Use Of Platinum Group Metals Research Articles

Renaissance of Chlorine Evolution Reaction: Emerging Theory and Catalytic Materials.

Chlorine (Cl2) is one of the most important commodity chemicals that has found widespread utility in chemical industry. Most Cl2 is currently produced via the chlorine evolution reaction (CER) at the anode of chlor-alkali electrolyzers, for which precious group-metal-based mixed metal oxides (MMOs) have been used for more than half a century. However, MMOs suffer from the use of platinum-group metals, which are costly and scarce, and the selectivity issue arises from the parasitic oxygen evolution reaction. Over the last decade, the field of CER catalysis has seen dramatic advances in both the theory and discovery of new catalysts. Theoretical approaches have enabled a fundamental understanding of CER mechanisms and provided catalyst design principles. The exploration of new materials has led to the discovery of CER catalysts other than MMOs, including non-PGM-based oxides, atomically dispersed single-site catalysts, and organic molecules, with some of which following novel reaction pathways. This minireview provides an overview of the recent advances in CER electrocatalyst research and suggests future directions for this revitalized field.

Sustainability inspired fabrication of next generation neurostimulation and cardiac rhythm management electrodes via reactive hierarchical surface restructuring

Over the last two decades, platinum group metals (PGMs) and their alloys have dominated as the materials of choice for electrodes in long-term implantable neurostimulation and cardiac rhythm management devices due to their superior conductivity, mechanical and chemical stability, biocompatibility, corrosion resistance, radiopacity, and electrochemical performance. Despite these benefits, PGM manufacturing processes are extremely costly, complex, and challenging with potential health hazards. Additionally, the volatility in PGM prices and their high supply risk, combined with their scarce concentration of approximately 0.01 ppm in the earth’s upper crust and limited mining geographical areas, underscores their classification as critical raw materials, thus, their effective recovery or substitution worldwide is of paramount importance. Since postmortem recovery from deceased patients and/or refining of PGMs that are used in the manufacturing of the electrodes and microelectrode arrays is extremely rare, challenging, and highly costly, therefore, substitution of PGM-based electrodes with other biocompatible materials that can yield electrochemical performance values equal or greater than PGMs is the only viable and sustainable solution to reduce and ultimately substitute the use of PGMs in long-term implantable neurostimulation and cardiac rhythm management devices. In this article, we demonstrate for the first time how the novel technique of “reactive hierarchical surface restructuring” can be utilized on titanium—that is widely used in many non-stimulation medical device and implant applications—to manufacture biocompatible, low-cost, sustainable, and high-performing neurostimulation and cardiac rhythm management electrodes. We have shown how the surface of titanium electrodes with extremely poor electrochemical performance undergoes compositional and topographical transformations that result in electrodes with outstanding electrochemical performance.

Platinum Group Metals against Parasites: State of the Art and Future Perspectives

Background: Globally, parasitic diseases are considered among the neglected diseases. Clinically, several drugs are used in treatment, however due to drug resistance and multidrug resistance and the low investment in new research lines, there has been a failure in the treatment of parasitic illnesses. Objectives: The present mini-review is a comprehensive review of the use of platinum group metals as biological agents. It aims to establish the actual state of the art of these metal elements in the antiparasitic activity-specific area and define the future possibilities of action. Methods: The review comprises more than 100 research works done in this field. The differences between platinum group metals chemistry and their use as metal complexes with biological activity have been discussed. Results: This review highlighted the platinum group metal's potential as an antiparasitic agent for different diseases. Conclusion: The review will be helpful for the researchers involved in targeted drugs for parasitic disease therapy.

Efficient CO2 Conversion through a Novel Dual-Fiber Reactor System.

