Search

Realization of the full potential of single‐atom photoelectrocatalysts in sustainable energy generation requires careful consideration of the design of the host material. Here, a comprehensive methodology for the rational design of photoelectrocatalysts using anodic titanium dioxide (TiO2) nanofilm as a model platform is presented. The properties of these nanofilms are precisely engineered to elucidate synergies across structural, chemical, optoelectronic, and electrochemical properties to maximize the efficiency of the hydrogen evolution reaction (HER). These findings clearly demonstrate that thicker TiO2 nanofilms in anatase phase with pits on the surface can accommodate single‐atom platinum catalysts in an optimal configuration to increase HER performance. It is also evident that the electrolyte temperature can further enhance HER output through thermochemical effect. A judicious design incorporating all these factors into one system gives rise to a ten‐fold HER enhancement. However, the reusability of the host photoelectrocatalyst is limited by the leaching of the Pt atom, worsening HER. Density‐functional theory calculations have provided insights into the mechanism underlying the experimental observations in terms of moderate hydrogen adsorption and enhanced gas generation. This improved understanding of the critical factors determining HER performance in a model photoelectrocatalyst paves the way for future advances in scalable and translatable photoelectrocatalyst technologies. [ABSTRACT FROM AUTHOR]

In this paper, platinum nanoparticles with a size of less than 50 nm were rapidly and successfully synthesized in low-temperature molten salt using a microwave method. The morphology and structure of the product were characterized by SEM, TEM, EDX, XRD, etc. The TEM and SEM results showed that the prepared product was a nanostructure with concave and uniform size. The EDX result indicated that the product was pure Pt, and the XRD pattern showed that the diffraction peaks of the product were consistent with the standard spectrum of platinum. The obtained Pt/C nanoparticles exhibited remarkable electrochemical performance in a formic acid catalytic oxidation reaction (FAOR), with a peak mass current density of 502.00 mA·mg−1Pt and primarily following the direct catalytic oxidation pathway. In addition, in the chronoamperometry test, after 24 h, the mass-specific activity value of the Pt concave NPs/C catalyst (10.91 mA·mg−1Pt) was approximately 4.5 times that of Pt/C (JM) (2.35 mA·mg−1Pt). The Pt/C NPs exhibited much higher formic acid catalytic activity and stability than commercial Pt/C. The microwave method can be extended to the preparation of platinum-based alloys as well as other catalysts. [ABSTRACT FROM AUTHOR]

The growing demand for hydrogen–air fuel cells with a proton-exchange membrane has increased interest in the development of scalable technologies for the synthesis of Pt/C catalysts that will allow us to fine-tune the microstructure of such materials. We have developed a new in situ technique for controlling the kinetics of the transformation of a platinum precursor into its nanoparticles and deposited Pt/C catalysts, which might be applicable during the liquid-phase synthesis in concentrated solutions and carbon suspensions. The technique is based on the analysis of changes in the redox potential and the reaction medium coloring during the synthesis. The application of the developed technique under conditions of scaled production has made it possible to obtain Pt/C catalysts with 20% and 40% platinum loading, containing ultra-small metal nanoparticles with a narrow size distribution. The electrochemically active surface area of platinum and the mass activity of synthesized catalysts in the oxygen electroreduction reaction have proved to be significantly higher than those of commonly used commercial analogs. At the same time, despite the small size of nanoparticles, the catalysts' degradation rate turned out to be the same as that of commercial analogs. [ABSTRACT FROM AUTHOR]

Internal combustion engine fueled by carbon-free hydrogen (H2-ICE) offers a promising alternative for sustainable transportation. Herein, we report a facile and universal strategy through the physical mixing of Pt catalyst with zeolites to significantly improve the catalytic performance in the selective catalytic reduction of nitrogen oxides (NOx) with H2 (H2-SCR), a process aiming at NOx removal from H2-ICE. Via the physical mixing of Pt/TiO2 with Y zeolite (Pt/TiO2 + Y), a remarkable enhancement of NOx reduction activity and N2 selectivity was simultaneously achieved. The incorporation of Y zeolite effectively captured the in-situ generated water, fostering a water-rich environment surrounding the Pt active sites. This environment weakened the NO adsorption while concurrently promoting the H2 activation, leading to the strikingly elevated H2-SCR activity and N2 selectivity on Pt/TiO2 + Y catalyst. This study provides a unique, easy and sustainable physical mixing approach to achieve proficient heterogeneous catalysis for environmental applications. The integration of Pt-oxide catalyst systems with zeolites demonstrates considerable promise for reducing nitrogen oxide emissions at low temperatures from fossil-fuel or hydrogen-powered internal combustion engines. [ABSTRACT FROM AUTHOR]

To reduce the manufacturing cost of polymer electrolyte membrane fuel cells (PEMFCs), tests targeting the decrease of reaction temperature and the amount of reducing agent in the polyol method for the synthesis of Pt/C catalysts were conducted. The reaction temperature in the polyol method was changed from 50 to 160 °C. Through XRD and TGA, it was determined that the reduction of platinum ions by the oxidation of ethylene glycol started at 70 °C. Below a 60 °C reaction temperature, Pt (1 1 1) peaks in XRD were barely visible, indicating that no deposition occurred. TEM revealed that Pt particles were well-dispersed above a 100 °C reaction temperature. For manufacturing platinum catalysts using the polyol method, it was found that 100 °C is the optimal synthesis temperature. Additionally, it was found that similar performance can be achieved by adding water to decrease the amount of ethylene glycol during synthesis. Finally, considering various analyses, it is evident that the dispersion, size, and crystallinity of platinum particles had the most significant impact on performance. [ABSTRACT FROM AUTHOR]

The S-doped PtMn concave cubes enclosed with high index facet and regulatable surface strain are successfully fabricated by two steps hydrothermal method. The PtMnS 1.1 catalyst exhibits superior catalytic properties for ethanol electrooxidation reaction in acidic and alkaline media, which is ascribed to the optimal surface strain and unsaturated surface-active sites. [Display omitted] Surface strain engineering has proven to be an efficient strategy to enhance catalytic properties of platinum (Pt)-based catalysts for electrooxidation reactions. Herein, the S-doped PtMn concave cubes (CNCs) enclosed with high index facets (HIFs) and regulatable surface strain are successfully fabricated by two steps hydrothermal method. The S element with electrophilic property can modify the near-surface of PtMn nanocrystals, altering the electronic structure of Pt to effectively regulate the adsorption/desorption of intermediates in the ethanol electrooxidation reaction (EOR). The PtMnS 1.1 catalyst with optimal surface strain delivered extraordinary catalytic performance on EOR in acidic media, with a specific activity of 2.88 mA/cm2 and mass activity of 1.10 mA/μg Pt , which is 4.1 and 2.2 times larger than that of state-of-the-art Pt/C catalyst, respectively. Additionally, the PtMnS 1.1 catalyst also achieve excellent catalytic properties in alkaline electrolyte for EOR. The results of kinetic studies indicated that the surface strain and modified electronic structure can degrade the activation energy barrier during the process of EOR, which is beneficial for enhance the reaction rate. This work provides a promising approach to construct highly efficient electrocatalysts with tunable surface strain effects for clean energy electro-chemical reactions. [ABSTRACT FROM AUTHOR]

The oxygen reduction reaction (ORR) catalyzed by efficient and economical catalysts is critical for sustainable energy devices. Although the newly-emerging atomically dispersed platinum catalysts are highly attractive for maximizing atomic utilization, their catalytic selectivity and durability are severely limited by the inflexible valence transformation between Pt and supports. Here, we present a structure by anchoring Pt atoms onto valence-adjustable CuOx/Cu hybrid nanoparticle supports (Pt1-CuOx/Cu), in which the high-valence Cu (+2) in CuOx combined with zero-valent Cu (0) serves as a wide-range valence electron reservoir (0‒2e) to dynamically adjust the Pt 5d valence states during the ORR. In situ spectroscopic characterizations demonstrate that the dynamic evolution of the Pt 5d valence electron configurations could optimize the adsorption strength of *OOH intermediate and further accelerate the dissociation of O = O bonds for the four-electron ORR. As a result, the Pt1-CuOx/Cu catalysts deliver superior ORR performance with a significantly enhanced four-electron selectivity of over 97% and long-term durability. The electrochemical oxygen reduction reaction catalyzed by efficient and economical catalysts is critically important for sustainable energy devices. Here the authors report anchoring Pt atoms onto valence-adjustable CuOx/Cu hybrid nanoparticle to dynamically tune the Pt 5d valence states at the initial reaction stage for optimizing oxygen reduction performance. [ABSTRACT FROM AUTHOR]

