Search

A combination of experimental and numerical investigations on metallic silver and platinum nanoparticles deposited on silica substrates is presented, with a focus on metal–substrate interactions. Experimentally, the nanoparticles, obtained by ultra-high vacuum atom deposition, are characterized by grazing-incidence small-angle x-ray scattering and high resolution transmission electronic microscopy to determine their structure and morphology and, in particular, their aspect ratio (height/diameter), which quantifies the metal–substrate interaction, from the as-grown to equilibrium state. Numerically, the interactions between the metal and the silica species are modeled with the Lennard-Jones (12, 6) potential, with two parameters for each metal and silica species. The geometric parameters were found in the literature, while the energetic parameters were determined from our experimental measurements of the aspect ratio. The parameters are as follows: σAg–O = 0.278 nm, σAg–Si = 0.329 nm, ɛAg–O = 75 meV, and ɛAg–Si = 13 meV for Ag–silica and σPt–O = 0.273 nm, σPt–Si = 0.324 nm, ɛPt–O = 110 meV, and ɛPt–Si = 18 meV for Pt–silica. The proposed Ag–silica potential reproduces quantitatively the unexpected experimental observation of the variation of the aspect ratio for Ag nanoparticles larger than 5 nm, which has been interpreted as a consequence of the silica roughness. The nanoparticle orientation, structure, and disorder are also considered. This metal–silica potential for Ag and Pt should be helpful for further studies on pure metals as well as their alloys. [ABSTRACT FROM AUTHOR]

While metal nanoparticles are widely used, their small size makes them mechanically unstable. Extensive prior research has demonstrated that nanoparticles with sizes in the range of 10-50 nm fail by the surface nucleation of dislocations, which is a thermally activated process. Two different contributions have been suggested to cause the weakening of smaller particles: first, geometric effects such as increased surface curvature reduce the barrier for dislocation nucleation; second, surface diffusion happens faster on smaller particles, thus accelerating the formation of surface kinks which nucleate dislocations. These two factors are difficult to disentangle. Here we use in situ compression testing inside a transmission electron microscope to measure the strength and deformation behavior of platinum particles in three groups: 12 nm bare particles, 16 nm bare particles, and 12 nm silica-coated particles. Thermodynamics calculations show that, if surface diffusion were the dominant factor, the last two groups would show equal strengthening. Our experimental results refute this, instead demonstrating a 100% increase in mean yield strength with increased particle size and no statistically significant increase in strength due to the addition of a coating. A separate analysis of stable plastic flow corroborates the findings, showing an order-of-magnitude increase in the rate of dislocation nucleation with a change in particle size and no change with coating. Taken together, these results demonstrate that surface diffusion plays a far smaller role in the failure of nanoparticles by dislocations as compared to geometric factors that reduce the energy barrier for dislocation nucleation.

We report the direct fabrication of polycrystalline γ-Al 2 O 3 nanochains-supported Pt nanoparticles on macroscopic substrates, such as monolithic honeycombs and porous disc-typed ceramics, via chemical vapor deposition. We also investigate solid-gas reactions between the γ-Al 2 O 3 nanochains@Pt nanoparticles and CO using in-situ transmission electron microscopy (TEM). The SEM, TEM, STEM, and XRD patterns reveal that γ-Al 2 O 3 nanochains, 80 nm in diameter, were uniformly formed on the surfaces of macroscopic ceramic substrates. High-resolution TEM (HTEM) images confirm the polycrystalline and kinking structures connecting the nanochains. The coating thickness of γ-Al 2 O 3 nanochains layer is approximately 100㎛. The EDX images and XPS graphs indicate that Pt nanoparticles, 3.5 nm in diameter, are well-coated on the surfaces of the γ-Al 2 O 3 nanochains. The uniform distribution of Pt nanoparticles is precisely controlled utilizing autogenic pressure reaction. Additionally, in-situ observation significantly highlights the physicochemical phenomena of the γ-Al 2 O 3 nanochains@Pt nanoparticles over time under CO supply at 300 °C. Coke formation was accelerated on the surface of catalysts as increase of CO partial pressure increase, while Pt nanoparticles is very stable without the migration and aggregation. [Display omitted] [ABSTRACT FROM AUTHOR]

We fabricated a single-layer graphene-doped electric double-layer capacitor (EDLC) consisting of glass, indium tin oxide, graphene layers, gel electrolyte, deposited platinum, and a conductive separator. To find the appropriate doping materials and compositions of the EDLC, we conducted experiments using single-layer graphene and ZnO as doping materials. We also varied the doping concentrations of single-layer graphene to find the optimal concentration. The single-layer graphene EDLC was fabricated with different annealing and platinum deposition methods. Different electrolytes were also tested to determine the appropriate compositions and methods to fabricate the EDLC. The performance of the EDLC was assessed by measuring the capacitance, charge–discharge efficiency, charge–discharge cycle, and hysteresis area of cyclic voltammogram (CV). The results revealed that single-layer graphene was better than ZnO for doping the EDLC, and the appropriate concentration was 0.07 wt%. Annealing the single-layer graphene, depositing platinum, and using a gel electrolyte of 10 wt% polyvinyl alcohol (PVA) and 6 M potassium hydroxide (KOH) helped improve the performance of the single-layer graphene EDLC. The capacitance and charge–discharge efficiency were increased by 9.4–72.2 and 3.2–158.6%, respectively, depending on the methods and materials tested in this study. The charge–discharge cycle and hysteresis area were enhanced by 11.5–26.4 and 11.0–24.6%, respectively. Therefore, the annealed single-layer graphene-doped EDLC with deposited platinum and a gel electrolyte is recommended for use in electric vehicles (EVs) and advanced sensors because of its improved performance. [ABSTRACT FROM AUTHOR]

A robust catalyst for the electrochemical oxidation of formic acid (EOFA) was develop by depositing semi-spherical platinum nanoparticles (nano-Pt, <37 nm in diameters) as connected aggregates (ca. 106 nm in an average diameter) onto the surface of a glassy carbon (GC) rod (Pt/GC catalyst). This Pt/GC catalyst was further amended sequentially with spherical gold nanoparticles (nano-Au, ca. 50 nm in an average diameter) and iron oxide nanowires (nano-FeOx, ca. 30 nm in average diameter and 194 nm in average length). The layers' sequencing of the catalyst was critical in optimizing the catalyst's efficiency. Surprisingly, the modification of the Pt/GC catalyst first with nano-Au and next with nano-FeOx (FeOx/Au/Pt/GC catalyst) decreased the electrochemical surface area of nano-Pt ca. 16-times, which is highly desirable. Besides, it increased tremendously the activity (two-orders of magnitude), stability (ca. 18-fold) and tolerance against CO poisoning (7-times) of the catalyst for EOFA. Moreover, it saved up to ca. −236 mV in the onset potential of the "non-poisoning" dehydrogenation pathway of EOFA. It further retained a high mass activity of 300 A g−1. With the aid of multiple materials and electrochemical inspections, the catalyst's development was confirmed and the role of catalytic ingredients was elucidated. Interestingly, nano-Au hindered geometrically the adsorption of poisoning CO molecules onto the Pt surface, whereas nano-FeOx improved significantly the charge transfer kinetics of EOFA while mediating a faster mechanism. [Display omitted] • A nanostructured FeOx/Au/Pt/GC catalyst was successfully developed. • It boosted (2 order of magnitude) the activity toward the electrochemical oxidation of formic acid (EOFA). • It owned an improved stability (ca. 18-fold) and tolerance against CO poisoning (7-times), in relative to the Pt/GC catalyst. • It saved up to ca. −236 mV in the onset potential of the "non-poisoning" dehydrogenation pathway of EOFA. [ABSTRACT FROM AUTHOR]