Carbon dioxide (CO2) can be converted to valuable organic chemicals using light irradiation and photocatalysis. Today, light-energy loss, poor conversion efficiency, and low quantum efficiency (QE) hamper the application of photocatalytic CO2 reduction. To overcome these drawbacks, we developed an efficient photocatalytic reactor platform for producing formic acid (HCOOH) by coating an iron-based metal-organic framework (Fe-MOF) onto side-emitting polymeric optical fibers (POFs) and using hollow-fiber membranes (HFMs) to deliver bubble-free CO2. The photocatalyst, Fe-MOF with amine-group (-NH2) decoration, provided exceptional dissolved inorganic carbon (DIC) absorption. The dual-fiber system gave a CO2-to-HCOOH conversion rate of 116 ± 1.2 mM h-1 g-1, which is ≥18-fold higher than the rates in photocatalytic slurry systems. The 12% QE obtained using the POF was 18-fold greater than the QE obtained by a photocatalytic slurry. The conversion efficiency and product selectivity of CO2-to-HCOOH were up to 22 and 99%, respectively. Due to the dual efficiencies of bubble-free CO2 delivery and the high QE achieved using the POF platform, the dual-fiber system had energy consumption of only 0.60 ± 0.05 kWh mol-1, 3000-fold better than photocatalysis using slurry-based systems. This innovative dual-fiber design enables efficient CO2 valorization without the use of platinum group metals or rare earth elements.

Comparative catalytic performance of PGM-nanoparticle-doped alumina Xerogels and aerogels for potential application in automotive pollution mitigation

The structural (low density, high porosity), thermal (low thermal conductivity, high temperature stability), and chemical (high degree of tailorability) properties of aerogels make them attractive in a range of applications, including catalysis. The automotive industry relies on three-way-catalysts (TWCs) for automotive pollution mitigation, and TWCs in turn depend heavily on the use of platinum group metals (PGMs). Reduction of the use of PGMs in TWCs would be advantageous. To investigate the effect of aerogel structure and processing on three-way catalytic performance we prepared alumina wet gels doped with ca. 15 nm rhodium and palladium nanoparticles and dried them (1) supercritically to form aerogels and (2) under ambient conditions to form xerogels. Nanoparticle concentration was adjusted to ensure that both forms of the catalyst (aerogel and xerogel) had the same volumetric concentration of PGM after calcination to 800°C. Powder x-ray diffraction and transmission electron microscopy (TEM) confirmed the presence of PGMs. TEM images showed PGM particle agglomeration on the order of 40 to 200 nm in both the aerogel and xerogel materials. Gas adsorption analysis indicated that the aerogels have a surface area of 460 m2/g with most pores in the 2- to 100-nm range, whereas the xerogel surface area was 170 m2/g with a narrow pore distribution around 10 nm. Catalytic performance tests under a range of simulated automotive operating conditions show that, in all cases, the aerogels outperformed the xerogels. The aerogel light-off temperatures (the temperature at which a 50 % conversion is achieved) were 45 to 120 °C lower for the conversion of HCs, 25 to 55 °C lower for the conversion of CO and 40 to 145 °C lower for the conversion of NO. This study provides direct evidence that aerogel processing of catalysts provides catalytic performance benefits separate from the underlying chemistry of the catalysts.

Cathode Catalyst Layer Design in PEM Water Electrolysis toward Reduced Pt Loading and Hydrogen Crossover.

Reducing the use of platinum group metals is crucial for the large-scale deployment of proton exchange membrane (PEM) water electrolysis systems. The optimization of the cathode catalyst layer and decrease of the cathode Pt loading are usually overlooked due to the predominant focus of research on the anode. However, given the close relationship between the rate of hydrogen permeation through the membrane in an operating cell and the local hydrogen concentration near the membrane-cathode interface, the structural design of the cathode catalyst layer is considered to be of pivotal importance for reducing H2 crossover, particularly in combination with the use of thin (≲50 μm) membranes. In this study, we have conducted a detailed investigation on the cathode structural parameters, covering the Pt wt % of the Pt/C electrocatalyst, the type of carbon support (Vulcan and high surface area carbon, HSAC), and the ionomer content, with a goal to reduce Pt loading to 0.025 mgPt/cm2 while minimizing the rate of cell hydrogen crossover. We found that the electrochemical performance is mainly influenced by the changes in the interfacial contact resistance due to variations in the cathode thickness. Both the Pt wt % in Pt/C and the ionomer content showed a positive correlation with the measured H2 in O2% in the anode outlet, whereas the Pt loading exhibited an opposite trend. The rate of hydrogen crossover was analyzed in relation to the calculated local volumetric current density within the cathode catalyst layer. Based on the obtained hydrogen mass transfer coefficient, a cathode catalyst layer comprising 40 wt % Pt on HSAC support with an ionomer-to-carbon (I/C) ratio of 0.35 was found to be an optimum configuration for achieving a low Pt loading of 0.025 mgPt/cm2 and a reduced rate of hydrogen crossover.