This document discusses the importance of renewable and sustainable energy sources in light of the negative impact of fossil fuels on climate change. It focuses on the development of advanced catalytic materials for fuel cells, batteries, electrolysers, and solar cells. The research explores various types of fuel cells and investigates the mechanisms and kinetics of energy conversion reactions. Specific contributions include the oxidation of borohydride and the oxygen evolution reaction. The document also explores the use of PET bottle waste and perovskite-structured catalysts for energy conversion. The goal is to develop cost-effective and efficient catalysts for renewable energy generation and storage. The article discusses several studies on the development of catalytic materials for energy conversion reactions. These studies highlight the importance of diverse catalysts in renewable energy applications. [Extracted from the article]

Solar and wind energy for water electrolysis are gaining interest in contemporary times. In this context, platinum catalysts are commonly recognized as the standard for the hydrogen evolution reaction (HER), yet their effectiveness is constrained by their high cost and inadequate stability. Combining Ru and Ni lowers the material expense and greatly improves the electrocatalytic performance. Therefore, in the present study, a 3D nanostructured amorphous RuO2 aerogel is doped with various concentrations of Ni for enhanced HER activity. The results indicate that the 4% Ni‐RuO2 aerogel exhibits a 0D colloidal network featuring interconnected mesopores, with a high specific surface area of 241.5 m2·g−1. In addition, the 4% Ni‐RuO2 aerogel catalyst exhibits the lowest overpotentials of 63 and 122 mV at current densities of 10 and 50 mA·cm−2, respectively, along with enhanced hydrogen adsorption activity for the HER due to the 3D porous structure of the aerogel. However, a further increase in Ni doping leads to a decrease in HER activity due to a reduction in the number of catalytic Ru sites. The study found that doping with the optimum amount of Ni causes a redistribution of charges on the sample surface, thereby uncovering more reaction sites and enhancing the electrocatalytic performance. [ABSTRACT FROM AUTHOR]

UV-activated catalytic hydrosilation is a low-temperature crosslinking process that has attracted attention for its high efficiency and lower energy demand relative to thermal curing. In this study, formulations comprising industrially relevant model silanes and Pt photocatalysts trimethyl(methylcyclopentadienyl)platinum(IV) and trimethyl(pentamethylcyclopentadienyl)platinum(IV) (MeCpPtMe3 and Cp*PtMe3, respectively) were prepared with and without a photosensitizer (PS) and assessed for catalytic performance by a novel strategy. Photopolymerizations were initiated using different wavelengths from LEDs and monitored in real-time using an Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) "well" strategy to track the degree of cure in ultra-thin films by consumption of hydride via the disappearance of the Si-H bending absorption band at 915 cm−1. Irradiation of formulations with 365 nm excitation showed higher conversions relative to 400 nm light and improvements to calculated initial reaction rates by incorporation of a PS suggested increased sensitization to 365 nm irradiation. To the best of our knowledge, this is the first study to report catalytic performance, electronic absorption spectroscopic data, and the crystal structure of Cp*PtMe3. [ABSTRACT FROM AUTHOR]

Search for a Platinum metal-free catalyst for Proton Exchange Membrane Fuel Cells (PEMFCs) is a concern to scientists as the Pt-catalyzed electrode comprises about 45% of the entire fuel cell stack cost. Due to layered structure, Two-dimensional (2D) MoS2 nanostructured materials have recently drawn attention as effective catalysts for oxygen reduction reaction (ORR). The 1T-phase of MoS2 (1T-MoS2) has higher electronic conductivity than the 2H-phase (2H-MoS2); high surface area 1T-MoS2 can have high electrocatalytic activity towards PEFFCs. Here, we report hydrothermally synthesized 2H-MoS2 and solvothermally synthesized mixed 1T/2H-MoS2 phases as a catalyst for ORR in PEM Fuel Cells. Owing to the high BET-specific surface area, hybrid 1T/2H-MoS2 showed better ORR activity than 2H-MoS2. The limiting current density of the 1T/2H-MoS2 hybrid structure is ‒7.1 mA cm−2 compared to Pt/C (‒8.2 mA cm−2) at 1600 rpm. The Tafel slope values of 2H-MoS2, 1T/2H-MoS2, and Pt/C are 92.7 mV dec−1, 57.5 mV dec−1, and 39.3 mV dec−1, respectively. The electron transferred during ORR are 3.8 and 1.8, respectively, for 1T/2H-MoS2 and 2H-MoS2 (in 0.1 M KOH) ; suggesting less formation of undesirable peroxide formation than 2H-MoS2. The 1T/2H-MoS2 displays better electrochemical durability compared to 2H-MoS2 (after 2000 CV cycles). [ABSTRACT FROM AUTHOR]

[Display omitted] • Pt-NiCoMnO 4 catalysts are firstly prepared for FA oxidation in air. • 1 %Pt-NiCoMnO 4 achieves 100 % FA conversion at RT (GHSV: 5,964 h−1). • FA is converted into CO 2 with diverse forms of intermediates, e.g., DOM and HCOO–. • FA and O 2 are adsorbed preferably on the Pt and nearby Ni sites, respectively. • Platinum-nickel sites offer favorable electronic structures for FA oxidation. Formaldehyde (FA), a carcinogenic oxygenated volatile organic compound, is present ubiquitously in indoor air. As such, it is generally regarded as a critical target for air quality management. The oxidative removal of FA under dark and room-temperature (RT) conditions is of practical significance. A series of ternary nickel–cobalt-manganese oxide–supported platinum catalysts (Pt/NiCoMnO 4) have been synthesized for FA oxidative removal at RT in the dark. Their RT conversion values for 50 ppm FA (X FA) at 5,964 h−1 gas hourly space velocity (GHSV) decrease in the following order: 1 wt% Pt/NiCoMnO 4 (100 %) > 0.5 wt% Pt/NiCoMnO 4 (25 %) > 0.05 wt% Pt/NiCoMnO 4 (14 %) > NiCoMnO 4 (6 %). The catalytic performance of 1 wt% Pt/NiCoMnO 4 has been examined further under the control of various process variables (e.g., catalyst mass, flow rate, relative humidity, FA concentration, time on stream, and molecular oxygen content). The catalytic oxidation of FA at low temperatures (e.g., RT and 60 °C) is accounted for by Langmuir–Hinshelwood mechanism (single-site competitive-adsorption), while Mars van Krevelen kinetics is prevalent at higher temperatures. In situ diffuse-reflectance infrared Fourier-transform spectroscopy reveals that FA oxidation proceeds through a series of reaction intermediates such as DOM, HCOO–, and CO 3 2–. Based on the density functional theory simulations, the unique electronic structures of the nearest surface atoms (platinum and nickel) are suggested to be responsible for the superior catalytic activity of Pt/NiCoMnO 4. [ABSTRACT FROM AUTHOR]

For di-nitroaromatics hydrogenation, it is a challenge to achieve the multi-step hydrogenation with high activity and selectivity due to the complexity of the process involving two nitro groups. Consequently, many precious metal catalysts suffer from low activity for this multi-step hydrogenation reaction. Herein, we employ a fully exposed Pt clusters catalyst consisting of an average of four Pt atoms on nanodiamond@graphene (Ptn/ND@G), demonstrating excellent catalytic performance for the multi-step hydrogenation of 2,4-dinitrotoluene. The TOF (40647 h−1) of Ptn/ND@G is significantly superior to that of single Pt atoms catalyst, Pt nanoparticles catalyst, and even all the known catalysts. Density functional theory calculations and absorption experiments reveal that the synergetic interaction between the multiple active sites of Ptn/ND@G facilitate the co-adsorption/activation of reactants and H2, as well as the desorption of intermediates/products, which is the key for the higher catalytic activity than single Pt atoms catalyst and Pt nanoparticles catalyst. Hydrogenating di-nitroaromatics with high activity and selectivity is challenging due to the process's complexity. Here the authors present a fully exposed Pt clusters catalyst for 2,4-dinitrotoluene hydrogenation, suggesting that the synergy between multiple active sites and moderate adsorption behavior is crucial for the high catalytic activity. [ABSTRACT FROM AUTHOR]

