Michael Guiver

Tianjin University, State Key Laboratory of Engines, Faculty Member

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Papers by Michael Guiver

Advances in organic microporous membranes for CO2 separation

Energy & Environmental Science

This Perspective focuses on innovation and advanced design of membranes for carbon dioxide separa... more

Magnetic field alignment of stable proton-conducting channels in an electrolyte membrane

Nature Communications, 2019

Proton exchange membranes with short-pathway through-plane orientated proton conductivity are hig... more Proton exchange membranes with short-pathway through-plane orientated proton conductivity are highly desirable for use in proton exchange membrane fuel cells. Magnetic field is utilized to create oriented structure in proton exchange membranes. Previously, this has only been carried out by proton nonconductive metal oxide-based fillers. Here, under a strong magnetic field, a proton-conducting paramagnetic complex based on ferrocyanide-coordinated polymer and phosphotungstic acid is used to prepare composite membranes with highly conductive through-plane-aligned proton channels. Gratifyingly, this strategy simultaneously overcomes the high water-solubility of phosphotungstic acid in composite membranes, thereby preventing its leaching and the subsequent loss of membrane conductivity. The ferrocyanide groups in the coordinated polymer, via redox cycle, can continuously consume free radicals, thus helping to improve the long-term in situ membrane durability. The composite membranes exh...

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Field Grand Challenge for Membrane Science and Technology

Frontiers in Membrane Science and Technology, 2022

A membrane can be defined broadly as a physical barrier, which allows the selective passage of sp... more A membrane can be defined broadly as a physical barrier, which allows the selective passage of species from one side to the other under a driving force, or which controls the rate of permeation. Across the spectrum of separations or membrane processes, the species may be organic or aqueous liquids, solutes, vapors, gases, ions or electrons. An example of controlled transport of species is drug delivery. One of the advantages of a membrane process is the avoidance of a phase change, which may typically occur for conventional separation processes. Another advantage is the relatively small footprint of a membrane system, and its scalability and flexibility of onsite “at source” operation, for example, a small water treatment plant (Hoek and Tarabara, 2013; Baker, 2004). The earliest accounts of membrane transport extend back over 200 years, and involved studies on biological as well as some synthetic membranes. Biological membranes are ubiquitous across the plant and animal kingdom, serving a multitude of functions. They have had eons to evolve intricate channels and pore structures and transport mechanisms with exquisite control over the permeation and selective passage of bioactive molecules, ions, water, and gases. In modern membrane science and technology, they serve as inspiration for the design of new membranes, through structural architecture or transport mechanisms. Much earlier work on synthetic membranes was on morphologies that could be thought of as having symmetric or dense structures, which had substantial resistance to transport, resulting in a low transmembrane flux of permeating species. While dense membranes enable the intrinsic properties to be studied in detail, draw useful structure-property relationships, and develop theoretic understanding of transport, they are impractical for industrial separation because of low product permeation. The pivotal point in membrane science occurred in 1961, which was the start of the transformation from academic curiosity to industrial application. This was the development of the first practical membrane with sufficiently high water permeation for desalination of seawater, a process termed “reverse osmosis” (RO). It was an integrally-skinned asymmetric membrane with a thin selective layer made from cellulose acetate, developed by Loeb and Sourirajan, while at the University of California, Los Angeles (UCLA). Shortly after this, Sourirajan moved to the National Research Council (NRC), Canada, at the main Ottawa campus, and established a world-renowned membrane program that was to last several decades (Matsuura, 2020; Lau and Feng, 2021). My long career and interest in membrane research began in January 1981 and spans about 4 decades. Having completed my Master’s degree in natural products chemistry at Carleton University, Canada in 1980, circumstances led me to return to Canada from the United Kingdom in January 1981, and I started a research contract on membrane materials at NRC. During my yearly NRC contracts, I completed my PhD at Carleton University while working at NRC, eventually becoming a Research Officer in 1987, at what was at that time, one of the major hubs Edited and reviewed by: Jong Hak Kim, Yonsei University, South Korea

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Advances in high permeability polymer-based membrane materials for CO2 separations

Energy & Environmental Science, 2016

This review summarizes the major advances since 2012 in highly permeable and CO2-selective polyme... more

Metal-induced ordered microporous polymers for fabricating large-area gas separation membranes

Nature Materials, 2018

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Magnetic-field-oriented mixed-valence-stabilized ferrocenium anion-exchange membranes for fuel cells

Nature Energy

Fuel cells with an operational range of –20 °C to 200 °C enabled by phosphoric acid-doped intrinsically ultramicroporous membranes

Nature Energy

Self-adjusting anode catalyst layer for smart water management in anion exchange membrane fuel cells

Cell Reports Physical Science

Zhang et al. report the design of a catalyst layer with stratified, gradient nanopores for self-a... more Zhang et al. report the design of a catalyst layer with stratified, gradient nanopores for self-adjusting moisture (including adsorption, retention, and removal). The advanced catalyst layer may provide a strategy for simplifying fuel cell systems to obtain membrane electrode assemblies with smart water management ability.

