、镶嵌法等; (2)通过空间限域策略将金属纳米颗粒封装的方式提高金属纳米粒子的稳定性, 包括利用一维的空心管状材料、二维的超薄材料以及三位的空心球(笼)材料等; (3)通过提高载体(主要为氧化物载体)的稳定性以提高催化剂整体稳定性, 包括对载体进行修饰、包覆、杂化等方式. 本工作所综述的提高生物质水相加氢金属催化剂稳定性的策略为高稳定性催化剂的设计指出了方向.
刘晓艳, 蓝国钧, 李振清, 钱丽华, 刘健, 李瑛. 用于生物质水相加氢多相负载型金属催化剂的稳定策略[J]. 催化学报, 2021, 42(5): 694-709.
Xiaoyan Liu, Guojun Lan, Zhenqing Li, Lihua Qian, Jian Liu, Ying Li. Stabilization of heterogeneous hydrogenation catalysts for the aqueous-phase reactions of renewable feedstocks[J]. Chinese Journal of Catalysis, 2021, 42(5): 694-709.
Fig. 1. (a) Conversion of BA over Ru/FDU catalyst as a function of the solvent composition (water/hexane). (b) Adsorption free energies of BA on the pure and water-mediated Ru (0001) surfaces. (c) DFT-calculated reaction paths of the BA hydrogenation on the water-mediated (red) and pure (black) Ru (0001) surfaces. During the first hydrogenation step on the water-mediate surface, one H* atom is consumed from the adsorbed H2O. The insets display the atomic structures of the reaction intermediates. The red, grey, white, and dark cyan spheres represent O, C, H, and Ru atoms, respectively. Reproduced with permission from Ref. [15]. Copyright 2019, Wiley-VCH.
Fig. 1. (a) Conversion of BA over Ru/FDU catalyst as a function of the solvent composition (water/hexane). (b) Adsorption free energies of BA on the pure and water-mediated Ru (0001) surfaces. (c) DFT-calculated reaction paths of the BA hydrogenation on the water-mediated (red) and pure (black) Ru (0001) surfaces. During the first hydrogenation step on the water-mediate surface, one H* atom is consumed from the adsorbed H2O. The insets display the atomic structures of the reaction intermediates. The red, grey, white, and dark cyan spheres represent O, C, H, and Ru atoms, respectively. Reproduced with permission from Ref. [15]. Copyright 2019, Wiley-VCH.
Fig. 2. (a) A scheme describing the carbon pre-treatment with surface oxygen groups by the two-step liquid oxidation method. SFG and SA denote the concentration of SFGs and surface area, respectively. (b) Dispersion of Ru NPs in Ru/AC-x as a function of the total concentration of acidic SFGs on the AC surface. (c) Benzene conversion as a function of the reaction time for Ru/AC-x. Reproduced with permission from Ref. [83]. Copyright 2014, Wiley-VCH.
Fig. 2. (a) A scheme describing the carbon pre-treatment with surface oxygen groups by the two-step liquid oxidation method. SFG and SA denote the concentration of SFGs and surface area, respectively. (b) Dispersion of Ru NPs in Ru/AC-x as a function of the total concentration of acidic SFGs on the AC surface. (c) Benzene conversion as a function of the reaction time for Ru/AC-x. Reproduced with permission from Ref. [83]. Copyright 2014, Wiley-VCH.
Fig. 3. (a) Schematic illustration of the preparation of Pd/NHPC-NH2 catalyst. (b) High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and high-resolution TEM (HRTEM) (inset) images of Pd/NHPC-NH2. (c) Pd 3d X-ray photoelectron spectra of Pd/NHPC-NH2 (a, top) and Pd/NHPC (b, medium) catalysts. (d) A possible reaction pathway for the dehydrogenation of formic acid over Pd/NHPC-NH2. (e) Recyclability of Pd/NHPC-NH2 catalyst for the dehydrogenation of formic acid. Reaction conditions: 1.0 M of formic acid, 2.5 mL, nPd/nFA = 0.01, 25 °C. Reproduced with permission from Ref. [88]. Copyright 2019, Royal Society of Chemistry.
Fig. 3. (a) Schematic illustration of the preparation of Pd/NHPC-NH2 catalyst. (b) High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and high-resolution TEM (HRTEM) (inset) images of Pd/NHPC-NH2. (c) Pd 3d X-ray photoelectron spectra of Pd/NHPC-NH2 (a, top) and Pd/NHPC (b, medium) catalysts. (d) A possible reaction pathway for the dehydrogenation of formic acid over Pd/NHPC-NH2. (e) Recyclability of Pd/NHPC-NH2 catalyst for the dehydrogenation of formic acid. Reaction conditions: 1.0 M of formic acid, 2.5 mL, nPd/nFA = 0.01, 25 °C. Reproduced with permission from Ref. [88]. Copyright 2019, Royal Society of Chemistry.
