Imperial College London

ProfessorMaryRyan

Central FacultyOffice of the Provost

Vice-Provost (Research and Enterprise)
 
 
 
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Contact

 

+44 (0)20 7594 6755m.p.ryan

 
 
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Location

 

B338Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

270 results found

Tort R, Bagger A, Westhead O, Kondo Y, Khobnya A, Winiwarter A, Davies BJV, Walsh A, Katayama Y, Yamada Y, Ryan MP, Titirici M-M, Stephens IELet al., 2024, Correction to "Searching for the Rules of Electrochemical Nitrogen Fixation"., ACS Catal, Vol: 14, Pages: 3169-3170, ISSN: 2155-5435

[This corrects the article DOI: 10.1021/acscatal.3c03951.].

Journal article

Thornton DB, Davies BJV, Scott SB, Aguadero A, Ryan MP, Stephens IELet al., 2024, Probing Degradation in Lithium Ion Batteries with On-Chip Electrochemistry Mass Spectrometry., Angew Chem Int Ed Engl, Vol: 63

The rapid uptake of lithium ion batteries (LIBs) for large scale electric vehicle and energy storage applications requires a deeper understanding of the degradation mechanisms. Capacity fade is due to the complex interplay between phase transitions, electrolyte decomposition and transition metal dissolution; many of these poorly understood parasitic reactions evolve gases as a side product. Here we present an on-chip electrochemistry mass spectrometry method that enables ultra-sensitive, fully quantified and time resolved detection of volatile species evolving from an operating LIB. The technique's electrochemical performance and mass transport is described by a finite element model and then experimentally used to demonstrate the variety of new insights into LIB performance. We show the versatility of the technique, including (a) observation of oxygen evolving from a LiNiMnCoO2 cathode and (b) the solid electrolyte interphase formation reaction on graphite in a variety of electrolytes, enabling the deconvolution of lithium inventory loss (c) the first direct evidence, by virtue of the improved time resolution of our technique, that carbon dioxide reduction to ethylene takes place in a lithium ion battery. The emerging insight will guide and validate battery lifetime models, as well as inform the design of longer lasting batteries.

Journal article

Hongrutai N, Sarma SC, Zhou Y, Kellner S, Pedersen A, Adourian K, Tyrrell H, Ryan MP, Panpranot J, Barrio Jet al., 2024, Sequential deposition of FeNC-Cu tandem CO<inf>2</inf> reduction electrocatalysts towards the low overpotential production of C<inf>2+</inf> alcohols, JPhys Materials, Vol: 7

Tandem CO2 reduction electrocatalysts that combine a material that selectively produces CO with Cu are capable of producing hydrocarbons at low overpotentials and high selectivity. However, controlling the spatial distribution and the catalytic activity of the CO-making catalyst remains a challenge. In this work, a novel tandem electrocatalyst that overcomes limitations of simple Cu catalysts, namely selectivity and efficiency at low overpotential, is presented. The tandem electrocatalysts are prepared through a sequential spray coating protocol, using a single atom Fe in N-doped C (FeNC) as the selective CO-producing catalyst and commercial Cu nanopowder. The high faradaic efficiency towards CO of FeNC (99% observed at −0.60 V vs. RHE) provides a high CO coverage to the Cu particles, leading to reduced hydrogen evolution and the selective formation of ethanol and n-propanol at a much low overpotential than that of bare Cu.

Journal article

Zhu C, Miao L, Xie J, Xu H, Han Y, Liu J, Ryan MP, Guo Let al., 2023, Magnetic field effects on the corrosion behavior of magnetocaloric alloys LaFe13.9Si1.4 under paramagnetic states, JOURNAL OF ALLOYS AND COMPOUNDS, Vol: 968, ISSN: 0925-8388

Journal article

Wang S, Shen Z, Omirkhan A, Gavalda-Diaz O, Ryan MP, Giuliani Fet al., 2023, Determining the fundamental failure modes in Ni-rich lithium ion battery cathodes, Journal of the European Ceramic Society, Vol: 43, Pages: 7553-7560, ISSN: 0955-2219

