Syed Salma S, Jacob Liyamol, Bharath G, Haija Mohammed Abu, Kaushik Anupama, Banat Fawzi
Department of Chemical Engineering, Khalifa University of Science and Technology, P. O. Box: 2533, Abu Dhabi, United Arab Emirates.
Department of Mechanical and Materials Engineering, Khalifa University of Science and Technology, P. O. Box: 2533, Abu Dhabi, United Arab Emirates.
Environ Res. 2023 Apr 1;222:115280. doi: 10.1016/j.envres.2023.115280. Epub 2023 Jan 16.
In recent years, photoelectrocatalysis of gold nanoparticles (Au NPs) has received considerable attention due to their potential to improve catalytic efficiency. Herein, ultra-small Au NPs were successfully synthesized in a single pot using olea europea leaf extract as a green reducing agent for the degradation of 4-nitrophenol. The TEM images showed uniform distribution and spherical shape of Au NPs with an average diameter of 5 nm. Taking advantage of the ability of Au nanoparticles to absorb visible and near-infrared light, 4-nitrophenol can be successfully reduced in the presence of NaBH. Additionally, the electrochemical activity of the fabricated Au photocathode was investigated by linear sweep voltammetry in the dark and at VIS-NIR light irradiation. This showed an increased photocurrent density of 27 mA cm with an onset potential of -0.71 V. This indicates that the Au photocathode is highly active at VIS-NIR light. Interestingly, the Au photocathode showed a higher current density of 37 mA cm with an onset potential of -0.6 V in the presence of 4-nitrophenol during VIS-NIR irradiation, indicating that 4-nitrophenol was efficiently reduced by the photocathode. The Au photocathode completely reduced 4-nitrophenol in the wastewater within 35 min. Recyclability studies showed that the Au NPs photocathode exhibited higher stability over multiple cycles, confirming the ability of the electrode to treat wastewater over a longer period of time. This study demonstrates the effectiveness of the photoelectrochemical (PEC) process in reducing organic compounds in wastewater.
近年来，金纳米颗粒（Au NPs）的光电催化因其提高催化效率的潜力而受到广泛关注。在此，以油橄榄叶提取物作为绿色还原剂，在单锅中成功合成了超小金纳米颗粒用于降解4-硝基苯酚。透射电子显微镜（TEM）图像显示金纳米颗粒呈均匀分布且为球形，平均直径为5纳米。利用金纳米颗粒吸收可见光和近红外光的能力，在硼氢化钠存在的情况下可成功还原4-硝基苯酚。此外，通过线性扫描伏安法在黑暗和可见光-近红外光照射下研究了制备的金光阴极的电化学活性。结果表明光电流密度增加到27 mA/cm²，起始电位为-0.71 V。这表明金光阴极在可见光-近红外光下具有高活性。有趣的是，在可见光-近红外光照射期间，在4-硝基苯酚存在的情况下，金光阴极显示出更高的电流密度，为37 mA/cm²，起始电位为-0.6 V，这表明4-硝基苯酚被光阴极有效还原。金光阴极在35分钟内完全还原了废水中的4-硝基苯酚。可回收性研究表明，金纳米颗粒光阴极在多个循环中表现出更高的稳定性，证实了该电极在更长时间内处理废水的能力。这项研究证明了光电化学（PEC）过程在还原废水中有机化合物方面的有效性。