Fig. 4. (a) A nitrogen-doped carbon support for metal sites. Reproduced with permission from Ref. [92]. Copyright 2019 Wiley-VCH. (b) Schematic illustration of the synthesis route for the ordered mesoporous Fe1/N-C catalyst. (c) An SEM image, an aberration-corrected HAADF-STEM image, and energy-dispersive X-ray spectroscopy maps of Fe1/N-C catalyst. Reproduced with permission from Ref. [93]. Copyright 2019 American Chemical Society. (d) An HAADF-STEM image of Co single atoms/AC@N-CNTs. The Co clusters and single atoms are marked with the yellow and red circles, respectively. (e) Catalytic performance of Co single atoms/AC@N-CNTs during quionline hydrogenation. Reaction conditions: 5 mg of catalyst, 0.5 mmol of quionline, 5 mL of ethanol, 100 °C, 2 MPa H2 pressure. (f) Reusability of Co single atoms/AC@N-CNTs-L catalyst. Reproduced with permission from Ref. [94]. Copyright 2019 Wiley-VCH. (g) Schematic illustration of the fabricated Ru/N-CS-850 catalyst. (i,j) TEM and HRTEM images of Ru/N-CS-850. (k) Reusability of Ru/N-CS-850 catalyst during the hydrogenation of levulinic acid. Reaction conditions: 18 mg of catalyst, 17.8 mmol of levulinic acid, 20 mL of water, 70 °C, 4 MPa H2 pressure, 1 h. Reproduced with permission from Ref. [62]. Copyright 2019, Elsevier.
Fig. 4. (a) A nitrogen-doped carbon support for metal sites. Reproduced with permission from Ref. [92]. Copyright 2019 Wiley-VCH. (b) Schematic illustration of the synthesis route for the ordered mesoporous Fe1/N-C catalyst. (c) An SEM image, an aberration-corrected HAADF-STEM image, and energy-dispersive X-ray spectroscopy maps of Fe1/N-C catalyst. Reproduced with permission from Ref. [93]. Copyright 2019 American Chemical Society. (d) An HAADF-STEM image of Co single atoms/AC@N-CNTs. The Co clusters and single atoms are marked with the yellow and red circles, respectively. (e) Catalytic performance of Co single atoms/AC@N-CNTs during quionline hydrogenation. Reaction conditions: 5 mg of catalyst, 0.5 mmol of quionline, 5 mL of ethanol, 100 °C, 2 MPa H2 pressure. (f) Reusability of Co single atoms/AC@N-CNTs-L catalyst. Reproduced with permission from Ref. [94]. Copyright 2019 Wiley-VCH. (g) Schematic illustration of the fabricated Ru/N-CS-850 catalyst. (i,j) TEM and HRTEM images of Ru/N-CS-850. (k) Reusability of Ru/N-CS-850 catalyst during the hydrogenation of levulinic acid. Reaction conditions: 18 mg of catalyst, 17.8 mmol of levulinic acid, 20 mL of water, 70 °C, 4 MPa H2 pressure, 1 h. Reproduced with permission from Ref. [62]. Copyright 2019, Elsevier.
Fig. 5. MNPs confined in long channels. The image of CNTs is reproduced with permission from Ref. [97]. Copyright 2015, Oxford University Press. The image of SBA-15 is reproduced with permission from Ref. [98]. Copyright 2018, Elsevier.
Fig. 5. MNPs confined in long channels. The image of CNTs is reproduced with permission from Ref. [97]. Copyright 2015, Oxford University Press. The image of SBA-15 is reproduced with permission from Ref. [98]. Copyright 2018, Elsevier.
Fig. 6. (a) Schematic illustration of the synthesis of hollow yolk-shell YS-Au@HMCs nanoreactors. (b) Reusability of YS-Au@HMCs catalysts for the conversion of 4-nitrophenol. Reproduced with permission from Ref. [103]. Copyright 2018, Elsevier. (c) Schematic illustration of the fabrication of yolk-shell-structured Pd&ZnO@carbon catalyst. The blue, purple, yellow, green, and gray colors refer to ZIF-8, the polymer layer, MNPs, ZnO particles, and the carbon layer, respectively. (d) TEM, HAADF-STEM, and elemental mapping images of Pd&Zn@carbon. (e-f) Catalytic performance and reusability of Pd&Zn@carbon, Pd/ZnO, and Pd/C catalysts utilized for phenylacetylene hydrogenation. Reaction conditions: 30 °C, 60 min, 20 mg of catalyst, 1 bar H2, 2.9 mmol of substrate, 25 mL of ethanol solvent. Reproduced with permission from Ref. [100]. Copyright 2018, Wiley-VCH.