Metal–support interaction plays a critical role in determining the eventual catalytic activity of metals loaded on supporting substrates. This interaction can sometimes cause a significant drop in the metallic property of the loaded metal and, hence, a drop in catalytic activity in the reactions, especially in those for which low charge carrier transfer resistance is a necessary parameter. Therefore, there should be a case-by-case experimental or theoretical (or both) in-depth investigation to understand the role of support on each metal. Here, onto a layered porous carbon nitride (g-CN), we grew single crystalline Pt nanodisks (Pt@g-CN) with a lateral average size of 21 nm, followed by various characterisations such as electron microscopy techniques, and the measurement of electrocatalytic activity in the O2 reduction reaction (ORR). We found that intercalating Pt nanodisks in the g-CN interlayers causes an increase in electrocatalytic activity. We investigated the bonding mechanism between carbon support and platinum using density functional theory and applied the d-band theory to understand the catalytic performance. Analysis of Pt's density of states and electronic population across layers sheds light on the catalytic behaviour of Pt nanoparticles, particularly in relation to their thickness and proximity to the g-CN support interface. Our simulation reveals an optimum thickness of ~11 Å, under which the catalytic performance deteriorates. [ABSTRACT FROM AUTHOR]

In this work, the electrochemical oxidation of carbohydrates (glucose, fructose, and sucrose) was induced at the interface of Pt-nanoparticles supported on different carbon-based materials as carbon vulcan (C) and carbon black (CB). It was found that the support plays an important role during carbohydrates electro-oxidation as demonstrated by electrochemical techniques. In this context, current-concentration profiles of the redox peaks show the behavior of the pathways at carbohydrates-based solutions. Herein, the trend of current measured was glucose > sucrose > fructose, attributed to differences in the organic functional groups and chain-structure. Raman, XRD, SEM-EDS and XPS put in clear important structural, morphological, and electronic differences linked with the intrinsic nature of the obtained material. Differential Electrochemical Mass Spectroscopy (DEMS) indicated that the selectivity and the conversion of the formed reaction products during oxidation is linked with the catalyst nature (distribution, particle size) and the interaction with the carbon-based support. [ABSTRACT FROM AUTHOR]

Increased demand for ethylene has motivated direct ethane dehydrogenation over Pt-based catalysts. PtSn/γ-Al2O3 and PtSnZnCa/γ-Al2O3 catalysts were investigated with the aim of understanding the effect of the pretreatment environment on the state of dispersed Pt for ethane dehydrogenation. The catalysts were prepared by the impregnation method and pretreated in different environments like static air (SA), flowing air (FA), and nitrogen (N2) atmospheres. A comprehensive characterization of the catalysts was performed using Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), Temperature-Programmed Reduction (TPR), NH3 Temperature-Programmed Desorption (NH3-TPD), X-ray photoelectron spectroscopy (XPS), and Transmission Electron Microscopy (TEM) techniques. The results reveal that the PtSn on Al2O3 catalyst pretreated in the static air environment (PtSn-SA) exhibits 21% ethylene yield with 95% selectivity at 625 °C. XPS analysis found more platinum and tin on the catalyst surface after static air treatment. The overall acidity of the catalysts decreased after thermal treatment in static air. Elemental mapping demonstrated that Pt agglomeration was pronounced in catalysts calcined under flowing air and nitrogen. These factors are responsible for the enhanced activity of the PtSn-SA catalyst compared to the other catalysts. The addition of Zn and Ca to the PtSn catalysts increases the yield of the catalyst calcined in static air (PtSnZnCa-SA). The PtSnZnCa-SA catalyst showed the highest ethylene yield of 27% with 99% selectivity and highly stable activity at 625 °C for 10 h. [ABSTRACT FROM AUTHOR]

Background: Biogeochemical processing of metals including the fabrication of novel nanomaterials from metal contaminated waste streams by microbial cells is an area of intense interest in the environmental sciences. Results: Here we focus on the fate of Ce during the microbial reduction of a suite of Ce-bearing ferrihydrites with between 0.2 and 4.2 mol% Ce. Cerium K-edge X-ray absorption near edge structure (XANES) analyses showed that trivalent and tetravalent cerium co-existed, with a higher proportion of tetravalent cerium observed with increasing Ce-bearing of the ferrihydrite. The subsurface metal-reducing bacterium Geobacter sulfurreducens was used to bioreduce Ce-bearing ferrihydrite, and with 0.2 mol% and 0.5 mol% Ce, an Fe(II)-bearing mineral, magnetite (Fe(II)(III)2O4), formed alongside a small amount of goethite (FeOOH). At higher Ce-doping (1.4 mol% and 4.2 mol%) Fe(III) bioreduction was inhibited and goethite dominated the final products. During microbial Fe(III) reduction Ce was not released to solution, suggesting Ce remained associated with the Fe minerals during redox cycling, even at high Ce loadings. In addition, Fe L2,3 X-ray magnetic circular dichroism (XMCD) analyses suggested that Ce partially incorporated into the Fe(III) crystallographic sites in the magnetite. The use of Ce-bearing biomagnetite prepared in this study was tested for hydrogen fuel cell catalyst applications. Platinum/carbon black electrodes were fabricated, containing 10% biomagnetite with 0.2 mol% Ce in the catalyst. The addition of bioreduced Ce-magnetite improved the electrode durability when compared to a normal Pt/CB catalyst. Conclusion: Different concentrations of Ce can inhibit the bioreduction of Fe(III) minerals, resulting in the formation of different bioreduction products. Bioprocessing of Fe-minerals to form Ce-containing magnetite (potentially from waste sources) offers a sustainable route to the production of fuel cell catalysts with improved performance. [ABSTRACT FROM AUTHOR]

Membrane materials with osmium nanoparticles have been recently reported for bulk membranes and supported composite membrane systems. In the present paper, a catalytic material based on osmium dispersed in n–decanol (nD) or n–dodecanol (nDD) is presented, which also works as an emulsion membrane. The hydrogenation of p–nitrophenol (PNP) is carried out in a reaction and separation column in which an emulsion in the acid-receiving phase is dispersed in an osmium nanodispersion in n–alcohols. The variables of the PNP conversion process and p–aminophenol (PAP) transport are as follows: the nature of the membrane alcohol, the flow regime, the pH difference between the source and receiving phases and the number of operating cycles. The conversion results are in all cases better for nD than nDD. The counter-current flow regime is superior to the co-current flow. Increasing the pH difference between the source and receiving phases amplifies the process. The number of operating cycles is limited to five, after which the regeneration of the membrane dispersion is required. The apparent catalytic rate constant (kapp) of the new catalytic material based on the emulsion membrane with the nanodispersion of osmium nanoparticles (0.1 × 10−3 s−1 for n–dodecanol and 0.9 × 10−3 s−1 for n–decanol) is lower by an order of magnitude compared to those based on adsorption on catalysts from the platinum metal group. The advantage of the tested membrane catalytic material is that it extracts p–aminophenol in the acid-receiving phase. [ABSTRACT FROM AUTHOR]

Graphene is a good support for immobilizing catalysts, due to its large theoretical specific surface area and high electric conductivity. Solid chemical converted graphene, in a form with multiple layers, decreases the practical specific surface area. Building pores in graphene can increase specific surface area and provide anchor sites for catalysts. In this study, we have prepared porous graphene (PG) via the process of equilibrium precipitation followed by carbothermal reduction of ZnO. During the equilibrium precipitation process, hydrolyzed N,N-dimethylformamide sluggishly generates hydroxyl groups which transform Zn2+ into amorphous ZnO nanodots anchored on reduced graphene oxide. After carbothermal reduction of zinc oxide, micropores are formed in PG. When the Zn2+ feeding amount is 0.12 mmol, the average size of the Pt nanoparticles on PG in the catalyst is 7.25 nm. The resulting Pt/PG exhibited the highest turnover frequency of 511.6 min−1 for ammonia borane hydrolysis, which is 2.43 times that for Pt on graphene without the addition of Zn2+. Therefore, PG treated via equilibrium precipitation and subsequent carbothermal reduction can serve as an effective support for the catalytic hydrolysis of ammonia borane. [ABSTRACT FROM AUTHOR]

