本文關鍵詞：鋅、鉍系光催化劑的控制合成及性能研究　出處：《河南師范大學》2016年碩士論文　論文類型：學位論文

  更多相關文章： ZnO Bi_2WO_6 水熱微乳液法 水熱法 光催化

【摘要】：近年來,隨著半導體光催化技術的不斷發(fā)展,利用半導體光催化材料降解廢水中的有機污染物以及光解水制氫技術有望成為解決環(huán)境和能源問題的有效途徑。在眾多的半導體光催化材料中,氧化鋅(ZnO)和鎢酸鉍(Bi_2WO_6)由于其活性高、穩(wěn)定性好、制備成本低等優(yōu)點而成為學者們的研究重點。盡管ZnO禁帶寬度較大,只在紫外光下有較好的響應,對太陽光的利用率較低,但改性后的ZnO仍有較高的應用價值。Bi_2WO_6禁帶寬度窄,可有效利用太陽光,展現(xiàn)出良好的工業(yè)應用前景。然而在實際光催化過程中,Bi_2WO_6材料的光生電子和空穴極易復合,光子利用率低,限制了其在工業(yè)中的大量應用。為了提高ZnO和Bi_2WO_6光催化材料的活性,本文從形貌控制和結構調整兩方面著手分別對其進行改性,主要研究內容如下:(1)以乙酸鋅為原料,CTAB為表面活性劑,正己醇為助表面活性劑,利用水熱微乳液法在水熱溫度140℃,水熱時間為14 h的條件下成功制備出3D花狀微球結構的ZnO光催化劑。通過XRD和SEM考察一系列反應時間產(chǎn)物的形貌和結構,提出了3D花狀微球結構的可能生長機理。此外,考察了不同形貌的ZnO在紫外光下對亞甲基藍溶液的降解活性,結果表明3D花狀微球結構的ZnO具有較好的光催化活性,其原因可能與其較高的結晶度和特殊的3D分層微球結構的協(xié)同作用有關。(2)以L-賴氨酸為模板劑采用水熱法成功合成納米銀和片狀g-C_3N_4修飾的Bi_2WO_6微球,研究了Ag和g-C_3N_4的負載量對Bi_2WO_6光催化活性的影響,得出適宜的負載條件,即當摻入3%的g-C_3N_4且摻入0.5%的Ag時負載樣品對羅丹明B染料的降解率最高。與純Bi_2WO_6光催化材料相比,負載型Bi_2WO_6光催化性能提高的原因歸結于Ag和g-C_3N_4的協(xié)同作用促進了光生電子和空穴的有效分離。(3)采用水熱法制備出Bi_2WO_6/MoS_2復合材料,采用瞬態(tài)電流和線性掃描伏安法對所制備樣品做了電化學性能測試。結果表明,由于材料的化學復合以及半導體之間光電子的轉移,當摻入5%Bi_2WO_6時MoS_2復合樣品具有較低的初始電位(-50 mV)和較小的塔菲爾斜率(96 mV dec-1),表現(xiàn)出更好光催化制氫性能。
[Abstract]:In recent years, with the continuous development of semiconductor photocatalytic technology. Using semiconductor photocatalytic materials to degrade organic pollutants in wastewater and photolysis water to produce hydrogen technology is expected to be an effective way to solve environmental and energy problems in many semiconductor photocatalytic materials. Zinc oxide (ZnO) and bismuth tungstate (Bi2WO6) have become the research focus of scholars because of their high activity, good stability, low preparation cost and so on, despite the wide band gap of ZnO. But the modified ZnO still has higher application value. Bi2WO6 has a narrow band gap, which can effectively utilize solar light. However, in the process of photocatalysis, the photogenerated electrons and holes of Bikes _ 2WO _ 6 materials are easy to be recombined, and the photon utilization rate is low. In order to improve the activity of ZnO and Bi_2WO_6 photocatalytic materials, the morphology control and structure adjustment were used to modify them respectively. The main research contents are as follows: (1) with zinc acetate as raw material, CTAB as surfactant and n-hexanol as cosurfactant, hydrothermal microemulsion method was used at 140 鈩，

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