Challenges associated with in-service mechanical degradation of Li-ion battery cathodes has prompted a transition from polycrystalline to single crystal cathode materials. Whilst for single crystal materials, dislocation-assisted crack formation is assumed to be the dominating failure mechanism throughout battery life, there is little direct information about their mechanical behaviour, and mechanistic understanding remains elusive. Here, we demonstrated, using in situ micromechanical testing, direct measurement of local mechanical properties within LiNi0.8Mn0.1Co0.1O2 single crystalline domains. We elucidated the dislocation slip systems, their critical stresses, and how slip facilitate cracking. We then compared single crystal and polycrystal deformation behaviour. Our findings answer two fundamental questions critical to understanding cathode degradation: What dislocation slip systems operate in Ni-rich cathode materials? And how does slip cause fracture? This knowledge unlocks our ability to develop tools for lifetime prediction and failure risk assessment, as well as in designing novel cathode materials with increased toughness in-service.

Journal article

Tort R, Bagger A, Westhead O, Kondo Y, Khobnya A, Winiwarter A, Davies BJV, Walsh A, Katayama Y, Yamada Y, Ryan MP, Titirici M-M, Stephens IELet al., 2023, Searching for the rules of electrochemical nitrogen fixation, ACS Catalysis, Vol: 13, Pages: 14513-14522, ISSN: 2155-5435

Li-mediated ammonia synthesis is, thus far, the only electrochemical method for heterogeneous decentralized ammonia production. The unique selectivity of the solid electrode provides an alternative to one of the largest heterogeneous thermal catalytic processes. However, it is burdened with intrinsic energy losses, operating at a Li plating potential. In this work, we survey the periodic table to understand the fundamental features that make Li stand out. Through density functional theory calculations and experimentation on chemistries analogous to lithium (e.g., Na, Mg, Ca), we find that lithium is unique in several ways. It combines a stable nitride that readily decomposes to ammonia with an ideal solid electrolyte interphase, balancing reagents at the reactive interface. We propose descriptors based on simulated formation and binding energies of key intermediates and further on hard and soft acids and bases (HSAB principle) to generalize such features. The survey will help the community toward electrochemical systems beyond Li for nitrogen fixation.

Journal article

Mousley P, Nicklin C, Pramana S, van den Bosch C, Ryan M, Skinner Set al., 2023, Temperature effect on surface structure of single crystal SrLaAlO4(001), APL Materials, Vol: 11, ISSN: 2166-532X

Development of next generation electrochemical devices such as solid oxide cells requires control of the charge transfer processes across key interfaces. Structural strain at electrolyte:electrode interfaces could potentially alter the devices charge transport properties, therefore understanding the structural behaviour of electrode surfaces at operating conditions is important. The functional oxide single crystal substrate SrLaAlO4 has been well-characterised with bulk structure studies, however there are very few studies of SrLaAlO4 surface structures. Here we present an investigation of the surface structure of SrLaAlO4(001) substrates using surface X-ray diffraction, under UHV conditions (10−10 torr) with the substrate held at either room temperature or 650 ◦C. Best-fit models using a 1:1 ratio of Sr:La showed significant distortions to the surface AlO6 octahedra.

Journal article

Ji C, Zhou H, Tang S, Sharma P, Ryan MP, Jason Riley D, Xie Fet al., 2023, Advances in three-component plasmonic-assisted heterostructures for enhanced photocatalysis and photoelectrochemical catalysis, Materials Today, Vol: 70, Pages: 137-160, ISSN: 1369-7021

Traditional semiconductor materials such as metal-oxide-based photoelectrodes have been extensively explored for energy and environmental applications. However, their performance is hindered by poor light absorption, high charge recombination rates, and low surface kinetics. The incorporation of metal–organic framework (MOF) and plasmonic structures into semiconductors is one of the most promising strategies to achieve performances beyond those of bare MOF and/or conventional semiconductors. This review summarises the rational design of semiconductor-based photoelectrodes incorporating MOFs and plasmonic metals for hybrid photoelectrochemical catalysis and photocatalysis, with a wide variety of parameters including photoactivity, conductivity, catalytic property, surface morphology, porous architecture and bandgap alignment. Moreover, applications of this new generation of composite photoelectrodes in water splitting, CO2 reduction and pollution degradation are discussed in detail. The challenges and prospects of plasmonic MOF nanocomposites in eco-friendly and cost-efficient technologies for practical applications in water splitting, CO2 reduction and environmental remediation are also highlighted.