Purpose: Bacterial infections pose a serious threat to human health. For many years, there has been a search for materials that would inhibit their development. It was decided to take a closer look at various elastomeric materials with the addition of chitosan. Mixtures based on silicone, silicone with a platinum catalyst, acrylonitrile-butadiene rubber, natural rubber, and ethylene-propylene-diene rubber were developed and tested for antibacterial and physico-mechanical properties. The dispersion of chitosan in the elastomer was also investigated using a scanning electron microscope. Of the tested mixtures, three were selected, characterised by the best antibacterial and physico-mechanical properties and a very good dispersion of chitosan in the matrix. The mixtures were based on silicone, silicone with a platinum catalyst and natural rubber. Tests were performed to measure the release of compounds into water for these mixtures. Furthermore, cytotoxicity with L929 cells and cytocompatibility in direct contact with MG63 cells were investigated for silicone samples. The results showed that these materials were not toxic to mammalian cells and supported their growth. The best bactericidal properties against E. coli and S. aureus strains compared to the other tested materials (>99.0-99.9% of killed bacteria) were shown by samples made of silicone and silicone with a platinum catalyst and added chitosan. At the same time, the best physico-mechanical properties were found for the samples with chitosan based on silicone with added platinum and natural rubber. Developed materials appeared to be good candidates for manufacturing medical equipment on which the adhesion and growth of bacteria should be prevented. [ABSTRACT FROM AUTHOR]

Modification of the interfacial oxygen atom in the PdSn alloy significantly enhances the electrocatalytic activity of the oxygen reduction reaction, which has demonstrated exceptional performance in zinc-air batteries. [Display omitted] Modifying the surface of a catalyst with heteroatoms can regulate the interfacial atomic valence state and adjust the charge distribution, which is promising for obtaining desirable platinum carbon catalyst (Pt/C)-matched oxygen reduction reaction (ORR) catalytic performance. Here, we developed an efficient method to access O-rich crystalline interfacial-exposed palladium-tin alloy (1 1 1) crystal surfaces [Pd 3 Sn (1 1 1)] for highly efficient ORR via direct reduction of Pd/Sn metal salt species that are well dispersed in a nitrogen, phosphorus-doped carbonaceous (NPC) substrate. In addition to the other materials, preembedded Pd/Sn metal salt species in NPC control the release of metal sources upon reduction in the liquid phase, resulting in the grafting of an as-prepared PdSn alloy with many merits, such as efficient electron conduction, short-range crystallinity and increased crystal interface exposure. The presence of a considerable quantity of oxygen atoms at the interface of small-sized PdSn alloys on NPC substrates has been methodically verified by powder X-ray diffraction, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy characterizations. The PdSn-O sample exhibited excellent ORR activity, achieving an onset potential of ∼0.99 V and a half-wave potential of ∼0.88 V at 1600 rpm in O 2 -saturated 1.0 M KOH. Density functional theory simulations of pure Pd, Pd-O, the PdSn alloy and PdSn-O suggest that interfacial oxygen atom modification is responsible for the significantly improved ORR activity. The assembled zinc-air battery provides a high specific power of 218.9 mW cm−2 and a specific capacity of 810.6 mAh g Z n - 1. Our approach has the potential to stimulate the preparation of O-rich crystalline interfacial-exposed alloy compounds for other energy conversion applications. [ABSTRACT FROM AUTHOR]

Aqueous-phase reforming (APR) is an attractive process to produce bio-based hydrogen from waste biomass streams, during which the catalyst stability is often challenged due to the harsh reaction conditions. In this work, three Pt-based catalysts supported on C, AlO(OH), and ZrO2 were investigated for the APR of hydroxyacetone solution in a fixed bed reactor at 225 °C and 35 bar. Among them, the Pt/C catalyst showed the highest turnover frequency for H2 production (TOF of 8.9 molH2 molPt -1 min -1) and the longest catalyst stability. Over the AlO(OH) and ZrO2 supported Pt catalysts, the side reactions consuming H2, formation of coke, and Pt sintering result in a low H2 production and the fast catalyst deactivation. The proposed reaction pathways suggest that a promising APR catalyst should reform all oxygenates in the aqueous phase, minimize the hydrogenation of the oxygenates, maximize the WGS reaction, and inhibit the condensation and coking reactions for maximizing the hydrogen yield and a stable catalytic performance. [ABSTRACT FROM AUTHOR]

Proton-exchange membrane fuel cells are one of the most promising energy conversion technologies for both automotive and stationary applications. Scientists are testing a number of solutions to increase the durability of cells, especially catalysts, which are the most expensive component. These solutions include, among others, the modification of the composition and morphology of supported nanoparticles, the platinum–support interface, and the support itself. A detailed understanding of the mechanism of platinum degradation and the subsequent improvement of the durability of the entire cell requires the development of methods for effectively monitoring the behavior of catalytic nanoparticles under various cell operating conditions. The Identical-Location Transmission Electron Microscopy (IL-TEM) method makes it possible to visually track structural and morphological changes in the catalyst directly. Because the tests are performed with a liquid electrolyte imitating a membrane, they provide better control of the degradation conditions and, consequently, facilitate the understanding of nanoparticle degradation processes in various operating conditions. This review is primarily intended to disseminate knowledge about this technique to scientists using electron microscopy in the study of energy materials and to draw attention to issues related to the characterization of the structure of carbon supports. [ABSTRACT FROM AUTHOR]

A bimetallic AuNTP@Pt-IR808 nanoplatform with photothermal-promoted CAT/POD dual-enzyme activity was constructed for enhanced PTT/PDT/catalytic therapy. [Display omitted] Ultrasmall platinum (Pt) nanozymes are used for catalytic therapy and oxygen (O 2)-dependent photodynamic therapy (PDT) by harnessing the dual-enzyme activities of catalase (CAT) and peroxidase (POD). However, their applications as nanocatalysts are limited due to their low catalytic activity. Herein, we constructed a photothermal-promoted bimetallic nanoplatform (AuNTP@Pt-IR808) by depositing ultrasmall Pt nano-islands and modifying 1-(5-Carboxypentyl)-2-(2-(3-(2-(1-(5-carboxypentyl)-3,3-dimethylindolin-2-ylidene)ethylidene)-2-chlorocyclohex-1-en-1-yl)vinyl)-3,3-dimethyl-3H-indol-1-ium bromide (IR808) on gold nanotetrapod (AuNTP) with CAT/POD activities to enhance PDT/catalytic therapy. In the tumor microenvironment, the ultrasmall Pt can catalyze endogenous hydrogen peroxide (H 2 O 2) to produce O 2 , relieving tumor hypoxia and enhancing the PDT performance. Moreover, AuNTP integration into the bimetallic nanoplatform showed good electron transfer properties and promoted the POD activity of ultrasmall Pt. Importantly, AuNTP@Pt-IR808 possessed higher photothermal conversion performance than single AuNTPs, which enhanced photothermal therapy (PTT). It also accelerated the CAT/POD dual-enzyme activities, and promoted the generation of singlet oxygen (1O 2) and hydroxyl radical (OH). By enhancing the performances of PTT/PDT/catalytic therapy, the developed AuNTP@Pt-IR808 nanoplatform demonstrated good antitumor efficacy against breast cancer. [ABSTRACT FROM AUTHOR]

