Andrew I. Minett

A multifunctional nano-heterostructured electrocatalyst of transition metal/metal oxide (nickel/nickel oxide) embedded on nitrogen-doped graphene is reported.

A facile synthesis method to produce nitrogen-doped graphene containing a high atomic percentage of pyridinic N and graphitic N via the thermal annealing of graphene oxide and uric acid is reported. The method yielded N-doped graphene nanosheets that had high surface areas and that contained 9.22 at% nitrogen, which was present in four bonding configurations with a high ratio of pyridinic N and graphitic N. The synthesized N-doped graphene showed excellent capacitance properties, which led to the fabrication of a stacked electrode supercapacitor cell of 2-electrode configuration with a specific capacitance of 230 F g⁻¹ at a current density of 1 A g⁻¹ and with a remarkably high energy density of 62.6 W h kg⁻¹ in aqueous electrolyte. Additionally, this material showed superior properties as an electrocatalyst for both the oxygen-reduction reaction (ORR) and oxygen evolution reaction (OER), producing high current density primarily via the four-electron pathway for ORR at a current density of −4.3 mA cm⁻² and OER activity of a generating current density of 10 mA cm⁻² at 1.74 V vs. RHE in alkaline media. Hence, this dual-natured N-doped graphene could provide a platform for developing nanostructured graphene-based advanced energy storage and conversion devices.

Raman spectroscopy is among the primary techniques for the characterisation of graphene materials, as it provides insights into the quality of measured graphenes including their structure and conductivity as well as the presence of dopants. However, our ability to draw conclusions based on such spectra is limited by a lack of understanding regarding the origins of the peaks. Consequently, traditional characterisation techniques, which estimate the quality of the graphene material using the intensity ratio between the D and the G peaks, are unreliable for both GO and rGO. Herein we reanalyse the Raman spectra of graphenes and show that traditional methods rely upon an apparent G peak which is in fact a superposition of the G and D’ peaks. We use this understanding to develop a new Raman characterisation method for graphenes that considers the D’ peak by using its overtone the 2D’. We demonstrate the superiority and consistency of this method for calculating the oxygen content of graphenes and use the relationship between the D’ peak and graphene quality to define three regimes. This has important implications for purification techniques because, once GO is reduced beyond a critical threshold, further reduction offers limited gain in conductivity.

In many countries, including New Zealand, the demand for rheumatology services exceeds their supply, resulting in some patients experiencing long delays or being denied access. The principal aim of this work was to create a validated, transparent, and fair system for determining access to rheumatology services. A panel of 5 rheumatologists, 6 primary care physicians, and 4 nurse specialists ranked a series of 25 clinical scenarios in order of priority to see a rheumatologist. Important determining factors were weighted in an iterative process to generate a multidimensional additive point score to determine access to rheumatology service. The score comprises 6 domains of 2 to 4 items weighted to give a total score out of 100. The effect of the problem on the patient's life and role, the presence of an inflammatory rheumatic disease, appropriateness of current treatment, and the ability of the rheumatologist to influence the current symptoms and future prognosis were felt to be critical factors in determining access to the service. The score showed a strong correlation with the rankings agreed by the clinical panel, and the overall intraclass correlation coefficient for the rheumatologists was 0.698. Our score has face validity, is easy to perform, and has been assessed by an independent panel of rheumatologists as providing a fair system for determining access to rheumatology services. The system is acceptable to primary care physicians and has been adopted by our local primary care organizations.

Though feasible for CO methanations in gas-cleaning applications ([CO] < 1%), carbon-nanotube-supported catalysts have never been implemented for the production of synthetic natural gas. To achieve sufficiently active catalysts, NiO particles were grafted onto multiwalled carbon nanotubes (MWNTs) using a modified incipient wetness impregnation technique that produced particles ranging from 3 to 18 nm in diameter. The reducibility of the deposited NiO particles was studied, as were the thermal stability and surface area of the composites. The materials were then applied as catalysts for CO methanation in syn gas, where CO concentration is greater than 9%, to synthesise synthetic natural gas (SNG) at atmospheric pressure. Ni/MWNTs containing only 13 wt% Ni catalysed the methanation of CO, achieving ~95% CO conversion and ~85% selectivity for CH₄. The factors affecting the activity and stability of the composites were studied, and a method to regenerate the Ni/MWNTs catalyst was developed. Following regeneration, the developed catalysts could be reused with small losses in activity and selectivity.

Adding Ni to a supported Pt catalyst for aqueous phase reforming allowed the Pt content to be reduced to one third, with a slight increase in H₂ yield.

CaO sorbents for CO₂ capture are much more stable when supported on a ceramic; however, the rational design of such supported sorbents has only recently been considered. We designed and prepared new CO₂ sorbents by supporting CaO on meso- and macro/mesoporous supports made of materials that are stable under conditions relevant to CO₂ capture in pre-combustion CO₂ sorption. The resulting sorbents were used to capture and release carbon dioxide (CO₂), and one demonstrated excellent stability over 30 cycles, taking up nearly twice as much CO₂ over these thirty cycles as a related material that lacked a tailored structure.

The successful commercialization of smart wearable garments is hindered by the lack of fully integrated carbon-based energy storage devices into smart wearables. Since electrodes are the active components that determine the performance of energy storage systems, it is important to rationally design and engineer hierarchical architectures atboth the nano- and macroscale that can enjoy all of the necessary requirements for a perfect electrode. Here we demonstrate a large-scale flexible fabrication of highly porous high-performance multifunctional graphene oxide (GO) and rGO fibers and yarns by taking advantage of the intrinsic soft self-assembly behavior of ultralarge graphene oxide liquid crystalline dispersions. The produced yarns, which are the only practical form of these architectures for real-life device applications, were found to be mechanically robust (Young’s modulus in excess of 29 GPa) and exhibited high native electrical conductivity (2508 ± 632 S m^–1) and exceptionally high specific surface area (2605 m² g^–1 before reduction and 2210 m² g^–1 after reduction). Furthermore, the highly porous nature of these architectures enabled us to translate the superior electrochemical properties of individual graphene sheets into practical everyday use devices with complex geometrical architectures. The as-prepared final architectures exhibited an open network structure with a continuous ion transport network, resulting in unrivaled charge storage capacity (409 F g^–1 at 1 A g^–1) and rate capability (56 F g^–1 at 100 A g^–1) while maintaining their strong flexible nature.