Applied Catalysis A: General ( IF 5.5 ) Pub Date : 2017-08-25 , DOI: 10.1016/j.apcata.2017.08.033 Raquel P. Rocha , O. Salomé G.P. Soares , Alexandra G. Gonçalves , José J.M. Órfão , M. Fernando R. Pereira , José L. Figueiredo
In this work, a comprehensive study was performed regarding the incorporation of N-groups into the multi-walled carbon nanotube sp2 network, namely, quaternary nitrogen, pyrrolic and pyridinic groups. An easy to handle, solvent-free post-doping method, combining a mechanical treatment under ball-milling followed by thermal treatments under inert atmosphere or ammonia was developed. Different nitrogen precursors (melamine, urea, NH3), different precursor/CNT ratios, presence of O-containing surface groups and final temperatures of the thermal treatment were evaluated towards the generation of active and stable N-species. The materials were characterized in terms of texture and surface chemistry by several techniques: N2 adsorption, XPS, TPD, TGA and elemental analysis. The catalytic performance of the novel N-doped CNTs was evaluated in the oxidation of oxalic acid and phenol (used as model pollutants) by catalytic wet air oxidation (CWAO). Catalytic oxidation of model pollutants is faster in the presence of samples rich in nitrogen, and also favoured in the absence of O-containing surface groups on the CNT surface.
中文翻译:
氮掺杂碳纳米管的不同合成方法及其在催化湿空气氧化中的用途
在这项工作中,进行了有关将N-基团纳入多壁碳纳米管sp2网络的综合研究,即季氮基,吡咯基和吡啶基。开发了一种易于处理,无溶剂的后掺杂方法,该方法将球磨下的机械处理与惰性气氛或氨气下的热处理相结合。对不同的氮前体(三聚氰胺,尿素,NH 3),不同的前体/ CNT比,含O的表面基团的存在以及热处理的最终温度进行了评估,以求生成活性和稳定的N物种。通过几种技术对材料的织构和表面化学特性进行了表征:N 2吸附,XPS,TPD,TGA和元素分析。在催化湿空气氧化法(CWAO)对草酸和苯酚(用作模型污染物)的氧化中,评估了新型N掺杂CNTs的催化性能。在存在富含氮的样品的情况下,模型污染物的催化氧化更快,并且在CNT表面上不存在含O的表面基团的情况下,也有利于模型污染物的催化氧化。