Lan Phung Thi, Hao Nguyen Hoang, Hieu Nguyen Trung, Ha Nguyen Thi Thu, Brown C Trevor, Cam Le Minh
Faculty of Chemistry, Hanoi National University of Education 136 Xuan Thuy, Cau Giay Hanoi Vietnam
College of Education, Vinh University 182 Le Duan Vinh Nghe An Vietnam.
RSC Adv. 2024 Jun 13;14(27):19014-19028. doi: 10.1039/d4ra02658f. eCollection 2024 Jun 12.
Graphitic carbon nitride supported silver nanoparticles (AgNPs/g-CN) with 1%, 3%, and 5% AgNPs were successfully synthesized by an "" method with ultrasound of a mixture of AgNP solution and g-CN. The AgNP solution was prepared by chemical reduction with trisodium citrate, and g-CN was synthesized from the urea precursor. The supported nanoparticles were characterized by X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption-desorption (BET), Fourier transformation infrared (FTIR) and Raman spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), photoluminescence spectroscopy (PL), electron paramagnetic resonance (EPR) and electrochemical impedance spectroscopy (EIS) Nyquist plots. The visible light-driven photocurrent measurement was performed by three on-off cycles of intermittent irradiation. The analyses show that AgNPs were evenly dispersed on g-CN, and have sizes ranging from 40 to 50 nm. The optical properties of the AgNPs/g-CN material were significantly enhanced due to the plasmonic effect of AgNPs. The photocatalytic activity of catalysts was evaluated by 2,4-D degradation under visible light irradiation ( > 420 nm). In the reaction conditions: pH 2.2; (2,4-D) 40 ppm; a m/v ratio of 0.5 g L, AgNPs/g-CN materials exhibit superior photocatalytic activity compared to the pristine g-CN. The studies on the influence of free radicals and photogenerated holes, h, show that ˙OH, O˙, and h play decisive roles in the photocatalytic activity of AgNPs/g-CN. The TOC result indicates the minimal toxicity of the by-products formed during the 2,4-D degradation. In addition, the AgNPs/g-CN catalytic activity under direct sunlight irradiation was similar to that under artificial UV irradiation. Based on these results, a possible mechanism is proposed to explain the enhanced photocatalytic activity and stability of AgNPs/g-CN. Theoretical calculations on the interaction between 2,4-D and g-CN, Ag/g-CN was also performed. The calculated results show that the adsorption of 2,4-D on Ag-modified g-CN is significantly more effective compared to pristine g-CN.
通过超声处理硝酸银纳米颗粒（AgNP）溶液和石墨相氮化碳（g-CN）的混合物，成功合成了负载有1%、3%和5%AgNP的石墨相氮化碳负载型银纳米颗粒（AgNPs/g-CN）。AgNP溶液通过柠檬酸钠化学还原法制备，g-CN由尿素前驱体合成。通过X射线衍射光谱（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、氮吸附-脱附（BET）、傅里叶变换红外光谱（FTIR）和拉曼光谱、紫外-可见漫反射光谱（UV-Vis DRS）、光致发光光谱（PL）、电子顺磁共振（EPR）和电化学阻抗谱（EIS）奈奎斯特图对负载型纳米颗粒进行了表征。通过三个间歇照射的开关循环进行可见光驱动光电流测量。分析表明，AgNP均匀分散在g-CN上，尺寸范围为40至50nm。由于AgNP的等离子体效应，AgNPs/g-CN材料的光学性能得到显著增强。通过在可见光照射（>420nm）下降解2,4-二氯苯氧乙酸（2,4-D）来评估催化剂的光催化活性。在反应条件为：pH 2.2；2,4-D浓度40ppm；质量/体积比为0.5g/L时，与原始g-CN相比，AgNPs/g-CN材料表现出优异的光催化活性。对自由基和光生空穴h的影响研究表明，˙OH、O˙和h在AgNPs/g-CN的光催化活性中起决定性作用。总有机碳（TOC）结果表明，2,4-D降解过程中形成的副产物毒性最小。此外，AgNPs/g-CN在阳光直射下的催化活性与在人工紫外线照射下相似。基于这些结果，提出了一种可能的机制来解释AgNPs/g-CN增强的光催化活性和稳定性。还对2,4-D与g-CN、Ag/g-CN之间的相互作用进行了理论计算。计算结果表明，与原始g-CN相比，2,4-D在Ag修饰的g-CN上的吸附效果显著更好。
