When aquatic exposure ends but effects persist: metal-dependent recovery dynamics.

Friction-induced electrochemical activation of platinum group metals via electromechanical coupling

Density functional theory and time-dependent calculations were performed to investigation the electronic interaction mechanisms between the anticancer drug Sunvozertinib and boron nitride (B12N12) nanocages encapsulated, and doped with Ni and Pt metals. Adsorption energies resulted displayed that Ni doping remarkably increases the thermodynamic stability and strengthens the chemical affinity of the complex, while Pt doping shows little weaker yet still favorable adsorption compared to the minimal physisorption seen with the encapsulated and pristine BN systems. Analysis of quantum reactivity descriptors and frontier orbitals sugested a reduced band gap and notable charge transfer in the doped B12N12 nanocages, indicating modified electronic conductivity and potential applications in sensing. Also, TD-DFT absorption spectra demonstrated red-shifted transitions upon drug adsorption, affirming orbital coupling between the drug molecule and dopant sites. Supplementary investigations, including density of states (DOS) and reduced density gradient (RDG) approaches, displayed evidence of partially covalent interactions specifically in the Ni-doped model. Analysis of Electron localization function (ELF) maps indicated sharing of localized electron. Collectively, these findings propose that Ni-doped B12N12 nanocages are an excellent platform for efficient drug loading and controlled delivery of Sunvozertinib drug. Against, encapsulated BN nanocages act as inert systems suitable for sustained drug release purposes.

Electrocatalysts, suitable for at-scale applications, must integrate high activity, long-term durability, and cost-effectiveness, with the latter presenting a major challenge for platinum-group-metal (PGM) electrocatalysts. Alkaline systems enable the use of cost-effective transition metals. However, developing non-PGM electrocatalysts that can catalyze the high-potential oxygen evolution reaction (OER) with high stability remains challenging. Here, we report on metallic Ni catalysts with a Co- and Fe-rich shell (Ni@FeCo), which, during OER operation, transforms into an active oxide shell. Anion exchange membrane water electrolyzers (AEMWEs) employing Ni@FeCo catalysts exhibited excellent performance, reaching 10 A cm-2 at 2.18 V. Operando X-ray characterizations revealed the oxidation of Co and Fe, while Ni remained mostly metallic across all AEMWE operating potentials. Structural characterization, by scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS), revealed that the active Ni@FeCo catalysts feature a metallic Ni core and a Ni-Fe-Co spinel oxide shell. This metal-core/oxide-shell heterostructure provides efficient electron transport and OER activity while remaining stable under AEMWE operating potentials. The Ni@FeCo catalysts operated stably for over 1700 h in an AEMWE, highlighting their potential for practical applications and demonstrating a viable strategy for designing nonprecious metal-based electrocatalysts.

Electronic regulation of Fe-N5 sites via Zn coordination for high-efficiency oxygen reduction and rechargeable zinc-air batteries.

The escalating world demand for strategic metals like Cu, Co, and Ni calls for efficient and environmentally friendly extraction methods to overcome traditional sulfide ore processing limitations. The conventional pyrometallurgical and acid-based hydrometallurgical routes are hampered by high energy requirements, environmental degradation, and poor metal yields due to passivation layers and undesired gangue reactions, or poor flotation recoveries to produce smeltable concentrates due to magnesium and iron constraints. This research examines alkaline glycine-based leaching as an alternative hydrometallurgical process to recover Cu, Co, and Ni from low-grade polymetallic sulfide ores (2.21% Ni, 0.18% Co, 0.45% Cu, P80 (80 should be a subscript)), which often contain platinum group metals as well. The research aimed to develop an integrated approach to recover these metals from low-grade concentrates. The primary operating parameters, such as glycine-to-Ni molar ratio, pH regulators, dissolved oxygen (DO) concentration, agitation speed, solids ratio, and temperature, were evaluated to determine the extraction of the metals. The results showed that when the glycine/Ni molar ratio was 6:1, double the stoichiometric requirement for the formation of the anionic tris-glycinato Ni (II) and Co(II) complexes, the extraction of Ni and Co was 82.3% and 82%, respectively. In contrast, the extraction of Cu was greater at lower glycine concentrations at the initial leaching stages. Dissolved oxygen (DO) concentration had a major influence on metal recovery, with the maximum extraction being 69.1% Ni, 65.3% Co, and 76.3% Cu at 25 mg/L DO. Optimization of 400 rpm stirring rates enhanced mass transfer and oxygen consumption by 30% from sub-optimal stirring rates. Cu and Co recovery by sodium sulfide precipitation was more than 99.9% Cu, and 98.9% Co. Nickel precipitation was not as effective because, presumably, back-oxidation of nickel sulfides in alkaline conditions occurred. This effect, coupled with the presence of Platinum Group Metals (PGMs), indicates that higher temperature and nitrogen purging would be necessary to improve Ni recovery. The implications of these observations identify the potential for glycine-based leaching to be used as a green, selective, and efficient process to treat refractory sulfide ores with higher recovery of metal content and enhanced sustainability compared to conventional extraction routes. • Alkaline glycine leaching enabled high base metal extraction, achieving 82.3% Ni, 82.0% Co, and 76.3% Cu. • Dissolved oxygen significantly enhanced metal recovery, increasing Ni extraction from 42.6% (no DO) to 69.1% (25 ppm DO). • Glycine leaching accommodated up to 30% solids content, maintaining high extraction efficiencies and reducing processing costs. • Copper recovery via sodium sulfide precipitation exceeded 99.9%, while Co recovery reached 98.9%, demonstrating effective downstream metal recovery.

