Search Results (1,281)

Developing cost-effective alternatives to platinum-based catalysts remains paramount for commercializing anion exchange membrane fuel cells (AEMFCs). We report a metal-free nitrogen-doped carbon catalyst derived from a rationally designed polyurea–polyimine copolymer that outperforms commercial 20 wt% Pt/C in superior relative durability and methanol tolerance. Strategic integration of polyurea’s pore-forming capability with polyimine’s thermal stability enabled the synthesis of a catalyst (NC-1000N) featuring ultrahigh surface area (1276.5 m² g⁻¹), optimal nitrogen speciation (20.5% pyridinic-N, 45.3% graphitic-N), and enhanced graphitization, which improves the electrical conductivity of catalysts. NC-1000N exhibited exceptional oxygen reduction performance with an onset potential of 0.96 V, almost four-electron selectivity (n = 3.87), a medium Tafel slope (105 mV dec⁻¹), and minimal charge transfer resistance (46.74 Ω). When evaluated in single-cell AEMFCs, NC-1000N delivered a peak power density of 372.1 mW cm⁻², which is 26% higher than Pt/C at equivalent loading, while demonstrating superior stability (94.8% retention after 7 h) and complete methanol tolerance. Systematic pyrolysis temperature optimization (800–1000 °C) revealed critical structure–property relationships governing catalyst evolution from disordered precursor to highly graphitic, nitrogen-enriched carbon with precisely engineered active sites. This work establishes polymer-derived carbons and provides design principles for scalable synthesis of high-performance metal-free electrocatalysts for sustainable energy conversion technologies. Full article

Hydrogen (H₂) has emerged as a promising next-generation energy carrier with significant potential to mitigate climate change and environmental pollution. The hydrogen evolution reaction (HER) is the critical half-reaction directly responsible for hydrogen production. Efficient HER electrocatalysts must exhibit low overpotential values and fast reaction kinetics to achieve high catalytic performance. While platinum (Pt) remains the benchmark catalyst due to its ideal hydrogen adsorption energy, high electrical conductivity, and superior chemical stability, further innovations are essential. This review summarizes recent advances in Pt-based HER catalysts, focusing on two primary design strategies: metal-level engineering and support-level engineering. These approaches allow for precise control over electronic structures, active site distributions, and interfacial properties, paving the way for next-generation HER electrocatalysts. Full article

This paper presents the results of an experimental investigation of woody biomass combustion under real operating conditions of a heating boiler equipped with an integrated platinum-promoted oxidation catalyst (Pt-OX) and vanadium-based catalytic reactor (V-CAT) system for pollutant emission reduction, particularly nitrogen oxides (NO_x). Various configurations of the catalytic flue gas treatment system were investigated, including single-stage, dual-stage, and multi-stage vanadium- and platinum-based catalytic reactor arrangements. The investigated system incorporated platinum-promoted oxidation catalysts and a vanadium-based monolithic catalytic reactor. No external ammonia or urea injection was applied during the experimental campaign. Therefore, the catalytic system was evaluated under realistic biomass combustion conditions involving nitrogen-containing species naturally generated during fuel conversion processes. The obtained thermal and emission parameters were compared with those recorded during boiler operation without catalytic treatment. The investigated catalytic configurations significantly reduced pollutant emissions, with the highest-performing arrangement decreasing NO emissions from 112 ppm to 11 ppm, corresponding to a reduction efficiency exceeding 90%. The results demonstrate the potential of integrated catalytic reactor systems for improving the environmental performance of small-scale biomass-fired heating units operating under real conditions. Full article