This research highlights the synthesis of carbon nanostructures using the catalytic chemical vapor deposition (CCVD) method, a hybrid process combining chemical vapor deposition (CVD) and Gas-Solid Heterogeneous Catalysis (GSHC). Intermetallic catalysts, LaNi 5 Pt x (x = 0, 0.05, 0.5, 1.0), were fabricated through an arc melting procedure to serve as templates for the catalytic conversion of carbon precursors into solid materials. These catalysts, featuring the ferromagnetic transition metal Ni, tend to aggregate into larger particles, reducing the rate of hydrocarbon cracking at the catalyst surface. Rare earth metals like Lanthanum were introduced to form an alloy with a higher melting point to prevent thermal aggregation. Additionally, Pt was incorporated to modify the catalytic properties of the alloy. The study primarily explores the impact of catalyst composition on carbon nanotube (CNT) production. The introduction of platinum content to the catalyst influences the rate at which Ni is filled. The research aimed to alter the catalyst's composition by varying platinum doping in the Pauli paramagnetic lanthanum nickel alloy (LaNi 5) to understand the growth mechanism and morphological variations of Ni-filled CNTs. Platinum and lanthanum oxides significantly influence nickel filling in CNTs, resulting in an increased filling rate as the catalyst's Pt content varies from 0 to 1.0. However, higher Pt doping content disrupts the CNT structure with spontaneous nickel encapsulation. [ABSTRACT FROM AUTHOR]

Biowaste-derived carbon materials are a sustainable, environmentally friendly, and cost-effective way to create valuable materials. Activated carbon can be a supporting material for electrocatalysts because of its large specific surface area and porosity. However, activated carbon has low catalytic activity and needs to be functionalized with heteroatoms, metals, and combinations to improve conductivity and catalytic activity. Ruthenium (Ru) catalysts have great potential to replace bench market catalysts in hydrogen evolution reaction (HER) applications due to their similar hydrogen bond strength and relatively lower price. This study reports on the synthesis and characterizations of carbon-supported Ru catalysts with large surface areas (~ 1171 m2 g−1) derived from coffee waste. The uniformly dispersed Ru nanoparticles on the porous carbon has excellent electrocatalytic activity and outperformed the commercial catalyst platinum on carbon (Pt/C) toward the HER. As-synthesized catalyst needed only 27 mV to reach a current density of 10 mA cm−2, 58.4 mV dec−1 Tafel slope, and excellent long-term stability. Considering these results, the Ru nanoparticles on coffee waste-derived porous carbon can be utilized as excellent material that can replace platinum-based catalysts for the HER and contribute to the development of eco-friendly and low-cost electrocatalyst materials. [ABSTRACT FROM AUTHOR]

Background: The efficacy of subsequent therapy after poly-ADP-ribose polymerase (PARP) inhibitor maintenance treatment has raised concerns. Retrospective studies show worse outcomes for platinum-based chemotherapy after progression of PARP inhibitor-maintenance therapy, especially in BRCA-mutant patients. We aimed to describe subsequent therapy in ovarian cancer patients after PARP inhibitor-maintenance therapy and evaluate their response to treatment. We focused on chemotherapy for patients with a progression-free interval (PFI) of ≥ 6 months after prior platinum treatment, based on BRCA status. Methods: We analyzed real-world data from Peking University Cancer Hospital, subsequent therapy after progression to PARP inhibitor-maintenance therapy for epithelial ovarian cancer between January 2016 and December 2022. Clinicopathological characteristics and treatment outcomes were extracted from medical records. The last follow-up was in May 2023. Results: A total of 102 patients were included, of which 29 (28.4%) had a germline BRCA1/2 mutation and 73 (71.6%) exhibited BRCA1/2 wild-type mutations. The PARP inhibitors used were Olaparib (n = 62, 60.8%), Niraparib (n = 35, 34.3%), and others (n = 5, 4.9%). The overall response rate (ORR) was 41.2%, and the median time to second progression (mTTSP) was 8.1 months (95%CI 5.8–10.2). Of 91 platinum-sensitive patients (PFI ≥ 6 months) after progression to PARP inhibitor-maintenance therapy, 65 patients subsequently received platinum regimens. Among them, 30 had received one line of chemotherapy before PARP inhibitor-maintenance therapy. Analysis of these 30 patients by BRCA status showed an ORR of 16.7% versus 33.3% and mTTSP of 7.1 (95% CI 4.9–9.1) versus 6.2 months (95% CI 3.7–8.3, P = 0.550), for BRCA-mutant and wild-type patients, respectively. For the remaining 35 patients who had received two or more lines of chemotherapy before PARP inhibitor-maintenance therapy, ORR was 57.1% versus 42.9%, and mTTSP was 18.0 (95% CI 5.0–31.0) versus 8.0 months (95% CI 4.9–11.1, P = 0.199), for BRCA-mutant and wild-type patients, respectively. Conclusion: No differences in survival outcomes were observed among patients with different BRCA statuses. Furthermore, for patients who had undergone two or more lines of chemotherapy before PARP inhibitor maintenance therapy, no negative effects of PARP inhibitors on subsequent treatment were found, regardless of BRCA status. [ABSTRACT FROM AUTHOR]

Catalytic oxidation is widely recognized as a highly effective approach for eliminating highly toxic CO. The current challenge lies in designing catalysts that possess exceptional low-temperature activity and stability. In this work, we have prepared ultrafine platinum particles of ~1 nm diameter dispersed on a MgFe2O4 support and found that the addition of 3 wt.% FeOx into the 3Pt/MgFe2O4 significantly improves its activity and stability. At an ultra-low temperature of 30 °C, the CO can be totally converted to CO2 over 3FeOx-3Pt/MgFe2O4. High and stable performances of CO-catalytic oxidation can be obtained at 60 °C on 3FeOx-3Pt/MgFe2O4 over 35 min on-stream at WHSV = 30,000 mL/(g·h). Based on a series of characterizations including BET, XRD, ICP, STEM, H2-TPR, XPS, CO-DRIFT, O2-TPD and CO-TPD, it was disclosed that the relatively high activity and stability of 3FeOx-3Pt/MgFe2O4 is due to the fact that the addition of FeOx could facilitate the antioxidant capacity of Pt and oxygen mobility and increase the proportion of adsorbed oxygen species and the amounts of adsorbed CO. These results are helpful in designing Pt-based catalysts exhibiting higher activity and stability at low temperatures for the catalytic oxidation of CO. [ABSTRACT FROM AUTHOR]

Nowadays, the depletion of non‐renewable energy sources has become a prominent issue, and environmental concerns such as air pollution stemming from vehicle emissions have reached a critical stage. In this manuscript, we introduce a novel approach for the fabrication of Pt/C catalysts on a large scale, utilizing a simple, rapid, and continuous pipeline microwave synthesis method. Moreover, we incorporate a heating treatment process in an N2−H2 (5 % H2) environment to enhance the activity and durability of the catalyst. The synthesized Pt/C‐400 catalyst demonstrates an impressive electrochemical active surface area of 103.2 m2/gpt and a mass‐specific activity of 315 mA/mg at a half‐wave potential of 0.9 V. Following 30000 cycles of Pt attenuation testing and 30000 cycles of carrier attenuation testing, the Pt/C‐400 catalyst exhibits a remarkable retention rate of 75 %. Furthermore, based on single‐cell testing, the Pt/C‐400 catalyst achieves a voltage of 0.606 V at a current density of 2000 mA/cm2, surpassing the performance of other Pt/C catalysts discussed in this article. This study presents an efficient and practical method for large‐scale synthesis of high‐performance and durable catalysts. The findings hold significant implications for the commercialization of Proton Exchange Membrane Fuel Cells and contribute to addressing the pressing need for sustainable energy solutions. [ABSTRACT FROM AUTHOR]

Hydrogen production techniques based on solar-water splitting have emerged as carbon-free energy systems. Many researchers have developed highly efficient thin-film photoelectrochemical (PEC) devices made of low-cost and earth-abundant materials. However, solar water splitting systems suffer from short lifetimes due to catalyst instability that is attributed to both chemical dissolution and mechanical stress produced by hydrogen bubbles. A recent study found that the nanoporous hydrogel could prevent the structural degradation of the PEC devices. In this study, we investigate the protection mechanism of the hydrogel-based overlayer by engineering its porous structure using the cryogelation technique. Tests for cryogel overlayers with varied pore structures, such as disconnected micropores, interconnected micropores, and surface macropores, reveal that the hydrogen gas trapped in the cryogel protector reduce shear stress at the catalyst surface by providing bubble nucleation sites. The cryogelated overlayer effectively preserves the uniformly distributed platinum catalyst particles on the device surface for over 200 h. Our finding can help establish semi-permanent photoelectrochemical devices to realize a carbon-free society. Photoelectrodes made of earth-abundant materials can contribute to low-cost and carbon-free hydrogen production, but suffer from a short lifetime. Here the authors report cryogel overlayer to increase the operation time of the device by regulating evolving hydrogen bubble dynamics. [ABSTRACT FROM AUTHOR]