Tunable wettability of Chitosan-Biochar composites for Oil-Water separation and noble metal recovery.

Rational design of metal nanoclusters for environmental monitoring: A review.

Tailored recovery of platinum group metals by co‑treatment of spent automotive catalysts and copper dross

The distribution and geochemical controls of platinum-group elements in Iranian ophiolitic chromites

The ease of hydrogen-activation by platinum-group metals in combination with metal nanoparticle-halloysite support interactions impactsthe catalytic hydrogenation of tetrasubstituted alkenes. Thus, Pd, Pt, and Ru nanoparticles were synthesized in a one-pot process using quinidine as a stabilizer,immobilized on halloysite nanotubes at low and high metal loadings. Structural analysesrevealed that low metal loading favors small, well-dispersed nanoparticles, whereas higher loading induces aggregation except for Ru. Among all materials, Pd-A (4.1 wt% Pd) displayed the best balance between particle size and homogeneous distribution on the support, resulting in the highest catalytic activity and chemoselectivity. Moreover, Pd-A enables the hydrogenation of sterically demanding endocyclic and exocyclic oxazolidinones under mild conditions (3bar H2, 80 °C-100 °C), affording the corresponding saturated products with completesyn-diastereoselectivity. Deuteration studies using multi-nuclear NMR demonstrate that hydrogenation of the endocyclic oxazolidinone proceeds via direct addition to the tetrasubstituted C═C bond, accompanied by benzylic H/D exchange arising from C-H activation. Overall, the study of the catalytic activity of the as-prepared metal nanocomposites in terms of reactivity and selectivity permitted to conclude that Pd-A, a zero-valent Pd-halloysite nanocomposite, is the best heterogeneous catalyst of the series in terms of activity and selectivity for the hydrogenation of sterically hindered alkenes.

Precise control over morphology and alloy configuration is essential for addressing complex reactions, such as the electrochemical CO2 reduction reaction (CO2RR), which proceeds through multiple intermediates and requires enhanced selectivity, activity and stability. However, achieving simultaneous regulation of these two structural features remains a formidable challenge. Here we report novel shape-controlled Cu-based solid-solution surface-alloy nanocrystals composed of Cu nanocube (NC) cores surrounded by atomically alloyed platinum-group metal shells (Cu/Cu1−xMx NCs, M = Pd, Pt, Ir, Ru) that alter CO2RR performance of Cu. In particular, surface alloying of Cu NCs with Ir switched product selectivity from C2H4 to HCOOH. Cu/Cu1−xIrx NCs exhibited superior HCOOH activity and stability compared with a Sn catalyst, which is a well-known element for producing HCOOH. Furthermore, Ir surface alloying preserved the cubic morphology of Cu NCs, whereas pure Cu degraded into nanograins. Our findings highlight a valuable approach to controlling reaction pathways through heteroatom interfaces and to designing highly active and stable electrocatalysts.

Platinum-group-metal (PGM) nanomaterials are prominent in chemical and energy conversions. To date, their scalable manufacturing is confined by complex post-processing or high-temperature calcination (≥ 800°C), which are often required for conventional small-sized nanoparticles. Herein, we have successfully developed a thermal buffer-assisted low-temperature (250°C) calcination strategy to create a sub-nano Ru metallene called "Ru clusterrene" for anion exchange membrane water electrolysis (AEMWE). The rational use of NaCl is pivotal for successful synthesis, serving as a "buffer" to prevent thermal runaway. Consequently, the Ru clusterrene exhibits an ultra-thin, fluid-like structure that enables strong interaction with the substrate and ensures maximized active site exposure. Importantly, this strategy costs only US$39.42/gRu, which is substantially lower than that of commercial Ru/C (Premetek, US$1407.50/gRu). The Ru clusterrene delivers an outstanding activity of 1.73 V@2 A cm‒2 and 2.0 V@5.4 A cm‒2, as well as an unprecedented stability for 1000h at 2 A cm‒2 (80°C) and 3500h at 1 A cm‒2 (50°C). More significantly, it exhibits a high stack performance in AEMWE (3.6 V@1 A cm‒2 and 2000 h@25 A), representing the most advanced level for AEMWE cathodecatalyst.