Air temperature measurements in atmospheric environmental monitoring are susceptible to radiation-induced bias under natural ventilation. This study develops a low-power naturally ventilated air temperature sensor and a correction method combining computational fluid dynamics (CFD) with machine learning. The sensor integrates a Pt100 thin-film platinum resistance probe (Heraeus Holding GmbH, Hanau, Germany), symmetric guide plates, and a dual aluminum-plate radiation shield to reduce radiative heating while improving airflow around the probe. A three-dimensional fluid–solid coupled heat-transfer model was established in ANSYS FLUENT 15.0 to optimize guide-plate spacing and inclination angle and quantify the effects of solar radiation, long-wave radiation, scattered radiation, air density, wind speed, solar elevation angle, and surface albedo on radiation error. CFD results identified a guide-plate spacing of 24 mm and an inclination angle of 45° as the preferred parameters. A multilayer perceptron (MLP) model trained with CFD-derived data was validated in field experiments using a Model 076B aspirated radiation shield (Met One Instruments, Inc., Grants Pass, OR, USA) as the reference. The model predicted radiation error with a root mean square error (RMSE) of 0.052 °C, a mean absolute error (MAE) of 0.042 °C, and a correlation coefficient of 0.92. The proposed sensor and correction method provide a low-power and easy-to-maintain approach for reducing radiation-induced bias in naturally ventilated air-temperature measurements, with potential applications in meteorological observation, air-quality monitoring, and agricultural microclimate assessment. Full article

The development of highly efficient, stable, and cost-effective non-precious metal electrocatalysts to replace conventional platinum-based materials holds profound significance for accelerating the commercialization of advanced energy conversion devices, such as zinc–air batteries (ZABs). Herein, we propose a facile and highly efficient strategy to prepare a defect-rich, highly active nitrogen-doped porous carbon-based electrocatalyst (denoted U-Fe-N-C, urea-assisted iron–nitrogen–carbon material), via high-temperature co-pyrolysis of heme with urea. Our results demonstrate that urea not only serves as an excellent nitrogen source during pyrolysis, introducing abundant topological defects and heteroatom doping sites, but also induces the carbon substrate to form a hierarchical sponge-like porous structure with a high specific surface area. This unique microenvironment effectively prevents the agglomeration of iron species at high temperatures, achieving enhanced dispersion of iron species stabilized within the nitrogen-rich carbon matrix. Electrochemical evaluations reveal that under the optimal synthesis conditions (a precursor mass ratio of 1:3, calcination at 900 °C), U-Fe-N-C exhibits excellent oxygen reduction reaction (ORR) catalytic performance, delivering a half-wave potential of 0.731 V vs. RHE, and shows long-term operational durability that significantly surpasses that of commercial Pt/C. Furthermore, liquid rechargeable zinc–air batteries assembled with U-Fe-N-C as the air cathode deliver remarkable cycling stability, operating for up to 270 h of charge–discharge cycling without noticeable performance degradation. This study not only provides useful insights into the mechanisms of pore formation and assistance but also offers a practical perspective for the rational design and scalable synthesis of high-performance metal–nitrogen–carbon (M-N-C) electrocatalysts. Full article

Platinum ditelluride (PtTe₂) is an emerging topological semimetal with intriguing optoelectronic properties. Scalable and controllable growth techniques are fundamental for its technological exploitation. Here, we synthesize large-area PtTe₂ films by tellurization of pre-deposited platinum layers. By selectively modifying the tellurization parameters, we demonstrate the possibility of controlling the layer orientation of tellurized films and of introducing microscopic corrugation in the PtTe₂ film. The first result is obtained by increasing the thermal budget of the process, which changes PtTe₂ preferential crystalline orientation from (001) to (1−13)/(103) growth directions. The latter result is achieved by modifying the heating rate of the process at a fixed growth temperature equal to 550 °C. From the Raman analysis of a wrinkled sample, we find the coexistence of tensile and compressive strains depending on the corrugation site. The demonstrated control over grain orientation and microscopic corrugation provides a powerful strategy to tailor the structural and strain landscape of topological semimetals, providing a robust platform for strain engineering. Full article

Fluorescence resonance energy transfer (FRET) was implemented in a photonic crystal-structured oxygen sensing film by incorporating fluorescein isothiocyanate (FITC) with platinum octaethylporphyrin (PtOEP). The highest Stern-Volmer quenching constant (K_SV = 20.20 ± 0.25) and maximum quenching ratio (21.81 ± 0.21) were achieved at a PtOEP:FITC molar ratio of 1:1. Compared to the control, the K_SV and maximum quenching ratio increased by 56.8% and 48.4%, respectively. Additionally, imidazole was introduced into the oxygen-sensing film via a casting method. The results demonstrated that imidazole effectively modulates the energy transfer efficiency between oxygen molecules and PtOEP. Under 20% O₂ and 100% O₂ atmospheres, the fluorescence intensity of the imidazole-modified film increased by 18.4% and 52.4%, respectively. Furthermore, imidazole provided excellent protection for PtOEP, yielding a fluorescence retention rate of 99.77% ± 0.18%. Full article