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Realizing small-flake graphene oxide membranes for ultrafast size-dependent organic solvent nanofiltration

Science Advances

Membranes for organic solvent nanofiltration (OSN) or solvent-resistant nanofiltration (SRNF) off... more Membranes for organic solvent nanofiltration (OSN) or solvent-resistant nanofiltration (SRNF) offer unprecedented opportunities for highly efficient and cost-competitive solvent recovery in the pharmaceutical industry. Here, we describe small-flake graphene oxide (SFGO) membranes for high-performance OSN applications. Our strategy exploits lateral dimension control to engineer shorter and less tortuous transport pathways for solvent molecules. By using La3+ as a cross-linker and spacer for intercalation, the SFGO membrane selective layer was stabilized, and size-dependent ultrafast selective molecular transport was achieved. The methanol permeance was up to 2.9-fold higher than its large-flake GO (LFGO) counterpart, with high selectivity toward three organic dyes. More importantly, the SFGO-La3+ membrane demonstrated robust stability for at least 24 hours under hydrodynamic stresses that are representative of realistic OSN operating conditions. These desirable attributes stem from t...

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A solution-processable and ultra-permeable conjugated microporous thermoset for selective hydrogen separation

Nature Communications

The synthesis of a polymer that combines the processability of plastics with the extreme rigidity... more The synthesis of a polymer that combines the processability of plastics with the extreme rigidity of cross-linked organic networks is highly attractive for molecular sieving applications. However, cross-linked networks are typically insoluble or infusible, preventing them from being processed as plastics. Here, we report a solution-processable conjugated microporous thermoset with permanent pores of ~0.4 nm, prepared by a simple heating process. When employed as a two-dimensional molecular sieving membrane for hydrogen separation, the membrane exhibits ultrahigh permeability with good selectivity for H2 over CO2, O2, N2, CH4, C3H6 and C3H8. The combined processability, structural rigidity and easy feasibility make this polymeric membrane promising for large-scale hydrogen separations of commercial and environmental relevance.

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Biomimetic Nanocones Enable High Ion Permselectivity

Angewandte Chemie International Edition

Conical-shaped transmembrane protein channels are essential for the transport of ions across lipi... more Conical-shaped transmembrane protein channels are essential for the transport of ions across lipid bilayers in biological tissues and organisms. Their artificial counterparts are of high applicative interest in biomedical sciences for biomolecule detection and selective ion permeation based on ionic-size and/or charge differences. However, industrial-scale applications such as seawater desalination, separation of mono- from divalent cations, and treatment of highly-saline industrial waste effluents are still big challenges for such biomimetic channels. Here, we report a simple and radically novel "monomer seeding", an experimental approach to grow ionically conductive biomimetic charged nanocone pores at the surface of an acid-functionalized membrane. These readily scalable nanocone membranes enable ultra-fast cation permeation (Na+ = 8.4× vs. Mg2+ = 1.4×) and high ion charge selectivity (Na+/Mg2+ = 6×) compared with the commercial state-of-the-art permselective membrane (CSO, SelemionTM, Japan) due to negligible surface resistances and positively charged conical pore walls, respectively.

A highly permeable graphene oxide membrane with fast and selective transport nanochannels for efficient carbon capture

Energy Environ. Sci.

Tailored physicochemical microenvironments in stacked graphene oxide nanochannels give membranes ... more

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Graphene Oxide Membranes with Heterogeneous Nanodomains for Efficient CO2 Separations

Angewandte Chemie International Edition

Achieving high membrane performance in terms of gas permeance and carbon dioxide selectivity is a... more Achieving high membrane performance in terms of gas permeance and carbon dioxide selectivity is an important target in carbon capture. Aiming to manipulate the channel affinity towards CO2 to implement efficient separations, gas separation membranes containing CO2 -philic and non-CO2 -philic nanodomains in the interlayer channels of graphene oxide (GO) were formed by intercalating poly(ethylene glycol) diamines (PEGDA). PEGDA reacts with epoxy groups on the GO surface, constructing CO2 -philic nanodomains and rendering a high sorption capacity, whereas unreacted GO surfaces give non-CO2 -philic nanodomains, rendering low-friction diffusion. Owing to the orderly stacking of nanochannels through cross-linking and the heterogeneous nanodomains with moderate CO2 affinity, a GO-PEGDA500 membrane exhibits a high CO2 permeance of 175.5 GPU and a CO2 /CH4 selectivity of 69.5, which is the highest performance reported for dry-state GO-stacking membranes.

Bioinspired Ultrastrong Solid Electrolytes with Fast Proton Conduction along 2D Channels

Advanced materials (Deerfield Beach, Fla.), Jan 6, 2017

Solid electrolytes have attracted much attention due to their great prospects in a number of ener... more Solid electrolytes have attracted much attention due to their great prospects in a number of energy- and environment-related applications including fuel cells. Fast ion transport and superior mechanical properties of solid electrolytes are both of critical significance for these devices to operate with high efficiency and long-term stability. To address a common tradeoff relationship between ionic conductivity and mechanical properties, electrolyte membranes with proton-conducting 2D channels and nacre-inspired architecture are reported. An unprecedented combination of high proton conductivity (326 mS cm(-1) at 80 °C) and superior mechanical properties (tensile strength of 250 MPa) are achieved due to the integration of exceptionally continuous 2D channels and nacre-inspired brick-and-mortar architecture into one materials system. Moreover, the membrane exhibits higher power density than Nafion 212 membrane, but with a comparative weight of only ≈0.1, indicating potential savings in...

