渗透
材料科学
选择性
石墨烯
膜
多孔性
化学工程
气体分离
纳米技术
分析化学(期刊)
复合材料
渗透
色谱法
有机化学
化学
生物化学
工程类
催化作用
作者
Timur Ashirov,A. Özgür Yazaydın,Ali Coskun
标识
DOI:10.1002/adma.202106785
摘要
Porous graphene membranes have emerged as promising alternatives for gas-separation applications due to their atomic thickness enabling ultrahigh permeance, but they suffer from low gas selectivity. Whereas decreasing the pore size below 3 nm is expected to increase the gas selectivity due to molecular sieving, it is rather challenging to generate a large number of uniform small pores on the graphene surface. Here, a pore-narrowing approach via gold deposition onto porous graphene surface is introduced to tune the pore size and thickness of the membrane to achieve a large number of small pores. Through the systematic approach, the ideal combination is determined as pore size below 3 nm, obtained at the thickness of 100 nm, to attain high selectivity and high permeance. The resulting membrane shows a H2 /CO2 separation factor of 31.3 at H2 permeance of 2.23 × 105 GPU (1 GPU = 3.35 × 10-10 mol s-1 m-2 Pa-1 ), which is the highest value reported to date in the 105 GPU permeance range. This result is explained by comparing the predicted binding energies of gas molecules with the Au surface, -5.3 versus -21 kJ mol-1 for H2 and CO2 , respectively, increased surface-gas interactions and molecular-sieving effect with decreasing pore size.
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