Gerhard (Gerry) F. Swiegers

• PhD
• Professor (Full) at University of Wollongong

The activity and stability of a heterogeneous water oxidation catalyst inspired by the Photosystem II - Oxygen Evolving Center (PSII-OEC) is reported. Ca-doped birnessite MnOx supported on a liquid crystalline reduced graphene oxide (LCrGO) substrate exhibited unprecedented performance for an abiological catalyst at pH 7, including an exceedingly l...

Previous studies have shown that partially coating electrode surfaces with patterns of ‘islands’ of hydrophobic tetrafluoroethylene (PTFE; Teflon) may lead to more energy efficient gas generation. This occurred because the gas bubbles formed preferentially on the PTFE, thereby freeing up the catalytically active metallic surfaces to produce the gas...

This study employs density functional theory at the SMD/B3LYP-D3/6-311+G(2d,p),def2-TZVPP//SMD/B3LYP-D3/6-31G(d),SDD level of theory to explore the mechanistic details of O2 generation from tBuOOH, using H218O as the solvent, in the presence...

Tailoring conductive polymers with inorganic photocatalysts, which provide photoinduced electron-hole generation, have significantly enhanced composites leading to excellent photoelectrodes. In this work, MnFe2O4 nanoparticles prepared by a hydrothermal method were combined with polyaniline to prepare mixed (hybrid) slurries, which were cast onto f...

The low activation barrier for O−O coupling in the closed‐cubane Oxygen‐Evolving Centre (OEC) of Photosystem II (PSII) requires water coordination with the Mn4 ′dangler′ ion in the Mn(V)‐oxo fragment. This coordination transforms the Mn(V)‐oxo complex into a more reactive Mn4(IV)‐oxyl species, enhancing O−O coupling. This study explains the mechani...

The experimentally reported Mn(IV)Mn(III) complex [Mn2(μ-O)2(terpy)2(OH2)2]3+ has been observed catalyzing O2 generation with oxidants like ClO- and HSO5-. Previous mechanistic studies primarily focused on O2 generation with HSO5-, concluding that...

The corrected 'Calculators' excel file can be downloaded free of charge from the Supporting Information at https://pubs.acs.org/doi/10.1021/acs.jced.3c00625

An activated carbon (AC) with a high surface area of 4320.7 m2/g was synthesized via the chemical and thermal processing of walnut residues. The resulting activated charcoal was characterized by various techniques, including Brunauer–Emmett–Teller (BET) surface area analysis, scanning electron microscopy (SEM), and IR spectroscopy. The prepared act...

: An activated carbon (AC) with a high surface area of 4320.7 m2/g was synthesized by chemical and thermal processing of walnut residues. The resulting activated charcoal was characterized by various techniques, including Brunauer-Emmett-Teller (BET) surface area analysis, scanning elec-tron microscopy (SEM), and IR spectroscopy. The prepared activ...

The cathode and anode of a ‘bubble-free’ ‘capillary-fed’ water electrolysis cell that was previously reported to consume only 40.4 kWh kg-1 hydrogen under standard commercial operating conditions, have been separately investigated for the incidence of gas bubble formation during operation. Adaptions of a voltage fluctuation and an acoustic emission...

In this study, new composite materials comprising zeolitic imidazolate framework (ZIF) structures and microchannel glass (MCG) plates were fabricated using the hydrothermal method and their morphological and spectral properties were investigated using XRD, SEM, FTIR, and Raman spectroscopy. XRD studies of powder samples revealed the presence of an...

Green' hydrogen produced from water electrolysis powered by renewable energy will play a critical role in the future global energy transition to 'net zero' carbon emissions. To this end, intensive efforts are needed to improve the energy efficiency with which green hydrogen can be made and thereby reduce its cost. A key required effort in this resp...

The cathode and anode of a ‘bubble-free’ ‘capillary-fed’ water electrolysis cell that was previously reported to consume only 40.4 kWh kg-1 hydrogen under standard commercial operating conditions, have been separately...

An activated charcoal with a high surface area of 4320–3800 m2/g with significant adsorption properties was prepared by the chemical and thermal processing of walnut residues. Iraqi walnut shells were sonicated with different ratios of potassium hydroxide (KOH). The mixture was then calcined at different temperatures using an electric oven until th...

