Preparation of nitrogen-doped porous carlbon by ammonia gas treatment and the effects of N-doping on water adsorption
Preparation of nitrogen-doped porous carlbon by ammonia gas treatment and the effects of N-doping on water adsorption
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DOI：
10.1016/j.carbon.2011.12.033
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发表时间：
2012-04-01
期刊：
影响因子：
10.9
通讯作者：
Katoh, Masahiro
中科院分区：
文献类型：
--
作者：
Horikawa, Toshihide;Sakao, Noriyuki;Katoh, Masahiro
在间苯二酚-甲醛冰箱炭化过程中，采用NH3-N-2混合气体高温处理法制备了掺氮多孔炭(N-RFCC)。为了说明N掺杂对吸附行为的影响，我们进行了水的吸附，发现水的吸附量与低压区的氮含量直接相关(P/P-O<；0.3)。将理论水吸附模型Horikawa-Do(HD)模型应用于N-RFCC的吸附等温线，分析了氮掺杂对吸附机理的影响。用Boehm滴定法测得N-RFCC的官能团浓度与未掺杂的RFCC的官能团浓度基本相同，但N-RFCC在低压区的吸水量较大。这是由于部分掺杂的氮原子作为官能团，贡献了官能团的总浓度。饱和浓度取决于水分子的堆积分数，而堆积分数又取决于孔径大小。N-RFCC的堆积分数大于RFCC的堆积分数，这可能是由于水团簇与N掺杂表面的高亲和力导致表面疏水性降低所致。(C)2011爱思唯尔有限公司。保留所有权利。
Nitrogen-doped porous carbons (N-RFCC) were prepared by NH3-N-2 mixture gas treatment at high temperature during the carbonization process on resorcinol-formaldehyde cryogels. To show the role of N-doping on the adsorption behavior we carried out water adsorption, and it was found that the amount of water adsorbed is directly related to the nitrogen content over the low pressure region (P/P-o < 0.3). Applying the theoretical water adsorption model, Horikawa-Do (HD) model, to the adsorption isotherms of N-RFCCs, we could analyze the effects of nitrogen-doping on the adsorption mechanism. Although the concentration of functional groups of N-RFCC is almost equal to that of the non-doped RFCC, which was measured by Boehm titration method, the water adsorbed amounts of N-RFCCs over the low pressure region were larger. This is due to part of the doped nitrogen atoms act as functional groups, contributing to the total concentration of functional groups. The saturated concentrations depend on the packing fraction of water molecules, which in turn depends on the pore size. The packing fractions of N-RFCCs are larger than those of RFCCs, and this could be attributed to the high affinity between water clusters and N-doped surfaces, resulting in a reduced hydrophobicity of the surface. (C) 2011 Elsevier Ltd. All rights reserved.