3D-quantification of biomolecular covers using surface plasmon-polariton resonance experiment

Sensors and Actuators B: Chemical, 2008

The concentration of surface molecules N s and components of molecular susceptibility jl (ω) can ... more The concentration of surface molecules N s and components of molecular susceptibility jl (ω) can both be determined from surface plasmon-polariton resonance (SPPR) experiments, instead of effective layer thickness and index of refraction, which are usually determined. The theoretical consideration of a molecular layer as monolayer of separated 3D-oscillators provides a new perspective for investigating molecules during SPPR experiment. It is shown that SPPR response and the form of the reflective curve depend on the form of a biomolecule and its orientation relative to the surface of the metal-carrier of plasmon oscillations. The experimental data for immunological reaction for the calculation of surface molecular concentration and mass of biomolecular covering are presented.

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Highly Conductive Anion-Exchange Membranes from Microporous Tröger's Base Polymers

Angewandte Chemie (International ed. in English), Sep 9, 2016

The development of polymeric anion-exchange membranes (AEMs) combining high ion conductivity and ... more The development of polymeric anion-exchange membranes (AEMs) combining high ion conductivity and long-term stability is a major challenge for materials chemistry. AEMs with regularly distributed fixed cationic groups, based on the formation of microporous polymers containing the V-shape rigid Tröger's base units, are reported for the first time. Despite their simple preparation, which involves only two synthetic steps using commercially available precursors, the polymers provide AEMs with exceptional hydroxide conductivity at relatively low ion-exchange capacity, as well as a high swelling resistance and chemical stability. An unprecedented hydroxide conductivity of 164.4 mS cm(-1) is obtained at a relatively a low ion-exchange capacity of 0.82 mmol g(-1) under optimal operating conditions. The exceptional anion conductivity appears related to the intrinsic microporosity of the charged polymer matrix, which facilitates rapid anion transport.

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Robust ultrathin nanoporous MOF membrane with intra-crystalline defects for fast water transport

Nature Communications

Rational design of high-performance stable metal–organic framework (MOF) membranes is challenging... more Rational design of high-performance stable metal–organic framework (MOF) membranes is challenging, especially for the sustainable treatment of hypersaline waters to address critical global environmental issues. Herein, a molecular-level intra-crystalline defect strategy combined with a selective layer thinning protocol is proposed to fabricate robust ultrathin missing-linker UiO-66 (ML-UiO-66) membrane to enable fast water permeation. Besides almost complete salt rejection, high and stable water flux is achieved even under long-term pervaporation operation in hash environments, which effectively addresses challenging stability issues. Then, detailed structural characterizations are employed to identify the type, chemical functionality, and density of intra-crystalline missing-linker defects. Moreover, molecular dynamics simulations shed light on the positive atomistic role of these defects, which are responsible for substantially enhancing structural hydrophilicity and enlarging por...

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Enhancement of Proton Transport by Nanochannels in Comb‐Shaped Copoly (arylene ether sulfone) s

Efficient and selective transport of protons is critical both in biological contexts and in mater... more Efficient and selective transport of protons is critical both in biological contexts and in materials for renewable energy. [1] In hydrogen fuel cells, for example, after oxidation of molecular hydrogen at the anode, the resulting protons must be transported across a proton selective membrane to reach the cathode. This membrane, often referred to as the proton exchange membrane (PEM), has been one of the bottlenecks to achieving affordable fuelcell technology. [2] Among the various types of proton exchange membranes, arylene-based polymers are attracting much attention as alternatives to perfluorinated polymer membranes, such as Nafion ® , because arylene-based PEMs have advantages over the perfluorinated membranes in terms of cost, monomer safety, and structural diversity. [3] However, a critica issue that severely hampers FC performance is PEMs that simultaneously provide high proton conductivity that does not decline precipitously with decreasing relative humidity. In the case of automotive application, the U.S. Department of Energy has established a target of about 10-1 S/cm for the proton conductivity of the membrane at 120 o C and 50% relative humidity (RH) operating conditions. [3a] In a low-humidity environment, dehydration of the PEMs typically occurs and the collapse of the physical architecture of the membrane leads to a significant loss of conductivity. [4] As a consequence, the performance of current PEM-based devices is critically dependent on the operating humidity of the membranes. [5] The key to proton transport in PEMs is believed to be nanochannels of sulfonic acid groups, through which 'hydrated' protons can pass efficiently. [6] Several approaches have been examined to form nanochannels for arylene-based PEMs, and thus improve proton conductivity under conditions of reduced humidity

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Novel PA-doped polybenzimidazole membranes with high doping level, high proton conductivity and high stability for HT-PEMFCs

RSC Advances

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Recent Insights on Catalyst Layers for Anion Exchange Membrane Fuel Cells

Advanced Science

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