Platinum group metals (PGMs: Pt, Pd, Rh, Ru, Os, Ir) are critical strategic metals. Spent automotive catalysts (SACs) represent one of the most significant secondary sources of PGMs, and their recovery is essential for alleviating the supply–demand imbalance. In the recycling chain, pyrometallurgical processing of SACs generates Fe-Si-based alloy concentrates (termed Fe−Si−PGMs), serving as an important yet challenging intermediate resource for PGM recovery. This review first summarizes the pyrometallurgical and hydrometallurgical processes used for recovering PGMs from SACs, before shifting its focus to the treatment technologies for PGMs in Fe–Si–PGMs alloy. These techniques, including direct extraction, extraction following desilication (via alkaline roasting, slagging, or hydrometallurgical routes), and in situ mechanochemical extraction, are critically evaluated in terms of their advantages and limitations. Furthermore, given that the accurate quantification of trace-level yet high-value PGMs represents another key challenge in the recovery chain due to complex sample matrices, this work systematically outlines and compares the analytical methods commonly employed, such as fire assay, spectroscopic and mass spectrometric techniques, electrochemical methods, and alkali fusion. Finally, several recommendations are provided regarding PGM recovery from SACs, with emphasis on Fe−Si−PGMs alloy processing and analytical methods for PGMs. Full article

A new method has been established for determining trace amounts of platinum in water using ion liquid (IL)-dispersive liquid–liquid microextraction (DLLME) combined with graphite furnace atomic absorption spectroscopy (GFAAS). The method is based on the use of a self-prepared reagent, 5-(5-cyano-2-pyridineazo)-2,4-diaminotoluene (5-CN-PADAT), as a chelating agent, which reacts with Pt(IV) to form a hydrophobic chelate. The extraction solvent is 1-octyl-3-methylimidazolium hexafluorophosphate ([C₈mim][PF₆]), and ethyl acetate is used as the dispersive solvent. After the extraction is completed, the extraction phase formed by [C₈mim][PF₆] and ethyl acetate has a relatively low viscosity and can be directly used for the determination of GFAAS. A single-factor rotational method was employed to optimize conditions affecting DLLME extraction efficiency. The interactions among the factors affecting DLLME were analyzed using response surface optimization (RSM). Under optimal conditions, platinum concentrations exhibited good linearity within the range of 40–280 ng/mL, with a detection limit of 0.3 ng/mL. AGREEprep was used to discuss the ecological friendliness of the method, demonstrating its low cost, ease of operation, simple equipment requirements, and environmental friendliness. When applied to determining trace amounts of platinum in water samples, the results were satisfactory. Full article

Azolium-derived metallates are well-established intermediates in metal–N-heterocyclic carbene chemistry; however, their potential as standalone therapeutic agents remains largely unexplored. Herein, we report the first systematic biological investigation of a diverse family of Au(I), Cu(I), Pt(II), Pd(II), and Ru(II) metallates paired with functionalized azolium cations. The complexes were synthesized quantitatively through a simple, atom-economical, and purification-free protocol under aerobic conditions in technical-grade green solvents. Structural characterization by multinuclear NMR spectroscopy and single-crystal X-ray diffraction confirmed metallate formation and enabled the first isolation and crystallographic characterization of unprecedented azolium-derived ruthenates. The antiproliferative activity of the complexes was evaluated against cisplatin-sensitive (A2780) and cisplatin-resistant (A2780cis) ovarian cancer cell lines, alongside non-cancerous MRC-5 fibroblasts. Backbone-functionalized derivatives emerged as the most potent compounds, displaying activities comparable or superior to cisplatin in A2780 cells and up to 1000-fold higher potency in the resistant A2780cis model. Notably, unlike cisplatin, the metallates retained nearly unchanged IC₅₀ values across both ovarian cancer lines, strongly suggesting resistance-evasive mechanisms of action. While benzylazido- and methyl guanosine-derived complexes generally exhibited lower overall potency, several members retained significant activity in resistant cells while showing markedly reduced toxicity toward normal fibroblasts, highlighting promising selectivity profiles. Ethoxide-functionalized derivatives and platinum-based metallates combined pronounced anticancer activity with favourable therapeutic windows. Overall, this work establishes azolium-derived metallates as a previously overlooked class of metal-based anticancer agents combining exceptional synthetic accessibility, broad structural tunability, and remarkable activity against platinum-resistant ovarian cancer. Full article