Green Chemistry of the Future: Co-Electrosynthesis of Biobased Platform Chemicals and Hydrogen

The European Green Deal sends a strong signal for a climate-friendly and CO2-neutral economy. An important aspect to support this is a sustainable and reduced use of resources as well as efficient and green conversion technologies for renewable value-added products. For this reason, electrosynthetic approaches become increasingly important, as electrochemistry fulfils several criteria of green chemistry and offers the possibility to directly use current from renewable energy sources [3]. However, electrolysis and electrosynthesis currently often require the use of platinum group metals (PGM) and need separators, which are mostly based on perfluorinated and polyfluorinated alkyl substances (PFSA). Classical water electrolysis for production of green hydrogen also requires high overvoltage’s, which is due to the oxygen evolution reaction (OER). This is where coupling systems come in, in which the sluggish OER is replaced by a thermodynamically more efficient reaction, such as the electrooxidation of organic substances (EOO). An example of this is the electrooxidation of biobased 5-HMF or various sugars (xylose, glucose) to platform chemicals. When coupled with the hydrogen evolution reaction (HER), the EOO of 5-HMF to 2,5-furandicarboxylicacid (FDCA) requires a theoretical cell voltage of 0.3 V. In contrast, theoretical cell voltages of 1.23 V are required for the OER/HER [5]. With the focus on sustainable and energy-efficient systems, the simultaneous production of platform chemicals and green H2 via paired electrolysis offers high potential. [1-7]Previous studies have mainly focused on electrode materials, morphology and its electrocatalytic activity in divided batch cells. A strongly alkaline environment is considered advantageous for the electro-organic oxidation reaction, while the HER is reported to be kinetically slower in alkaline than in acidic conditions. Overall, the coupled electrolysis of H2 and platform chemicals is described as a promising technology in the development stage. [5-7]In this context, the present research explores paired electrosynthesis of platform chemicals and H2 to advance sustainable and efficient energy sources. A central goal is the prototype development of an undivided flow reactor in TRL4. Particular attention will be paid to mild operating conditions (such as a mild-alkaline environment, low operating pressures and low temperatures), PGM-free catalysts and the elimination of PFSA materials. To achieve this goal, various milestones have been defined. Among them is the development of 3D electrodes with suitable and selective catalysts. These are to be electrochemically tested in a flow-through test cell on a laboratory scale. In order to create a basis for analysis, the electrode reactions were first investigated electrochemically in a typical divided H-cell and reference measurements were carried out on nickel-based materials. In this work, NiOOH sheet and foam electrodes were electrochemically produced and subsequently investigated by cyclic voltammetry (CV) followed by bulk electrolysis. On this basis, suitable analytics (HPLC, UV-VIS) were also determined to quantify and classify the derivatives of the electrosynthesis process. These pre-experiments form the basis for the ongoing development of initial concept ideas for a modular test cell that allows various materials and structures to be electrochemically investigated.Overall, this research contributes to advancing sustainable and efficient energy sources and enabling the production of platform chemicals from renewable raw materials. Acknowledgments The authors thank the European Union’s Horizon Europe research and innovation programme under grant agreement N° 101070856 ELOBIO (Electrolysis of Biomass) for funding.

Nitrogen-doped carbon as selectively permeable layer to enhance the anti-poisoning ability of hydrogen oxidation reaction catalysts for hydroxide exchange membrane fuel cells

The use of platinum group metals (PGMs) as the catalysts and the requirement of high purity H2 are the two aspects resulting in the high cost of the polymer electrolyte membrane fuel cells. Herein, we report that nitrogen-doped carbon encapsulated nickel nanoparticles (Ni@NC) as stable hydrogen oxidation reaction catalysts, which allows the use of PGM-free anode catalysts durably and feeding crude hydrogen. The hydroxide exchange membrane fuel cell using Ni@NC as the anode catalyst illustrates steady performance for more than 200 h, while the Ni/C cell fails within 7 h. The current density loss is less than 10% by feeding H2 with 100 ppm of CO for 24 h, which is much better than those using Pt/C or Ni/C. The anti-poisoning feature is attributed to the block effect of the NC shell, while the defects allow the permeation of H2, thus catalyzing the hydrogen oxidation reaction.