Journal article

Xu J, Fu M, Ji C, Centeno A, Kim DK, Evers K, Heutz SEM, Oulton R, Ryan MP, Xie Fet al., 2023, Plasmonic‐enhanced NIR‐II downconversion fluorescence beyond 1500 nm from core–shell–shell lanthanide nanoparticles, Advanced Optical Materials, Vol: 11, ISSN: 2195-1071

This paper reports on the light amplification of NaGdF4:Yb,Er,Ce@NaGdF4:Yb,Nd@NaGdF4 core–shell–shell downconversion nanoparticles (CSS-DCNPs) in the near-infrared second biological window (NIR-II: 1000–1700 nm) by plasmonic nanostructures. Through a precisely controlled plasmonic metallic nanostructure, fluorescence from Yb3+ induced 1000 nm emission, Nd3+ induced 1060 nm emission, and Er3+ induced 1527 nm emission are enhanced 1.6-fold, 1.7-fold, and 2.2-fold, respectively, under an 808 nm laser excitation for the CSS-DCNPs coupled with a gold hole-cap nanoarray (Au-HCNA), while the Er3+ induced 1527 nm emission under a 980 nm laser excitation is enhanced up to 6-fold. To gain insight into the enhancement mechanism, the plasmonic modulation of Er3+ induced NIR-II emission at 1550 nm under 980 nm excitation is studied by FDTD simulation and lifetime measurements, showing the observed fluorescence enhancement can be attributed to a combination of enhanced excitation and an increased radiative decay rate.

Journal article

Aberdeen S, Cali E, Vandeperre L, Ryan MPet al., 2023, Selective radionuclide and heavy metal sorption using functionalised magnetic nanoparticles for environmental remediation, JOURNAL OF MATERIALS CHEMISTRY A, Vol: 11, Pages: 15855-15867, ISSN: 2050-7488

Journal article

Westhead O, Spry M, Bagger A, Shen Z, Yadegari H, Favero S, Tort R, Titirici M, Ryan MP, Jervis R, Katayama Y, Aguadero A, Regoutz A, Grimaud A, Stephens IELet al., 2023, The role of ion solvation in lithium mediated nitrogen reduction, Journal of Materials Chemistry A, Vol: 11, Pages: 12746-12758, ISSN: 2050-7488

Since its verification in 2019, there have been numerous high-profile papers reporting improved efficiency of lithium-mediated electrochemical nitrogen reduction to make ammonia. However, the literature lacks any coherent investigation systematically linking bulk electrolyte properties to electrochemical performance and Solid Electrolyte Interphase (SEI) properties. In this study, we discover that the salt concentration has a remarkable effect on electrolyte stability: at concentrations of 0.6 M LiClO4 and above the electrode potential is stable for at least 12 hours at an applied current density of −2 mA cm−2 at ambient temperature and pressure. Conversely, at the lower concentrations explored in prior studies, the potential required to maintain a given N2 reduction current increased by 8 V within a period of 1 hour under the same conditions. The behaviour is linked more coordination of the salt anion and cation with increasing salt concentration in the electrolyte observed via Raman spectroscopy. Time of flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy reveal a more inorganic, and therefore more stable, SEI layer is formed with increasing salt concentration. A drop in faradaic efficiency for nitrogen reduction is seen at concentrations higher than 0.6 M LiClO4, which is attributed to a combination of a decrease in nitrogen solubility and diffusivity as well as increased SEI conductivity as measured by electrochemical impedance spectroscopy.

Journal article

Wang S, Burdett P, Lovell E, Bettles R, Wilson N, Ryan M, Giuliani Fet al., 2023, Fracture properties of La(Fe,Mn,Si)13 magnetocaloric materials, Materials Letters, Vol: 338, Pages: 1-4, ISSN: 0167-577X

La(Fe,Mn,Si)13 alloys are a promising material family for magnetic refrigeration. Challenges associated with their structural integrity during device assembly and operation requires deep understanding of the mechanical properties. Here we developed a workflow to quantitatively study the fracture properties of La(Fe,Mn,Si)13 plates used in magnetic cooling devices. We employed microstructural characterisation, optical examination of defects, and four-point bending tests of samples with known defect sizes to evaluate their mechanical performance. We established the residual strength curve which directly links observed defects to mechanical strength. The estimated fracture toughness KC of hydrogenated La(Fe,Mn,Si)13 is approximately 4 MPa·m1/2 for the geometry employed. The established relationship between strength and crack length enables the prediction of mechanical performance through examination of defects via optical microscopy, therefore can be used industrially for directing plate selection to guarantee the mechanical stability of refrigeration devices.