[Display omitted] There are currently almost no ternary platinum-based nanosheets used for acidic oxygen reduction reactions (ORR) due to the difficulty in synthesizing ternary nanosheets with high Pt content. In this work, several ultrathin platinum-palladium-copper nanosheets (PtPdCu NSs) with a thickness of around 1.90 nm were prepared via a microwave heating-assisted method. Microwave heating allows a large number of Pt atoms to deposit into PdCu nanosheets, forming Pt-based ternary nanosheets with high Pt content. Among them, Pt 38 Pd 50 Cu 12 NSs catalyst displays the highest mass activity (MA) measured in 0.1 M HClO 4 of 0.932 A/mg Pt+Pd which is 8.6 times of that Pt/C. Besides, Pt 38 Pd 50 Cu 12 NSs catalyst also exhibits excellent stability with an extremely low MA attenuation after 80,000 cycles accelerated durability testing (ADT) tests. In the single cell tests, the Pt 38 Pd 50 Cu 12 NSs catalyst manifests higher maximum power density of 796 mW cm−2 than Pt/C of 606 mW cm−2. Density functional theory (DFT) calculations indicate the weaker adsorption between Pt and O-species in Pt 38 Pd 50 Cu 12 NSs leads to a significant enhancement of ORR activity. This study provides a new strategy to design and prepare ultrathin Pt-based trimetallic nanosheets as efficient and durable ORR catalysts. [ABSTRACT FROM AUTHOR]

Sche me 2. The Methanol oxidation reaction mechanism in acidic media is shown schematically. [Display omitted] • Carbon nanoboxes (CNB) were prepared using MOF strategy to facilitate their ion and electron transport. • Pt/PProDOT/CNB catalysts with hollow structure, porous weave and nitrogen doped structure advantages. • Pt/PProDOT/CNB and Pt/CNB exhibit excellent catalytic activity, CO tolerance, and long-term stability. • The PProDOT/CNB interface accelerates reaction kinetics. • In situ polymerisation enables PProDOT to modify CNB uniformly. To improve the efficiency of the methanol oxidation reaction (MOR) in direct methanol fuel cells (DMFCs), it is essential to develop catalysts with high catalytic activity. However, constructing polyatomic doped carbon nanomaterials and understanding the interaction mechanisms between dopant elements remain significant challenges. In this study, we propose nitrogen-doped carbon nanobox (CNB) derived from Zeolitic Imidazolate Framework-67 (ZIF-67) crystals as precursors to serve as carriers for highly efficient platinum nanoparticles (Pt NPs). We synthesized platinum/poly(3,4-propylenedioxythiophene)/carbon nanobox (Pt/PProDOT/CNB) composites by wrapping CNB around PProDOT films via in situ oxidative polymerization. This unique structural design provides several advantages to the catalyst, including a large active surface area, numerous accessible electrocatalytic active centers, an optimized electronic structure, and good electronic conductivity. The Pt/PProDOT/CNB composites demonstrated excellent methanol oxidation performance, with a remarkable mass activity (MA) of 1639.9 mA mg-1 Pt and a high electrochemical active surface area (ECSA) of 160.8 m2/g. Furthermore, the catalyst exhibited good CO resistance and outstanding durability. [ABSTRACT FROM AUTHOR]

Nitrogen-doped carbon microspheres (NCS) with large specific surface areas and abundant pore sizes were synthesized using renewable oatmeal as the precursor. Platinum nanoparticles (Pt NPs) were loaded onto the NCS substrate using the reduction and linkage effects of polyoxometalates (POM). The synthesized three-component nanocomposite of Pt/POM/NCS exhibited outstanding performance in the electrocatalysis of adrenaline. [Display omitted] • The biocarbon prepared from oatmeal is environmentally friendly, inexpensive, and easy to obtain. • Utilizing the dual benefits of POM as a connecting and reducing agent, Pt NPs are efficiently loaded onto the surface of NCS. • NCS, with their excellent conductivity, serve as an effective carrier to prevent the aggregation of Pt NPs. • This work further broadens the application of biocarbon materials in electrochemical sensing. In this study, we innovatively synthesized nitrogen-doped carbon microspheres (NCS) derived from oatmeal. By utilizing polyoxometalates (POM) as both reducing and linking agents, we achieved uniform loading of platinum nanoparticles (Pt NPs) onto the surface of the NCS. The composite nanoparticles constructed from Pt/polyoxometalate/nitrogen-doped carbon microspheres (Pt/POM/NCS) fully exploit the synergistic catalytic effect, demonstrating superior performance in adrenaline detection. The method has a linear range of 2.59 to 1109.59 μM, a detection limit as low as 0.25 μM (S/N = 3), and a sensitivity of 0.74 μA μM−1 cm−2. Additionally, it exhibits high stability and strong anti-interference ability. The recoveries in human serum were 98.51 % to 101.25 %. [ABSTRACT FROM AUTHOR]

We have designed a polymer, hc-TBtd-COP incorporating a Wurster-type redox-active building unit for the in situ reduction and nucleation of platinum nanoparticles which forms an organic polymer-wrapped metal nanoparticle composite. This composite exhibits exceptional mass activity (MA) (about 5 times larger than 20% Pt/C at 0.9 V vs. RHE) and specific activity (SA) (approximately 2 times larger than 20% Pt/C at 0.9 V vs. RHE) for the oxygen reduction reaction. The efficient electrocatalysis results from higher catalytic site dispersion and superior atom utilization efficiency. This research contributes to the advancement of composite materials for enhanced electrocatalytic performance. [ABSTRACT FROM AUTHOR]

The "New Journal of Chemistry" published by the Royal Society of Chemistry features a variety of research papers on topics such as bioelectrocatalysis, photovoltaic properties, and electrochemical studies. The journal aims to connect the global chemistry community through high-impact publications and training courses. The articles cover a range of subjects, including the synthesis of materials for energy applications, catalysis, and optical properties of compounds. [Extracted from the article]

Atomically ordered intermetallic Pt‐based nanoparticles, recognized as advanced electrocatalysts, exhibit superior activity for the oxygen reduction reaction (ORR) in fuel cell cathodes. Nevertheless, the formation of these ordered structures typically necessitates elevated annealing temperatures, which can accelerate particle growth and diminished reactivity. In this study, we synthesized carbon‐supported platinum‐cobalt intermetallic compounds (PtCo‐IMCs) with sub‐4 nm particle sizes and uniform distribution. These catalysts, characterized by high platinum content and exceptional ORR activity, are specifically tailored for heavy‐duty vehicle (HDV) applications. The PtCo‐IMCs exhibited significantly enhanced catalytic performance and durability compared to conventional Pt‐based catalysts, utilizing platinum nanoparticles as nucleation sites to promote growth. This method effectively retained smaller particle sizes while achieving a higher degree of ordering and alloying during high‐temperature annealing. Optimization of the annealing temperature resulted in peak activity and stability at 800 °C. The mass activity (MA) of the PtCo‐800 catalyst was 2.7‐fold and 1.8‐fold that of the commercial Pt/C and disordered PtCo catalysts, respectively. Additionally, the single cell employing the PtCo‐800 catalyst showed a minimal voltage loss of only 27 mV at a current density of 2 A cm−2 after 30,000 cycles of the accelerated durability test (ADT), underscoring its long‐term stability. This work provides an efficient method for the preparation of high loading ORR electrocatalyst with excellent durability. [ABSTRACT FROM AUTHOR]

