FeO(OH)-TiO_2/CoPi复合光阳极的制备及其光电催化氧化水性能  

Preparation and Photoelectrocatalytic Water Oxidation Properties of FeO(OH)-TiO_2 /CoPi Composite Photoanodes

作　　者：金涛[1] 许頔[1] 刁鹏[1] 项民[1] 

机构地区：[1]北京航空航天大学材料科学与工程学院,空天材料与服役教育部重点实验室,北京100191

出　　处：《物理化学学报》2012年第10期2276-2284,共9页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(20973020;21173016);高等学校博士学科点基金(20101102110002);新世纪人才支持计划(NCET-08-0034)资助项目~~

摘　　要：采用溶胶-凝胶法制备了TiO2纳米晶,并通过浸渍技术在其表面引入了FeO(OH).采用紫外-可见(UV-Vis)吸收光谱确定了引入FeO(OH)的最佳Fe3+浓度.通过电化学法在FeO(OH)-TiO2光阳极上沉积了催化水分解制备氧气的钴基催化剂(CoPi),得到了FeO(OH)-TiO2/CoPi复合光阳极.利用透射电镜(TEM),高分辨透射电镜(HRTEM),X射线衍射(XRD),扫描电镜(SEM)对TiO2纳米晶,FeO(OH)-TiO2以及FeO(OH)-TiO2/CoPi复合光阳极进行了表征,采用电化学和光电化学技术研究了中性条件下FeO(OH)-TiO2/CoPi复合光阳极的光电催化分解水性能.结果表明,TiO2纳米晶为梭形的锐钛矿,其表面修饰的FeO(OH)为针铁矿型,且当前驱体溶液中Fe3+与TiO2的质量比为0.05%时得到的FeO(OH)-TiO2具有最佳的光吸收效果.形成FeO(OH)-TiO2/CoPi复合光阳极后,在光照条件下CoPi电催化分解水制备氧气的过电位显著降低.TiO2表面FeO(OH)的引入增加了光阳极对可见光的吸收能力,同时光阳极表面沉积的CoPi有效地利用了FeO(OH)-TiO2产生的光生空穴,将水氧化形成氧气,从而在光照条件下显著提高了CoPi催化氧化水的效率.TiO2 nanocrystals were synthesized using a sol-gel method, and then the impregnationtechnique was used to modify the surface of the TiO2 nanocrystals with FeO（OH）. The optimal concentration of Fe3. for the modification of the TiO2 nanocrystals was determined by UV-Vis spectroscopy. A cobalt-phosphate （CoPi） water oxidation catalyst was electrochemically deposited onto the FeO（OH）- TiO2 photoanodes. The resulting FeO（OH）-TiOJCoPi composite photoanodes were systematically characterized by transmission electron microscopy （TEM）, high-resolution transmission electron microscopy （HRTEM）, X-ray diffraction （XRD）, and scanning electron microscopy （SEM）, and the photoelectrochemical water oxidation properties of the FeO（OH）-TiO2/CoPi composite photoanodes were investigated in neutral conditions by electrochemical and photoelectrochemical methods. The results indicated that the TiO2 particles were pure anatase nanocrystals, and the FeO（OH） phase on the TiO2 surfaces was goethite. The optimal light absorption properties of the FeO（OH）-TJO2 photoanodes were achieved when the photoanodes were prepared in the precursor solution with a Fe^3＋：TiO2 mass ratio of 0.05%. The overpotential for oxygen evolution on the FeO（OH）-TiO2/CoPi composite photoanodes underillumination decreased significantly compared with that obtained on the CoPi catalyst. The high oxygen evolution activity of the composite photoanodes can be attributed to modification of FeO（OH） on TiO2 nanocrystal surfaces changing the light absorption band from the ultraviolet to the visible region and CoPi inhibited hole-electron recombination through facilitating the photon-induced hole transfer for water oxidation.

关 键 词：氢氧化氧化铁 二氧化钛纳米晶 钴基磷酸盐催化剂 光电催化分解水制氧气 光生空穴 

分 类 号：O611.4[理学—无机化学] O643.32[理学—化学]