Thin-Film Heterostructures Based on Co/Ni Synthetic Antiferromagnets on Polymer Tapes: Toward Sustainable Flexible Spintronics.

Synthetic antiferromagnets with perpendicular magnetic anisotropy (PMA-SAFs) have gained growing attention for both conventional and next-generation spin-based technologies. While the progress of PMA-SAF spintronic devices on rigid substrates has been remarkable, only few examples of flexible thin-film heterostructures are reported in the literature, all containing platinum group metals (PGMs). Systems based on Co/Ni may offer additional advantages with respect to devices containing PGMs, i.e., low damping and high spin polarization. Moreover, limiting the use of PGMs may relieve the demand for critical raw materials and reduce the environmental impact of related technologies, thus contributing to the transition toward a more sustainable future. Here, we discuss for the first time the realization of Co/Ni-based PMA-SAFs on polymer tapes and exploit it to obtain flexible giant magneto-resistive spin valves (GMR-SVs) with perpendicular magnetic anisotropy. Several combinations of buffer and capping layers (i.e., Pt, Pd, and Cu/Ta) are also investigated. High-quality flexible SAFs with a fully compensated antiferromagnetic region and SVs with a sizable GMR ratio (up to 4.4%), in line with the values reported in the literature for similar systems on rigid substrates, were obtained in all cases. However, we demonstrate that PGMs allows achieving the best results when used as a buffer layer, while Cu is the best choice as a capping layer to optimize the properties of the stacks. We justify the role of buffer and capping layers in terms of different interdiffusion mechanisms occurring at the interface between the metallic layers. These results, along with the high robustness of the samples' properties against bending (up to 180°), indicate that complex and bendable Co/Ni-based heterostructures with reduced content of PGMs can be obtained on flexible tapes, allowing for the development of novel flexible and sustainable spintronic devices for applications in many fields including wearable electronics, soft robotics, and biomedicine.

Synthesis and Characterization of Core-Shell Cu-Ru, Cu-Rh, and Cu-Ir Nanoparticles.

Optimizing the use of expensive precious metals is critical to developing sustainable and low-cost processes for heterogeneous catalysis or electrochemistry. Here, we report a synthesis method that yields core-shell Cu-Ru, Cu-Rh, and Cu-Ir nanoparticles with the platinum-group metals segregated on the surface. The synthesis of Cu-Ru, Cu-Rh, and Cu-Ir particles allows maximization of the surface area of these metals and improves catalytic performance. Furthermore, the Cu core can be selectively etched to obtain nanoshells of the platinum-group metal components, leading to a further increase in the active surface area. Characterization of the samples was performed with X-ray absorption spectroscopy, X-ray powder diffraction, and ex situ and in situ transmission electron microscopy. CO oxidation was used as a reference reaction: the three core-shell particles and derivatives exhibited promising catalyst performance and stability after redox cycling. These results suggest that this synthesis approach may optimize the use of platinum-group metals in catalytic applications.

Exhaustive Syntheses of Deuterium-labelled Compounds

Deuterium (2H, D) is a stable isotope of hydrogen (1H). Deuterium-incorporated (labelled) compounds are widely utilized in various scientific fields such as mechanistic studies of organic reactions, elucidation of drug metabolism, application as tracers for microanalysis. Recently, development of heavy drugs and molecular imaging using techniques such as neutron scattering and Raman spectroscopy are spotlighted. We have developed various deuterium-incorporated compounds using D2O as an inexpensive deuterium source to construct novel functional materials. The use of platinum group metals on carbon as catalysts could result in the multi-deuteration of compounds in the mixed solvents of 2-propanol and D2O, and site-selectively deuterated compounds can be synthesized by organocatalytic methods. In this review, the latter deuteration methods using organocatalysts and their applications are summarized. Terminal alkynes smoothly underwent deuterium incorporation by using triethylamine as an organic base or a solid resin possessing the tertiary amine moiety in the same molecule to give mono-deuterated alkynes. These compounds were partially reduced over our prepared specific palladium catalyst under atmospheric D2 gas to produce tri-deuterated alkenes. Achiral or chiral di-deuterated β-nitro alcohols were also prepared by the organic-base-catalyzed deuteration of nitromethane, followed by nitroaldol reactions in a one pot manner. The mono-deuteration of aromatic aldehyde could be effectively catalyzed by N-heterocyclic carbene. Furthermore, the α-deuteration of aliphatic aldehydes using a basic resin catalyst and the subsequent Knoevenagel condensation with malononitrile could provide γ-deuterium-incorporated α,β-unsaturated nitrile derivatives. The deuterated compounds thus obtained can be important synthetic precursors to construct the deuterium-incorporated target functional materials.

