scholarly journals Enhanced Selective Hydrogen Permeation through Graphdiyne Membrane: A Theoretical Study

Membranes ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 286
Author(s):  
Quan Liu ◽  
Long Cheng ◽  
Gongping Liu

Graphdiyne (GDY), with uniform pores and atomic thickness, is attracting widespread attention for application in H2 separation in recent years. However, the challenge lies in the rational design of GDYs for fast and selective H2 permeation. By MD and DFT calculations, several flexible GDYs were constructed to investigate the permeation properties of four pure gas (H2, N2, CO2, and CH4) and three equimolar binary mixtures (H2/N2, H2/CO2, and H2/CH4) in this study. When the pore size is smaller than 2.1 Å, the GDYs acted as an exceptional filter for H2 with an approximately infinite H2 selectivity. Beyond the size-sieving effect, in the separation process of binary mixtures, the blocking effect arising from the strong gas–membrane interaction was proven to greatly impede H2 permeation. After understanding the mechanism, the H2 permeance of the mixtures of H2/CO2 was further increased to 2.84 × 105 GPU by reducing the blocking effect with the addition of a tiny amount of surface charges, without sacrificing the selectivity. This theoretical study provides an additional atomic understanding of H2 permeation crossing GDYs, indicating that the GDY membrane could be a potential candidate for H2 purification.

2009 ◽  
Vol 68 (3) ◽  
pp. 403-410 ◽  
Author(s):  
W.M. Tucho ◽  
H.J. Venvik ◽  
M. Stange ◽  
J.C. Walmsley ◽  
R. Holmestad ◽  
...  

2011 ◽  
Vol 199-200 ◽  
pp. 426-430
Author(s):  
Bo Quan Jiang ◽  
Jiang Nan Zhang ◽  
Yu De Liu ◽  
Jian Guo Zou

The osmosis pressure was introduced to improve the conventional electroless plating process for preparing porous ceramic supported Pd/Ag inorganic composite membrane. The effects of temperature (t), molar ratio of hydrazine to total metal ions(y), molar ratio of silver ions to palladium ions(x), concentrations of ethylene diamine tetraacetic acid (EDTA) and sucrose solution on the metal deposition rate, silver content in alloy film, surface morphology of film and permeation properties of the membrane were investigated and their optimal conditions were determined to be: [MET]=5mM, x = 20%, y = 1, [EDTA] = 40g•L-1, t = 40 °C, pH =11 and sucrose solution concentration of 6 M. Under these optimal conditions, the prepared Pd/Ag alloy film with thickness of 7.9 μm demonstrated good permeation properties with nitrogen free and hydrogen permeation rate of 8.8×10-3m3•m-2•s-1at 0.3 MPa and 473 K.


2008 ◽  
Vol 19 (10) ◽  
pp. 1256-1259 ◽  
Author(s):  
Ming Ya Cai ◽  
Hui Xia Luo ◽  
Zhong Li ◽  
Armin Feldhoff ◽  
Jürgen Caro ◽  
...  

2013 ◽  
Vol 12 (01) ◽  
pp. 1250099 ◽  
Author(s):  
K. HATUA ◽  
PRASANTA K. NANDI

A number of charge transferring molecules with varying electron donor, acceptor and π-conjugative paths have been considered for the theoretical study of their NLO properties in terms of the linear polarizability and the ground state dipole moment. The equilibrium structures are calculated at the HF, MP2 and B3LYP levels, respectively. The longitudinal components of NLO coefficients are calculated by using HF, MP2, B3LYP, BHHLYP, CAM-B3LYP, and wB97XD methods for 6-31+G(p,d) and 6-311++G(p,d) basis sets. The hyperpolarizabilities obtained at different levels of calculation showed a fairly consistent trend. The relationships between hyperpolarizabilities, polarizability and ground state dipole moment have been proposed by considering only the two-level term in the standard sum-over-state (SOS) expressions and the generalized Thomas–Kuhn (TK) sum rule. The ab initio calculated first- and second-hyperpolarizabilities fairly correlate with the reduced 2-level contributions relating to the linear polarizability and ground state dipole moment. For a given length of conjugation the stronger enhancement of cubic polarizability arises from the increase of quadratic polarizability for comparable values of linear polarizability and dipole moment. The idea developed in the present work can be used to make a rational design of potential NLO-phores.


2016 ◽  
Vol 120 (28) ◽  
pp. 15147-15152 ◽  
Author(s):  
Wei Mao ◽  
Markus Wilde ◽  
Takumi Chikada ◽  
Shohei Ogura ◽  
Katsuyuki Fukutani ◽  
...  

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