(1. 湖南科技大學(xué) 材料科學(xué)與工程學(xué)院，湘潭411201；
2. 湖南科技大學(xué) 高溫耐磨材料及制備技術(shù)湖南省國防科技重點(diǎn)實驗室，湘潭411201；
3. 湖南科技大學(xué) 精細(xì)聚合物可控制備及功能應(yīng)用湖南省重點(diǎn)實驗室，湘潭411201；
4. 湖南科技大學(xué) 新能源儲存與轉(zhuǎn)換先進(jìn)材料湖南省重點(diǎn)實驗室，湘潭411201)
摘 要: 通過水熱合成和熱處理相結(jié)合的方法制備p-n型CaFe2O4/WO3異質(zhì)結(jié)復(fù)合材料。采用XRD、SEM、TEM、EDS、BET及UV-Vis-DRS對材料結(jié)構(gòu)和性能進(jìn)行表征和測試，并研究了水溶性染料亞甲基藍(lán)(Methylene blue)的光催化降解。結(jié)果表明：相對于單相WO3，p-n型CaFe2O4/WO3復(fù)合材料的響應(yīng)范圍明顯地擴(kuò)展到更高波長的可見光區(qū)，能高效地實現(xiàn)光催化降解有機(jī)染料亞甲基藍(lán)。CaFe2O4/WO3質(zhì)量比為5%的CaFe2O4/WO3復(fù)合材料比表面積為19.7 m2/g，孔徑分布在20~150 nm之間；在模擬可見光降解50 mg/L的亞甲基藍(lán)實驗中，其在6 h內(nèi)的降解率達(dá)到了90%，重復(fù)3次的光催化降解率仍有86%，降解反應(yīng)速率常數(shù)ka為0.180 h-1，顯示出優(yōu)異的光催化降解能力和循環(huán)穩(wěn)定性。降解機(jī)理研究表明，WO3和CaFe2O4之間的價帶和導(dǎo)帶關(guān)系滿足能級匹配條件，可形成p-n型CaFe2O4/WO3異質(zhì)結(jié)，從而提高復(fù)合材料的光催化活性。
關(guān)鍵字: 可見光響應(yīng)；CaFe2O4/WO3；p-n型異質(zhì)結(jié)；復(fù)合半導(dǎo)體；光催化
（1. School of Materials Science and Engineering, Hunan University of Science and Technology, Xiangtan 411201, China;
2. Hunan Provincial Key Defense Laboratory of High Temperature Wear-resisting Materials and Preparation Technology, Hunan University of Science and Technology, Xiangtan 411201, China;
3. Hunan Provincial Key Laboratory of Controllable Preparation and Functional Application of Fine Polymers, Hunan University of Science and Technology, Xiangtan 411201, China;
4. Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion, Hunan University of Science and Technology, Xiangtan 411201, China）
Abstract:The p-CaFe2O4/n-WO3 heterojunction semiconductor composites were prepared by hydrothermal method and heat treatment. The p-CaFe2O4/n-WO3 composites were characterized by XRD, TEM，SEM, EDS, BET and UV-is-DRS. The results show that p-CaFe2O4/n-WO3 composite has red shift of a strong absorption peak to visible region (＞460 nm), showing visible-light responded photocatalysis on methylene blue. The specific surface area of CaFe2O4/WO3composite with 5% in mass ratio is 19.7 m2/g and the BJH pore size distribution focuses on 20-150 nm. During the experiment for simulating visible photodegradation of 50 mg/L methylene blue solution, the photocatalytic degradation rate of CaFe2O4/WO3composite with 5% in mass ratio reaches 90% in 6 h and is still above 86% after three cycles, and the degradation reaction rate constant ka is 0.180 h-1, showing excellent photocatalytic activity and cycle stability. The degradation mechanism studies show that the valence band and guide band relationships between WO3 and CaFe2O4 satisfies the energy level matching conditions and can form p-CaFe2O4/n-WO3 heterojunction, thus improving the photocatalytic activity of the composite.
Key words: visible light response; CaFe2O4/WO3; p-n type heterojunction; compound-semiconductor; photocatalyst
