【摘要】：光催化氧化技術(shù)由于其具有高效無污染等優(yōu)點受到廣大研究者的關(guān)注,提高光催化性能和實現(xiàn)可回收利用,是將光催化技術(shù)推向?qū)嶋H應(yīng)用的關(guān)鍵。本文通過將BiOBr和有序Ti02納米管陣列(TNTAs)薄膜進行復(fù)合形成異質(zhì)結(jié),實現(xiàn)將BiOBr較強的可見光光催化性能和穩(wěn)定性與Ti02納米管陣列的可回收利用性相結(jié)合,獲得結(jié)合了兩者優(yōu)點的BiOBr/TiO2納米異質(zhì)陣列薄膜光催化劑。由于BiOBr對可見光的響應(yīng)有限,并在此基礎(chǔ)上對其進行貴金屬Pt修飾進一步提高其可見光光催化性能。主要研究結(jié)果如下：(1)以氟化銨的乙二醇溶液為電解液,通過陽極氧化法在60 V電壓下氧化6h制備獲得有序Ti02納米管陣列薄膜。通過改變電解液中的水含量來研究其對Ti02納米管陣列管間距的影響。結(jié)果表明水含量的最佳參數(shù)為7%,該條件下制備的Ti02納米管陣列管徑約為150 nm,管與管之間的間隙清晰可見,并且陣列薄膜不易從基底上脫落。(2)采用循環(huán)浸漬法制備了BiOBr/TiO2納米異質(zhì)陣列薄膜(BiOBr/TNTAs),并研究不同的影響因素如反應(yīng)物濃度、水浴溫度、浸漬時間、浸漬遍數(shù)對其影響。結(jié)果表明最佳的制備工藝參數(shù)為：反應(yīng)物濃度0.5 mM,水浴溫度40℃,浸漬時間2 min,浸漬遍數(shù)2遍。對于此條件下制備的BiOBr/TNTAs,可以觀察到在Ti02納米管內(nèi)外表面上負(fù)載了大量細(xì)小的納米片,并且納米管的管口和管間距仍清晰可見。另外研究了BiOBr/TNTAs的光催化性能,并對其機理進行了分析。結(jié)果表明BiOBr/TNTAs-2樣品的光催化性能最佳,其原因可歸結(jié)為以下幾個因素：BiOBr對可見光的吸收,BiOBr/TNTAs異質(zhì)結(jié)的形成,較大的比表面積。在以上幾個因素的共同作用下,促使BiOBr/TNTAs-2樣品具有較好的可見光響應(yīng)和較高的量子利用效率,從而使得其具有優(yōu)異的光催化性能。(3)通過溶劑熱法引入貴金屬Pt。首先通過實驗分析確定Pt和BiOBr的沉積順序,結(jié)果表明通過先沉積Pt后沉積BiOBr來制備Pt-BiOBr/TiO2納米異質(zhì)陣列薄膜(Pt-BiOBr/TNTAs)的實驗順序較為合理。其次研究了不同的氯鉑酸濃度對樣品形貌的影響,結(jié)果表明,隨著氯鉑酸濃度的增加,Pt納米顆粒的數(shù)量和尺寸增加,當(dāng)濃度過大時,納米顆粒開始團聚在一起,將管口覆蓋,從而選定了氯鉑酸的最佳濃度為2 mM。最后研究了BiOBr沉積過程中浸漬遍數(shù)對其形貌和性能的影響并對其機理進行了分析。結(jié)果表明隨著浸漬遍數(shù)的增加,BiOBr納米片的沉積量隨之上升,并且過量的負(fù)載會導(dǎo)致納米管的堵塞。浸漬遍數(shù)為2的Pt-BiOBr/TNTAs-2具有最佳的光催化性能,并得出Pt-BiOBr/TNTAs-2光催化性能最佳的原因可歸結(jié)于以下幾個因素：①Pt的等離子共振效應(yīng)使得Pt可以吸收可見光,并且可以作為電子陷阱俘獲電子,②BiOBr的可見光響應(yīng),③Pt和BiOBr適當(dāng)?shù)呢?fù)載量使得其具有較大的比表面積,④Pt-BiOBr/TNTAs中不同種類的異質(zhì)結(jié)的形成促進了光生電子空穴對的分離。
[Abstract]:Photocatalytic oxidation technology has attracted many researchers' attention because of its high efficiency and no pollution. Improving photocatalytic performance and realizing recycling is the key to the application of photocatalytic technology. In this paper, BiOBr and ordered Ti02 nanotube array (TNTAs) films are combined to form heterojunction to combine the strong visible photocatalytic properties and stability of BiOBr with the recyclability of Ti02 nanotube arrays. The photocatalyst of BiOBr/TiO2 nanoscale heterostructure array film was obtained by combining the advantages of both. Because the response of BiOBr to visible light is limited, and on the basis of this, the Pt modification of BiOBr can further improve the photocatalytic performance of visible light. The main results are as follows: (1) the ordered Ti02 nanotube array films were prepared by anodic oxidation at 60 V voltage with ethylene glycol solution of ammonium fluoride as electrolyte. The effect of water content on the spacing of Ti02 nanotube arrays was studied by changing the water content in the electrolyte. The results show that the optimum parameter of water content is 7 and the diameter of the Ti02 nanotube array is about 150nm.The gap between the tubes is clearly visible. The BiOBr/TiO2 nanoscale heterostructure array (BiOBr/TNTAs) thin films were prepared by cyclic impregnation method. The effects of different factors such as reactant concentration, water bath temperature, impregnation time and number of impregnation times on it were studied. The results showed that the optimum preparation parameters were as follows: reactant concentration 0.5 mm, water bath temperature 40 鈩，

本文編號：2139518