Colloidal, surfactant‐free platinum nanoparticles were prepared via a self‐built continuous impinging jet microreactor synthesis process in alkaline aqueous methanol solution (Co4CatTM process). In these syntheses, methanol functions as a reducing agent as well as an additional solvent. Especially the synthesis of surfactant‐free nanoparticles remained challenging, and additionally, the transfer of this synthesis into a continuous process required several optimization steps. In this contribution we present highly controllable final particle sizes by adjusting process temperature, platinum precursor concentration and molar ratio of the hydroxide and platinum precursor used. The size objective of the surfactant‐free Pt nanoparticles was a range of 1 – 10 nm, due to the intended application in various catalytic processes, especially as PEMFC electrocatalyst. Dynamic light scattering (DLS), ζ‐potential measurements, transmission electron microscopy (TEM) and UV/Vis spectroscopy were used to monitor the particle stability over a certain period of time and study the rate of the reduction reaction in more detail. [ABSTRACT FROM AUTHOR]

Aquatic environments host various living organisms with active molecular systems, such as the enzymes in the thylakoid membrane that realise photosynthesis. Various challenges in achieving artificial photosynthesis, such as water splitting, have been studied using both inorganic and organic molecules. However, several problems persist, including diffusion-limited reactions and multiple redox reactions in the liquid phase. In this Feature Article, we discuss the significant challenges in using polymer networks as active mediators for photoinduced water splitting. In the creation of artificial chloroplasts, polymer networks offer various advantages, such as stable dispersions of multiple types of functional molecules and close molecular arrangements. To incorporate these features, stepwise synthesis and integration can be utilized during the hierarchical construction of polymer networks. The constituent molecules such as ruthenium complex and platinum nanoparticles in the photoinduced electron transfer circuits are closely arranged to smoothly operate forward reactions by polymer networks. The quantum efficiency of photoinduced H2 generation in gel systems is considerably higher than that of conventional solution systems. Additionally, a thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm) network of microgels can be used to integrate catalytic nanoparticles into the inside by using the electrostatic interaction and the mesh size changes. By focusing on the redox changes of copolymerised molecules that induce swelling/shrinking at a constant temperature, active electron transfer can be precisely achieved using the coil–globule transition of the PNIPAAm having viologen. This article highlights the potential of polymer networks to develop strategies for active electron transfer and energy conversion systems similar to those found in living organisms. [ABSTRACT FROM AUTHOR]

Solar hydrogen production with semiconductor photocatalyst particles typically requires co‐catalysts, but since co‐catalysts are often deposited in situ, the rate of their nucleation/growth and role in parasitic light absorption are not well controlled. Herein a halted photodeposition‐dialysis method is introduced that affords unprecedented control over platinum (Pt) co‐catalyst loading and morphology on bulk heterojunction organic semiconductor photocatalyst nanoparticles. Pt loading and surface distribution are controlled by tuning the initial Pt precursor concentration and photodeposition time followed by removal of unreacted Pt precursor via dialysis. Applying this method with typical Pt deposition conditions gives a max H2 evolution rate of 140 mmol h−1 g−1 (based on semiconductor mass) with only 15.2 wt.% Pt deposited and suggests an optimum loading of <20 wt.% Pt, above which parasitic light absorption decreases the H2 evolution rate. Moreover, a peak H2 evolution >30 mmol h−1 g−1 is achieved with a Pt loading of only 1.01 wt.% by tuning the deposition conditions to favor a more uniform Pt coverage with small clusters and single atoms over larger Pt NPs. This represents a performance more than eight times higher compared to typical Pt photodepositions (based on Pt) and gives critical insights into optimizing performance. [ABSTRACT FROM AUTHOR]

An efficient hydrogen evolution reaction catalyst of ultrafine Pt nanoparticles loaded onto N-doped CoO was synthesized. This catalyst displayed high electrocatalytic activity and stability. The outstanding performance is attributed to the interactions between the active sites and support, as well as the regulation of the electronic structure through covalent nitrogen bridging. [ABSTRACT FROM AUTHOR]

α-Glucosidase (α-Glu) is implicated in the progression and pathogenesis of type II diabetes (T2D). In this study, we developed a rapid colorimetric technique using platinum nanoparticles stabilized by chitosan (Ch-PtNPs) to detect α-Glu activity and its inhibitor. The Ch-PtNPs facilitate the conversion of 3,3′,5,5′-tetramethylbenzidine (TMB) into oxidized TMB (oxTMB) in the presence of dissolved O2. The catalytic hydrolysis of 2-O-α-d-glucopyranosyl-l-ascorbic acid (AA-2G) by α-Glu produces ascorbic acid (AA), which reduces oxTMB to TMB, leading to the fading of the blue color. However, the presence of α-Glu inhibitors (AGIs) hinders the generation of AA, allowing Ch-PtNPs to re-oxidize colorless TMB back to blue oxTMB. This unique phenomenon enables the colorimetric detection of α-Glu activity and AGIs. The linear range for α-Glu was found to be 0.1–1.0 U mL−1 and the detection limit was 0.026 U mL−1. Additionally, the half-maximal inhibition value (IC50) for acarbose, an α-Glu inhibitor, was calculated to be 0.4769 mM. Excitingly, this sensing platform successfully detected α-Glu activity in human serum samples and effectively screened AGIs. These promising findings highlight the potential application of the proposed strategy in clinical diabetes diagnosis and drug discovery. [ABSTRACT FROM AUTHOR]

In this study, graphene oxide supported platin, nickel and cobalt trimetallic nanoparticles (PtNiCo@GO) were prepared by the impregnation/reduction method. The catalytic performances of PtNiCo@GO catalysts prepared with different atomic ratios were investigated for hydrogen production and electro-oxidation of ammonia-borane (AB). For hydrolysis of ammonia-borane, Pt 0.8 Ni 0.1 Co 0.1 @GO catalyst exhibited higher catalytic activity than Pt 0.6 Ni 0.2 Co 0.2 @GO, Pt 0.4 Ni 0.3 Co 0.3 @GO, and Pt 0.2 Ni 0.4 Co 0.4 @GO. The hydrogen generation rate and turnover frequency values were found to be 540 mL min−1g−1 and 42.8 min−1, respectively, in the experiment conducted at 35 °C, 0.5 mmol AB, and 50 mg Pt 0.8 Ni 0.1 Co 0.1 @GO catalyst. The activation parameters (E a , ΔH # , and ΔS # ) in the catalytic hydrolysis of AB were obtained at 42.22 kJ/mol, 31.95 kJ/mol and −114.82 J/(mol × K), respectively. The effects of the PtNiCo@GO catalyst on AB electro-oxidation were made at a scanning rate of 100 mV/s in the potential range of - 1V/+1V against Ag/AgCl, and chronoamperometry measurements were made at constant potentials of - 0.2V, 0.1V and 0.4V. For cyclic voltammetry and chronoamperometry measurements, 5 mM [Fe(CN) 6 ]3/4 (1 M KCl) redox probe and 1 M NaOH + 50 mM AB solution were used. • GO-supported PtNiCo trimetallic NPs were prepared by easy and reproducible way. • PtNiCo NPs in the catalyst system have a mean size of 3.16 ± 0.24 nm. • TOF value of the catalyst is 38.57 min−1 for NH 3 BH 3 hydrolysis at 298 K. • GO-supported PtNiCo trimetallic NPs could be recycled for at least seven runs. • The Pt 0.8 Ni 0.1 Co 0.1 @GO catalyst has the best AB electro-oxidation activity. [ABSTRACT FROM AUTHOR]