Fig. 6. (a) Schematic illustration of the synthesis of hollow yolk-shell YS-Au@HMCs nanoreactors. (b) Reusability of YS-Au@HMCs catalysts for the conversion of 4-nitrophenol. Reproduced with permission from Ref. [103]. Copyright 2018, Elsevier. (c) Schematic illustration of the fabrication of yolk-shell-structured Pd&ZnO@carbon catalyst. The blue, purple, yellow, green, and gray colors refer to ZIF-8, the polymer layer, MNPs, ZnO particles, and the carbon layer, respectively. (d) TEM, HAADF-STEM, and elemental mapping images of Pd&Zn@carbon. (e-f) Catalytic performance and reusability of Pd&Zn@carbon, Pd/ZnO, and Pd/C catalysts utilized for phenylacetylene hydrogenation. Reaction conditions: 30 °C, 60 min, 20 mg of catalyst, 1 bar H2, 2.9 mmol of substrate, 25 mL of ethanol solvent. Reproduced with permission from Ref. [100]. Copyright 2018, Wiley-VCH.
Fig. 7. Schematic diagrams of the “overcoat”-type encapsulated catalysts. Reproduced with permission from Refs. [39] and [107]. Copyright 2016/2018, American Chemistry Society.
Fig. 7. Schematic diagrams of the “overcoat”-type encapsulated catalysts. Reproduced with permission from Refs. [39] and [107]. Copyright 2016/2018, American Chemistry Society.
Fig. 8. (a) Illustration of the catalyst preparation procedure. (b,c) TEM images of CNF30@Ni@CNT catalyst. (d) Results of the catalyst reuse study conducted for the reductive aminantion of levulinic acid with benzyl amine over CNF30@Ni@CNT (black), Ni@CNT (red), and Ni/C (green) catalysts. Reaction conditions: 10 mmol of levulinic acid, 10 mmol of benzyl amine, 0.03 g of catalyst, 10 wt% of Ni, 4 mL of gamma-valerolactone solvent, 3.0 MPa H2, 130 °C, and 4 h. Reproduced with permission from Ref. [104]. Copyright 2017, American Chemistry Society.
Fig. 8. (a) Illustration of the catalyst preparation procedure. (b,c) TEM images of CNF30@Ni@CNT catalyst. (d) Results of the catalyst reuse study conducted for the reductive aminantion of levulinic acid with benzyl amine over CNF30@Ni@CNT (black), Ni@CNT (red), and Ni/C (green) catalysts. Reaction conditions: 10 mmol of levulinic acid, 10 mmol of benzyl amine, 0.03 g of catalyst, 10 wt% of Ni, 4 mL of gamma-valerolactone solvent, 3.0 MPa H2, 130 °C, and 4 h. Reproduced with permission from Ref. [104]. Copyright 2017, American Chemistry Society.
Fig. 9. (a-c) Schematic illustration and TEM images describing the formation of carbon-embedded metal spheres. Reproduced with permission from Ref. [76]. (d,e) Schematic illustration and TEM image describing for formation of the carbon-embedded MNPs. Carbon precursor: chitosan. Reproduced with permission from Ref. [110]. Copyright 2018, American Chemistry Society. (f) Schematic illustration of the formation of Ru spheres semi-embedded in mesoporous carbon (Ru-MC). (g) Reusability of Ru-MC catalyst for levulinic acid conversion. TEM images of the (h) fresh and (i) used Ru-MC catalysts. Reaction conditions: 17.8 mmol of levulinic acid, 18 mg of catalyst (2 wt%), 70 °C, 4 MPa H2, 1 h, 20 mL water solvent. Reproduced with permission from Ref. [111]. Copyright 2018, Elsevier.
Fig. 9. (a-c) Schematic illustration and TEM images describing the formation of carbon-embedded metal spheres. Reproduced with permission from Ref. [76]. (d,e) Schematic illustration and TEM image describing for formation of the carbon-embedded MNPs. Carbon precursor: chitosan. Reproduced with permission from Ref. [110]. Copyright 2018, American Chemistry Society. (f) Schematic illustration of the formation of Ru spheres semi-embedded in mesoporous carbon (Ru-MC). (g) Reusability of Ru-MC catalyst for levulinic acid conversion. TEM images of the (h) fresh and (i) used Ru-MC catalysts. Reaction conditions: 17.8 mmol of levulinic acid, 18 mg of catalyst (2 wt%), 70 °C, 4 MPa H2, 1 h, 20 mL water solvent. Reproduced with permission from Ref. [111]. Copyright 2018, Elsevier.