Exploring an active and cost-effective electrocatalyst alternative to carbon-supported platinum nanoparticles for alkaline hydrogen evolution reaction (HER) have remained elusive to date. Here, we report a catalyst based on platinum single atoms (SAs) doped into the hetero-interfaced Ru/RuO2 support (referred to as Pt-Ru/RuO2), which features a low HER overpotential, an excellent stability and a distinctly enhanced cost-based activity compared to commercial Pt/C and Ru/C in 1 M KOH. Advanced physico-chemical characterizations disclose that the sluggish water dissociation is accelerated by RuO2 while Pt SAs and the metallic Ru facilitate the subsequent H* combination. Theoretical calculations correlate with the experimental findings. Furthermore, Pt-Ru/RuO2 only requires 1.90 V to reach 1 A cm−2 and delivers a high price activity in the anion exchange membrane water electrolyzer, outperforming the benchmark Pt/C. This research offers a feasible guidance for developing the noble metal-based catalysts with high performance and low cost toward practical H2 production. Exploring an active and cost-effective catalyst for alkaline hydrogen evolution reaction remains elusive to date. Here, the authors report the platinum single-atoms doped ruthenium/ruthenium oxides showing distinctly enhanced catalytic performance. [ABSTRACT FROM AUTHOR]

Platinum is known as the best catalyst for the hydrogen evolution reaction (HER) but the scarcity and high cost of Pt limit its widespread applicability. Herein, the role of the underlying substrate on the HER activity of dispersed Pt atoms is uncovered. A direct current magnetron sputtering technique is utilized to deposit transition metal (TM) thin films of W, Ti, and Ta as underlying substrates for extremely low loading of Pt (<1.5 at%). The electrocatalytic performance of as‐synthesized samples for the HER is examined in both alkali and acidic media. The results show that despite the low loading of Pt, the Pt/TM catalysts produce hydrogen at a rate comparable to that of pristine bulk Pt. Pt/TM catalysts also display good stability with less than 5% decay in performance after 10 h of continuous HER operation. Based on the computational study, the excellent performance is attributed to the modified electronic properties of the Pt atoms, offering ideal binding energy for HER due to interaction with the underlying substrates. This work provides a robust and industry‐friendly route toward designing efficient catalytic systems for important electrochemical reactions such as HER and others. [ABSTRACT FROM AUTHOR]

Platinum (Pt) is extensively employed as a catalyst in fuel cells owing to its remarkable catalytic activity. However, the commercial utilization of Pt-based catalysts is impeded by their elevated cost and limited availability. Enhancing the stability of Pt-based catalysts is of considerable significance. In this study, the degradation of Pt-based catalysts under storage conditions has been investigated. Both the oxygen and light will cause the degradation of Pt in storage conditions. However, the oxidation caused by light and oxygen alone is very slight and the oxidation of Pt is obvious when oxygen and light work together. The described findings provide new sights into investigating the degradation mechanism of Pt-based catalysts. [ABSTRACT FROM AUTHOR]

In this work, a series of novel mixed metal oxide (MMO) electrodes with the composition Ti/RuO2Sb2O4Ptx (0 ≤ x ≤ 10.0) were developed, envisaging their application in a reversible electrochemical cell based on the chloralkaline process as an energy storage system. These electrodes were synthesized via the ionic liquid method. Comprehensive physical, chemical, and electrochemical characterizations were conducted to evaluate their performance. The feasibility of employing these electrodes within reversible processes was explored, using the products generated during the electrolytic operation of the system for fuel cell operation. During the electrolyzer operation, higher current densities resulted in enhanced current efficiencies for the production of oxidized chlorine species. Notably, the presence of platinum in the catalyst exhibited a negligible impact on the coulombic efficiency at low current densities where water oxidation predominates. However, at higher current densities, the presence of platinum significantly improved coulombic efficiency, approaching values of approximately 60%. Transitioning to a fuel cell operation, despite the improved kinetic performance associated with a higher platinum content, the process efficiency was predominantly governed by ohmic losses. Curiously, the MMO electrode made without platinum (Ti/(RuO2)70-(Sb2O4)30) displayed the lowest ohmic losses. This study establishes optimal conditions for future investigations into this promising possibility, which holds great potential for energy storage via chloralkaline-based reversible reactions. [ABSTRACT FROM AUTHOR]

Platinum electrocatalysts on graphene-like supports have recently attracted research interest as components of electrochemical devices based on hydrogen oxidation reactions in acid media due to their improved electrochemical properties, high stability, and conductivity. Within the current work, hydrogen adsorption and the recombination effects of a proton and hydroxonium on a graphene-based electrocatalyst were investigated using density functional theory. The interaction between ions and the platinum surface was simulated for various configurations, including different initial ion distances and angles relative to the surface of the graphene sheet as well as different adsorptions on various Pt atoms (vertices or faces for Pt13 and Pt14 nanoclusters). Then, the geometry optimization was performed. Changes in the density of states during the reactions were studied to analyze the occurrences and alterations of the interactions. A comparative analysis of the obtained adsorption energies of H+ and H3O+ with experimental data was conducted. The energy was calculated to be less in absolute value, and intermediates were more stable in adsorption models with the H–Pt–Gr angle of 90° than in models with the angle of 180°. Strong chemical bonding for models with H–Pt distances less than 2 Å was observed from the DOS. [ABSTRACT FROM AUTHOR]

Ruthenium (Ru) has been recognized as a prospective candidate to substitute platinum catalysts in water‐splitting‐based hydrogen production. However, minimizing the Ru contents, optimizing the water dissociation energy of Ru sites, and enhancing the long‐term stability are extremely required, but still face a great challenge. Here, we report on creating tungsten oxide‐anchored Ru clusters (Ru–WOx) with electron‐rich and anti‐corrosive microenvironments for efficient and robust seawater splitting. Benefiting from the abundant oxygen vacancy structure in tungsten oxide support, the Ru–WOx exhibits strong Ru–O and Ru–W bonds at the interface. Our study elucidates that the strong Ru–O bonds in Ru–WOx may accelerate the water dissociation kinetics, and the Ru–W bonds will lead to the strong metal–support interaction and electrons transfer from W to Ru. The optimal Ru–WOx catalysts exhibit a low overpotential of 29 and 218 mV at the current density of 10 mA cm−2 in alkaline and seawater media, respectively. The outstanding long‐term stability discloses that the Ru–WOx catalysts own efficient corrosion resistance in seawater electrolysis. We believe that this work offers new insights into the essential roles of electron‐rich and anti‐corrosive microenvironments in Ru‐based catalysts and provide a new pathway to design efficient and robust cathodes for seawater splitting. [ABSTRACT FROM AUTHOR]

Understanding the spin distribution in FeN4-doped graphene nanoribbons with zigzag and armchair terminations is crucial for tuning the electronic properties of graphene-supported non-platinum catalysts. Since the spin-polarized carbon and iron electronic states may act together to change the electronic properties of the doped graphene, we provide in this work a systematic evaluation using a periodic density-functional theory-based method of the variation of spin-moment distribution and electronic properties with the position and orientation of the FeN4 defects, and the edge terminations of the graphene nanoribbons. Antiferromagnetic and ferromagnetic spin ordering of the zigzag edges were considered. We reveal that the electronic structures in both zigzag and armchair geometries are very sensitive to the location of FeN4 defects, changing from semi-conducting (in-plane defect location) to half-metallic (at-edge defect location). The introduction of FeN4 defects at edge positions cancels the known dependence of the magnetic and electronic proper-ties of undoped graphene nanoribbons on their edge geometries. The implications of the reported results for catalysis are also discussed in view of the presented electronic and magnetic properties. [ABSTRACT FROM AUTHOR]