Sustainable methanol formation from CO2/H2 is potentially a key process in the post-fossil chemical industry. In this study, Hf- and Zr-based metal-organic framework (MOF) materials with UiO-67 topology, functionalized with Pt nanoparticles, have been tested for CO2 hydrogenation at 30 bar and 170–240°C. The highest methanol formation rate, 14 molmethanol molPt−1 h−1, was obtained over a Hf-based catalyst, compared with the maximum of 6.2 molmethanol molPt−1 h−1 for the best Zr-based analogue. However, changing the node metal did not significantly affect product distribution or apparent activation energy for methanol formation (44–52 kJ mol−1), strongly indicating that the higher activity of the Hf-based analogues is associated with a higher number of active sites. Both catalysts showed stable catalytic performance during testing under kinetic conditions, but the addition of 2 vol% water to the feed induced catalyst deactivation, in particular the Hf-MOFs. Interestingly, mainly methanol and methane formation rates decreased, while CO formation rates were less affected by deactivation. No direct correlation was found between catalytic stability and framework stability (crystallinity, specific surface area). Experimental and computational studies suggest that water adsorption strength to the MOF node may affect the relative catalytic stability of Hf-UiO-67-Pt versus Zr-UiO-67-Pt methanol catalysts. This article is part of the discussion meeting issue 'Green carbon for the chemical industry of the future'. [ABSTRACT FROM AUTHOR]

Overcoming the trade‐off between the graphitization of the carbon substrate and enhanced electronic metal–support interaction (EMSI) and intrinsic activity of Pt‐C catalysts remains a major challenge for ensuring the durable operation of energy conversion devices. This article presents a hybrid catalyst consisting of PtFe nanoparticles and single Pt and Fe atoms supported on N‐doped carbon (PtFeNPs@PtFeSAs‐N‐C), which exhibits improved activities in hydrogen evolution and oxygen reduction reactions (HER and ORR, respectively) and has excellent durability owing to the high graphitization, rich edge defects, and porosity of the carbon in PtFeNPs@PtFeSAs‐N‐C, as well as strong EMSI between the PtFe nanoparticles and edge‐defective carbon embedded with Pt and Fe atoms. According to theoretical calculations, the strong EMSI optimizes the H* adsorption–desorption and facilitates the adsorption OOH*, accelerating the HER and ORR processes. A novel flow seawater‐Al/acid hybrid fuel cell using the PtFeNPs@PtFeSAs‐N‐C cathode can serve as a high‐efficiency energy conversion device that delivers a high power density of 109.5 mW cm−2 while producing H2 at a significantly high rate of 271.6 L m−2 h−1. Moreover, PtFeNPs@PtFeSAs‐N‐C exhibits a remarkable performance (high power density of 298.0 mW cm−2 and long‐term durability of 1000 h) in a flow Zn–air battery. [ABSTRACT FROM AUTHOR]

Ambient sunlight‐driven photothermal green syngas production via reverse water‐gas shift (RWGS) reaction is important for carbon neutrality, which lacks efficient and inexpensive catalysts at low temperatures. This studydemonstrates that the scalable Fe3O4 supported with K atoms modified Ag nanoparticles (AgK/Fe3O4) exhibits a RWGS CO production rate of 1089 mmol g−1 h−1 at 300 °C and 100% CO selectivity through dynamic structural reconstruction, surpassing all reported platinum‐based catalysts. In situ characterization and theoretical simulation indicate that the AgK nanoparticles activate H2 to reduce Fe3O4 as metallic Fe. Subsequently, the metallic Fe spontaneously reacts with CO2 to form CO and Fe3O4, thereby facilitating low‐temperature RWGS. Owing to its superior low‐temperature performance, AgK/Fe3O4 equipped with a homemade photothermal device achieves one sun‐driven photothermal RWGS with a CO production rate of 1925 mmol g−1 h−1 and a 38.7% solar to enthalpy energy conversion efficiency. Furthermore, the enlarged outdoor demonstration yields 100.6 m3day−1 of green syngas with an H2/CO ratio of 3. This work paves the way for designing efficient platinum‐free CO2 hydrogenation catalysts and introduces a new approach for sunlight‐driven scalable green syngas production. [ABSTRACT FROM AUTHOR]

One of the most significant steps for the widespread application of Proton Exchange Membrane Fuel Cells (PEMFC) is the development of an efficient and corrosion-resistant electrocatalyst for Hydrogen Oxidation Reaction (HOR). To achieve an enhanced electrocatalytic activity towards HOR, we developed a carbon-free electrocatalyst that performs on par with the Pt/C commercial-based catalyst. Pt nanoparticles dispersed on hydrogenated WO 3 surfaces were synthesized and experimentally shown to be an efficient HOR electrocatalyst. Furthermore, different characterizations and electrochemical studies validate the performances of all the hydrogenated samples. Pt/a-WO 3 /H400, hydrogenated at 400 °C, exhibits excellent electrocatalytic activity in terms of onset potential, limiting current density, and electrochemical surface area (ECSA). The membrane electrode assembly (MEA) was fabricated, and its single-cell performance was carried out using Pt/a-WO 3 /H300, Pt/a-WO 3 /H400, and Pt/a-WO 3 /H500 at the anode with Pt loading of 0.125 mg/cm2. The single-cell performance of Pt/a-WO 3 /H400 as anode electrocatalyst has the highest power density (540 mW/cm2) at 50 °C and high durability, compared to Pt/C. The enhanced electrocatalytic performance is attributed to the synergistic catalytic effect between Pt nanoparticles and the WO 3-x interface. This occurs due to the preferential orientation of the highly active (002) facet and the creation of an optimum amount of oxygen vacancies due to the hydrogenation impact. • a-WO 3 hydrogenated at different temperatures (300 °C, 400 °C, 500 °C) synthesized. • Pt/a-WO 3 /H400, hydrogenated at 400 °C, have the highest electrocatalytic activity. • Pt/a-WO 3 /H400 shows maximum power density 540 mWcm−2 at Pt loading 0.125 mgcm−2. • Presence of optimum oxygen vacancies in the a-WO 3 /H400 hydrogenated surface. • Robust SMSI interaction between Pt and a-WO 3 /H400 interface observed. [Display omitted] [ABSTRACT FROM AUTHOR]

Biohybrid solar fuel catalysts leverage natural light-driven enzymes to produce valuable fuel products. One useful biological platform for such a system is photosystem I, a pigment-protein complex that captures sunlight and converts it into chemical energy with near unity quantum efficiency, which generates low potential reducing equivalents for metabolism. Realizing and understanding the molecular basis for an approach that utilizes those electrons and stores solar energy as a fuel is therefore appealing. Here, we report the 2.27-Å global resolution cryo-EM structure of a photosystem I complex with bound platinum nanoparticles that catalyzes light-driven H2 production. The platinum nanoparticle binding sites and possible stabilizing interactions are described. Overall, the investigation reveals a direct structural look at a photon-to-fuels photosynthetic biohybrid system. Natural photosynthesis converts sunlight into chemical energy. Here, the authors present the 2.27-Å cryo-EM structure of Photosystem I bound to platinum nanoparticles, revealing insights into photon-to-fuel catalytic activity for hydrogen production. [ABSTRACT FROM AUTHOR]

The single‐entity electrochemistry (SEE) of electrocatalytic platinum (Pt) single nanoparticles (NPs) on a less electrocatalytic silver (Ag) ultramicroelectrode (UME) surface was investigated using the electrocatalytic amplification method. Two characteristic types of current responses—current staircases and blips (or spikes)—were observed during single NP collision experiments, depending on the applied potential at the Ag UME. Notably, at applied potentials of 0.13 and 0.17 V, the Ag UME becomes passive due to the formation of a delicate oxide layer, resulting in a highly stable background current. This leads to an enhanced signal‐to‐noise (S/N) ratio, attributed to the low background current, when using Ag UME compared to commonly used UMEs such as Au, C, Ni, and Hg for the SEE of Pt NPs. The exceptionally low background current can provide a significant advantage for detailed observation of SEE signals and further mechanistic studies based on the current response. [ABSTRACT FROM AUTHOR]

