本研究使用常溫沉澱法以不用前驅鹽與反應環境合成三種α-Bi2O3，發現添加油酸之樣品O6N60在可見光下對甲基橙具有最高降解率，因此將其作為下一階段合成之晶種，後藉由二階段沉澱法在常溫下不需經額外熱處理合成以α-Bi2O3為主體之混合相α/δ-Bi2O3，吸收光譜結果發現兩相之吸收波段均落於可見光範圍內，可利用可見光作為光催化之能量來源，PL光譜分析可證實混合相可降低電子電洞復合率且α/δ-Bi2O3在特定相組成比例下(α: δ=9:1)展現比純α-Bi2O3更高的甲基橙染料降解效率。透過比對實驗結果與兩相能帶結構推測降解反應機制，發現電洞與超氧離子為Bi2O3降解甲基橙系統之主要活性反應因子;亦確認兩相接面間光激發載子的移動方向，激發後電子δ-Bi2O3由移動至α-Bi2O3，而電洞則是相反方向。以光沉積法將奈米級Pt金屬粒子負載於Bi2O3可進一步增強對染料的降解效率，經由反應速率計算，可見光下α/δ-Bi2O3+1wt%Pt降解染料甲基橙效率是純α-Bi2O3的4倍。另一方面，將光觸媒投入產氫實驗中，發現表面負載Pt為效率提升的重點要素，而由於δ-Bi2O3結構中過渡元素V價數傾向於捕捉電子而使混合相產氫效率降低。

This work demonstrates the synthesis of α/δ mixed phase bismuth (III) oxide (Bi2O3) at room temperature using a two-step precipitation method. Photoluminescence spectroscopic analysis confirms that the mixed phase could form the homojunction to reduce the electron–hole pair recombination rate and that α/δ-Bi2O3 under a specific phase composition ratio (α:δ = 9:1) exhibits higher methyl orange dye degradation than pure α-Bi2O3. By comparing the experimental results and the two-phase energy band structure to speculate the degradation reaction mechanism, this study finds that the holes and superoxide ions are the main active reaction factors of the Bi2O3 degradation system for methyl orange. Experimental results confirm that α/δ-Bi2O3 can be used as a potential hydrogen production material.

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