Integrating trace amounts of Pd nanoparticles into Mo3N2 nanobelts for an improved hydrogen evolution reaction.

Significant efforts have been directed towards the use of transition metal nitrides as electrocatalysts for the hydrogen evolution reaction (HER). Molybdenum nitride, despite its potential for scalable production, suffers from the bottleneck of poor catalytic activity. Furthermore the kinetics of the water dissociation process ought to be improved for enhancing its potential. Here, we report a facile method for the incorporation of a trace amount of Pd nanoparticles into Mo3N2 nanobelts (0.75 Pd/Mo3N2) for an enhanced HER in both acidic and alkaline solutions. When employed for the HER, the 0.75 wt% Pd/Mo3N2 nanobelt delivers excellent catalytic activity with overpotentials of 45 and 65 mV in 0.5 M H2SO4 and 1 M KOH at a current density of 10 mA cm-2. As-prepared 0.75 wt% Pd/Mo3N2 displays a smaller Tafel slope and offers substantial stability in both acidic and alkaline media under the same operating conditions. The improved performance of the as-prepared 0.75 wt% Pd/Mo3N2 points to fast charge transfer, higher electrical conductivity and synergistic effects between Pd and Mo. This work displays a direct method for reducing the use and cost associated with the use of platinum-group metals while also delivering superior HER catalytic performance.

Tackling material constraints on the exponential growth of the energy transition

Tackling material constraints on the exponential growth of the energy transition

(Invited) Non-PGM Electrocatalysts for PEM Fuel Cells: Origin of Their Instability

Proton exchange membrane fuel cells (PEMFCs) have earned substantial commercial and government interests worldwide as highly promising renewable energy power sources for various applications (e.g., electric vehicles). However, a key contributor to their high cost remains the use of Platinum Group Metals (PGM) catalysts, especially at the cathode where the oxygen reduction reaction (ORR) is much more sluggish than the hydrogen oxidation reaction (HOR) occurring at the anode. The replacement of PGM catalysts by PGM-free catalysts at the cathode has so far been mainly hampered by the poor stability of the most active and performing PGM-free catalysts [1,2] that would otherwise become serious contenders to PGM catalysts. It is therefore important to determine the origin of the instability plaguing the PGM-free catalysts [3-8]. Based on our highly performing catalyst (Nature Commun., 2011, 2, 416) [2], INRS team has devoted, during recent years, much attention to the instability of this PGM-free catalyst [3-8]. This communication will present our very recent work on the catalyst stability which is summarized in two publications in Energy and Environmental Science [6, 8]. Our catalyst was obtained by ball milling ZIF-8, FeAc and 1,10 Phenanthroline, followed by two heat-treatments in Ar and in NH3. Via a systematic study of the instability behavior of the catalyst at different fuel cell potentials from 0.8 to 0.2 V at 80 °C and 25 °C, we discovered that the decay of the current density always involves the superposition of a fast and a slow exponential decay. With the combination of various characterization (e.g., BET, NAA and Mössbauer spectroscopy), we concluded that the fast exponential decay of the current density was the result of the specific demetalation of FeNx sites located in the micropores of the catalyst. Following this work, we explored the behavior of this catalyst before and after fluorination by F2 at room temperature. We discovered that all Fe-based catalytic sites were poisoned by reaction with F2, but not the ORR active CNx sites (and edge carbon sites) located at the surface of the catalyst carbonaceous support. Consequently, the instability behavior of fluorinated catalysts was found to be different from that of pristine catalyst, but similar to that of MOF_CNx_Ar+NH3 (a catalyst devoid of Fe, with only CNx sites and edge carbon sites). Further, the F2-poisoned catalysts can be partially reactivated under different heat-treatments. With a systematic study by fuel cell, BET, IR, TGA, XPS, XAS, as well as DFT and thermodynamic calculations, all the results demonstrate that the root-causes of instability of the FeN4 and CNx catalytic sites do not have the same origin. The two models (from INRS and Los Alamos) proposed so far to describe the instability curves of Fe-based catalysts will also be discussed.

