Department of Chemistry, Kannur University, Kannur, Kerala, 670 327, India.
Environ Sci Pollut Res Int. 2023 Sep;30(42):96114-96124. doi: 10.1007/s11356-023-29115-2. Epub 2023 Aug 11.
In this work, a simple and environmentally friendly approach has been followed to synthesize amine-functionalized reduced graphene oxide (RGO)-supported silver nanoparticle (AgNPs) having superior catalytic efficiency towards the reduction of organic pollutants. RGO/AgNPs nanohybrid was synthesized by a one-pot hydrothermal reduction of silver nitrate in the presence of amino-propyl trimethoxy silane (APTMS)-functionalized graphene oxide (GO) nanosheets. The structural and morphological characterization of as-synthesized RGO/AgNPs nanohybrid was done by using XRD, SEM, TEM, FT-IR, and Raman spectroscopy techniques. APTMS plays an important role in controlling the size of anchored AgNPs on the nanohybrid in the present study. The -NH groups on the surface of APTMS-modified GO function as effective and well-organized nucleation centers facilitating uniform growth of discrete and smaller-sized spherical AgNPs on the surface of RGO nanosheets. In the absence of APTMS, the nanohybrid comprised of bigger-sized AgNPs with few hundred of nanometers in dimension. The catalytic efficiency of RGO/AgNPs nanohybrid was evaluated for the reduction of two model organic pollutants: 4-nitrophenol (4-NP) and methylene blue (MB). Due to the synergistic effects of RGO, APTMS, and Ag components, RGO/AgNPs nanohybrid developed in the present study exhibited superior catalytic activity towards the reduction of 4-NP and MB in comparison with previously reported graphene/graphene oxide/reduced graphene oxide-supported AgNPs catalysts. The catalytic reduction of 4-NP and MB followed pseudo-unimolecular kinetics and the rate constants were found to be 18.83 × 10 s and 131.5 ×10 s respectively for 4-NP and MB. Furthermore, RGO/AgNPs nanohybrid showed admirable recyclability with negligible loss in its activity until five recycle runs. The superior catalytic activity, favorable kinetic parameters, and sustained catalytic efficiency after recycling make RGO/AgNPs nanohybrid a promising catalyst for the reduction of organic pollutants in environmental remediation.
在这项工作中，我们采用了一种简单且环保的方法合成了胺功能化还原氧化石墨烯（RGO）负载的银纳米粒子（AgNPs），该纳米粒子在催化还原有机污染物方面具有卓越的效率。RGO/AgNPs 纳米杂化物是通过在氨基丙基三甲氧基硅烷（APTMS）功能化的氧化石墨烯（GO）纳米片存在下，一锅水热还原硝酸银合成的。通过 XRD、SEM、TEM、FT-IR 和拉曼光谱技术对合成的 RGO/AgNPs 纳米杂化物进行了结构和形态表征。在本研究中，APTMS 发挥了重要作用，控制了锚定在纳米杂化物上的 AgNPs 的尺寸。APTMS 修饰的 GO 表面上的-NH 基团作为有效的、组织良好的成核中心，有利于离散的、较小尺寸的球形 AgNPs 在 RGO 纳米片表面上均匀生长。在没有 APTMS 的情况下，纳米杂化物由尺寸为几百纳米的较大尺寸的 AgNPs 组成。评估了 RGO/AgNPs 纳米杂化物对两种模型有机污染物：4-硝基苯酚（4-NP）和亚甲基蓝（MB）的还原效率。由于 RGO、APTMS 和 Ag 成分的协同作用，与之前报道的石墨烯/氧化石墨烯/还原氧化石墨烯负载 AgNPs 催化剂相比，本研究中制备的 RGO/AgNPs 纳米杂化物对 4-NP 和 MB 的还原表现出优异的催化活性。4-NP 和 MB 的催化还原遵循准单分子动力学，4-NP 和 MB 的速率常数分别为 18.83×10 s 和 131.5×10 s。此外，RGO/AgNPs 纳米杂化物具有令人钦佩的可回收性，其活性在五次循环运行中几乎没有损失。优异的催化活性、有利的动力学参数和回收后的持续催化效率使 RGO/AgNPs 纳米杂化物成为环境修复中还原有机污染物的有前途的催化剂。
