Enhancing sulfacetamide degradation by peroxymonosulfate activation with N-doped graphene produced through delicately-controlled nitrogen functionalization via tweaking thermal annealing processes
Enhancing sulfacetamide degradation by peroxymonosulfate activation with N-doped graphene produced through delicately-controlled nitrogen functionalization via tweaking thermal annealing processes
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DOI：
10.1016/j.apcatb.2017.11.071
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发表时间：
2018-06-05
影响因子：
22.1
通讯作者：
Lim, Teik-Thye
中科院分区：
文献类型：
--
作者：
Chen, Xiao;Oh, Wen-Da;Lim, Teik-Thye
将氧化石墨烯（GO）和尿素热处理制备氮掺杂石墨烯（NG），并将其用于活化过硫酸盐（PMS）降解磺胺醋酰（SAM）。通过调节热处理温度，可以精细地控制NG的活性官能团（石墨基N、吡啶基N、吡咯基N、一氧化氮和C=O）的含量和催化性能。需要>= 500摄氏度的热退火温度以产生被赋予通过PMS活化的SAM降解的催化活性的NG。NG 600（NG在600 ℃下制备）具有高N掺杂水平（16.0wt%）和最佳量的吡啶N（38.4%N）、吡咯N（31.8%N）、石墨N（25.9%N）和C=O基团（43.7%O），表现出最突出的催化活性来活化PMS。与其他优化的合成方法相比，具有受控N键合构型的NG 600具有更高的SAM降解效率。比表面积（SSA）对SAM降解性能的贡献小于N掺杂。PMS用量和催化剂负载量的增加都有利于天然气的催化性能。NO_3 ~-的存在对SAM的降解影响不大，而C-1（-）和腐殖酸则降低了SAM的降解速率。利用化学清除剂和电子顺磁共振（EPR）研究的实验表明，SAM的降解过程主要遵循自由基途径与硫酸根自由基（SO 4中心点（-））作为主要的活性氧物种在非自由基途径。密度泛函理论（DFT）计算表明，石墨N可以促进PMS吸附NG和SAM降解。该研究加深了对NG表面不同含氮官能团在PMS活化中作用的认识。
Nitrogen-doped graphenes (NG) fabricated through thermal annealing of graphene oxide (GO) and urea was applied to activate peroxymonosulfate (PMS) for sulfacetamide (SAM) degradation. The contents of reactive functional groups (graphitic N, pyridinic N, pyrrolic N, nitric oxide and C=O) and catalytic performance of NG were delicately controlled by adjusting thermal annealing temperature. Thermal annealing temperature of >= 500 degrees C was required to produce the NG endowed with catalytic activity for SAM degradation via PMS activation. NG600 (NG prepared at 600 degrees C) with a high N doping level (16.0 wt%) and a most optimum amount of pyridinic N (38.4%N), pyrrolic N (31.8%N), graphitic N (25.9%N) and C=O groups (43.7%O) exhibited the most outstanding catalytic activity to activate PMS. NG600 with the controlled N bonding configurations possessed a higher SAM degradation efficiency than NGs prepared via other optimized synthesis methods The specific surface area (SSA) contributed less significantly than N doping to the SAM degradation performance. Increments in the PMS dosage and catalyst loading were both conducive to the catalytic performance of NG. The presence of NO3- in the NG600/PMS system had a negligible influence on SAM degradation but C-l(-) and humic acid decreased the SAM degradation rate. Experiments using chemical scavengers and electron paramagnetic resonance (EPR) study revealed that SAM degradation process follows predominantly the radical pathway with sulfate radical (SO4 center dot(-)) as the main reactive oxygen species over the non-radical pathway. Density functional theory (DFT) calculations suggest that graphitic N can facilitate PMS adsorption on the NG and SAM degradation. This study improves the understanding on the role of different surface N functional groups of NG in the PMS activation.