半導體奈米晶體由於其強電子轉移能力和高催化反應活性，被廣泛用作各式化學反應之光催化劑，如用於降解水源中之有機染料分子。然而，作為性能優異的光催化劑，半導體奈米晶體於實際應用上仍存在聚集、反應過程中的光腐蝕與回收過程中的損耗等問題需要解決。針對這些問題，有必要提高光催化劑“活性電荷”的利用效率及其在回收過程中的穩定性。
在此通過將未反應的“活性電荷”轉移到其他具有催化活性物質之上以減少為反應的“活性電荷”與半導體材料產生光腐蝕現象。並且利用將具有光催化效果之奈米晶體固定在高分子基質之上以防止催化過程中奈米晶體因聚集而降低奈米晶體之催化特性，除此也可以利用此固著效果來增加回收之穩定性，使奈米晶體可以永續使用。此論文中具有三種成份的奈米晶體：氧化亞銅-氧化鋅-銀奈米晶體(Cu2O-ZnO-AgNC)，被用作為光催化劑於可見光範圍下降解剛果紅分子，此三成份之奈米晶體展示出高催化反應性與回收過程之高穩定性。在可見光激發下，Cu2O-ZnO-AgNC作為光催化劑的高反應性源自於產生大量之“活性電荷”:來自於AgNC晶體的熱電子和來自於Cu2O晶體的激發電子-電洞對。並且通過將未反應的“活性電荷”轉移到對剛果紅具有反應性之ZnO晶體上，進一步增加催化活性，同時亦可以抑制未反應的“活性電荷”對Cu2O晶體的光腐蝕現象。這些結果說明可經由設計奈米晶體之分子能隙與材料間的電荷轉移來合成具有高催化性能與高穩定的催化劑或光催化劑用於各式化學反應。

Semiconductor nanocrystals are widely used as photocatalyst for the degradation of organic dye molecules due to their strong electron transfer ability and high catalytic reactivity. However, as a photocatalyst with excellent performance, semiconductor nanocrystals still have some issues, such as aggregation, photocorrosion during the reactions, and loss during recycling that need to be addressed. In response to these problems, it is necessary to improve the using efficiency of “active charges” of photocatalysts and their stability in the recycling process, which can be achieved by transferring the unreacted “active charges” to other active materials and fixing the photocatalysts in the polymer matrix, respectively. Here, we designed nanocrystal with three components, Cu2O-ZnO-AgNC (silver nanocube), as photocatalysts with high stability and high reactivity for degradation of Congo red molecules under irradiation in the visible light range. The high reactivity of Cu2O-ZnO-AgNC as a photocatalyst can be contributed to the generation of “active charges”, hot electrons from AgNC and excited electron-hole pairs from Cu2O, under visible light irradiation. And the photocorrosion of Cu2O can be suppressed by transferring the unreacted “active charges” to ZnO and the photocatalytic performance can be further improved. These results enable the design and synthesis of catalysts or photocatalysts with high catalytic performance for various reduction reactions.

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