Nkwachukwu Oluchi V, Muzenda Charles, Jayeola Kehinde D, Sebokolodi Tsholofelo I, Sipuka Dimpo S, Cretin Marc, Zhou Minghua, Nkosi Duduzile, Arotiba Omotayo A
Department of Chemical Sciences, University of Johannesburg, Doornfontein 2028, South Africa.
Centre for Nanomaterials Science Research, University of Johannesburg, Doornfontein 2028, South Africa.
Materials (Basel). 2023 Mar 30;16(7):2769. doi: 10.3390/ma16072769.
Electrodeposited bismuth ferrite (BiFeO) thin films on fluorine-doped tin oxide (FTO) substrate were employed as photoanodes in the photoelectrocatalytic degradation of methylene blue. The BiFeO thin films electrodeposited for 300 s, 600 s, 1200 s, 1800 s and 3600 s were characterised with XRD, field emission scanning electron microscopy (FESEM) and UV-vis diffuse reflectance spectroscopy. SEM images displayed different morphology at different electrodeposition times which affects the photoelectrocatalytic (PEC) performances. The FESEM cross-sectional area was used to measure the thickness of the film. The optical properties showed that the band gaps of the photoanodes were increasing as the electrodeposition time increased. The photocurrent response obtained showed that all thin film photoanodes responded to visible light and lower charge transfer resistance (from electrochemical impedance spectroscopy studies) was observed with photoanodes electrodeposited at a shorter time compared to those at a longer time. The PEC application of the photoanode for the removal of methylene blue (MB) dye in water showed that the percentage degradation decreased with an increase in electrodeposition time with removal rates of 97.6% and 70% observed in 300 s and 3600 s electrodeposition time, respectively. The extent of mineralisation was measured by total organic carbon and reusability studies were carried out. Control experiments such as adsorption, photolysis, photocatalysis and electrocatalysis processes were also investigated in comparison with PEC. The electrodeposition approach with citric acid exhibited improved electrode stability while mitigating the problem of catalyst leaching or peeling off during the PEC process.
将沉积在氟掺杂氧化锡（FTO）衬底上的铁酸铋（BiFeO）薄膜用作光阳极，用于光催化降解亚甲基蓝。对电沉积300秒、600秒、1200秒、1800秒和3600秒的BiFeO薄膜进行了X射线衍射（XRD）、场发射扫描电子显微镜（FESEM）和紫外可见漫反射光谱表征。扫描电子显微镜（SEM）图像显示，在不同的电沉积时间下，薄膜具有不同的形貌，这会影响光电催化（PEC）性能。利用FESEM横截面面积测量薄膜厚度。光学性质表明，随着电沉积时间的增加，光阳极的带隙增大。获得的光电流响应表明，所有薄膜光阳极都对可见光有响应，并且与电沉积时间较长的光阳极相比，电沉积时间较短的光阳极具有更低的电荷转移电阻（来自电化学阻抗谱研究）。光阳极用于去除水中亚甲基蓝（MB）染料的PEC应用表明，随着电沉积时间的增加，降解百分比降低，在电沉积时间为300秒和3600秒时，去除率分别为97.6%和70%。通过总有机碳测量矿化程度，并进行了可重复使用性研究。与PEC相比，还研究了吸附、光解、光催化和电催化等对照实验。柠檬酸电沉积方法提高了电极稳定性，同时减轻了PEC过程中催化剂浸出或剥落的问题。