Most botanical species contain various types of bioactive compounds. This study focusses on the extraction and identification of bioactive compounds from Calicotome spinosa (Gorse), including flavones, α-linolenic acid and sugar. During the investigation of gorse flowers, leaves and bark, flavones were isolated from the bark and leaves. Calicotome...

Photocatalytic materials are being investigated as effective bactericides due to their superior ability to inactivate a broad range of dangerous microbes. In this study, the following two types of bacteria were employed for bactericidal purposes: Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). The shape...

Renewable, or green, hydrogen will play a critical role in the decarbonisation of hard-to-abate sectors and will therefore be important in limiting global warming. However, renewable hydrogen is not cost-competitive with fossil fuels, due to the moderate energy efficiency and high capital costs of traditional water electrolysers. Here a unique conc...

The coordination of oxo-manganese clusters to edge-functionalised graphene (EFG) offers a potential route to advanced water oxidation electrodes with exceptional electrochemical surface area and electron transport properties. Previously, we have...

Tailoring conductive polymers with inorganic photocatalysts, which provide photoinduced electron-hole generation, have significantly enhanced composites leading to excellent photoelectrodes. In this work, MnFe2O4 nanoparticles prepared by a hydrothermal method were combined with polyaniline to prepare mixed (hybrid) slurries, which were cast onto f...

Commercial water electrolysis cells require a resistive, ion-permeable, gas-impermeable separator membrane between the electrodes to stop the hydrogen bubbles from mixing with the oxygen bubbles, and vice versa. This work reviews the current status of ‘membraneless’ water electrolysis cells that avoid need for such a separator membrane. Three diffe...

This work describes how conducting polymer nanocomposites can be employed as synergistic supports that significantly accelerate the rate of electro-catalysis. The nanocomposite PEDOT/nano-Co3O4/rGO is discussed as an example in this respect, which is specific for photo electro-catalytic oxygen (O2) generation from water using light (PEDOT = poly (3...

This work describes how conducting polymer nanocomposites can be employed as syn-ergistic supports that significantly accelerate the rate of electro-catalysis. The nanocomposite PE-DOT/nano-Co3O4/rGO is discussed as an example in this respect, which is specific for photo electro-catalytic oxygen (O2) generation from water using light (PEDOT = poly...

Water electrolysis powered by renewable electricity will likely be critical to a future hydrogen economy. However, the typical use of strongly acidic or alkaline electrolytes necessitates the use of expensive materials, while bubbles add to capital and operational costs, due to blocking of the electrode surface and the necessary use of pumps and ga...

In this work we examine the benefits of using carefully designed tri-component composites to fabricate flexible photocathode electrodes for photo-electrocatalytic hydrogen (H2) generation from neutral pH water. We report H2 production by a tri-component composite thin-film containing CuO nanowires (CuO NW), reduced graphene oxide (rGO) and polypyrr...

Highly efficient and inexpensive electrochemical splitting of water into hydrogen and oxygen gas constitutes the most critical capability needed for the development of a future hydrogen economy based on renewable...

Water electrolysis powered by renewable electricity will likely be critical to a future hydrogen economy. However, bubbles produced during water electrolysis add to capital and operational costs, due to blocking of the electrode surface and the necessary use of pumps and gas-liquid separators in electrolyser systems. Here ‘bubble-free’ electrocatal...

The use of graphenic carbon is attractive as a basal or intermediate support for catalytic particles in advanced catalytic electrodes. This popularity is motivated by its excellent electrical properties and ability to form foliated conformal coatings of exceptional surface area and flexibility. Surface- and edge-functionalisation of graphene sheets...

Correction for ‘The prospects of developing a highly energy-efficient water electrolyser by eliminating or mitigating bubble effects’ by Gerhard F. Swiegers et al. , Sustainable Energy Fuels , 2021, 5 , 1280–1310, DOI: 10.1039/D0SE01886D.

Porous silicon has generated interest in scientific community after its photoluminescence discovery and thereafter, research was focused on to the chemical functionalization of silicon and subsequent anchoring of nanoparticles onto silicon surface. In the present work, the porous silicon has been effectively modified with magnetic nanoparticles whi...