Journal article

Rodenkirchen C, Ackerman AK, Mignanelli PM, Cliff A, Wise GJ, Breul P, Douglas JO, Bagot PAJ, Moody MP, Appleton M, Ryan MP, Hardy MC, Pedrazzini S, Stone HJet al., 2023, Effect of Alloying on the Microstructure, Phase Stability, Hardness, and Partitioning Behavior of a New Dual-Superlattice Nickel-Based Superalloy, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, Vol: 54, Pages: 1902-1923, ISSN: 1073-5623

Journal article

Tian T, Xu J, Abdolazizi A, Ji C, Hou J, Riley DJ, Yan C, Ryan MP, Xie F, Petit Cet al., 2023, Occurrence, geochemical characteristics, enrichment, and ecological risks of rare earth elements in sediments of "the Yellow river- Estuary- bay" system*, MATERIALS TODAY NANO, Vol: 21, ISSN: 2588-8420

Journal article

Tan Z, Berry A, Charalambides M, Mijic A, Pearse W, Porter A, Ryan M, Shorten R, Stettler M, Tetley T, Wright S, Masen Met al., 2023, Tyre wear particles are toxic for us and the environment

This briefing paper discusses the current knowledge on the effects of tyre wear particles on our health and environment, highlights the need for an ambitious research agenda to build further understanding of the impacts on people and nature and develop solutions, and includes recommendations for policymakers.

Report

Pek ME, Ackerman AK, Appleton M, Ryan MP, Pedrazzini Set al., 2023, Development of a novel, impurity-scavenging, corrosion-resistant coating for Ni-based superalloy CMSX-4, Oxidation of Metals, Vol: 99, Pages: 3-13, ISSN: 0030-770X

Sulfur, a common impurity arising from atmospheric and environmental contamination, is highly corrosive and detrimental to the lifespan of nickel superalloys in jet engines. However, sulfur-scavenging coatings have yet to be explored. Our study presents the successful development of a stable, uniform, impurity-scavenging Ni-Mn coating on Ni-based superalloy CMSX-4, through electroplating. The coating was characterised via combined scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy. An optimal coating thickness of > 600 nm was deposited. The coated alloy was exposed to corrosive salt mixture 98% Na2SO4–2% NaCl at 550 °C for 100 h, mimicking engine exposure conditions, thereby proving that the coating successfully trapped sulfur and prevented its diffusion into an underlying alloy. This work presents a promising development for the prevention of sulfur-induced corrosion in industrial setting such as gas turbine engine, where the effects of sulfur diffusion into the bulk alloy could lead to premature failure.

Journal article

Wang S, Douglas JO, Lovell E, Wilson N, Guo L, Gault B, Ryan MP, Giuliani Fet al., 2023, Near-atomic scale chemical analysis of interfaces in a La(Fe,Mn,Si)13-based magnetocaloric material, Scripta Materialia, Vol: 224, Pages: 1-6, ISSN: 1359-6462

La(Fe,Mn,Si)13-based magnetocaloric materials are one of the most promising material families for the realisation of near-room temperature magnetic refrigeration. The functional and mechanical properties of these materials crucially depend on their chemistry, which is difficult to control at interfaces between microstructural units. Atom probe tomography was employed to reveal the local elemental distribution at the α-Fe/1:13 phase boundary and the 1:13/1:13 grain boundary. Strong Mn segregation (and Fe depletion) at the α-Fe/1:13 phase boundary suggests the potential effect of phase boundary area on the Curie temperature of the material. A local off-1:13 stoichiometry layer at the 1:13/1:13 grain boundary may adversely affect the magnetocaloric performance. Routes to mitigate the negative effects of interfaces on the functional and mechanical performance of these materials are discussed, in order to achieve durable and efficient operation of magnetic cooling devices.