Fig. 10. Adjustments performed for the partial embedment of Ru NPs into the carbon framework of Ru-OMC catalysts. Reproduced with permission from Ref. [114]. Copyright 2014, Wiley-VCH.
Fig. 10. Adjustments performed for the partial embedment of Ru NPs into the carbon framework of Ru-OMC catalysts. Reproduced with permission from Ref. [114]. Copyright 2014, Wiley-VCH.
Fig. 12. (a) Schematic of the Co/ZrLa0.2Ox structure. (b) Effect of recycling on the catalytic performance of Co/ZrLa0.2Ox. Reaction conditions: 100 mg of furfural, 50 mg of Co/ZrLa0.2Ox in 10 mL of water, 40 °C, 2 MPa H2, 10 h. Reproduced with permission from Ref. [41]. Copyright 2018, American Chemistry Society.
Fig. 12. (a) Schematic of the Co/ZrLa0.2Ox structure. (b) Effect of recycling on the catalytic performance of Co/ZrLa0.2Ox. Reaction conditions: 100 mg of furfural, 50 mg of Co/ZrLa0.2Ox in 10 mL of water, 40 °C, 2 MPa H2, 10 h. Reproduced with permission from Ref. [41]. Copyright 2018, American Chemistry Society.
Fig. 13. (a) Preparation of the graphitic carbon/oxide composite (gc-γ-Al2O3) by chemical vapor deposition. (b) An optical micrograph of the gc-γ-Al2O3 sample. (c) A Raman spectroscopy map of the region marked by the box in panel (b). (d) Relative SAs, total pore volumes, and average particle sizes of the γ-Al2O3 and gc-γ-Al2O3 catalysts before and after the hydrothermal treatment (expressed in %). (e) Specific propylene glycol formation rates plotted as functions of the time on stream for the two Ru catalysts (5 wt% Ru) during the liquid-phase hydrogenation of lactic acid to propylene glycol at a temperature of 120 °C and H2 pressure of 500 psi (5 wt% lactic acid/H2O). Reproduced with permission from Ref. [121]. Copyright 2015, Wiley-VCH.
Fig. 13. (a) Preparation of the graphitic carbon/oxide composite (gc-γ-Al2O3) by chemical vapor deposition. (b) An optical micrograph of the gc-γ-Al2O3 sample. (c) A Raman spectroscopy map of the region marked by the box in panel (b). (d) Relative SAs, total pore volumes, and average particle sizes of the γ-Al2O3 and gc-γ-Al2O3 catalysts before and after the hydrothermal treatment (expressed in %). (e) Specific propylene glycol formation rates plotted as functions of the time on stream for the two Ru catalysts (5 wt% Ru) during the liquid-phase hydrogenation of lactic acid to propylene glycol at a temperature of 120 °C and H2 pressure of 500 psi (5 wt% lactic acid/H2O). Reproduced with permission from Ref. [121]. Copyright 2015, Wiley-VCH.
Fig. 14. (a) Schematic illustration of the in-situ synthesis of 0.6 wt% Ir@ZrO2@C catalyst. (b,c) High-resolution STEM image and EDX maps of Ir@ZrO2@C catalyst. (d) Time profiles of the catalytic conversion of 10 wt% levulinic acid in water over 0.6 wt% Ir@ZrO2@C catalyst. Results of the recycling experiments conducted for (e) 0.6 wt% Ir/ZrO2 (20 min), (f) 0.6 wt% Ir@ZrO2@C (1 h) in a pH = 3 aqueous solution, and (g) 0.6 wt% Ir@ZrO2@C (1 h) in a pH = 1 aqueous solution. Reaction conditions: T = 180 °C, PH2 = 4 MPa, aqueous solution of 10 wt% levulinic acid. Reproduced with permission from Ref. [128]. Copyright 2019, Elsevier.