Thin films of polypyrrole (PPy) containing nano-Ni ('nano-Ni’) (as catalyst) and reduced graphene oxide (rGO) (as conductor) have been studied as photo)electrocatalysts of the oxygen (O2)-evolution reaction (OER) (at 0.8 V vs Ag/AgCl, in 0.2M Na2SO4, pH 12) and the hydrogen (H2)-evolution reaction (HER) (at -0.75 V vs Ag/AgCl, in 0.05M H2SO4/0.2M N...

Mn-based oxides, particularly CaMn oxides, have recently attracted significant practical interest as a new class of catalyst due to their elemental and structural similarity to the natural oxygen evolving cluster (OEC) in photosynthetic plant cells. However, their performance as oxygen-generating anodes in photoelectrochemical cells has not been st...

Amplifying catalysis by thoughtful exploitation of synergistic effects with interacting supports is a new field of potentially great significance. It is particularly relevant for solar‐assisted reactions that are currently too poorly catalyzed to be practically viable, such as photoelectrochemical splitting of water to produce hydrogen and oxygen....

Light-driven water-splitting to generate hydrogen and oxygen from water is typically carried out in an electrochemical cell with an external voltage greater than 1.23 V applied between the electrodes. In this work, we examined the use of a concentration/chemical bias as a means of facilitating water-splitting under light illumination without the ne...

A new class of ‘bubble-free’ alkaline electrolyzer with electrodes comprising of PTFE-based Gortex gas diffusion layers coated with catalysts, is described (PTFE = poly(tetrafluoroethylene)). At 80 oC (Eo cell 1.18 V), the electrolyzers displayed the lowest cell onset potentials (1.28 V) yet reported, indicating that they exhibit the highest known...

Featured Application CaMn2O4, a green biomimetic catalyst, has the potential to generate oxygen by splitting water for sustainability applications. Abstract Calcium manganese oxide catalysts are a new class of redox catalysts with significant importance because of their structural similarity to natural oxygen-evolving complex in plant cells and th...

A significant and long-standing problem in electrochemistry has involved the need for gas diffusion electrodes that are ‘flood-proof’ and ‘leak-proof’ when operated with liquid electrolyte. The absence of a solution to this problem has, effectively, made it unviable to use gas diffusion electrodes in many electrochemical manufacturing processes, es...

This work reports a composite of poly(3,4-ethylenedioxythiophene) (PEDOT) that is notably more catalytically active for hydrogen generation than the industry-standard benchmark catalyst, Pt, under the same conditions. A PEDOT thin-film containing nanoparticulate Ni (nano-Ni) and reduced graphene oxide (rGO) in the specific molar ratio of 5.6 (C; PE...

Despite their potential for facilitating high activity, thin-film conducting polymer supports have, historically, expedited only relatively weak performances in catalytic water oxidation (with current densities in the A/cm2 range). In this work we have investigated the conditions under which thin-film conducting polymers may synergistically amplif...

In this work we report a novel liquid-acid electrochemical cell containing Gortex-based gas diffusion electrodes, layered with suitable catalysts and current collectors, that is capable of sustainably extracting pure hydrogen from methane mixtures containing as little as 5% hydrogen. The origin of its efficiency appears to derive from the solid-liq...

Numerous electric and gas utilities are actively pursuing “power-to-gas” technology, which involves using unwanted, excess renewable energy to manufacture hydrogen gas (H2) that is then injected into the existing natural gas pipeline network in 5–10% by volume. This work reports an alkaline fuel cell that has the potential to harness such gas mixtu...

In this work, the electrochemical etching of p-type silicon was performed in aqueous ethanol-surfactant solutions and the dependence of morphology and luminescent properties of porous silicon with respect to the etching parameters and silicon resistivities have been studied. The obtained porous silicon structures have been studied using various cha...

This work reports photo-demetallation studies of thin-layer, electropolymerized poly(3,4-ethylenedioxythiophene) (PEDOT) loaded with low levels of: (i) an anionic Mn porphyrin monomer (5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrinato manganese(III) chloride (MnTPPS)), and (ii) an anionic Mn porphyrin polymer (poly(5-(4-vinylphenyl)-10,15,20-tris(...

