Determination method of angstrom pore size distribution with molecular statistical method

采用高分辨率分子吸附法研究了非晶碳的微孔结构。特别是对超微孔结构进行了细致的研究。在10^<-9> ~ 1的宽相对压力范围内，利用激光探测器在超高真空和高灵敏度重变系统中构建了新型吸附装置，测量了氮气和氩气的吸附等温线。该宽压吸附装置可测量均匀超微孔碳在77 K下的氮吸附等温线。我们正试图发展一种新的理论来分析这些宽压力范围的吸附等温线。密度泛函理论（DFT）的一种新的计算解析方法。利用高分辨氮吸附等温线对活性炭的微孔大小分布进行了研究。DFT可以给出0.5 ~数nm范围内的微孔大小分布，并采用大正则蒙特卡罗模拟（GCMC）模拟了活性炭纤维在77 K下的氮化吸附等温线的微孔大小分布。在这种情况下，权函数的选择仍然会对孔径分布产生严重影响，因此必须对方法进行改进。利用氮气和氩气吸附等温线在303 K下对分子筛碳的超微孔进行了测定。采用水蒸气吸附法测定微孔体积。实验吸附等温线与GCMC模拟等温线的比较提供了精确的超微孔尺寸。该方法可测定超微孔尺寸，精度为0.02 nm。

The micropore structures of noncrystalline carbons were examined by high resolution molecular adsorption. In particular ultramicropore-range structures were studied carefully. The nitrogen and argon adsorption isotherms were measured over a wide relative pressure range of 10^<-9> to 1 by construction of a new adsorption equipment from ultrahigh vacuum level and high sensitive weight change system with the aid of a laser detector. This wide pressure adsorption equipment can measure the nitrogen adsorption isotherm of even ultramicroporous carbon at 77 K.We are trying to develop a new theory for analysis of these wide pressure range adsorption isotherms.A new analytical method of a density functional theory (DFT) for calculation. of the micropore size distribution of activated carbon from the high resolution nitrogen adsorption isotherms at 77 K was developed. The DFT can give the micropore size distribution from 0.5 to several nm. Also grand canonical Monte Carlo simulation (GCMC) simulation was applied to determine the micropore size distribution of activated carbon fiber using nitroged adsorption isotherm at 77 K.In this case, the selection of the weight function still gave a serious influence on the pore size distribution and thereby the method must be improved.The nitrogen and argon adsorption isotherms at 303 K was used for determination of ultramicropores of molecular sieve carbons with the aid of GCMC simulation. The micropore volume was determined by water vapor adsorption. The comparison of the experimental adsorption isotherm at 303 K with the GCMC simulated isotherm provides the exact ultramicropore size. This method can determine the ultramicropore size with the accuracy of 0.02 nm.