{"title":"Unveiling the impact of nitrogen-doped graphene quantum dots on improving the photocatalytic performance of CuWO4 nanocomposite","authors":"Parthivi Aloni, Prashanth Venkatesan, Arun Prakash Sundaresan, Deblina Roy, Rohit Kumar Ranjan, Ankit Sharma, Ruey-An Doong, N. Clament Sagaya Selvam","doi":"10.1016/j.apsusc.2024.162130","DOIUrl":null,"url":null,"abstract":"In this study, nitrogen-doped graphene quantum dots (NGQD) decorated CuWO<sub>4</sub> nanocomposite (NGQD-CuWO<sub>4</sub>) were synthesized for enhanced photocatalytic tetracycline (TC) degradation under visible light irradiation. The incorporation of NGQDs significantly increased light absorption, narrowed the band gap, and improved charge transfer in CuWO<sub>4</sub>, leading to enhanced photocatalytic efficiency. TEM analysis confirmed the successful integration of NGQDs with CuWO<sub>4</sub>, showing uniform dispersion and lattice fringes, while Raman spectra revealed the characteristic D and G bands of NGQDs, indicating their graphene-like properties. The optimal NGQD loading (3NGQD-CuWO<sub>4</sub>) achieved a degradation efficiency of 99 % within 90 min, exhibiting a three-fold increase in performance compared to pure CuWO<sub>4</sub>. Photocurrent measurements indicated that incorporating NGQD enhanced the charge separation in CuWO<sub>4</sub> displaying the highest photocurrent density. The lowest charge transfer resistance observed in the hybrid photocatalyst is confirmed by electrochemical impedance spectroscopy (EIS), indicating the significant role of NGQD in increasing the charge transfer kinetics. Optical studies further demonstrated a significant red shift in the absorption spectrum and a reduction in the band gap from 2.43 eV for pure CuWO<sub>4</sub> to 2.29 eV for the 3NGQD-CuWO<sub>4</sub> composite. Kinetic studies indicated a pseudo-first-order reaction with a rate constant three times higher for NGQD-CuWO<sub>4</sub> compared to CuWO<sub>4</sub> alone. Hydroxyl radicals (•OH) were identified as the main reactive species responsible for degradation. This work highlights that NGQD incorporation makes CuWO<sub>4</sub> an efficient, stable, and promising photocatalyst for environmental applications, particularly in treating pharmaceutical-contaminated water.","PeriodicalId":247,"journal":{"name":"Applied Surface Science","volume":"78 1","pages":""},"PeriodicalIF":6.3000,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Applied Surface Science","FirstCategoryId":"88","ListUrlMain":"https://doi.org/10.1016/j.apsusc.2024.162130","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
In this study, nitrogen-doped graphene quantum dots (NGQD) decorated CuWO4 nanocomposite (NGQD-CuWO4) were synthesized for enhanced photocatalytic tetracycline (TC) degradation under visible light irradiation. The incorporation of NGQDs significantly increased light absorption, narrowed the band gap, and improved charge transfer in CuWO4, leading to enhanced photocatalytic efficiency. TEM analysis confirmed the successful integration of NGQDs with CuWO4, showing uniform dispersion and lattice fringes, while Raman spectra revealed the characteristic D and G bands of NGQDs, indicating their graphene-like properties. The optimal NGQD loading (3NGQD-CuWO4) achieved a degradation efficiency of 99 % within 90 min, exhibiting a three-fold increase in performance compared to pure CuWO4. Photocurrent measurements indicated that incorporating NGQD enhanced the charge separation in CuWO4 displaying the highest photocurrent density. The lowest charge transfer resistance observed in the hybrid photocatalyst is confirmed by electrochemical impedance spectroscopy (EIS), indicating the significant role of NGQD in increasing the charge transfer kinetics. Optical studies further demonstrated a significant red shift in the absorption spectrum and a reduction in the band gap from 2.43 eV for pure CuWO4 to 2.29 eV for the 3NGQD-CuWO4 composite. Kinetic studies indicated a pseudo-first-order reaction with a rate constant three times higher for NGQD-CuWO4 compared to CuWO4 alone. Hydroxyl radicals (•OH) were identified as the main reactive species responsible for degradation. This work highlights that NGQD incorporation makes CuWO4 an efficient, stable, and promising photocatalyst for environmental applications, particularly in treating pharmaceutical-contaminated water.
期刊介绍:
Applied Surface Science covers topics contributing to a better understanding of surfaces, interfaces, nanostructures and their applications. The journal is concerned with scientific research on the atomic and molecular level of material properties determined with specific surface analytical techniques and/or computational methods, as well as the processing of such structures.