Studying the ORR activity of platinum-based electrocatalysts is an urgent task in the development of materials for proton-exchange membrane fuel cells. The catalytic ink composition and the formation technique of a thin layer at the RDE play a significant role in studying ORR activity. The use of a polymer ionomer in the catalytic ink provides viscosity as well as proton conductivity. Nafion is widely used as an ionomer for research both at the RDE and in the MEA. The search for ionomers is a priority task in the development of the MEA components to replace Nafion. The study also considers the possibility of using the LF4-SK polymer as an alternative ionomer. The comparative results on the composition and techniques of applying the catalytic layer using LF4-SK and Nafion ionomers are presented, and the influence of the catalytic ink composition on the electrochemical characteristics of commercial platinum–carbon catalysts and a highly efficient platinum catalyst based on an N-doped carbon support is assessed. [ABSTRACT FROM AUTHOR]

The asymmetrical growth of a single‐wall carbon nanotube (SWCNT) by introducing a change of a local atomic structure, is usually inevitable and supposed to have a profound effect on the chirality control and property tailor. However, the breaking of the symmetry during SWCNT growth remains unexplored and its origins at the atomic‐scale are elusive. Here, environmental transmission electron microscopy is used to capture the process of breaking the symmetry of a growing SWCNT from a sub‐2‐nm platinum catalyst nanoparticle in real‐time, demonstrating that topological defects formed on the side of a SWCNT can serve as a buffer for stress release and inherently break its axis‐symmetrical growth. Atomic‐level details reveal the importance of the tube‐catalyst interface and how the atom rearrangement of the solid‐state platinum catalyst around the interface influences the final tubular structure. The active sites responsible for trapping carbon dimers and providing enough driving force for carbon incorporation and asymmetric growth are shown to be low‐coordination step edges, as confirmed by theoretical simulations. [ABSTRACT FROM AUTHOR]

The use of platinum-free (Pt) cathode electrocatalysts for oxygen reduction reactions (ORRs) has been significantly studied over the past decade, improving slow reaction mechanisms. For many significant energy conversion and storage technologies, including fuel cells and metal–air batteries, the ORR is a crucial process. These have motivated the development of highly active and long-lasting platinum-free electrocatalysts, which cost less than proton exchange membrane fuel cells (PEMFCs). Researchers have identified a novel, non-precious carbon-based electrocatalyst material as the most effective substitute for platinum (Pt) electrocatalysts. Rich sources, outstanding electrical conductivity, adaptable molecular structures, and environmental compatibility are just a few of its benefits. Additionally, the increased surface area and the simplicity of regulating its structure can significantly improve the electrocatalyst's reactive sites and mass transport. Other benefits include the use of heteroatoms and single or multiple metal atoms, which are capable of acting as extremely effective ORR electrocatalysts. The rapid innovations in non-precious carbon-based nanomaterials in the ORR electrocatalyst field are the main topics of this review. As a result, this review provides an overview of the basic ORR reaction and the mechanism of the active sites in non-precious carbon-based electrocatalysts. Further analysis of the development, performance, and evaluation of these systems is provided in more detail. Furthermore, the significance of doping is highlighted and discussed, which shows how researchers can enhance the properties of electrocatalysts. Finally, this review discusses the existing challenges and expectations for the development of highly efficient and inexpensive electrocatalysts that are linked to crucial technologies in this expanding field. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pt/CrCoNi was designed to alleviate the CO ads -posion of Pt-based catalysts for MOR. • The *OH generation ability of CrCoNi was important for the oxidation of Pt-CO ads. • The optimum Pt/CrCoNi(OA) exhibited a mass activity of 3785 A g Pt -1. • Pt/CrCoNi(OA) enabled ∼ 14 h i-t with a termination activity of 19.0 A g Pt -1. • Pt/CrCoNi(OA) induced only a 5.6% loss of activity after 10,000 CV cycles. As high-efficiency anode methanol oxidation catalysts, platinum-based materials have always occupied a dominant place since the inception of direct methanol fuel cells (DMFCs). However, because of the strong adsorption of intermediates, Pt-active centers are easily poisoned and induce serious activity loss. Here, we investigate the same commonality of the oxygen evolution reaction (OER) and methanol oxidation reaction (MOR) mechanism in Pt/CrCoNi complex catalysts and establish a relationship between them to help screen appropriate synergistic materials and reduce activity loss. With this strategy, the OER activity of Pt/CrCoNi is modified via temperature and oxygen pressure control, and the OER overpotential and MOR durability show a positive correlation. The MOR performance of the final optimized Pt/CrCoNi (7.5–225 Torr oxygen pressure and 400 °C annealing, OA) film reaches an advanced level in the Pt-based MOR catalysts and shows a mass activity of 3785 A g Pt -1, as well as a good durability of 50000 s in the alkaline solution. [ABSTRACT FROM AUTHOR]

Loss of electrochemical surface area in proton-exchange membrane is of large practical importance, since membrane degradation largely affects the durability and life of fuel cells. In this paper, the electrokinetic model developed by Holby and Morgan is considered. The paper describes degradation mechanisms in membrane catalyst presented by platinum dissolution, platinum diffusion, and platinum oxide formation. A one-dimensional model is governed by nonlinear reaction–diffusion equations given in a cathodic catalyst layer using Butler–Volmer relationships for reaction rates. The governing system is endowed with initial conditions, mixed no-flux boundary condition at the interface with gas diffusion layer, and a perfectly absorbing condition at the membrane boundary. In cyclic voltammetry tests, a non-symmetric square waveform is applied for the electric potential difference between 0.6 and 0.9 V held for 10 and 30 s, respectively, according to the protocol of European Fuel Cell and Hydrogen Joint Undertaking. Aimed at mitigation strategies, the impact of cycling operating conditions and model parameters on the loss rate of active area is investigated. The global behavior with respect to variation of parameters is performed using the method of sensitivity analysis. Finding feasible and unfeasible values helps to determine the range of test parameters employed in the model. Comprehensive results of numerical simulation tests are presented and discussed. [ABSTRACT FROM AUTHOR]

Using a hierarchy of three sigmoid growth models with increasing complexity, i.e., number of parameters, we reanalyzed kinetic data for heterogeneous nucleation—the number of nuclei N(t) vs. time t—from archetypical experiments on the electrodeposition of mercury on platinum by I. Markov and E. Stoycheva, to obtain two scales: Nmax and τ. The universal character of the studied phenomenon was revealed when replotting the original data as α ≡ N(t)/Nmax vs. t/τ. Yet the simplest model, the recently introduced α21 model which is aimed to describe diffusion-limited growth in 2D, α21 = tanh2(2t/τ21), fits all datasets with an R2 ≥ 0.989. This can be rationalized by attracting the non-classical notion of two-step nucleation—the nuclei form in a metastable phase which, in this case, grows on the electrode surface. Beyond the universality, we find the dependence of the two obtained scales on the overvoltage, which is increased systematically from 83 to 88 mV to generate the six N(t) datasets for each of the two electrode types—planar and hemispherical. Surprisingly, for one of them, the planar electrode, there is a discontinuity in the dependence—an almost horizontal jump from 85 to 86 mV, while for the hemispherical electrode, τ decreases smoothly. [ABSTRACT FROM AUTHOR]

Catalytic Janus colloids, with one hemi‐sphere covered by a hydrogen peroxide reduction catalyst such as platinum, represent one of the most experimentally explored examples of self‐motile active colloid systems. This paper comparatively investigates the motile behavior of symmetrical catalytic colloids produced by a solution‐based metal salt reduction process. Despite the significant differences in the distribution of catalytic activity, this study finds that the motion produced by symmetrical colloids is equivalent to that previously reported for Janus colloids. It also shows that introducing a Janus structure to the symmetrical colloids via masking does not significantly modify their motion. These findings could indicate that very subtle variations in surface reactivity can be sufficient to produce Janus‐like active Brownian particle‐type motion, or that a symmetry‐breaking phenomena is present. The study will consequently motivate fresh theoretical attention and also demonstrate a straightforward route to access large quantities of motile active colloids, which are expected to show subtly different phenomenology compared to those with Janus structures. [ABSTRACT FROM AUTHOR]

