本研究利用磁性四氧化三鐵來做為磁核，製備出具磁性二氧化鈦。為了解加入磁核後磁性二氧化鈦顆粒的光催化活性及磁核對光觸媒反應之影響，因此將以不同製備條件(如: 鍛燒溫度、酸洗時間、鐵鈦比)，去探討磁性二氧化鈦是否因為磁核的存在或是製備條件的不同，而影響其光催化分解反應。以可見光照射結果顯示光溶解程度皆小於儀器偵測極限，而經由紫外光照實驗結果顯示，磁性二氧化鈦發生光溶解現象，光溶解現象會依照不同酸洗時間、鍛燒溫度以及鐵鈦比的不同而改變。以不同製備條件顆粒測試光催降解程度，結果顯示光溶解現象會影響二氧化鈦光催化反應。另利用純二氧化鈦添加鐵離子於甲醇溶液中，了解光溶出之鐵離子對光催化之影響，結果顯示，鐵離子濃度越高，光催化反應衰減越劇。而二氧化鈦須經由鍛燒使二氧化鈦結晶，當以鍛燒溫度為400℃、450℃、500℃下測試光催化反應，結果顯示光催化反應依鍛燒溫度上升而下降。將本實驗室製備出磁性二氧化鈦以可見光光照，結果顯示在可見光下磁性二氧化鈦有較低的催化效果。 Magnetic titanium dioxide particles were synthesized. The effects of preparation parameters, such as Fe/Ti weight ratio, period of acid wash, and calcinations temperature on photodissolution of magnetite nanoparticles were studied. The influences of photodissolution of the magnetite nanoparticles on the photon-assisted catalysis were also investigated. Photocatalysis of methanol to formaldehyde was conducted. Photocatalysis by pure TiO2 with addition of Fe3+ ions in the methanol solution was performed to examine the effects of photo-dissolved iron on the photocatalytic ability magnetic titanium dioxide. The results showed that severe acid wash would destroy the matrix of TiO2 and increase the surface area of magnetic TiO2 particles. Thus, when the acid wash time was too long, more Fe3O4 were washed out. Also, as the calcinations temperature increased, the photodissolution of magnetite decreased, which maybe because the crystalline of TiO2 shifted from anatase to rutile, in which the binding between rutile and magnetite were stronger. As the iron concentration in the solution increased, the photocatalysis of methanol decreased. Our preliminary tests also showed that the magnetic TiO2 synthesized in this work has weak photocatalytic ability by visible light.