Fig. 14. (a) Schematic illustration of the in-situ synthesis of 0.6 wt% Ir@ZrO2@C catalyst. (b,c) High-resolution STEM image and EDX maps of Ir@ZrO2@C catalyst. (d) Time profiles of the catalytic conversion of 10 wt% levulinic acid in water over 0.6 wt% Ir@ZrO2@C catalyst. Results of the recycling experiments conducted for (e) 0.6 wt% Ir/ZrO2 (20 min), (f) 0.6 wt% Ir@ZrO2@C (1 h) in a pH = 3 aqueous solution, and (g) 0.6 wt% Ir@ZrO2@C (1 h) in a pH = 1 aqueous solution. Reaction conditions: T = 180 °C, PH2 = 4 MPa, aqueous solution of 10 wt% levulinic acid. Reproduced with permission from Ref. [128]. Copyright 2019, Elsevier.
|
[1] | 安国庆, 张晓伟, 张灿阳, 高鸿毅, 刘斯奇, 秦耕, 齐辉, Jitti Kasemchainan, 张建伟, 王戈. 金属有机骨架基绿色催化剂在醇氧化反应中的研究应用[J]. 催化学报, 2023, 50(7): 126-174. |
[2] | 董兴宗, 刘广业, 陈兆安, 张权, 徐云鹏, 刘中民. 性能优异的Pd-[DBU][Cl]/AC无汞催化剂在乙炔氢氯化中的应用[J]. 催化学报, 2023, 46(3): 137-147. |
[3] | 黄志鹏, 杨阳, 穆骏驹, 李根恒, 韩建宇, 任濮宁, 张健, 罗能超, 韩克利, 王峰. 利用金属-自由基相互作用调控自由基的定向转化[J]. 催化学报, 2023, 45(2): 120-131. |
[4] | Diab khalafallah, 张运祥, 王昊, Jong-Min Lee, 张勤芳. 联产混合电解水策略实现节能电化学制氢的最新进展[J]. 催化学报, 2023, 55(12): 44-115. |
[5] | 吴立清, 梁庆, 赵家仪, 朱娟, 贾宏男, 张伟, 蔡苹, 罗威. 铋掺杂的二氧化钌催化剂用于高效酸性水氧化[J]. 催化学报, 2023, 55(12): 182-190. |
[6] | 李航杰, 肖月华, 肖佳乐, 范凯, 李炳宽, 李晓龙, 王亮, 肖丰收. 镓改性的铜基疏水催化剂用于CO2选择性加氢制二甲醚的研究[J]. 催化学报, 2023, 54(11): 178-187. |
[7] | 顾宇, 王磊, 徐柏庆, 施慧. 金属-水界面催化的分子机制: 加氢与氧化反应[J]. 催化学报, 2023, 54(11): 1-55. |
[8] | 付先彪. 关于电还原硝酸根反应的思考[J]. 催化学报, 2023, 53(10): 8-12. |
[9] | 商禹, 丁云轩, 张培立, 王梅, 贾玉飞, 徐云龙, 李亚晴, 范科, 孙立成. 吡啶氮或吡咯氮: 氮掺杂碳催化剂在电催化还原CO2中活性中心研究[J]. 催化学报, 2022, 43(9): 2405-2413. |
[10] | 孙万军, 朱佳玉, 张美玉, 孟翔宇, 陈梦雪, 冯钰, 陈新龙, 丁勇. 钴基非均相催化剂在光催化水分解、二氧化碳还原和氮还原的研究进展与展望[J]. 催化学报, 2022, 43(9): 2273-2300. |
[11] | 杨旭港, 刘宗辉, 魏国良, 顾宇, 施慧. 固-水界面的酸碱催化反应中水分子和溶剂化离子的角色[J]. 催化学报, 2022, 43(8): 1964-1990. |
[12] | 蒋亚飞, 刘锦程, 许聪俏, 李隽, 肖海. 打破合成氨反应中线性标度关系的碗型活性位点设计: 来自LaRuSi及其同构电子化物的启示[J]. 催化学报, 2022, 43(8): 2183-2192. |
[13] | 欧阳, 李松达, 王飞, 段心怡, 袁文涛, 杨杭生, 张泽, 王勇. 二氧化钛负载的铂纳米颗粒在CO和O2环境下表面平台位点和台阶位点的可逆转变[J]. 催化学报, 2022, 43(8): 2026-2033. |
[14] | 蒋国星, 张龙海, 邹文午, 张伟锋, 王秀军, 宋慧宇, 崔志明, 杜丽. 精确可控串联策略触发高效的氧还原活性[J]. 催化学报, 2022, 43(4): 1042-1048. |
[15] | 王春鹏, 王哲, 毛善俊, 陈志荣, 王勇. 多相催化剂活性位点的配位环境及其对催化性能的影响[J]. 催化学报, 2022, 43(4): 928-955. |
阅读次数 | ||||||
全文 |
|
|||||
摘要 |
|
|||||