ABSTRACT This study presents an optimised hydrometallurgical method for the recovery and separation of platinum group metals (PGMs) – platinum (Pt), palladium (Pd), and rhodium (Rh) – from spent automotive catalysts using an HCl–H₂O₂ leaching system followed by selective precipitation. Batch leaching experiments were conducted to assess the effects of key parameters, including HCl/H₂O₂ ratio, acid concentration, temperature, and leaching time. Maximum leaching efficiencies of 92.4% for Pd, 90.8% for Pt, and 79.6% for Rh were achieved under 9 M HCl, 0.8 vol.% H₂O₂, and 60°C. Kinetic analysis showed a first-order reaction model, with Pd dissolving fastest (k = 1.76 h−¹) and Rh the slowest (k = 0.66 h−¹). Thermodynamic evaluation indicated that Rh dissolution is more energy-demanding (ΔH = 17343 J/mol, ΔS = 49.64 J/mol·K). Selective precipitation yielded 99.5% Pt, 99.3% Pd, and 95.4% Rh. The novelty of this work lies in the integration of kinetic and thermodynamic modelling, providing a deeper understanding of the dissolution behaviour of Pt, Pd and particularly Rh, which has been challenging to recover efficiently in previous studies. This method offers an environmentally friendly, efficient alternative to conventional pyrometallurgical and ammonia-based methods for PGMs recovery from secondary resources.

ABSTRACTBackgroundThe role of carboplatin in neoadjuvant chemotherapy for triple‐negative breast cancer (TNBC) remains controversial, particularly in settings where access to immunotherapy is limited. This study evaluated the real‐world impact of adding carboplatin to neoadjuvant chemotherapy on pathological complete response (pCR) and survival outcomes in patients with TNBC.MethodsThis retrospective multicenter study included patients with nonmetastatic TNBC treated with neoadjuvant anthracycline‐ and taxane‐based chemotherapy between 2018 and 2023 at three oncology centers in Turkey. Patients were grouped according to receipt of platinum‐containing therapy. Survival outcomes were estimated using the Kaplan–Meier method and compared with the log‐rank test. Cox regression analyses were performed to evaluate factors associated with survival. Propensity score matching was also performed as a supportive analysis.ResultsA total of 142 patients were included, of whom 45 (32.2%) received platinum‐containing neoadjuvant chemotherapy. Overall, 80 patients (56.3%) achieved pCR. The pCR rate was significantly higher in the platinum group than in the non‐platinum group (68.9% vs. 50.5%, p = 0.031). After a median follow‐up of 57 months, 24 deaths and 33 DFS events were observed. Median OS and DFS were not reached. The 60‐month OS rate was 96.0% in the platinum group and 73.9% in the non‐platinum group (log‐rank p = 0.027), whereas the 60‐month DFS rates were 86.1% and 67.6%, respectively (log‐rank p = 0.139). Patients who achieved pCR had significantly better OS and DFS than those with residual disease. In the propensity score‐matched cohort, non‐platinum treatment remained associated with inferior OS and DFS.ConclusionsIn this multicenter real‐world cohort, carboplatin was associated with a higher pCR rate and numerically favorable survival outcomes. These findings may be clinically relevant where immunotherapy is not readily accessible but should be considered hypothesis‐generating and require prospective validation.

The retreatment of secondary tailings for platinum group metals recovery presents a range of potential challenges, which vary depending on the nature of the original ore and the type of pretreatment it was subjected to. These challenges include the prevalence of ultrafine particles, which promote slimes coatings on valuable minerals, hinder bubble-particle attachment, increase pulp viscosity, and lead to higher gangue entrainment; surface oxidation of minerals, which alters their floatability; and the presence of deleterious gangue minerals and residual platinum group metal species that are inherently difficult to recover by flotation. This study compares the batch flotation performance across a range of tailings samples from the eastern and western limbs of the Bushveld Complex. A complementary mineralogical analysis was conducted to gain deeper insights into mineral behaviour. The paper evaluates these findings to identify the key factors contributing to poor platinum group metal performance.

