本研究主要探討銀與碳共同改質二氧化鈦之紫外光與可見光應答光催化活性，選用一般商業用銳鈦礦(anatase)晶相的ST-01進行改質程序，係因ST-01具有較大的能隙值而使其應用之激發光波長範圍受到限制，並且ST-01雖具有高表面積，但其缺乏良好電子與電洞的分離機制而影響其光催化活性，因此藉由銀與碳共同改質的方式，以提升其於紫外光與可見光激發下的反應活性，並且探討其光催化活性之來源。
實驗中係選用醇類與硝酸銀作為碳與銀之前驅物，利用含浸法(Impregnation)進行表面改質，並由碳摻雜量、鍛燒溫度、碳前驅物種類與銀含量等實驗變因中找出最佳操作參數，藉以釐清硝酸銀與碳分別對於二氧化鈦活性的影響，亦進一步探討兩者共伴效應的影響。物性分析係以XRD檢測樣品於改質前後之晶相結構與晶粒大小的變化、Raman分析摻雜於觸媒表面之碳結構、XPS分析改質物於二氧化鈦表面之化學組態、ATR-FTIR檢測光觸媒之表面官能基、TGA分析觸媒表面之碳摻雜量、UV-Vis量測二氧化鈦於改質前後光吸收度與能隙值的變化、PL分析觸媒之電子與電洞的再結合率等，並以光催化液相甲基橙的降解反應與氣相氮氧化物的氧化反應，探討觸媒之光催化活性。
碳摻雜於二氧化鈦表面可有效提升其可見光吸收能力，拓展其光激發波長的範圍，但是其電子與電洞的再結合率仍過高；銀改質二氧化鈦雖可有效抑制其電子與電洞的再結合，卻無法有效縮減其能隙值而使其無法受可見光的激發產生活性。因此，藉由兩者的結合，除可大幅縮減二氧化鈦的能隙值，亦能有效抑制光激發電子與電洞的再結合。此外，藉由硝酸銀的添加可有助於碳前驅物於鍛燒過程中的碳化反應，使銀與碳共同改質二氧化鈦表面具有較多碳酸鹽類的官能基，且銀改質可有效提升二氧化鈦表面氫氧官能基的含量。因此，藉由硝酸銀與碳共同改質的方式，可有效提升二氧化鈦之紫外光與可見光的光催化活性。

In this study, we focused on the ultraviolet-light-responsively and visible-light-responsively photoactivity of silver-carbon co-doped titania. The commercially available anatase-phase titania, ST-01, was used as the raw material for modification. The practical application of ST-01 in the visible region is limited due to its large band gap. Moreover, the activity of ST-01 is moderate due to the lack of good separation rate of the photoinduced charge carries, even though it has large specific surface area. In this work, the Ag-C co-doped modification was applied to enhance the photoactivity under both ultraviolet and visible illuminations, and the rational mechanism was also investigated in detail.
The Ag-C co-doped TiO2 was prepared by an impregnation method using alcohols and silver nitrate as the carbon and silver sources, respectively. The optimum preparation parameters were obtained by studying the effects of amount of alcohol, calcination temperature, kind of carbon precursor, and amount of silver. The individual effects of silver nitrate and carbonaceous species on the photoactivity of titania were clarified from the results of series experiments, and the reason for the synergistic effect between silver nitrate and alcohol for the improvement of photoactivity was also obtained.
Physical characterization of silver-carbon codoped titania sample, including crystal structure, grain size, carbon structure, chemical states of dopants, surface functional groups, carbon content, band gap, and charge carries recombination rate, were identified using X-ray diffraction,
Raman spectroscopy, X-ray photoelectron spectroscopy, fourier transform infrared spectroscopy, thermal gravity analysis, UV-visible absorption spectra, and photoluminescence, respectively. The activities of the synthesized photocatalysts were evaluated for the oxidation of NO and decolorization of dye under illuminations by ultraviolet and visible light.
The visible-light absorption of titania could be enhanced by the carbon-modification at its surface, but the electron-hole recombination rate was not still reduced efficiently. In the contrast, the charge carries separation efficiency of titania could be improved with using Ag species as dopant, but its band gap would not be narrowed effectively. Therefore, the properly Ag-C co-doped process could not only obviously narrow the band gap of titania, but also effectively suppress the charge carries recombination. In addition, the carbonization effect of the carbon precursor would be improved with the presence of silver nitrate, leading to plenty of carbonate and hydroxyl groups produced on the photocatalyst. Therefore, the ultraviolet-light-responsively and visible-light- responsively photoactivities of titania would be both greatly enhanced by the synergistic effect between silver and carbon species.

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