Journal article

Morton W, Joyce C, Taylor J, Ryan M, Angioletti-Uberti S, Xie Fet al., 2023, Modeling Au nanostar geometry in bulk solutions., The Journal of Physical Chemistry C: Energy Conversion and Storage, Optical and Electronic Devices, Interfaces, Nanomaterials, and Hard Matter, Vol: 127, Pages: 1680-1686, ISSN: 1932-7447

The findings within make it possible to reference gold nanostars based on their geometric properties, similar to how a radius describes a nanosphere, rather than just the LSPR of the structure-the current practice. The average tip approximation presented reduces the complexity of nanostars in discrete dipole approximation simulations. By matching the projected area and LSPR of the modeled nanostars to synthesized nanostars, the volume, surface area, and number of tips can be approximated without a lengthy characterization process. Knowing the nanoparticle geometry can determine drug carrier capacity, an approximate number of hot spots for EM imaging, and how the particle will interact with cells. The geometric data obtained will drive the biological application and increase the usability of this particle class.

Journal article

Tort R, Westhead O, Spry M, Davies BJV, Ryan MP, Titirici M-M, Stephens IELet al., 2023, Nonaqueous Li-mediated nitrogen reduction: taking control of potentials, ACS Energy Letters, Vol: 8, Pages: 1003-1009, ISSN: 2380-8195

The performance of the Li-mediated ammonia synthesis has progressed dramatically since its recent reintroduction. However, fundamental understanding of this reaction is slower paced, due to the many uncontrolled variables influencing it. To address this, we developed a true nonaqueous LiFePO4 reference electrode, providing both a redox anchor from which to measure potentials against and estimates of sources of energy efficiency loss. We demonstrate its stable electrochemical potential in operation using different N2- and H2-saturated electrolytes. Using this reference, we uncover the relation between partial current density and potentials. While the counter electrode potential increases linearly with current, the working electrode remains stable at lithium plating, suggesting it to be the only electrochemical step involved in this process. We also use the LiFePO4/Li+ equilibrium as a tool to probe Li-ion activity changes in situ. We hope to drive the field toward more defined systems to allow a holistic understanding of this reaction.

Journal article

Westhead O, Spry M, Bagger A, Shen Z, Yadegari H, Favero S, Tort R, Titirici M, Ryan MP, Jervis R, Katayama Y, Aguadero A, Regoutz A, Grimaud A, Stephens IELet al., 2023, Correction: The role of ion solvation in lithium mediated nitrogen reduction, Journal of Materials Chemistry A, Vol: 11, Pages: 13039-13039, ISSN: 2050-7488

Correction for ‘The role of ion solvation in lithium mediated nitrogen reduction’ by O. Westhead et al., J. Mater. Chem. A, 2023, https://doi.org/10.1039/D2TA07686A.

Journal article

Alsalem MM, Ryan MP, Campbell AN, Campbell KSet al., 2023, Modelling of CO<inf>2</inf> corrosion and FeCO<inf>3</inf> formation in NaCl solutions, Chemical Engineering Journal, Vol: 451, ISSN: 1385-8947

The corrosivity of carbon dioxide (CO2) corrosion and iron carbonate (FeCO3) layer formation in sodium chloride (NaCl) solutions (1–12 % w/v) were investigated through electrochemical experiments and modelling. Relying on electrochemical measurements (Potentiodynamic polarisation) and simplified current density expressions (employing only H+ activity), reaction enthalpies (ΔH) and rate constants (Kr) for Fe dissolution, H2 evolution and H2O reduction reactions were estimated over a temperature range of 40–80 °C. Additionally, a revised FeCO3 precipitation rate expression was developed based on a newly derived FeCO3 solubility product (Ksp), integrating the effects of temperature and ionic strength (using activity coefficients). Collectively, this yielded a new CO2 corrosion prediction model accounting for the presence of a developing layer of FeCO3 in NaCl solutions. The model was validated over a broad range of conditions (pH, temperature, pressure and NaCl concentrations) by employing the corrosion rate and FeCO3 characteristics as metrics. Notably, it was shown that the activities of dissolved CO2 and Cl− were not essential to predict the electrochemical response of anodic processes. Furthermore, it was demonstrated that increasing NaCl concentration resulted in a complexly evolving environment where porous, less protective FeCO3 layers were formed.

