CAJ | 학술논문

在酸性水溶液中(pH=2.0),采用电化学还原(ER)方法对BiVO4薄膜电极进行预处理,并探讨了其对薄膜电极光电化学氧化水性能的影响.结果表明,这种预处理可显著提高电极的光电化学氧化水的性能,且具有良好的光电化学稳定性.利用扫描电子显微镜、X射线衍射、拉曼光谱、光电子能谱、紫外-可见漫反射光谱、荧光光谱、电化学阻抗谱及Mott-Schottky等方法对ER处理前后的电极进行了表征.结果表明, ER预处理使电极粗糙度增大,表面积增大约1.4倍；电极材料的晶型无明显变化,但V-O对称伸缩振动略有红移；表面Bi, V和O结合能变小, Bi3+部分被还原, Bi/V原子比增大；ER处理导致电极平带电位负移,光生载流子在薄膜电极/溶液界面转移速率加快,表面复合速率降低.这些变化和表面积增加是BiVO4电极光电化学性能提高的主要原因.
재산성수용액중(pH=2.0),채용전화학환원(ER)방법대BiVO4박막전겁진행예처리,병탐토료기대박막전겁광전화학양화수성능적영향.결과표명,저충예처리가현저제고전겁적광전화학양화수적성능,차구유량호적광전화학은정성.이용소묘전자현미경、X사선연사、랍만광보、광전자능보、자외-가견만반사광보、형광광보、전화학조항보급Mott-Schottky등방법대ER처리전후적전겁진행료표정.결과표명, ER예처리사전겁조조도증대,표면적증대약1.4배；전겁재료적정형무명현변화,단V-O대칭신축진동략유홍이；표면Bi, V화O결합능변소, Bi3+부분피환원, Bi/V원자비증대；ER처리도치전겁평대전위부이,광생재류자재박막전겁/용액계면전이속솔가쾌,표면복합속솔강저.저사변화화표면적증가시BiVO4전겁광전화학성능제고적주요원인.
BiVO4 thin film electrodes were pretreated by electrochemical reduction( ER) in acid aqueous so-lutions(pH=2), and its impact on the performance of photoelectrochemical oxidation of water was tested. The results show that this treatment enhances the photoelectrochemical oxidation of water over the BiVO4 thin film electrodes and the treated electrodes have a good photoelectrochemical stability. The untreated and ER treated electrode films were characterized by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy, photoluminescence, electrochemi-cal impedance spectroscopy, Mott-Schottky measurements, etc. From a physical chemistry perspective, the ER pretreatment resulted an increase of the roughness of the electrode with increasing in surface area by a fac-tor of 1.4;no detectable change in crystalline but a slightly red-shift in the V-O symmetric stretching;a de-crease in binding energy for the surface Bi, V and O; partly reduction of Bi3+ with an increase in the atom ratio of Bi/V on the surface. From the view of photoelectrochemistry, due to ER treatment, the flatband poten-tial for the electrode was negatively shifted, the charge-transfer rate of photocarriers at the electrode/solution interface was accelerated while the surface recombination rate was decreased. These changes and the increased surface area are the main reasons for the enhanced photoelectrochemical performance.