P/Si-TiO2光觸媒厚膜的製備與特性分析

Preparation and characterization of P/Si-TiO2 photocatalytic thick films

鄭昭韋(Chao-Wei Cheng)

指導教授 ： 余宣賦

淡江大學/工學院/化學工程與材料工程學系碩士班/碩士(2018年)

https://doi.org/10.6846/TKU.2018.00137

摘要

高光催化能力的P/Si-TiO2厚膜以溶膠-凝膠法、旋轉塗布技術和棒塗技術穩固地附著於FTO導電玻璃基材上。製備過程中，首先使用溶膠-凝膠法與旋轉塗布技術將鈦酸正四乙酯的醇溶液塗布於FTO玻璃表面以形成緻密的TiO2薄膜來作為TiO2光觸媒厚膜的基底層。接著，以煆燒後具高結晶度的凝膠衍生P/Si- TiO2奈米粉體來調配漿料，再以12 μm塗布棒將漿料塗布於基材上，所得濕膜再經熱處理以製得TiO2光觸媒厚膜。製備之薄膜、粉體及厚膜經由X-光繞射分析、紫外光-可見光光譜儀、掃描式電子顯微鏡、表面輪廓儀和百格測試(ASTM D 3359-95)等來分析樣品特性。厚膜的光催化能力以光降解水中亞甲基藍(MB)所計算得的特徵時間常數(τ)來表示，τ越小代表光催化能力越好。結果顯示，以煆燒800 °C之粉體配製塗布漿料，並控制其固含量為20 wt.%所製得的厚膜中銳鈦礦TiO2結晶度高且具有較適當的微結構，所以整體呈現較優異的光催化能力，光催化反應6小時能夠分解81 mol%的MB(特徵時間常數τ值為3.59±0.5 %小時)；在相同條件與反應時間下TiO2薄膜只能分解29 mol%的MB(τ =18 ±0.1%小時)。P/Si-TiO2厚膜的光催化能力數倍高於TiO2薄膜。動力學探討得知，TiO2厚膜的光催化效能與光催化面積(NS; N:數目, S:面積)呈正比關係，與光照強度(I)呈指數關係。將不同實驗條件下量測所得τ進行數據的擬合分析得到其關係式為τ=[(0.052N+0.002)I^0.338 ]^(-1)，此關係式可充分地描述TiO2光觸媒厚膜降解水中MB的光催化行為表現。

關鍵字

二氧化鈦 ； 厚膜 ； 光催化能力 ； 溶膠-凝膠法製程

並列摘要

P/Si-TiO2 thick films with high photocatalytic activities firmly adhered on FTO glass substrates were prepared using the sol-gel method, spin-coating and bar-coating techniques. The TiO2 thin film coated on the FTO glass substrate, as a base layer for P/Si-TiO2 thick film, was formed via a spin-coating technique. The slurry containing the gel-derived P/Si-TiO2 nanoparticles was then bar-coated on the TiO2 base layer, followed by calcining at 550 °C to form the photocatalytic thick film on the FTO glass substrates. The specimens were characterized using X-ray diffractometer, ultraviolet-visible spectro- photometer, scanning electron microscope, stylus profiler and adhesion test (ASTM D 3359-95). By photocatalytic degradation of methylene blue (MB), the photocatalytic activities of the films were measured and represented using the corresponding characteristic time constant (τ). Smaller τ is, the higher is the photocatalytic ability of the film. The P/Si-TiO2 thick film, prepared from the slurry containing 20 wt.% of the calcined P/Si-TiO2 powder at 800 °C, gave the superior performance in photocatalysis; this thick film had τ=3.59 hours and decomposed about 81 mole% of MB in the water after 6 h, under irradiation 365-nm UV light. For the sake of comparison, the TiO2 thin film decomposed 29 mol% MB in water (τ= 18 hours) under the same conditions. Kinetic analysis showed that the photocatalytic abilities of P/Si-TiO2 thick films are directly proportional to the photocatalytic area (NS; N: number of specimens, S: area), and have a power relationship with light intensity (I). By experimental data fitting, it was found that τ = [(0.052N+0.002)I0.338]-1, which can well predict the characteristic time constant of the P/Si-TiO2 thick films at different operation conditions.

並列關鍵字

TiO2 ； thick film ； photocatalysis ； sol-gel process

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