Control of Edge/in-Plane Interactions toward Robust, Highly Proton Conductive Graphene Oxide Membranes

Abstract

Graphene oxide (GO) membrane, bearing well-aligned interlayer nanochannels and well-defined physicochemical properties, promises fast proton transport. However, the deficiency of proton donor groups on the basal plane of GO and weak interlamellar interactions between the adjacent nanosheets often cause low proton conduction capability and poor water stability. Herein, we incorporate sulfonated graphene quantum dots (SGQD) into GO membrane to solve the above dilemma via synergistically controlling the edge electrostatic interaction and in-plane π–π interaction of SGQD with GO nanosheets. SGQD with three different kinds of electron-withdrawing groups are employed to modulate the edge electrostatic interactions and improve the water swelling resistant property of GO membranes. Meanwhile, SGQD with abundant proton donor groups assemble on the sp2 domain of GO via in-plane π–π interaction and confer the GO membranes with low-energy-barrier proton transport channels. As a result, the GO membrane achieves an enhanced proton conductivity of 324 mS cm–1, maximum power density of 161.6 mW cm–2, and superior water stability when immersed into water for one month. This study demonstrates a strategy for independent manipulation of conductive function and nonconductive function to fabricate high-performance proton exchange membranes.

Super-assembly of freestanding graphene oxide-aramid fiber membrane with T-mode subnanochannels for sensitive ion transport

“…18 GO membranes, as a member of 2D membranes, have inspired scientists to study their transport properties and mechanisms owing to their abundant water-transport pathways through assembled GO laminates. 19 In addition, GO membranes bearing well-aligned interlayer nanochannels and well-defined physicochemical properties 20 promise fast proton transport 21 and energy conversion. 22 Therefore, they have great potential in the construction of nanofluidic devices for selective ion transport.…”

pH‐Responsive Biocompatible Fluorescent Core‐Shell Nanogel for Intracellular Imaging and Control Drug Release

“…[ 25 ] These transitions fuse around 400 nm due to the confinement of the excited‐state energy by the surface states, resulting in powerful emission. [ 17,26 ] The fluorescence Fe 2 O 3 @C@PEG‐COOH nanogel showed emission spectrum from 350 to 700 nm (Figure 2e). More quantitatively, the Fe 2 O 3 @C@PEG‐COOH nanogel exhibit a broad emission peaking at 499 nm upon excitation at 450 nm (Figure 2e) and this emission is relatively pH‐independent over a very large pH range from 1 to 9, as shown in Figure S3, Supporting Information, which is very desirable for drug delivery, senor, and other biological applications.…”

Mixed-dimensional membranes: chemistry and structure–property relationships

“…In particular, GOQDs are nanometer-size fragments of GO nanosheets and they possess the same structure as GO nanosheets, resulting in great compatibility with GO nanosheets, so that they can be intercalated between adjacent GO nanosheets to prevent the close stacking of GO nanosheets and act as ''nanowedges'' for the control of 2D nanochannels. 37 Nanoparticles of different sizes are used to intercalate between adjacent 2D materials to control the interlayer spacing to achieve high permeability; meanwhile, functional nanoparticles can be utilized to endow the membranes with special functions, for example, photocatalytic degradation of foulants. 38 3.2.2 Chemical control of 2D nanochannels and bulk structures.…”