Securing Platinum-Group Metals for Transport Low-Carbon Transition

Summary Fuel cell technology is the key to transport low-carbon transition. It depends on the catalysis from platinum-group metals, the rarest metals on Earth. However, due to the limited reserve, it is critical to evaluate whether global platinum resources can meet the increasing demand. This paper aims to account whether current platinum resources can support future fuel cell vehicle deployment for 140 countries for the period 2000–2100 by establishing a technology-rich, bottom-up model. It is found that, under a wide range of scenarios, the primary resource demand is significantly lower than the supply capacity at the global level. This result confirms that fuel cell vehicles have the potential to significantly contribute to global decarbonization strategies. However, challenges exist at regional and national levels. Most regions will rely heavily on resource import from the few countries with substantial resource endowments but with political instability, implying potential supply risks.

Cobalt oxide-based materials as non-PGM catalyst for HER in PEM electrolysis and in situ XAS characterization of its functional state

• Evaluation of cobalt oxide-based materials as cathode catalyst in PEM electrolyzer. • Optimum amount of carbon additive results in high performance. • Co 3 O 4 -based catalyst outperforms Pt at high cell potentials. • In situ XAS of Co 3 O 4 -electrode catalysts under PEM electrolysis conditions. • Dynamic changes of Co 2+ /Co 3+ fractions with temperature and applied potential. The polymer electrolyte membrane (PEM)-based electrolysis technology is a promising mean to split water and store renewable energy in the form of clean fuel, hydrogen. However, its high price due to the use of platinum group metals (PGMs) as catalyst materials generally makes the technology cost-restrictive. Herein we present the performance evaluation of cobalt oxide in PEM electrolysis as cathode catalyst where hydrogen evolution reaction (HER) takes place. Performance comparison of non-PGM catalysts (CoO, Co 3 O 4 and MoS 2 ) revealed that better performance was attained with Co 3 O 4 and it was further improved by mixing with an electrically conducting carbon material (Vulcan). An optimum amount of the carbon additive was found, and the best performance was recorded at 47 wt% Co 3 O 4 over the total amount. At 2.05 V, 47 wt% Co 3 O 4 -based catalyst (0.55 A/cm 2 ) outperformed 47 wt% MoS 2 -based one (0.51 A/cm 2 ). More importantly, the performance of the former at 2.3 V (1.12 A/cm 2 ) surpassed even that of Pt-black (1.11 A/cm 2 ). In situ XAS study of the Co 3 O 4 -based material under PEM electrolysis conditions revealed dynamic interchange of Co 3+ and Co 2+ fractions, which was attributed to ultimately boost the HER performance.

(Invited) How Can We Maintain the Excellent Performance of the PEM Electrolyzer without the Use of Platinum Group Metals?

The PEM electrolyzer is superior to the alkaline as well as the solid oxide electrolyzers when it comes to rate capability and practical footprint. The cell owes its attractive properties to the combination of a good oxygen reduction catalyst and a durable and highly conductive membrane. The story could end here and often it does, but it is important to realize that there is also a severe limitation to the large-scale roll-out of this system. It relies on platinum group metals for catalysts and in most cases also noble metal coatings of cell components to limit the contact resistance in the acidic environment. The noble metal issue (cost and availability) and the prospects for replacement of iridium oxide as oxygen catalyst are discussed. Platinum replacement is an active field within PEM fuel cell research. Why is that not the case to a similar extent for PEM electrolyzers? Finally, an alternative route to electrolyzers with rate capability like the PEM electrolyzers, but without the use of noble metals is suggested.

