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Johnson Matthey Technology Review - Fast Track
Accepted manuscripts have been peer reviewed (where appropriate) and accepted for publication but have not yet been copyedited, house styled, proofread or typeset. The final published version may contain differences as a result of these procedures.
12
Fast Track articles
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Theoretical Study on Copper Adsorption on ZnO Surfaces
Available online: 23 April 2024More LessABSTRACT: The study of Cu on ZnO surfaces is a topic of ongoing research due to the importance of Cu as a promoter in the low-temperature synthesis of methanol, the water-gas shift process, and methanol steam reforming. The role of ZnO in support-ing the stabilization of the Cu atoms and promoting the CO2 hydrogenation reaction is multifaceted and involves a range of physical and chemical factors. In this work, we used density functional theory (DFT) calculations to investigate the Cu adsorp-tion on ZnO surfaces on different sites. Bader charge analysis, adsorption energy, and phonon inelastic neutron scattering (INS) associated with most stable systems were calculated and compared with previous theoretical and experimental results. We found that atomic Cu adsorption on hollow site of ZnO(111) is the most stable site and most favorable site for Cu adsorption compar-ing to other ZnO surfaces. This is due to the strong metal-oxygen interaction between Cu and the ZnO surface. We concluded that further studies are needed to investigate the catalytic activity of this catalyst under realistic reaction conditions with realistic models of Cu supported on ZnO.
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Effect of Hf on the Microstructure and Mechanical Property of Pt-15Ir-xHf-0.5Y Alloy
Available online: 23 April 2024More LessThe influence of Hf content on the recrystallization and aging behavior of hot-rolled Pt-15Ir-xHf-0.5Y alloy was investigated by SEM, EBSD and hardness tests. The results show that the alloy texture evolves from a multi-peak one biased towards rolling direction-transverse direction (RD-TD) in the hot rolling state to a multi-peak one symmetrical along the normal direction (ND) after recrystallization annealing. The fibrous grains become equiaxial after recrystallization annealing, increase of Hf content refines the grains. Pt-15Ir-xHf-0.5Y alloy exhibits age-hardening behavior at the temperature range of 600°C~900°C, which is due to the precipitation of (Pt, Ir)5Y phase. Increasing Hf addition effectively improves the hardness through promoting the precipitated amount of (Pt, Ir)5Y phase. However, the internal oxidation within grain boundaries is deteriorated with the high-content Hf addition. The results of this study provide an insight into tailoring the microstructures and mechanical properties of the Pt-Ir high-temperature alloys.
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A New Approach to Ti-HA Bio Composite: Pressure-Assisted Coating on the Antibacterial and Electrochemical Properties of Ti6Al4V
Available online: 23 April 2024More LessThis study aims to coat Ti6Al4V alloy with Ti-xHA (x=2.5-10wt.%) mixture to improve its surface properties. A new approach using a powder metallurgical pressure-assisted sintering method was applied to the coating process. The in-situ sintering and coating process was performed at 950°C for 45 min in a vacuum atmosphere of 10-4 mbar. A pressure of 50MPa was applied during the sintering process. Staphylococcus aureus (ATCC 29213) and Escherichia coli (ATCC 25922) cultures were used to determine the antibacterial activity of the sintered and coated samples. The electrochemical properties of the samples were studied by Tafel extrapolation and potentiodynamic polarization tests. The results showed that the coating layer containing wt.%7.5 of HA increased the antibacterial property against gram-positive and gram-negative bacterial cultures. Furthermore, it was determined that the icorr value of the material decreased, and the corrosion resistance improved with an increasing HA ratio. In addition, no active-passive oxidation zone formation was observed up to 2000 mV in the HA-added samples.
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A Comprehensive Exploration of Biomass Gasification Technologies Advancing United Nations Sustainable Development Goals
Available online: 11 April 2024More LessAbstract: The pursuit of sustainable energy sources on a worldwide scale is a crucial and pressing matter, with the United Nations Sustainable Development Goals (UNSDGs) offering a comprehensive framework for properly addressing this challenge. This paper provides an overview of the various technologies now available for the process of biomass gasification. Compared to other renewable energy sources, which have undergone significant technological advancements in recent years, the field of biomass conversion is still relatively new. Keeping up with the newest breakthroughs becomes increasingly crucial as new conversion techniques are rapidly being created. Keeping up with the latest advancements and potential enhancements in biofuel conversion technology is essential due to their rapid development. In the thermochemical conversion process called "biomass gasification," biomass solid source materials are degraded or incompletely burned in an oxygen-free or oxygen-deficient high-temperature atmosphere, resulting in the production of biomass gas. Biomass gas can be utilized in industry to directly power industrial boilers for steam production, as well as for cooking or heating purposes in rural areas. The purified biomass gas can be utilized to operate a generator set, so facilitating the provision of electricity to areas lacking access to it. The utilization of biomass gasification technology alters the traditional approach of directly igniting biomass to generate power. Gasification technology converts biomass into a clean and combustible gas, significantly improving the efficiency of using biomass energy. This essay will largely concentrate on the methodologies and protocols employed in biomass gasification. The article provides an overview of various gasification procedures and the potential applications of the resulting products. It delves into different biomass gasification techniques, including upstream, gasification, and downstream processes, highlighting their importance in transforming biomass into clean and combustible gases. The review focuses on methodologies and protocols employed in biomass gasification, recognizing its pivotal role in sustainable energy generation. Additionally, the article discusses the challenges associated with gasification technology, such as tar formation, biomass heterogeneity, and uneven biomass supply in different seasons. It emphasizes the need for further research and infrastructure development to overcome these barriers and facilitate the efficient distribution and commercialization of biomass gasification technology. Overall, the scope of the article extends to providing insights into the status, challenges, and future prospects of biomass gasification for achieving sustainable energy goals.
