School of Chemistry and Biochemistry, TIET-Virginia Tech Center of Excellence in Emerging Materials, Thapar Institute of Engineering and Technology, Patiala, 147004, India.
Materials Science and Engineering Department, Virginia Tech, Blacksburg, VA, 24061-0237, USA.
Environ Sci Pollut Res Int. 2023 Sep;30(43):97660-97672. doi: 10.1007/s11356-023-29301-2. Epub 2023 Aug 19.
Graphene oxide (GO) has now emerged as one of the most promising materials in different areas such as photocatalysis, adsorption, and energy storage due to its high surface area, unique layered structure, etc. Among various types of precursors, anthracite coal has attracted a lot of attention nowadays as it affords GO a high concentration of sp carbons resulting in high conductivity and superior absorbance in the visible region. In this report, we have prepared GO-TiO nanocomposites as it is supposed to possess high photocatalytic activity owing to facile electron transmission from the conduction band of TiO to the GO surface resulting in a much lower degree of electron-hole pair recombination. To boost the photocatalytic activity further, TiO was coated with Ag nanoparticles as well. These hybrid structures were characterized by different analytical techniques, for example, XRD, HR-TEM, SEM, and Raman spectroscopy. The XRD pattern of these composites consists of characteristic peaks corresponding to GO, TiO, and Ag. The HR-TEM studies confirm the presence of GO layers, cube-shaped TiO, and spherical Ag nanoparticles. Phenol and 4-nitrophenol have been used as model pollutants to evaluate the photooxidation efficiencies under both UV and visible light irradiation. Under UV irradiation, the GO/Ag-TiO ternary nanocomposite shows better photooxidation efficiency (62%) compared to Ag-TiO (38%), GO-TiO (9%), GO (17%), and TiO (8%) toward phenol degradation. The GO/Ag-TiO is also having the highest photocatalytic activity toward the removal of phenol under visible light irradiation (34%). The ternary heterostructure (85%) also possesses superior photooxidation activity compared to Ag-TiO (44%) and GO-TiO (71%) toward the degradation of p-nitrophenol under UV light radiation for 60 min. The above observation reveals that the cooperative effect of Ag, TiO, and GO is playing a crucial role to result in the high photooxidation activity of the GO/Ag-TiO hetero-nanocomposites.
氧化石墨烯（GO）由于具有高比表面积、独特的层状结构等特点，现已成为光催化、吸附和储能等不同领域最有前途的材料之一。在各种类型的前体中，无烟煤受到了广泛关注，因为它赋予 GO 高浓度的 sp 碳，从而导致导电性高，在可见光区域的吸收率高。在本报告中，我们制备了 GO-TiO 纳米复合材料，因为据推测它具有高的光催化活性，这是由于 TiO 的导带中的电子很容易从 TiO 转移到 GO 表面，从而大大降低了电子-空穴对的复合程度。为了进一步提高光催化活性，还在 TiO 上包覆了 Ag 纳米粒子。这些杂化结构通过不同的分析技术进行了表征，例如 XRD、高分辨率透射电子显微镜（HR-TEM）、扫描电子显微镜（SEM）和拉曼光谱。这些复合材料的 XRD 图谱包含对应于 GO、TiO 和 Ag 的特征峰。HR-TEM 研究证实了 GO 层、立方体形 TiO 和球形 Ag 纳米粒子的存在。苯酚和 4-硝基苯酚已被用作模型污染物，以评估在 UV 和可见光照射下的光氧化效率。在 UV 照射下，GO/Ag-TiO 三元纳米复合材料对苯酚降解的光氧化效率（62%）优于 Ag-TiO（38%）、GO-TiO（9%）、GO（17%）和 TiO（8%）。GO/Ag-TiO 对可见光照射下苯酚的去除也具有最高的光催化活性（34%）。三元异质结构（85%）在 60 分钟的 UV 光辐射下对 4-硝基苯酚的降解也具有比 Ag-TiO（44%）和 GO-TiO（71%）更高的光氧化活性。上述观察结果表明，Ag、TiO 和 GO 的协同作用在导致 GO/Ag-TiO 异质纳米复合材料具有高光氧化活性方面起着至关重要的作用。