An electrochemical biosensor was created to identify the liver cancer marker alpha-fetoprotein (AFP) by employing nanocomposite materials. A combination of reduced graphene oxide (rGO) and molybdenum disulfide (MoS2) was selected as the substrate material for the sensor to prepare the PtNPs/MoS2@rGO electrochemical immunosensor. Among them, rGO has strong conductivity and MoS2 provides a large surface area for the anchoring of PtNPs for better attachment to the hybridized nanomaterials. Meanwhile, PtNPs exhibit consistent biocompatibility and excellent electrocatalytic activity. PtNPs also attach to hybrid nanomaterials and bind the antibody via the Pt–S bond, thereby furnishing the antibody with multiple binding sites for enhanced antibody adhesion. The immunosensor achieved ultra-sensitive AFP detection by exploiting the specific antigen–antibody binding. The structure and morphology of the PtNPs/MoS2@rGO composites were investigated by transmission electron microscopy (TEM), energy dispersive X-ray (EDS) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy, and the sensor was electrochemically characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under optimized conditions, using differential pulse voltammetry the biosensor detected AFP in serum within a linear range of 1 ~ 105 pg/mL, with a correlation coefficient (r2) of 0.9989, and a detection limit of 0.12 pg/mL (S/N = 3). The method offers a new approach for the ultrasensitive detection of serum AFP and is extremely selective, accurate, and precise with a relative standard deviation (RSD) of less than 6%. It has been successfully applied to the analysis of real human blood samples. [ABSTRACT FROM AUTHOR]

This study aims to investigate the effect of colloidal platinum nanoparticles (CPN) on the durability of resin-dentin bonding performance with contemporary adhesives. Sixty non-carious human maxillary premolars were subjected to microtensile bond strength (µTBS) testing and divided into two main groups: CPN-treated and untreated. Within each group, specimens were randomly allocated to Clearfil Megabond 2 (MB2), Scotchbond Universal Plus Adhesive with self-etch mode (SE-SUP), and etch-and-rinse mode (ER-SUP) subgroups (n = 10/group). CPN was applied to dentin in the MB2 and SE-SUP groups for 20 s, followed by rinsing before adhesive application. In the ER-SUP group, CPN was applied after etch-and-rinse. The µTBS was tested after 24 h, 6 months, and 1 year, and the fracture modes were observed using SEM. The µTBS data were analyzed using a two-way ANOVA and post-hoc Tukey HSD test (α = 0.05). An additional twelve premolars underwent TEM/STEM/EDX for ultra-morphological observations. The application of CPN significantly prevented a decline in the µTBS of both the MB2 and SE-SUP groups. No significant decrease was observed in the ER-SUP group, either with aging or CPN application. Ultra-morphological images revealed platinum nanoparticles attaching to the collagen fibrils of the hybrid layer regardless of aging. It was highlighted that the nanoparticles attached to the banded collagen in the aging groups were observed. CPN exhibits the potential in enhancing the longevity of resin-dentin bonding in SE mode. [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]

Interactions between gold metallic nanoparticles and molecular dyes have been well described by the nanometal surface energy transfer (NSET) mechanism. However, the expansion and testing of this model for nanoparticles of different metal composition is needed to develop a greater variety of nanosensors for medical and commercial applications. In this study, the NSET formula was slightly modified in the size-dependent dampening constant and skin depth terms to allow for modeling of different metals as well as testing the quenching effects created by variously sized gold, silver, copper, and platinum nanoparticles. Overall, the metal nanoparticles followed more closely the NSET prediction than for Förster resonance energy transfer, though scattering effects began to occur at 20 nm in the nanoparticle diameter. To further improve the NSET theoretical equation, an attempt was made to set a best-fit line of the NSET theoretical equation curve onto the Au and Ag data points. An exhaustive grid search optimizer was applied in the ranges for two variables, 0.1 ≤ C ≤ 2.0 and 0 ≤ α ≤ 4 , representing the metal dampening constant and the orientation of donor to the metal surface, respectively. Three different grid searches, starting from coarse (entire range) to finer (narrower range), resulted in more than one million total calculations with values C = 2.0 and α = 0.0736 . The results improved the calculation, but further analysis needed to be conducted in order to find any additional missing physics. With that motivation, two artificial intelligence/machine learning (AI/ML) algorithms, multilayer perception and least absolute shrinkage and selection operator regression, gave a correlation coefficient, R 2 , greater than 0.97 , indicating that the small dataset was not overfitting and was method-independent. This analysis indicates that an investigation is warranted to focus on deeper physics informed machine learning for the NSET equations. [ABSTRACT FROM AUTHOR]

[Display omitted] The electrocatalytic oxygen reduction reaction (ORR) is crucial for energy conversion systems such as fuel cells and metal-air batteries. Boron carbon nitrogen (BCN) is a novel functional material with a high specific surface area, excellent corrosion resistance, and outstanding electrochemical stability. These properties make BCN an effective ORR catalyst and a promising support for metal catalysts. This study leveraged the strong interaction between BCN and metals to anchor platinum nanoparticles (Pt NPs) onto the BCN surface (Pt/BCN), significantly enhancing the durability of traditional Pt/C catalysts in ORR. The half-wave potential of Pt/BCN is 0.927 V, higher than Pt/XC-72R (0.857 V) and commercial Pt/C (0.879 V). Notably, after 10,000 durability test cycles, the mass activity (MA) of Pt/XC-72R and commercial Pt/C decreased by 67 % and 75 %, respectively. Even after 50,000 cycles, Pt/BCN exhibited only a 54 % decrease in MA. Experimental data and density functional theory calculations confirmed increased electron transfer from Pt to the BCN support, indicating a strong electronic metal-support interaction (EMSI) between Pt and BCN. This strong EMSI effectively anchored the Pt NPs, preventing migration and aggregation during the ORR process. Consequently, our research introduces a novel electrocatalyst support material with significant potential for ORR and broader applications. [ABSTRACT FROM AUTHOR]

The performance of nickel and platinum bimetallic nanoparticles (NPs) supported on potassium niobate (KNbO3) is evaluated in the catalytic hydrolysis of sodium borohydride (NaBH4) to generate hydrogen (H2). KNbO3 was synthesized via a hydrothermal route using Nb2O5 and KOH as precursors. X-ray diffraction (XRD) confirmed the crystalline orthorhombic structure of KNbO3. The Ni/Pt NPs, with an average size of 4.66 nm and a spherical morphology, were uniformly dispersed on the surface of KNbO3 nanosheets. The N2 physisorption isotherms of KNbO3 and Ni/Pt NPs were classified as type V with H3 hysteresis, showing specific surface areas of 0.170 and 2.87 m2 g−1, respectively. Catalytic performance studies examined various Ni/Pt molar ratios, with the 1:3 ratio (mol/mol) demonstrating the highest efficiency. Kinetic analysis of NaBH4 hydrolysis showed that the data fit the pseudo-first-order model. An increase in temperature enhanced the hydrogen generation rate (HGR), reaching 2068.3 mL gcat−1 min−1 at 315.05 K. The apparent activation energy (Ea) was determined to be 29.9 kJ mol−1. Durability assays showed only an 11% decrease in activity after 11 catalytic cycles. Thus, a promising, easy-to-synthesize, and environmentally friendly catalyst for NaBH4 hydrolysis has been developed. [ABSTRACT FROM AUTHOR]