Herein, we report the dynamic nucleation and growth behavior of individual hydrogen microbubbles on a thin-film Pt ultramicroelectrode (UME). By depositing and patterning a thin layer of platinum metal on a transparent, conductive, but electrocatalytically inert indium-tin oxide (ITO) substrate, we are able to obtain individual Pt UMEs and use them to image hydrogen microbubbles formed by the hydrogen evolution reaction (HER) in an acid solution. The use of reflection microscopy and the semitransparent Pt UME allows us to observe hydrogen microbubbles as they nucleate on the UME surface, track their growth with time, and image their movement and bubble-bubble interaction on the electrode. Our results show that H2 microbubbles formed on a Pt UME tend to move toward the center of the microelectrode as they grow bigger in size and extend their contact area on the electrode. Our results suggest multiple microbubbles forming on the same electrode compete with each other for bubble growth, following a mechanism similar to Ostwald ripening.

Expensive platinum group metals (PGMs) are used to enhance the anodic oxygen evolution reaction (OER) kinetics, and they represent a real bottleneck in the commercialization of anion exchange membrane water electrolyzers (AEMWEs). Therefore, we present a scalable and economical homogeneous precipitation method to synthesize NixFe1‐xO nanoparticles with different Ni/Fe ratios, while reducing the dependence on expensive PGM‐based electrocatalysts. The effects of Ni/Fe ratios in the synthesized NixFe1‐xO, along with morphological and surface chemical characteristics, on electrocatalytic performance were thoroughly investigated with half‐cell measurements. Furthermore, critical electrode design factors, that is, ink composition and electrocatalyst loading, were scientifically investigated and optimized. Among the explored compositions, amorphous Ni0.28Fe0.72O and crystalline Ni0.66Fe0.34O exhibited superior OER activity, achieving mean overpotentials of 359 mV and 359.1 mV at 10 mA cm−2, respectively. This superior activity was attributed to a higher concentration of Ni3+ (NiOOH), a highly active compound for OER. These high‐performing samples were integrated as anodes in a lab‐scale AEMWE for device‐level evaluation. Ni0.28Fe0.72O achieved the highest performance at 80 °C, by delivering the current density of 7.81 A cm−2 against a cell voltage of 2.2 V. Whereas, Ni0.66Fe0.34O achieved a current density of 6.49 A cm−2 at 2.2 V. Both samples exhibited excellent stability during short‐term durability tests (ca. 90 h) at 1 A cm−2 and 80°C.

Many materials, including those containing platinum group elements and noble metals, form nanometer-thick plates (nanoplates) in a range of natural environments, including ore deposits and serpentinites. Materials research uses metallic nanoplates, such as 2D metal oxide/sulfide in applications ranging from superconductors to biomedical engineering, because of their unique properties. A few techniques with sufficient spatial resolution can analyze these nanomaterials, such as nano-secondary ion mass spectroscopy. An alternative is atom probe tomography (APT), which provides in situ major and trace element data with nanometer-scale resolution and can analyze nanoplates. This research describes a novel method to produce APT samples from geological nanoplates using focused ion beam (FIB) lift-out. The redeposited material is used to fill voids at the interface between the plate and the substrate, consolidating the wedge that is lifted out for analysis. A case study of APT specimen preparation from a ∼500-nm-thick FeS plate, separated from an olivine substrate, by voids, ≤20 µm3 in volume, is described. The method produces robust specimens that yield millions of atoms during APT analysis. This method can be applied to nanoplates of different compositions and thicknesses from a broad range of materials, and to free-standing films supported by window structures.

ABSTRACT Proton exchange membrane fuel cells hold immense potential for sustainable hydrogen energy utilization but face commercialization barriers due to reliance on costly platinum‐group‐metal (PGM) catalysts. Among PGM‐free alternatives, Fe‒N‒C catalysts have emerged as leading candidates due to their high oxygen reduction reaction activity; however, they suffer from rapid performance decay during initial operation. Understanding the degradation mechanisms of Fe‒N‒C catalysts is crucial for improving their stability and enabling their commercialization. Major degradation pathways include the demetalation of active sites, oxidation of carbon support, and collapse of triple‐phase boundaries. However, these pathways’ driving forces, temporal sequences, and relative contributions under varying operating conditions remain unclear. This review synthesizes pioneering studies elucidating the multiscale degradation pathways in Fe‒N‒C fuel cells, emphasizing the role of advanced characterization techniques in disentangling mechanistic complexities. By correlating structural evolution timelines with impacts of intrinsic structures and operational parameters, we establish a framework to guide targeted stabilization strategies, helping to address critical knowledge gaps toward durable Fe–N–C fuel cells.