Thin films of vapor-phase polymerized PEDOT incorporating various cationic Mn porphyrins were assessed for water oxidation catalysis under light illumination. Only Mn(III)TPP/PEDOT displayed a notable photocurrent and this was, counter-intuitively, greatest at the lowest loading levels examined. Studies revealed that a proportion of the Mn(III)TPP...

This work discusses the use of self-assembly in the designed synthesis of coordination compounds having higher structures. Different types of self-assembly are reviewed, along with factors that influence them. Several well-known synthetic strategies are described. The work focuses initially on self-assembly by discrete species in open solution but...

Water splitting is the general term for a chemical reaction in which water is separated into its constituent materials, oxygen and hydrogen. Hydrogen is widely considered to be an ideal fuel of the future due to its potential to replace fossil fuels. The key to an energy efficient water splitting process lies in catalysts that can carry out the wat...

Vapour phase polymerisation (vpp) of PEDOT to incorporate high levels of a sulphonated manganese porphyrin yields a vivid green conducting polymer that, under illumination, catalyzes selective oxidation of water from seawater from ca. 0.40 V (vs. NHE; Pt counter electrode) without observable chlorine formation. This onset potential is comparable to...

Introduction: Nature as a Complex System Common Features of Complex Systems and the Aims of Systems Chemistry Examples of Research in Systems Chemistry Conclusion: Systems Chemistry may have Implications in Other Fields References

Can we emulate nature's technology in chemistry? Through billions of years of evolution, Nature has generated some remarkable systems and substances that have made life on earth what it is today. Increasingly, scientists are seeking to mimic Nature's systems and processes in the lab in order to harness the power of Nature for the benefit of society...

What is Biomimicry and Bioinspiration? Why Seek Inspiration from, or Replicate Biology? Other Monikers: Bioutilization, Bioextraction, Bioderivation, and Bionics Biomimicry and Sustainability Biomimicry and Nanostructure Bioinspiration and Structural Hierarchies Bioinspiration and Self-Assembly Bioinspiration and Function Future Perspectives: Drawi...

Introduction A General Description of the Operation of Catalysts A Brief History of Our Understanding of the Operation of Enzymes Representative Studies of Bioinspired/Biomimetic Catalysts The Relationship Between Enzymatic Catalysis and Nonbiological Homogeneous and Heterogeneous Catalysis Selected High-Performance NonBiological Catalysts that Exp...

The present invention provides a method for marking thread or fibre. The thread or fibre is made to pass through a coating solution comprising particles of a marker material so as to apply the marker material to the thread or fibre (110). Thereafter, the thread or fibre is subjected to a curing process (120). Presence of the marker material is dete...

Radio Frequency Identification (RFID) is an emerging technology playing a vital role in modern automatic identification system. Chipless RFID is a new dimension in the field of radio-frequency application systems with immense potential to manufacture low-cost, multi-bit RFID tags for potential barcode replacement on polymer, paper, and other flexib...

This article reviews some of the recent work by fellows and associates of the Australian Research Council Centre of Excellence for Electromaterials Science (ACES) at Monash University and the University of Wollongong, as well as their collaborators, in the field of water oxidation and reduction catalysts. This work is focussed on the production of...

A flexible polymer for selective seawater splitting: Incorporation of a monomeric Mn-porphyrin that is normally catalytically inactive, into a flexible poly(terthiophene) film yields a remarkable light-assisted water oxidation catalyst with an apparent overpotential for water oxidation of a mere 0.09 V. The catalyst generates exclusively O(2) and n...

Photosystem II is a blueprint for the design of water oxidation catalysts for incorporation into photoelectrochemical devices capable of efficient solar hydrogen production. In this chapter, we review ongoing efforts to develop manganese water oxidation catalysts. These catalytic systems embody one or more of the key features observed in the PSII w...

A virtually identical cubical or cubane core structure appears to be a key commonality in several active homogeneous, heterogeneous and enzymatic wateroxidationcatalysts. We show that X-ray crystal structures of the CaMn3O4 core of the water oxidizing complex of Photosystem II coincide remarkably closely with comparable structures in a range of non...

A method and system for establishing integrity of an item is provided. The method comprises the steps of: performing laser-induced breakdown spectroscopy on an item to obtain a first representative spectrum ( 510); comparing the first representative spectrum to a plurality of stored laser-induced breakdown spectra (520); and establishing integrity...