Transition metal dichalcogenides (TMDs) have emerged as a focal point in electrocatalysis, particularly for the hydrogen evolution reaction (HER), owing to their notable catalytic activity, chemical stability, and cost‐efficiency. Despite these advantages, the challenge of devising a practical and economical method for their large‐scale application in HER remains an unresolved and critical issue. In this study, a facile, scalable, and cost‐effective approach is introduced for producing high‐yield, catalytically active TMD nanoparticles, including MoS2, MoSe2, RuS2, and RuSe2. These nanoparticles are synthesized through an aqueous room‐temperature process, which is not only environmentally friendly but also economically feasible for large‐scale production. Remarkably, these TMD nanoparticles exhibit versatile catalytic activity across a broad pH range for HER. Among them, RuSe2 nanoparticles demonstrate catalytic performance comparable to that of a commercial Pt/C electrode. Upon scaling up, the nanomaterials show great potential for integration into practical proton exchange membrane water electrolyzers, maintaining high efficiency even at large current densities and exhibiting very stable performance for up to 100 h. This research paves the way to a sustainable synthesis method of high‐performance catalysts, tailored for industrial hydrogen production applications. [ABSTRACT FROM AUTHOR]

Hydrogen fuel cells and water electrolyzers hold significant potential for net zero emission and climate change mitigation, but their practical applications are limited by the use of the precious-metal platinum as catalysts. In this study, a one-pot method is developed for the synthesis of PtCo x alloys supported on hybrid carbon materials, and it is found that the developed catalysts with reduced Pt loading can act as excellent bifunctional catalysts for both oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). Morphology and composition characterizations indicate uniform dispersion and adjustable composition of PtCo x alloys with the particle size of ∼3 nm on the carbon support. Among them, Pt 3 Co/C achieves the highest ORR performance with a high mass activity of 179.23 A/g and a specific activity of 3.15 A/m2 in acidic condition, and an extremely low overpotential of 47.6 mV at 10 mA/cm2 in alkaline media as a HER catalyst. This study presents a cost-effective approach for the development of high performance PtCo x /C catalysts, and confirms their potential application in hydrogen energy technologies. [Display omitted] • A facile one-pot synthesis approach of PtCo x /C is developed. • The PtCo x particles with the size of ∼3 nm disperses uniformly on carbon support. • The Pt 3 Co/C exhibits excellent catalytic activity towards both ORR and HER. • Catalytic performance can be optimized by adjusting synthesis conditions. [ABSTRACT FROM AUTHOR]

The interfacial characteristics of platinum (Pt) metal catalysts can be systematically regulated by interacting them with electropositive metals, leading to synergistic interactions for extensive catalytic applications. In this study, an evenly dispersed polyol-synthesized iron (Fe)-promoted Pt bimetallic nanoparticle (BNPs) system was embedded in MIL-101(Cr). The PtFe 2 @MIL-101(Cr) catalyst unveiled remarkable activity (86%) and selectivity (89%) for the superior hydrogenation of the targeted C O bond of cinnamaldehyde (CAL). The exceptional hydrogenation performance can be credited to the interplay of the geometric and electronic properties arising from charge shuttling between Fe and Pt within the homogenously distributed Pt–Fe bimetallic nanoparticle system. The experimental results indicate enhanced valence electrons in the Pt d-band through the mutual synergetic interface between the Pt and Fe BNPs. Consequently, these Fe–Pt sites functioned as interfacial electrophilic and nucleophilic (Lewis acid-base) sites, enhancing H 2 activation and facilitating C O bond conversion to yield unsaturated cinnamal alcohols (COL). Additionally, the narrow pores of MIL-101(Cr) encapsulating the Pt–Fe BNPs induced steric hindrance, allowing only C O bond hydrogenation. Furthermore, the PtFe 2 @MIL-101(Cr) catalyst maintained its optimal hydrogenation performance over five cycles, demonstrating no substantial loss in either CAL conversion or COL yield, thus endorsing the universal practical applicability of the catalyst. [Display omitted] • Polyol-synthesized iron (Fe) promoted Pt bimetallic nanoparticle (BNPs) systems embedded in MIL-101(Cr). • PtFe 2 @MIL-101(Cr) showed remarkable activity in the hydrogenation of cinnamaldehyde. • The exceptional performance can be attributed to the interplay of the geometric and electronic properties arising from the Pt–Fe BNPs. • The PtFe 2 @MIL-101(Cr) catalyst maintained optimal performance over a series of five cycles. [ABSTRACT FROM AUTHOR]

In the present work, exfoliated graphitic carbon nitride (g‐CN) is immobilized on carbon paper substrates by a simple electrophoretic route, and subsequently decorated with ultra‐low amounts (≈μg/cm2) of Pt nanoparticles (NPs) by cold plasma sputtering. Optimization of preparative conditions allowed a fine tuning of Pt NPs size, loading and distribution and thus a controlled tailoring of g‐CN/Pt interfacial interactions. Modulation of such features yielded g‐CN‐Pt‐based anode materials with appealing activity and stability towards the ethanol oxidation reaction (EOR) in alkaline aqueous solutions, as revealed by electrochemical tests both in the dark and under irradiation. The present results provide new insights on the design of nano‐engineered heterocomposites featuring improved performances thanks to Pt coupling with g‐CN, a low‐cost and environmentally friendly visible light‐active semiconductor. Overall, this work might open attractive avenues for the generation of green hydrogen via aqueous ethanol electrolysis and the photo‐promoted alcohol electrooxidation in fuel cells. [ABSTRACT FROM AUTHOR]

Recent advances in electrosynthesis of nanomaterials expanded structural and compositional variations accessible by the electrochemical method; however, reliably synthesizable morphological variety fall shy of that available by conventional solvothermal synthesis. In this communication, electrochemical preparation of surfactant‐free hollow nanoparticles is demonstrated. By anodic conversion of core‐shell precursors with metastable cores, hollowed nickel nanoparticles with uniform dimensions were synthesized and characterized. Implementation of TEM grids as the working electrodes, identical location tracking of the morphological evolution of single particles to anodic stimulus has been demonstrated. The synthesized nanoparticles were employed as catalysts for the alkaline hydrogen evolution reaction and exhibited catalytic rates that compare favorably to the Pt/C benchmark. This marks the first pure electrochemical synthesis of hollow nanoparticles and shall contribute to the structural diversification of electrosynthesized nanomaterials. [ABSTRACT FROM AUTHOR]

Oak bark, which is commonly used in the wood industry, has by-products often repurposed as fuel. Its extracts are rich in compounds with anticancer, antibacterial, antifungal, and anti-inflammatory properties. This study synthesized platinum nanoparticles (PtNPs) using aqueous extracts from Quercus dalechampii (QD), Q. frainetto (QF), and Q. petraea (QP). Key factors during nanoparticle formation included reaction time, metal ion concentration, pH, extract-to-metal ion ratio, and temperature. The PtNPs were characterized by dynamic light scattering, Fourier transform infrared spectroscopy, and transmission electron microscopy. The average diameters were 58.5 ± 7.6 nm for QD-PtNPs, 41.6 ± 5.4 nm for QF-PtNPs, and 41 ± 5.3 nm for QP-PtNPs. Antioxidant and antimicrobial activities were also analyzed. The QP-PtNPs had the highest DPPH (2,2-Diphenyl- 1-picrylhydrazyl), FRAP (Ferric Reducing Antioxidant Power), and CUPRAC (Cupric Reducing Antioxidant Capacity) free radical scavenging activities, while QD-PtNPs excelled in ABTS (2,2'-azinobis-(3- ethylbenzothiazoline-6-sulfonic acid)) scavenging. All PtNPs showed strong antimicrobial properties, particularly against Enterococcus faecalis, Escherichia coli, Candida krusei, and Candida auris. These findings suggest that Quercus-mediated PtNPs have significant potential for developing treatments against bacterial and fungal infections, with promising applications in medicine. [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]

