Ren Xiaohua, Guo Huanhuan, Feng Jinkui, Si Pengchao, Zhang Lin, Ci Lijie
SDU & Rice Joint Center for Carbon Nanomaterials, Key Laboratory for Liquid-Solid Structural Evolution & Processing of Materials (Ministry of Education), School of Materials Science and Engineering, Shandong University, Jinan 250061, China; Weifang University of Science and Technology, Weifang 262700, China.
SDU & Rice Joint Center for Carbon Nanomaterials, Key Laboratory for Liquid-Solid Structural Evolution & Processing of Materials (Ministry of Education), School of Materials Science and Engineering, Shandong University, Jinan 250061, China.
Chemosphere. 2018 Jan;191:389-399. doi: 10.1016/j.chemosphere.2017.10.076. Epub 2017 Oct 15.
3D porous N-doped reduced graphene oxide (N-rGO) aerogels were synthesized by a hydrothermal reduction of graphene oxide (GO) with urea and following freeze-drying process. N-rGO aerogels have a high BET surface of 499.70 m/g and a high N doping content (5.93-7.46 at%) including three kinds of N (graphitic, pyridinic and pyrrolic). Their high catalytic performance for phenol oxidation in aqueous solution was investigated by catalytic activation of persulfate (PS). We have demonstrated that N-rGO aerogels are promising metal-free catalysts for phenol removal. Kinetics studies indicate that phenol degradation follows first-order reaction kinetics with the reaction rate constant of 0.16799 min for N-rGO-A(1:30). Interestingly, the comparison of direct catalytic oxidation with adsorption-catalytic oxidation experiments indicates that adsorption plays an important role in the catalytic oxidation of phenol by decreasing the phenol degradation time. Spin density and adsorption modeling demonstrates that graphitic N in N-rGO plays the most important role for the catalytic performance by inducing high positive charge densities to adjacent carbon atoms and facilitating phenol adsorption on these carbon sites. Furthermore, the activation mechanism of persulfate (PS) on N-rGO was first investigated by DFT method and PS can be activated to generate strongly oxidative radical (SO·) by transferring electrons to N-rGO.
通过氧化石墨烯（GO）与尿素的水热还原以及随后的冷冻干燥过程，合成了3D多孔氮掺杂还原氧化石墨烯（N-rGO）气凝胶。N-rGO气凝胶具有499.70 m/g的高BET比表面积和高氮掺杂含量（5.93 - 7.46 at%），包括三种氮（石墨氮、吡啶氮和吡咯氮）。通过过硫酸盐（PS）的催化活化，研究了它们在水溶液中对苯酚氧化的高催化性能。我们已经证明，N-rGO气凝胶是用于去除苯酚的有前景的无金属催化剂。动力学研究表明，苯酚降解遵循一级反应动力学，N-rGO-A(1:30)的反应速率常数为0.16799 min⁻¹。有趣的是，直接催化氧化与吸附 - 催化氧化实验的比较表明，吸附通过缩短苯酚降解时间在苯酚的催化氧化中起重要作用。自旋密度和吸附建模表明，N-rGO中的石墨氮通过诱导相邻碳原子的高正电荷密度并促进苯酚在这些碳位点上的吸附，对催化性能起最重要的作用。此外，首次通过密度泛函理论（DFT）方法研究了过硫酸盐（PS）在N-rGO上的活化机制，PS可以通过向N-rGO转移电子而被活化以产生强氧化性自由基（SO₄·⁻）。