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Autonomous Structural Health Monitoring and Remaining Useful Life Estimation of Floating Offshore Wind Turbine Cables
Available online: 08 April 2024More LessAbstract— Floating offshore wind (FOW) farms are key in meeting Europe’s renewable energy targets, harnessing wind energy from waters 60m or deeper, where bottom-fixed farms are unfeasible. Additionally, floating structures allow for the installation of larger turbines than stationary farms, which in turn leads to a greater energy output. However, cable failures dramatically impact the energy transmission from the farms and cause most of the financial losses. Monitoring and maintenance tasks are challenging due to the harsh ocean conditions. The FLOW-CAM project, supported by European Union’s HORIZON 2020 program, studies the structural health monitoring (SHM) of defects in the power cables of the FOW farms which encompass inspection and detection applications. An SHM system integrated with a remotely operated vehicle (ROV) was developed for underwater inspection and maintenance, supporting collection and presentation of essential data through an advanced interface. Image data from underwater systems are analyzed using computer vision techniques. Investigations into cable defect detection and the estimation of corrosion and remaining useful life have been held to monitor cable health, achieving results close to reality. FLOW-CAM’s collective works establish a basis for advancing underwater inspection and maintenance, concentrating on the development of practical and effective tools and strategies to optimize the functionality and reliability of FOW farms.
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Active Sites of Cu/ZnO-Based Catalysts for CO2 Hydrogenation to Methanol
Available online: 14 March 2024More LessHeterogeneous Cu/ZnO-based catalysts are widely used for CO2 hydrogenation to methanol, but limitations remain for industrial applications. These include achieving high methanol selectivity and conversion, and mitigating deactivation by water poisoning. This review explores the role of active sites on Cu/ZnO-based catalysts in CO2 conversion. The synergistic interaction between Cu and ZnO is emphasized, particularly regarding interfacial effects on CO activation and formate formation. The discussion covers theoretical and experimental perspectives on active site characteristics, including defects, vacancies, steps, and strain. Additionally, the review explores the connection between Cu/ZnO-based catalysts properties and methanol synthesis activity. It examines how preparation methods influence catalyst performance and the impact of doping with elements like CeO2, Al2O3, and ZrO2 on CO2 conversion selectivity. We conclude that ZnO enhances Cu dispersion and promotes a synergistic effect at the interface, leading to improved catalytic performance.
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Ultrafast spectroscopy at the Central Laser Facility
Available online: 29 February 2024More LessIn this article, we will examine ultrafast spectroscopy techniques and applications, covering ‘time-resolved IR’ (TR-IR) spectroscopy, time resolved visible (TA) spectroscopy, two-dimensional IR (2D-IR) spectroscopy, Kerr-gated Raman spectroscopy, time-resolved Raman and surface sum-frequency generation (SSFG) spectroscopy. In addition to introducing each technique, we will cover some basics, such as what kinds of lasers are used and discuss how these techniques are applied to study a diversity of chemical problems such as photo-catalysis, photo-chemistry, electro-catalysis, battery electrode characterisation, zeolite characterisation and protein structural dynamics.
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Oxidation Kinetics of FeCr and FeCrAl Alloys: Influence of Secondary Processes
Available online: 29 February 2024More LessThe paper presents a mathematical model for describing of thermogravimetric curves of growth of scale with its simultaneous sublimation during oxidation of the surface of a metal or alloy. For alloys FeCr and FeCrAl, a decrease in the effective reaction area as a result of the formation of the oxide of the alloying element - lanthanum or yttrium (together with the formation of the main oxide - Cr2O3 or Al2O3) is considered. For metals, the case of increasing this area is also considered. During the oxidation of the chromia-forming alloy, another secondary process is added - the evaporation of Cr2O3. Therefore, the equations describing the kinetics of changes in mass of these alloys are different. Equations are also considered that make it possible to describe the kinetics of the oxidation process taking into account the initial non-isothermal heating. The formal equations of the oxidation process with an increase in the reaction surface as a result of crushing metal powder are also considered. The resulting equations are used to describe the kinetic curves of changes in the mass of the samples under study. The given equations can be considered as a more accurate approximation to describe the experimental data than the formulas known so far.