Pt-based intermetallic compound (IMC) nanoparticles have been considered the most promising catalysts for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFC). Herein, we propose a strategy for producing ordered Pt3(CoNi) ternary IMC nanoparticles supported on N-doped carbon materials. Particularly, the Co and Ni are originally embedded into ZIF-derived carbon, which diffuse into Pt nanocrystals to form Pt3(CoNi) nanoparticles. Moreover, a thin layer of carbon develops outside of Pt3(CoNi) nanoparticles during the cooling process, which contributes to stabilizing the Pt3(CoNi) on carbon supports. The optimal Pt3(CoNi) nanoparticle catalyst has achieved significantly enhanced activity and stability, exhibiting a half-wave potential of 0.885 V vs reversible hydrogen electrode (RHE) and losing only 16 mV after 10,000 potential cycles between 0.6 and 1.0 V. Unlike the direct-use commercial carbon (VXC-72) for depositing Pt, we utilized ZIF-derived carbon containing dispersed Co and Ni nanocluster or nanoparticles to prepare ordered Pt3(CoNi) intermetallic catalysts. [ABSTRACT FROM AUTHOR]

Transmission electron microscopy (TEM) plays a crucial role in heterogeneous catalysis for assessing the size distribution of supported metal nanoparticles. Typically, nanoparticle size is quantified by measuring the diameter under the assumption of spherical geometry, a simplification that limits the precision needed for advancing synthesis‐structure‐performance relationships. Currently, there is a lack of techniques that can reliably extract more meaningful information from atomically resolved TEM images, like nuclearity or geometry. Here, cycle‐consistent generative adversarial networks (CycleGANs) are explored to bridge experimental and simulated images, directly linking experimental observations with information from their underlying atomic structure. Using the versatile Pt/CeO2 (Pt particles centered ≈2 nm) catalyst synthesized by impregnation, large datasets of experimental scanning transmission electron micrographs and physical image simulations are created to train a CycleGAN. A subsequent size‐estimation network is developed to determine the nuclearity of imaged nanoparticles, providing plausible estimates for ≈70% of experimentally observed particles. This automatic approach enables precise size determination of supported nanoparticle‐based catalysts overcoming crystal orientation limitations of conventional techniques, promising high accuracy with sufficient training data. Tools like this are envisioned to be of great use in designing and characterizing catalytic materials with improved atomic precision. [ABSTRACT FROM AUTHOR]

Solid‐state dewetting is the heat‐induced agglomeration of thin metal films into defined nanoparticles (NPs). Dewetted Pt nanoparticles are investigated on F‐doped SnO2 (FTO) substrates as model binder‐free electrodes for the hydrogen evolution reaction (HER). Dewetting of Pt films into particles exposes the FTO substrate and the metal/support (Pt‐FTO) contact line. Despite the decrease in Pt electrochemical surface area (ECSA) upon dewetting, dewetted NPs show a >3‐fold increase in ECSA‐normalized HER activity compared to as‐deposited nanocrystalline Pt films. Electrodes designed with dewetted Pt NPs of different sizes show that the HER activity does not only correlate with the ECSA but also increases with increasing the Pt‐FTO contact line length. The smaller the NPs, the larger the Pt‐FTO contact line, and the higher the activity. This effect is ascribed to electronic metal‐support interaction (EMSI), due to electron transfer from FTO to Pt. It is proposed that EMSI effects alter the electronic structure of Pt sites near the Pt‐FTO contact line, facilitating the H2 evolution kinetics. When NPs are a few nm‐sized, a large mass fraction of Pt is affected by EMSI, resulting in a further increase of HER activity compared to NPs ≥10 nm despite the lower ECSA. [ABSTRACT FROM AUTHOR]

Platinum and ruthenium nanoparticles stabilised by an amine modified polymer immobilised ionic liquid (MNP@NH2-PEGPIILS, M = Pt, Ru) catalyse the hydrolytic liberation of hydrogen from dimethylamine borane (DMAB), ammonia borane (AB) and NaBH4 under mild conditions. While RuNP@NH2-PEGPIILS and PtNP@NH2-PEGPIILS catalyse the hydrolytic evolution of hydrogen from NaBH4 with comparable initial TOFs of 6,250 molesH2.molcat−1.h−1 and 5,900 molesH2.molcat−1.h−1, respectively, based on the total metal content, RuNP@NH2-PEGPIILS is a markedly more efficient catalyst for the dehydrogenation of DMAB and AB than its platinum counterpart, as RuNP@NH2-PEGPIILS gave initial TOFs of 8,300 molesH2.molcat−1.h−1 and 21,200 molesH2.molcat−1.h−1, respectively, compared with 3,050 molesH2.molcat−1.h−1 and 8,500 molesH2.molcat−1.h−1, respectively, for PtNP@NH2-PEGPIILS. Gratifyingly, for each substrate tested RuNP@NH2-PEGPIILS and PtNP@NH2-PEGPIILS were markedly more active than commercial 5wt % Ru/C and 5wt% Pt/C, respectively. The apparent activation energies of 55.7 kJ mol−1 and 27.9 kJ mol−1 for the catalytic hydrolysis of DMAB and AB, respectively, with RuNP@NH2-PEGPIILS are significantly lower than the respective activation energies of 74.6 kJ mol−1 and 35.7 kJ mol−1 for its platinum counterpart, commensurate with the markedly higher initial rates obtained with the RuNPs. In comparison, the apparent activation energies of 44.1 kJ mol−1 and 46.5 kJ mol−1, for the hydrolysis NaBH4 reflect the similar initial TOFs obtained for both catalysts. The difference in apparent activation energies for the hydrolysis of DMAB compared with AB also reflect the higher rates of hydrolysis for the latter. Stability and reuse studies revealed that RuNP@NH2-PEGPIILS recycled efficiently as high conversions for the hydrolysis of DMAB were maintained across five runs with the catalyst retaining 97% of its activity. [ABSTRACT FROM AUTHOR]

For global deployment of proton exchange membrane fuel cells, achieving optimal interaction between the components of the cathode active layer remains challenging. Studies addressing the effect of nanoparticle location (inside vs outside of pores) on performance and durability mostly compare porous and nonporous carbon supports, thus coming short of decoupling nanoparticle locality from carbon support effects. To address the influence of nanoparticle locality on performance and durability, new carbon‐supported electrocatalysts with designed and distinct nanoparticle localities are presented. The developed methodology allows to place Pt nanoparticles preferentially inside or outside of the mesopores of conductive carbon supports from materials under development at Cabot Corporation. Synthesis protocols are tuned to control nanoparticle size, crystallinity, and loading; this way the effect of Pt locality can be studied for two experimental carbon supports in isolation from all other parameters. For one carbon support, Pt active surface area and activity are significantly lower when nanoparticles are placed inside the pores. In contrast, for another, more graphitic carbon support, placing nanoparticles inside or outside of the carbon pores produces no appreciable difference in active surface area and performance rotating disk electrode measurements. Given their carefully tailored structure, these catalysts provide a framework for evaluating locality‐performance‐durability relationships. [ABSTRACT FROM AUTHOR]