This paper presents a thermal and power characterization of the NVIDIA Jetson AGX Orin deployed in a realistic outdoor edge AI enclosure, integrated with power supplies, a Long Term Evolution (LTE) module, and a thermostat-controlled fan, across an ambient temperature range from −20 °C to +40 °C. The device was tested in a climate chamber under two workloads: a synthetic CPU and GPU stress test, and a YOLOv8s inference workload (TensorRT FP16, 640 × 640 input). Internal temperatures were recorded using four calibrated platinum Resistance Temperature Detectors (RTD)—PT100/PT1000, while Jetson chip temperatures and power consumption were logged via tegrastats and jtop. At sub-zero ambient temperatures, heat dissipated by the device itself kept all components within their operating ranges down to −20 °C. At the +40 °C setpoint, the stress test triggered Jetson thermal throttling at GPU and CPU temperatures of +95.6 °C and +99.0 °C, respectively. Under the same conditions, the YOLOv8s inference workload sustained 108.8 frames per second (FPS) at 19.1 W average power, approximately half of the 36.5 W consumed under the stress test, with chip temperatures well below the throttling threshold. These findings indicate that synthetic stress tests substantially overestimate the thermal and power demands of the tested inference workload, and that the enclosure retains sufficient thermal headroom for outdoor edge device deployment. Full article

Food safety problems caused by pesticide residues, heavy metals, foodborne pathogens, mycotoxins and other hazards seriously threaten public health. Traditional detection methods have the limitations of cumbersome operation, high cost and poor stability, which make it difficult to meet the needs of rapid and sensitive detection on site. As a new material, nanozymes have the advantages of high stability, low cost and high catalytic activity, showing great application potential in food safety analysis. Among them, gold–platinum (AuPt) bimetallic nanozymes have attracted much attention due to their synergistic catalytic effect, good biocompatibility and modifiability. In this paper, the synthesis methods of AuPt bimetallic nanozymes were systematically reviewed, including chemical reduction, sol–gel, microemulsion, electrochemical deposition, and so on. The control effect of AuPt bimetallic nanozymes on catalytic activity was discussed from the aspects of composition, morphology, structure, external environment and composites with other nanomaterials. The research progress of AuPt bimetallic nanozymes in the detection of pesticide and veterinary drug residues, heavy metal ions, mycotoxins, foodborne pathogens, food additives and food freshness was introduced. Finally, the challenges and future development of AuPt bimetallic nanozymes in food safety analysis were prospected, aiming to provide theoretical reference and design ideas for the construction of a high-performance food safety rapid detection platform. Full article

Cisplatin remains a widely used anticancer agent; however, its effectiveness can be influenced by systemic toxicity, resistance mechanisms, and interactions with exogenous compounds. Nicotinamide (vitamin B3), an NAD⁺ precursor and a commonly used dietary supplement, is involved in cellular metabolism, redox homeostasis, and DNA repair pathways, which may potentially modulate the cellular responses to Platinum-based agents. Here, we combine chemical synthesis, computational studies, spectroscopic analysis, and biological assays to investigate the molecular and biological aspects of Cisplatin–Nicotinamide interactions. A novel cis-[Pt(NH₃)₂NicotinamideCl]NO₃ complex was obtained and its structure analyzed. Density functional theory (DFT) calculations indicate a thermodynamically favorable coordination of Nicotinamide to the first hydrolysis product of Cisplatin (CisPt1) with binding energies comparable to those calculated for nucleobase coordination under the same theoretical conditions. In non-small cell lung cancer cell lines (A549 and PC-9), in vitro results suggest that Nicotinamide pre-treatment reduces Cisplatin cytotoxicity under specific experimental conditions, but the pre-formed complex does not exert anticancer effects. These data are consistent with a model in which Nicotinamide may interact with reactive Cisplatin species, potentially contributing to the reduced availability of reactive Platinum(II) species. This work provides mechanistic insight into potential drug–nutrient interactions involving Platinum-based chemotherapy and highlights the need for further investigation under clinically relevant conditions in the near future. Full article

