TY - JOUR

T1 - Improved hydrogen selectivity of Surface Modified Graphite (SMG) membranes

T2 - Permeation experiments and characterisation by micro-Raman spectroscopy and XPS

AU - Wollbrink, A.

AU - Rüscher, C. H.

AU - Volgmann, K.

AU - Koch, J.

AU - Breuksch, A.

AU - Tegenkamp, C.

AU - Caro, J.

N1 - Funding information: The authors thank the Deutsche Forschungsgemeinschaft (DFG, Ca 147/19-1) and the National Natural Science Foundation of China (NSFC, 21322603) for financing the project “Hydrogen production from bio-methane and bio-ethanol in catalytic membrane reactors”. The project partner Prof. Y. Li and X. Zhu (Dalian) and also Dr. G. Dräger (LUH) are thanked for stimulating discussions.

PY - 2017/1/18

Y1 - 2017/1/18

N2 - Permeation experiments on Surface Modified Graphite (SMG) membranes showed an improved mixed gas separation factor α (H2/CO2) of 9.2 (+80%) and α (H2/H2O) of 10.2 (+70%) compared with the pristine graphite membranes with α (H2/CO2) of 5.1 and α (H2/H2O) of 6.0. The surface modification was obtained by the treatment with different silanes at 140 °C, for 2 h under reflux and continuous stirring in an argon atmosphere. The dried powders were pressed to discs and evaluated for the ternary feed mixture (41 vol.‐% H2/41 vol.‐% CO2/18 vol.‐% H2O). XPS analysis of the membrane surface revealed sp2and sp3hybridisation states, carbonyl, carboxyl groups and CFxbonds for the pristine and SMG membranes. Spatially resolved micro-focused Raman spectroscopy showed that the improved separation performance correlates with a specific modification of the G and D1 modes of the pristine graphite surface for each functionalisation carried out. Therefore, the improved performances result from the specific chemical and physical interactions of H2, CO2and H2O with the applied defect modifications of the SMG membranes.

AB - Permeation experiments on Surface Modified Graphite (SMG) membranes showed an improved mixed gas separation factor α (H2/CO2) of 9.2 (+80%) and α (H2/H2O) of 10.2 (+70%) compared with the pristine graphite membranes with α (H2/CO2) of 5.1 and α (H2/H2O) of 6.0. The surface modification was obtained by the treatment with different silanes at 140 °C, for 2 h under reflux and continuous stirring in an argon atmosphere. The dried powders were pressed to discs and evaluated for the ternary feed mixture (41 vol.‐% H2/41 vol.‐% CO2/18 vol.‐% H2O). XPS analysis of the membrane surface revealed sp2and sp3hybridisation states, carbonyl, carboxyl groups and CFxbonds for the pristine and SMG membranes. Spatially resolved micro-focused Raman spectroscopy showed that the improved separation performance correlates with a specific modification of the G and D1 modes of the pristine graphite surface for each functionalisation carried out. Therefore, the improved performances result from the specific chemical and physical interactions of H2, CO2and H2O with the applied defect modifications of the SMG membranes.

KW - G/D1 peak relationships

KW - Hydrogen-selective SMG membrane

KW - Micro-Raman spectroscopy/XPS

KW - Steam reforming

UR - http://www.scopus.com/inward/record.url?scp=85011082288&partnerID=8YFLogxK

U2 - 10.1016/j.memsci.2016.12.067

DO - 10.1016/j.memsci.2016.12.067

M3 - Article

AN - SCOPUS:85011082288

VL - 528

SP - 316

EP - 325

JO - Journal of membrane science

JF - Journal of membrane science

SN - 0376-7388

ER -