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2 results for au:Daviddi_E in:cond-mat

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Proton and molecular permeation through the basal plane of monolayer graphene oxide
Z.F. Wu, P. Z. Sun, O. J. Wahab, Y.-T. Tao, D. Barry, D. Periyanagounder, P. B. Pillai, Q. Dai, W. Q. Xiong, L. F. Vega, K. Lulla, S. J. Yuan, R. R. Nair, E. Daviddi, P. R. Unwin, A. K. Geim, M. Lozada-Hidalgo
Oct 26 2023 cond-mat.mtrl-sci physics.chem-ph arXiv:2310.16495v1

@misc{2310.16495, author = {Z.F.~Wu and P.~Z.~Sun and O.~J.~Wahab and Y.-T.~Tao and D.~Barry and D.~Periyanagounder and P.~B.~Pillai and Q.~Dai and W.~Q.~Xiong and L.~F.~Vega and K.~Lulla and S.~J.~Yuan and R.~R.~Nair and E.~Daviddi and P.~R.~Unwin and A.~K.~Geim and M.~Lozada-Hidalgo}, title = {{P}roton and molecular permeation through the basal plane of monolayer graphene oxide}, year = {2023}, eprint = {2310.16495}, note = {arXiv:2310.16495v1} }
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Two-dimensional (2D) materials offer a prospect of membranes that combine negligible gas permeability with high proton conductivity and could outperform the existing proton exchange membranes used in various applications including fuel cells. Graphene oxide (GO), a well-known 2D material, facilitates rapid proton transport along its basal plane but proton conductivity across it remains unknown. It is also often presumed that individual GO monolayers contain a large density of nanoscale pinholes that lead to considerable gas leakage across the GO basal plane. Here we show that relatively large, micrometer-scale areas of monolayer GO are impermeable to gases, including helium, while exhibiting proton conductivity through the basal plane which is nearly two orders of magnitude higher than that of graphene. These findings provide insights into the key properties of GO and demonstrate that chemical functionalization of 2D crystals can be utilized to enhance their proton transparency without compromising gas impermeability.
Proton transport through nanoscale corrugations in two-dimensional crystals
O. J. Wahab, E. Daviddi, B. Xin, P. Z. Sun, E. Griffin, A. W. Colburn, D. Barry, M. Yagmurcukardes, F. M. Peeters, A. K. Geim, M. Lozada-Hidalgo, P. R. Unwin
May 09 2023 cond-mat.mes-hall physics.chem-ph arXiv:2305.04655v1

@misc{2305.04655, author = {O.~J.~Wahab and E.~Daviddi and B.~Xin and P.~Z.~Sun and E.~Griffin and A.~W.~Colburn and D.~Barry and M.~Yagmurcukardes and F.~M.~Peeters and A.~K.~Geim and M.~Lozada-Hidalgo and P.~R.~Unwin}, title = {{P}roton transport through nanoscale corrugations in two-dimensional crystals}, year = {2023}, eprint = {2305.04655}, note = {arXiv:2305.04655v1} }
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Defect-free graphene is impermeable to all atoms and ions at ambient conditions. Experiments that can resolve gas flows of a few atoms per hour through micrometre-sized membranes found that monocrystalline graphene is completely impermeable to helium, the smallest of atoms. Such membranes were also shown to be impermeable to all ions, including the smallest one, lithium. On the other hand, graphene was reported to be highly permeable to protons, nuclei of hydrogen atoms. There is no consensus, however, either on the mechanism behind the unexpectedly high proton permeability or even on whether it requires defects in graphene's crystal lattice. Here using high resolution scanning electrochemical cell microscopy (SECCM), we show that, although proton permeation through mechanically-exfoliated monolayers of graphene and hexagonal boron nitride cannot be attributed to any structural defects, nanoscale non-flatness of 2D membranes greatly facilitates proton transport. The spatial distribution of proton currents visualized by SECCM reveals marked inhomogeneities that are strongly correlated with nanoscale wrinkles and other features where strain is accumulated. Our results highlight nanoscale morphology as an important parameter enabling proton transport through 2D crystals, mostly considered and modelled as flat, and suggest that strain and curvature can be used as additional degrees of freedom to control the proton permeability of 2D materials.