多级孔的氮掺杂葡萄糖衍生碳的催化氧化应用

Synthesis of glucose derived hierarchical nitrogen doped porous carbon for catalytic oxidation

摘要:

碳材料是以过硫酸氢钾（PMS）为氧化剂的高级氧化法（AOPs）的一种重要催化剂。以葡萄糖为碳源，NaNO3为模板和造孔剂，通过高温炭化法以及NH3高温后处理合成了氮掺杂多级孔碳材料NC-X-T〔X为NaNO3与葡萄糖的质量比，T为温度（℃）〕。采用氮气吸附-脱附、XRD、XPS、SEM、TEM对NC-X-T材料的比表面积、孔径分布、晶体结构、化学组成以及形貌进行了表征与测试。以NC-X-T为催化剂，以PMS为氧化剂，在不同实验条件下进行了苯酚的降解实验。结果表明，造孔和掺氮过程的协同可极大提升NC-X-T材料的催化性能（0.005 g NC-0.5-800，1.0 g/LPMS，在40 min内可将5.3×10-4 mol/L苯酚（100 mL）完全降解，反应速率常数高达0.397 min-1），优于大多数金属及非金属催化剂。利用XPS对降解过程中NC-X-T的稳定性进行了研究，证实碳材料的氧化是其失活的主要原因，经过高温无氧处理可以恢复其部分催化活性。

Abstract:

Here, hierarchically porous carbons are synthesized by carbonation under N2 atomsphere with glucose as carbon precursor and NaNO3 as the template. Then the samples are treated with NH3 at high temperature to obtain nitrogen doped porous carbons, which are labeled as NC-X-T (X refers to the weight ratio of NaNO3 and glucose, and T/oC refers to the annealing temperature). These materials are then characterized by N2 adsorption-desorption, XRD, XPS, SEM, and TEM to show their surface areas, pore size distribution, crystal structure, chemical composition, and morphologies detailly. Taking phenol as the model pollutant and peroxymonosulfate (PMS) as the oxidant, the effects of different experimental conditions on their catalytic performance are studied. The experimental results show that the synergistic effect of pore engineering and nitrogen doping process can greatly improve the catalytic performance of the catalyst. With 0.01 g/L PMS and 0.005 g NC-0.5-800 added, 5.3×10-4 mol/L phenol in 100 mL can be completely degraded with a rate constant of 0.397 min-1, which is superior to most metal and non-metal catalysts. Moreover, the NC-0.5-800 after stability test is characterized by XPS, and the oxidation of carbon frame is found to be the direct reason for their deactivation, while the activity can be partly recovered by high temperature calcination under N2 atmosphere.