MXene‐supported noble metal alloy catalysts exhibit remarkable electrocatalytic activity in various applications. However, there is no facile one‐step method for synthesizing these catalysts, because the synthesis of MXenes requires a strongly oxidizing environment and the preparation of platinum nanoalloys requires a strongly reducing environment and high temperatures. Hence, achieving coupling in one step is extremely challenging. In this paper, a straightforward one‐step molten salt method for preparing MXene‐supported platinum nanoalloy catalysts is proposed. The molten salt acts as the reaction medium to dissolve the transition metals and platinum ions at high temperatures. Transition metal ions oxidize the A‐site element from its MAX precursor at high temperatures, and the resulting transition metals further reduce platinum ions to form alloys. By coupling Al oxidation and platinum ion reduction using a molten salt solvent, this method directly converts Ti3AlC2 to a Pt‐M@Ti3C2Tx catalyst (where M denotes the transition metal). It further offers the possibility of extending the Pt‐M phase to binary, ternary, or quaternary platinum‐containing nanoalloys and converting the Al‐containing MAX phase to Ti2AlC and Ti3AlCN. Due to the strong interfacial interaction, the as‐prepared Pt‐Co@Ti3C2Tx is superior to commercial Pt/C (20 wt.%) in the hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

Replacing expensive platinum oxygen reduction reaction (ORR) catalysts with atomically dispersed single-atom catalysts is an effective way to improve the energy conversion efficiency of fuel cells. Herein, a series of single-atom catalysts, TM-N2O2Cx (TM=Sc-Zn) with TM-N2O2 active units, were designed, and their catalytic performance for electrocatalytic O2 reduction was investigated based on density functional theory. The results show that TM-N2O2Cx exhibits excellent catalytic activity and stability in acidic media. The eight catalysts (TM=Sc, Ti, V, Cr, Mn, Fe, Co, and Ni) are all 4e− reaction paths, among which Sc-N2O2Cx, Ti-N2O2Cx, and V-N2O2Cx follow dissociative mechanisms and the rest are consistent with associative mechanisms. In particular, Co-N2O2Cx and Ni-N2O2Cx enable a smooth reduction in O2 at small overpotentials (0.44 V and 0.49 V, respectively). Furthermore, a linear relationship between the adsorption free energies of the ORR oxygen-containing intermediates was evident, leading to the development of a volcano plot for the purpose of screening exceptional catalysts for ORR. This research will offer a novel strategy for the design and fabrication of exceptionally efficient non-precious metal catalysts on an atomic scale. [ABSTRACT FROM AUTHOR]

Dye-sensitized solar cells (DSSCs) are often viewed as the potential future of photovoltaic systems and have garnered significant attention in solar energy research. In this groundbreaking research, we introduced a novel solvothermal method to fabricate a unique "grass-like" pattern on fluorine-doped tin oxide glass (FTO), specifically designed for use as a counter electrode in dye-sensitized solar cell (DSSC) assemblies. Through rigorous structural and morphological evaluations, we ascertained the successful deposition of nickel cobalt sulfide (NCS) on the FTO surface, exhibiting the desired grass-like morphology. Electrocatalytic performance assessment of the developed NCS-1 showed results that intriguingly rivaled those of the acclaimed platinum catalyst, especially during the conversion of I3 to I− as observed through cyclic voltammetry. Remarkably, when integrated into a solar cell assembly, both NCS-1 and NCS-2 electrodes exhibited encouraging power conversion efficiencies of 6.60% and 6.29%, respectively. These results become particularly noteworthy when compared to the 7.19% efficiency of a conventional Pt-based electrode under similar testing conditions. Central to the performance of the NCS-1 and NCS-2 electrodes is their unique thin and sharp grass-like morphology. This structure, vividly showcased through scanning electron microscopy, provides a vast surface area and an abundance of catalytic sites, pivotal for the catalytic reactions involving the electrolytes in DSSCs. In summation, given their innovative synthesis approach, affordability, and remarkable electrocatalytic attributes, the newly developed NCS counter electrodes stand out as potent contenders in future dye-sensitized solar cell applications. [ABSTRACT FROM AUTHOR]

The development of a catalyst for the ammonium dinitramide (ADN)-based monopropellant system has been of growing interest in space research. In this study, we investigated the development methodology for the platinum hexaaluminate (Pt–LHA) catalyst. The reduction of Platinum was performed in muffle and tubular furnaces by considering the different heating rates, with or without hydrogen gas flow conditions. The dispersion of Platinum on LHA was confirmed by using SEM analysis; the particle size of Platinum in Pt–LHA-1 and Pt–LHA-11 was 5.1–9.1 μm and <100 nm, respectively. Notably, agglomeration of Platinum was observed when the catalyst was calcinated in a muffle furnace without air or H2 gas flow. Interestingly, the even dispersion of Platinum was revealed when the catalyst was calcinated in a tubular furnace at 4% H2 in N2 gas flow. As a result, Pt–LHA-7 to Pt–LHA-11 exhibited higher catalytic activity than Pt–LHA-1 to Pt–LHA-6 under H2O2 reactor conditions. The catalyst Pt–LHA-9 was further tested in a 1 N ADN thruster, demonstrating its capability to decompose the ADN-based monopropellant in an operation thruster. [ABSTRACT FROM AUTHOR]

Sonodynamic therapy (SDT) is a physical therapy that utilizes critical sonosensitizers triggered by ultrasound to achieve an effective non-invasive tumor treatment. However, the inadequate sonodynamic efficacy and low responsive activities of traditional inorganic sonosensitizers have hindered its practical application. Here, we rationally design a platinum–zinc oxide (Pt ZnO) sonosensitizer to significantly enhance the efficacy of SDT through its inherent bandgap structure and dual-nanozyme activities. The Pt ZnO possesses a narrow bandgap (2.89 eV) and an appropriate amount of oxygen defects, which promote the efficiency of electrons and holes separation and the generation of reactive oxygen species (ROS) under US irradiation. Simultaneously, the Pt ZnO exhibits both catalase-like and peroxidase-like activities, which effectively catalyze endogenous H 2 O 2 into a large number of O 2 and toxic hydroxyl radicals (•OH), thus achieving an efficient enhancement of SDT and catalytic therapy. Moreover, the Pt ZnO has significant glutathione consumption performance, further amplifying the oxidative stress. Ultimately, the Pt ZnO achieves a triple ROS amplification effect, with the yields of singlet oxygen (1O 2) and •OH reaching 859.1 % and 614.4 %, respectively, inducing a highly effective sono-catalytic therapy with a remarkable tumor inhibition rate of 98.1 %. This study expands the application of ZnO semiconductor heterojunctions in the nanomedicine area, and the simple yet efficient design of the Pt ZnO provides a strategy for the development of sonosensitizers. A platinum-zinc oxide (Pt ZnO) heterojunction sonosensitizer is constructed with dual-nanozyme activities and achieves a triple ROS amplification effect, leading to an efficient synergistic sono-catalytic therapy. The Pt ZnO owns an inherent narrow bandgap and abundant oxygen defects, thus exhibiting an efficient sonosensitizer performance. It also possesses both catalase-like and peroxidase-like activities, which effectively catalyze the endogenous H 2 O 2 into a large quantity of O 2 and toxic hydroxyl radicals, thereby enhancing the SDT and catalytic therapy. Furthermore, its prominent glutathione consumption performance further amplifies oxidative stress. The yields of singlet oxygen and hydroxyl radicals reach up to 859.1 % and 614.4 %, respectively, inducing a highly effective sono-catalytic therapy with an impressive tumor inhibition rate of 98.1 %. [Display omitted] [ABSTRACT FROM AUTHOR]

The response of catalytic hydrogen sensors with platinum-group catalysts (Pt + 3Pd, Pt, Pd, Ir, and Rh) in the room temperature range has been studied. It was demonstrated that a flameless catalytic hydrogen combustion reaction on the Pt and Pt + 3Pd catalysts occurs at 20 °C, which results in the heating of the sensing element of a catalytic sensor, and the microheater resistance increases. The microheater temperature was first measured, and it was shown that the temperature increases by 99 and 83 °C in the calibration gas mixture containing 0.96% vol. hydrogen for the Pt and Pt + 3Pd catalysts, respectively. A method has been provided for measuring hydrogen levels using a catalytic sensor without heating voltage input. [ABSTRACT FROM AUTHOR]