Life cycle impacts of three-way ceramic honeycomb catalytic converter in terms of disability adjusted life year

Abstract Catalytic converters in vehicles reduce emissions while the use of platinum group metals (PGMs) in them have negative health impacts both in the PGMs mining stage and at the end-of-life PGM recycling stage. This study was conducted to weigh the production-recycling phase impacts and the use phase benefits of a three-way honeycomb catalytic converter by using the disability adjusted life year (DALY) indicator over its cradle-to-cradle life cycle. We have combined the environmental life cycle assessment (LCA) approach with a method to account the workplace impact on human health, which may be adopted in social LCA. In general, a catalytic converter causes more loss of lives (11 days) then it saves (4.5 days) under the egalitarian value perspectives for the baseline production scenario with 160,000 km functional life. Contrary to that, under the same scenario and service life, the catalytic converter saves lives (5.5 days and approx. 6 days for the hierarchist and individualist perspectives, respectively) than it causes loss (about 1 day and 0.6 days for the hierarchist and individualist perspectives, respectively). The geographical hotspot analysis reveals that, while the catalytic converter save lives in Sweden where it is used; it causes more loss of lives elsewhere in the world, particularly in South Africa and Russia. Overall, the DALY varies between 0.62 days and 11.3 days, mainly due to differences in value perspectives. The study showed that increased use of recycled platinum group metals, extended functional life of the catalytic converter may alter the health balance of the product system. This human health-focused cradle to cradle life cycle case study identified methodological issues that need further attention, like development of occupational DALY characterization factors (CFs) for the countries involved in the production of three-way ceramic honeycomb catalytic converter, and emission DALY CFs for PGEs during the use phase of catalytic converter. From scenario analysis, it is observed that, the rise of electric vehicles may drastically alter the social lives lost impacts of catalytic converter.

Recycling of Palladium from Spent Catalysts Using Solvent Extraction—Some Critical Points

Electrical and electronics equipment and automotive and industrial catalysts are some examples of top technological devices whose functioning rely on the use of platinum-group metals (PGMs). The PGMs’ high economic value and difficult to replace technological properties, together with their scarcity in the Earth’s crust, justify concerns about their critical condition and reinforce the importance of developing recycling practices for PGM end-of-life materials. This article presents and discusses recent advances regarding the use of hydrometallurgical solvent extraction to recover one PGM, palladium, from spent catalysts. Two different tendencies are implicit in the literature concerning Pd(II) extraction: a few groups focus on the adjustment and optimization of current commercial extractants, while others prefer to design new extracting compounds. Actually, the leach solutions obtained from the treatment of anthropogenic materials generally exhibit different compositions when compared to those coming from the primary resources. The pros and cons of both approaches are critically discussed, and the assumptions backing some of the reported achievements are also appraised.

(Invited) Current Status on Ballard Fuel Cells and Future Catalyst Development

Hydrogen and fuel cell technologies offer a pathway to enable the use of clean energy systems to improve air quality, enhance energy security, and stimulate the global economy. Due to the significant advances in fuel cell technology over the last 25 years, fuel cells have become competitive in certain markets. Ballard Power Systems Inc. is recognized as a world leader in proton exchange membrane (PEM) fuel cell development and commercialization. At the heart of each Ballard PEM fuel cell product is a stack of unit cells based on Ballard’s proprietary technology, for unsurpassed performance, durability and versatility. Ballard draws on intellectual property together with unmatched know-how in key areas, including fuel cell MEA/stack development and systems integration. Ballard’s fuel cell products deliver the required functionality at the right scale with optimum performance and low lifecycle costs. This presentation will provide an overview of current status of Ballard fuel cell development. To enable wide-spread commercialization of fuel cells, particularly automotive applications, further cost reductions and durability improvements are still required. For longer term PEM fuel cell products, the catalyst is still a major cost factor due to the use of platinum group metals (PGMs). In addition to cost, these PGM catalysts have insufficient durability for certain long life applications, particularly at low catalyst loadings. Thus, the most significant remaining challenge for PEMFC catalysts will be to achieve excellent activity at low PGM loadings while also maintaining high durability/stability during operation. The advantages and possible limitations of various types of catalysts, such as Pt alloys (de-alloys), core-shell catalysts and shape-controlled nanocrystal catalysts will be assessed. This presentation will conclude with a discussion of potential future directions for PEMFC catalyst and catalyst layer research to help overcome the last remaining challenges of performance and durability and propel PEMFCs into the wider commercial market.