Titanium implants can achieve higher osseointegration when covered with titania nanotubes (TNT). Given their specific morphology, titania nanotubes are excellent substrates for subsequent modifications. In addition to anti-inflammatory drugs, cytotoxic drugs can also be used. It can be achieved by simple physical adsorption of the drug molecules or by their covalent bonding to the surface using a bridging ligand such as (3-mercaptopropyl)trimethoxysilane (MPTMS), for example. The last method was used successfully before. The purpose of the study is to test different modifications of this method to analyze factors that will improve the studied methodology. The study compares two methods of TNTs modification with cisplatin (CDDP) and its oxalate analog (CDOP): drop casting (DC) and the application of MPTMS and its ethoxy analog, MPTES, as bridging ligands. Pluronic L-61 and alkaline Piranha solutions were used as surface activators for TNT. Both activators are effective. Analysis of the fabricated samples was executed using ATR, SEM, SEM/EDX, and AFM. Covalent bonding of Pt(II) complexes to the TNT arrays with a bridging ligand results in a homogeneous layer containing Pt(II) complexes. They release the surface within one hour (the mean values of the k_obs for both complexes release in PBS and water are 9 · 10⁻³ s⁻¹ and 4.8 · 10⁻³ s⁻¹, respectively). Loading the Pt(II) complexes by drop casting yields layers with higher Pt (II) concentration (ca. 7.5%wt vs. ca. 3.2%wt for the second method and its variants) but lower homogeneity. No distinct general trends in the release rate on the TNT diameter were detected. The results show that modifying Ti6Al4V implants with titania nanotubes and further modifying them with platinum(II) complexes yields materials that can serve as carriers for anticancer platinum-based drugs. Full article

The development of sustainable technologies capable of simultaneously addressing environmental pollution and renewable energy production remains a major scientific challenge. In this work, titanium dioxide nanoparticles (GTiO₂) were synthesized through a plant-extract-assisted route using Punica granatum (pomegranate) peel extract and subsequently modified with platinum nanoparticles (Pt NPs) to obtain an efficient photocatalyst for the photoreforming of organic pollutants. The resulting Pt-GTiO₂ material exhibited an anatase crystal structure with an average crystallite size of approximately 12 nm and a specific surface area of about 140 m² g⁻¹. Comprehensive characterization using XRD, BET, TEM, FTIR, Raman, and photoluminescence spectroscopy (PL) revealed favorable structural and optoelectronic properties that promote efficient charge separation. The photocatalytic performance of Pt-GTiO₂ was evaluated through the simultaneous degradation of 2-naphthol, a priority aromatic pollutant, and hydrogen evolution under simulated solar irradiation in anaerobic conditions. Under the investigated conditions, Pt-GTiO₂ effectively promoted 2-naphthol degradation, with substantial but incomplete mineralization, as confirmed by TOC removal. The synthesized catalyst showed degradation efficiency higher than Pt-UV100 and comparable to Pt-P25, while exhibiting superior hydrogen evolution when compared with Pt-P25. Mechanistic investigations combining scavenger experiments, electron paramagnetic resonance (EPR) spectroscopy, and the identification of reaction intermediates suggest that photogenerated holes play a major role in the initial oxidation step under the mechanistic test conditions. The detected intermediates indicate that photoreforming proceeds via multiple pathways, including hydroxylation, ring-opening, reduction, and fragmentation. These findings highlight the potential of biogenic TiO₂-based photocatalysts for converting hazardous organic pollutants into clean hydrogen fuel while simultaneously achieving wastewater purification, offering a promising route toward sustainable environmental and energy technologies. Full article