Journal article

Stephens IEL, Chan K, Bagger A, Boettcher SW, Bonin J, Boutin E, Buckley AK, Buonsanti R, Cave ER, Chang X, Chee SW, da Silva AHM, de Luna P, Einsle O, Endrodi B, Escudero-Escribano M, de Araujo JVF, Figueiredo MC, Hahn C, Hansen KU, Haussener S, Hunegnaw S, Huo Z, Hwang YJ, Janaky C, Jayathilake BS, Jiao F, Jovanov ZP, Karimi P, Koper MTM, Kuhl KP, Lee WH, Liang Z, Liu X, Ma S, Ma M, Oh H-S, Robert M, Cuenya BR, Rossmeisl J, Roy C, Ryan MP, Sargent EH, Sebastian-Pascual P, Seger B, Steier L, Strasser P, Varela AS, Vos RE, Wang X, Xu B, Yadegari H, Zhou Yet al., 2022, 2022 roadmap on low temperature electrochemical CO<sub>2</sub> reduction, JOURNAL OF PHYSICS-ENERGY, Vol: 4, ISSN: 2515-7655

Journal article

Tian T, Xu J, Xiong Y, Ramanan N, Ryan M, Xie F, Petit Cet al., 2022, Cu-functionalised porous boron nitride derived from a metal–organic framework, Journal of Materials Chemistry A, Vol: 10, Pages: 20580-20592, ISSN: 2050-7488

Porous boron nitride (BN) displays promising properties for interfacial and bulk processes, e.g. molecular separation and storage, or (photo)catalysis. To maximise porous BN's potential in such applications, tuning and controlling its chemical and structural features is key. Functionalisation of porous BN with metal nanoparticle represents one possible route, albeit a hardly explored one. Metal–organic frameworks (MOFs) have been widely used as precursors to synthesise metal functionalised porous carbon-based materials, yet MOF-derived metal functionalised inorganic porous materials remain unexplored. Here, we hypothesise that MOFs could also serve as a platform to produce metal-functionalised porous BN. We have used a Cu-containing MOF, i.e. Cu/ZIF-8, as a precursor and successfully obtained porous BN functionalised with Cu nanoparticles (i.e. Cu/BN). While we have shown control of the Cu content, we have not yet demonstrated it for the nanoparticle size. The functionalisation has led to improved light harvesting and enhanced electron–hole separation, which have had a direct positive impact on the CO2 photoreduction activity (production formation rate 1.5 times higher than pristine BN and 12.5 times higher than g-C3N4). In addition, we have found that the metal in the MOF precursor impacts porous BN's purity. Unlike Cu/ZIF-8, a Co-containing ZIF-8 precursor led to porous C-BN (i.e. BN with a large amount of C in the structure). Overall, given the diversity of metals in MOFs, one could envision our approach as a method to produce a library of different metal functionalised porous BN samples.

Journal article

Xu J, Morton W, Jones D, Tabish TA, Ryan MP, Xie Fet al., 2022, Significant quantum yield enhancement for near infrared fluorescence dyes by silica templated silver nanorods, APPLIED PHYSICS REVIEWS, Vol: 9, ISSN: 1931-9401

Journal article

Rodenkirchen C, Appleton M, Ryan MP, Pedrazzini Set al., 2022, A review on atom probe and correlative microscopy studies of corrosion in nickel-based superalloys, Materials Research Society (MRS) Bulletin, Vol: 47, Pages: 706-717, ISSN: 0883-7694

This article discusses challenges faced in the development of new Ni-based superalloys for applications in the hottest sections of turbine engines and the use of atom probe tomography and correlative microscopy for characterization of these complex alloys with regards to microstructural and compositional design. The two strengthening phases γ and γ′ are introduced and the precipitation of topologically close-packed phases and their potential detrimental effects on superalloy properties are reviewed. Mechanisms of environmental degradation, namely oxidation and hot corrosion, are elucidated and recent research studies on a new phenomenon of hot corrosion at relatively low temperatures below 600°C are discussed. The effect of individual alloying elements on superalloy properties is reviewed, with a focus on Mo and W. The use of atom probe in correlation with state-of-the-art microscopy, spectroscopy and diffraction techniques to study and understand oxidation and corrosion of Ni-based superalloys, including crack tip investigations, is presented.