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Migration of Pt Nanoparticles via Volatile PtO2 during Lean High-Temperature Aging of Diesel Oxidation Catalysts
Available online: 14 February 2024More LessWhen Pt containing diesel oxidation catalysts (DOC) are exposed to high temperatures under lean conditions, the Pt nanoparticles form volatile PtO2 on the catalyst surface. The exhaust flow carries the volatile PtO2 to the downstream aftertreatment catalyst, such as the selective catalytic reduction (SCR) catalyst, that is responsible for reducing the NOx emissions, and can negatively impact its performance. Here we investigate the factors such as exposure time, temperature and DOC design characteristics for their impact on the PtO2 migration, by characterizing the amount of Pt deposited on the SCR catalyst at very low levels (< 5ppm), using ICP-OES (Inductively coupled plasma optical emission spectroscopy) fire assay technique. Our results indicate that well-dispersed Pt, not associated with Pd, is most prone to PtO2 migration. We also compare several methods to suppress the PtO2 migration from the DOC, such as sintering of the Pt nanoparticles, stabilizing the Pt nanoparticles via interaction with Pd or covering the Pt nanoparticles with a high surface area capture layer to trap the volatile PtO2.
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Synthesis and Characterization of Cellulose Acetate/Polyethylene Glycol Membrane from Pineapple Hump by Phase Inversion Method
Available online: 12 February 2024More LessCellulose is a natural polymer contained in growing fibers, such as pineapple fibers. Cellulose can be modified into cellulose acetate, a modified polymer that can be used in the synthesis of a cellulose acetate/polyethylene glycol (CA/PEG) membrane. The phase inversion method was used in this study to produce CA/PEG membranes. Variations in PEG concentration with a ratio of 1:1 to cellulose acetate, where variations in PEG concentrations used are 2%, 5%, and 8%. Acetone and dimethylformamide are used as organic solvents. Membrane morphological analysis using Scanning Electron Microscope (SEM) and functional group analysis using a Fourier Transform-Infrared (FT-IR) spectrometer were performed for membrane characterization. The result of the synthesis of the CA/PEG membrane is in the form of a thin white layer. The characterization results of the FT-IR spectrometer showed the vibration of the carbonyl bond at wavenumber 1729 cm-1 and the vibration of the hydroxyl bond torque at the wave number 648 cm-1, where the vibration intensity decreased with each addition to the concentration. The results of SEM characterization show that the increase in PEG concentration increases the percentage porosity of the membrane. The membranes with 2%, 5%, and 8% PEG have porosity percentages of 51.54%, 68.70%, and 73.50%, respectively. As the membrane with 2% PEG has the lowest percent porosity, it is more potential in removing or filtering solutes from a fluid.
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Ammonia Sprays for Combustion: A Review
Available online: 07 February 2024More LessAmmonia is a globally transported chemical used for a variety of applications, most notably, the production of fertilizer. Over the past decade, attention has been afforded to the use of ammonia as an energy carrier, coupling global supply of renewable energy to demand regions. Ammonia’s advantages as an energy carrier include its ease of liquefaction and established international transportation routes; overcoming its low reactivity, excessive production of nitrogen oxides, and its toxicity remain as challenges. For energy applications, fuel delivery is a critical aspect of effective combustion in boilers, burners and engines. Due to its adaptable phase change characteristics, ammonia fuel may be injected as a liquid or vapour, each with respective advantages or disadvantages. The focus of this review concerns the characterisation of liquid ammonia fuel injection for combustion, including recent research findings from experimental and simulation studies. Liquid ammonia injection can result in the highly dynamic so-called ‘flashing’ or ‘flash boiling’ phenomena. Research findings have been drawn from other related applications such as accidental hazardous releases. Bespoke optical experimental rigs together with diagnostic techniques and two-phase CFD simulations have enabled studies of the flashing jets under various initial/final conditions, with recent work also examining ammonia spray combustion. The review concludes with an insight into future trends and requirements for liquid ammonia combustion. Reciprocating engines for marine propulsion are cited as potential early adopters of ammonia energy.
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Preliminary Characterization of Thermal Upgrading of Nickel from Saprolite via Selective Reduction
Available online: 30 January 2024More LessAbstract. The mineralogical properties and distribution of information established in saprolite from Indonesia were investigated using X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy energy dispersion spectroscopy (SEM–EDS), and differential thermal analysis (DTA) measurements. The findings suggest that laterite ore has a complex inner core. The percentages of Ni, Fe, Mg, Al, and Si in saprolite are given in 1.82, 30.47, 10-20, 4.86, and 8.1 weight percent. Saprolite has 53.1 percent iron oxide/oxyhydroxide, 38.3 percent lizardite and 8.7 percent silicate. According to DTA, saprolite undergoes a phase shift from goethite to hematite at low temperatures (200-300ºC). This is a suitable phase to optimize nickel diffusion in iron. Furthermore, the thermal upgrading approach was utilized for this saprolite.
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