Membranes for CO2 capture should offer high permeant fluxes to keep membrane surface area small and material requirements low. Ag-supported, dual-phase, molten-carbonate membranes routinely demonstrate the highest CO2 fluxes in this class of membrane. However, using Ag as a support incurs high cost. Here, the non-equilibrium conditions of permeation were exploited to stimulate the self-assembly of a percolating, dendritic network of Ag from the molten carbonate. Multiple membrane support geometries and Ag incorporation methods were employed, demonstrating the generality of the approach, while X-ray micro-computed tomography confirmed that CO2 and O2 permeation stimulated self-assembly. We report the highest flux of Ag-supported molten-salt membranes to date (1.25 ml min-1 cm-2 at 650 °C) and ultrahigh permeability (9.4 × 10-11 mol m-1 s-1 Pa-1), surpassing the permeability requirement for economically-competitive post-combustion CO2 capture, all whilst reducing the membrane-volume-normalised demand for Ag by one order of magnitude.
Bibliographical noteFunding Information:
The authors wish to thank Dr Oliver B. Camus at Bath University for conducting mercury intrusion porosimetry measurements and Dr Maggie White at Newcastle University for conducting X-ray diffraction analyses. The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement Number 320725 and from the Engineering & Physical Sciences Research Council (EPSRC) via grants EP/M01486X/1, EP/P007767/1 and EP/P009050/1. X-ray access was supported by UCL and EPSRC under EP/M028100/1. L. A. M. would like to thank the Newcastle University EPSRC DTP. G. A. M. would like to thank the EPSRC for his Doctoral Prize Fellowship (EP/M50791X/1) and Newcastle University for a Newcastle University Academic Track (NUAcT) Fellowship. T. S. M. would like to thank the EPSRC for his Fellowship (EP/P023851/1). P. R. S. acknowledges the support of the Royal Academy of Engineering (CIET 1718/59). Data supporting this publication is available under a Creative Commons Attribution 4.0 International license, see DOI: 10.25405/data.ncl.9608369.
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ASJC Scopus subject areas
- Environmental Chemistry
- Renewable Energy, Sustainability and the Environment
- Nuclear Energy and Engineering