Journal article

Ramesh A, Laycock N, Shenai P, Barnes A, Van Santen H, Thyagarajan A, Abdullah AM, Ryan MPet al., 2022, Critical Deposit Loading Thresholds for Under Deposit Corrosion in Steam Generators, CORROSION, Vol: 77, Pages: 584-598, ISSN: 0010-9312

Journal article

Yallop M, Wang Y, Masuda S, Daniels J, Ockenden A, Masani H, Scott TB, Xie F, Ryan M, Jones C, Porter AEet al., 2022, Quantifying impacts of titanium dioxide nanoparticles on natural assemblages of riverine phytobenthos and phytoplankton in an outdoor setting, SCIENCE OF THE TOTAL ENVIRONMENT, Vol: 831, ISSN: 0048-9697

Journal article

Wang S, Gavalda-Diaz O, Luo T, Guo L, Lovell E, Wilson N, Gault B, Ryan MP, Giuliani Fet al., 2022, The effect of hydrogen on the multiscale mechanical behaviour of a La(Fe,Mn,Si)13-based magnetocaloric material, Journal of Alloys and Compounds, Vol: 906, Pages: 1-10, ISSN: 0925-8388

Magnetocaloric cooling offers the potential to improve the efficiency of refrigeration devices and hence cut the significant CO2 emissions associated with cooling processes. A critical issue in deployment of this technology is the mechanical degradation of the magnetocaloric material during processing and operation, leading to limited service-life. The mechanical properties of hydrogenated La(Fe,Mn,Si)13-based magnetocaloric material are studied using macroscale bending tests of polycrystalline specimens and in situ micropillar compression tests of single crystal specimens. The impact of hydrogenation on the mechanical properties are quantified. Understanding of the deformation/failure mechanisms is aided by characterization with transmission electron microscopy and atom probe tomography to reveal the arrangement of hydrogen atoms in the crystal lattice. Results indicate that the intrinsic strength of this material is ~3-6 GPa and is dependent on the crystal orientation. Single crystals under compressive load exhibit shearing along specific crystallographic planes. Hydrogen deteriorates the strength of La(Fe,Mn,Si)13 through promotion of transgranular fracture. The weakening effect of hydrogen on single crystals is anisotropic; it is significant upon shearing parallel to the {111} crystallographic planes but is negligible when the shear plane is {001}-oriented. APT analysis suggests that this is associated with the close arrangement of hydrogen atoms on {222} planes.

Journal article

Xu Z, Wang J, Guo Z, Xie F, Liu H, Yadegari H, Tebyetekerwa M, Ryan MP, Hu Y-S, Titirici M-Met al., 2022, The Role of Hydrothermal Carbonization in Sustainable Sodium-Ion Battery Anodes, ADVANCED ENERGY MATERIALS, Vol: 12, ISSN: 1614-6832

Journal article

Gomez-Gonzalez MA, Rehkamper M, Han Z, Ryan MP, Laycock A, Porter AEet al., 2022, ZnO Nanomaterials and Ionic Zn Partition within Wastewater Sludge Investigated by Isotopic Labeling, Global Challenges, Vol: 6, ISSN: 2056-6646

The increasing commercial use of engineered zinc oxide nanomaterials necessitates a thorough understanding of their behavior following their release into wastewater. Herein, the fates of zinc oxide nanoparticles (ZnO NPs) and ionic Zn in a real primary sludge collected from a municipal wastewater system are studied via stable isotope tracing at an environmentally relevant spiking concentration of 15.2 µg g−1. Due to rapid dissolution, nanoparticulate ZnO does not impart particle-specific effects, and the Zn ions from NP dissolution and ionic Zn display indistinguishable behavior as they partition equally between the solid, liquid, and ultrafiltrate phases of the sludge over a 4-h incubation period. This work provides important constraints on the behavior of engineered ZnO nanomaterials in primary sludge—the first barrier in a wastewater treatment plant—at low, realistic concentrations. As the calculated solid–liquid partition coefficients are significantly lower than those reported in prior studies that employ unreasonably high spiking concentrations, this work highlights the importance of using low, environmentally relevant doses of engineered nanomaterials in experiments to obtain accurate risk assessments.

Journal article

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