The catalytic activity of platinum for CO oxidation depends on the interaction of electron donation and back‐donation at the platinum center. Here we demonstrate that the platinum bromine nanoparticles with electron‐rich properties on bromine bonded with sp‐C in graphdiyne (PtBr NPs/Br‐GDY), which is formed by bromine ligand and constitutes an electrocatalyst with a high CO‐resistant for methanol oxidation reaction (MOR). The catalyst showed peak mass activity for MOR as high as 10.4 A mgPt−1, which is 20.8 times higher than the 20 % Pt/C. The catalyst also showed robust long‐term stability with slight current density decay after 100 hours at 35 mA cm−2. Structural characterization, experimental, and theoretical studies show that the electron donation from bromine makes the surface of platinum catalysts highly electron‐rich, and can strengthen the adsorption of CO as well as enhance π back‐donation of Pt to weaken the C−O bond to facilitate CO electrooxidation and enhance catalytic performance during MOR. The results highlight the importance of electron‐rich structure among active sites in Pt‐halogen catalysts and provide detailed insights into the new mechanism of CO electrooxidation to overcome CO poisoning at the Pt center on an orbital level. [ABSTRACT FROM AUTHOR]

Raman spectroscopic data of quenching phases in experiments on the dissolution of Pt in reduced carbonic fluid, containing about 30 mol % of CO, both with and without chlorine at P = 200 MPa and T = 950–1000°C are presented. Water content in the fluid was no more than 4.5 mol %. The only soluble form of Pt determined in the acetone solution of the quenching phases and in the experimental products is platinum carbonyl. Low concentrations of carbonyl (no more than a few ppm) become detectable using Raman spectroscopy due to the SERS effect (Surface-Enhanced Raman Scattering), which is possible in the presence of Pt nanoparticles in the objects under study. Platinum nanoparticles, formed at the decomposition of carbonyls, generates specific photoluminescence (PL) peak approximated by Gaussian with parameters FWHM = 1050–1300 cm–1, kmax = 2050–2100 cm–1 both in acetone solution and experimental samples. The spectra of CO (main band k ≈ 2050 cm–1) adsorbed on Pt nanoparticles supported on glassy carbon, formed during the decomposition of excess CO relative to the CCO buffer, corresponded to nanoparticle sizes of about 2 nm. No convincing evidence of a mixed chloride-carbonyl composition of platinum was found in the spectra, which may reflect the lower thermodynamic stability of these mixed complexes at high P-T parameters. Large concentrations of platinum Pt on carbon (up to 2000–3000 ppm) can be explained by the formation of the Pt-C matrix bond and the weakening of the Pt-CO bond in carbonyls, causing their decomposition. Unusual PL peaks were detected in samples from experiments with chlorine-containing fluids, very reminiscent of the PL background of noble metal nanoparticles and attributed to the effect of carbon nanoparticles. [ABSTRACT FROM AUTHOR]

Platinum (Pt) metal is widely acknowledged as a highly efficient electrocatalyst for hydrogen evolution reaction (HER) in acidic electrolyte. However, its performance in alkaline environments is significantly lower owing to the sluggish water dissociation step. Herein, we synthesized an ultrahigh Pt-mass-activity alkaline HER catalyst using microwave reduction method in air. Our catalyst, PtRu@CNT, comprises PtRu alloy nanoparticles uniformly loaded on carbon nanotubes, with Pt and Ru contents of 12.3 wt% and 4.5 wt%, respectively. The PtRu alloy nanoparticles have an average diameter of about 3 nm and a face-centered cubic structure, and the introduction of Ru has led to a modified electronic structure in Pt. As a result, an impressively low HER overpotential of 13 mV was achieved, significantly lower than commercial 20 wt% Pt/C (61 mV). PtRu@CNT exhibited a high turnover frequency based on metal mass of 3.06 s−1 at 100 mV, about 6 times higher than commercial Pt/C (0.46 s−1 at 100 mV), highlighting its excellent intrinsic activity. The HER mechanism of PtRu@CNT is a Volmer-Tafel mechanism, where the rate-limiting step changed to the recombination of hydrogen atoms from initial water dissociation, attributed to the presence of Ru. The alkaline HER activity of PtRu@CNT ranks among the best of currently reported Pt-based catalysts. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Tiangong University is the property of Journal of Tianjin Polytechnic University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

When platinum-containing diesel oxidation catalysts (DOC) are exposed to high temperatures under lean conditions, the platinum nanoparticles form volatile platinum dioxide on the catalyst surface. The exhaust flow carries the volatile platinum dioxide to the downstream aftertreatment catalyst, such as the selective catalytic reduction (SCR) catalyst, that is responsible for reducing the nitrogen oxides (NOx) emissions and can negatively impact its performance, by promoting the parasitic oxidation of ammonia. Here we investigate the factors such as exposure time, temperature and DOC design characteristics for their impact on the platinum dioxide migration, by characterising the amount of platinum deposited on the SCR catalyst at very low levels (<5 ppm), using inductively coupled plasma optical emission spectroscopy (ICP-OES) fire assay technique. Our results indicate that welldispersed platinum, not associated with palladium, is most prone to platinum dioxide migration. We also compare several methods to suppress the platinum dioxide migration from the DOC, such as sintering of the platinum nanoparticles, stabilising the platinum nanoparticles via interaction with palladium or covering the platinum nanoparticles with a high surface area capture layer to trap the volatile platinum dioxide. [ABSTRACT FROM AUTHOR]

The measurement of cardiac troponin I (cTnI) is of vital importance for the early diagnosis of acute myocardial infarction. In this study, an enhanced electrochemiluminescent immunoassay for the highly sensitive and precise determination of cTnI was reported. A biomimetic chip with nepenthes peristome surface microstructures to achieve single-layer microbead arrays and integrated microelectrode arrays (MEAs) for ECL detection was microfabricated. Ru@SiO2 nanoparticles were prepared as signal amplificators labeling immunomagnetic beads. Dendrimer-encapsulated platinum nanoparticles (Pt DENs) were electrochemically modified on ITO MEAs. The resulting Pt DEN-modified ITO MEAs preserved good optical transparency and exhibited an approximately 20-fold ECL signal amplification compared to that obtained from bare ITO. The method made full use of the biomimetic chip with Pt DENs to develop single-layer immunomagnetic bead arrays with increasingly catalyzed electrochemical oxidation of the [Ru(bpy)3]2+–TPA system. Consequently, a limit of detection calculated as 0.38 pg/mL (S/N = 3) was obtained with excellent selectivity, demonstrating significant potential for the detection of cTnI in clinical diagnostics. [ABSTRACT FROM AUTHOR]

• 10 wt% EG expandable graphite (EG) and TiO 2 nanocomposites are prepared using the high shear method. • Pt nanoparticles (NPs) were loaded on EG-TiO 2 to prepare the Pt/10EG-TiO 2 –10 catalyst. • EG doping and electrostatic adsorption achieve the closure of the dispersible space of pt NPs on EG-TiO 2. • Pt/10EG-TiO 2 –10 exhibits good CO oxidation activity and resistance to H 2 O and SO 2 at GHSV = 400,000 h −1. • EG doping increases the hydrophobicity of TiO 2 , reducing H 2 O adsorption and SO 2 oxidation by the catalyst. The expandable graphite (EG) modified TiO 2 nanocomposites were prepared by the high shear method using the TiO 2 nanoparticles (NPs) and EG as precursors, in which the amount of EG doped in TiO 2 was 10 wt.%. Followed by the impregnation method, adjusting the pH of the solution to 10, and using the electrostatic adsorption to achieve spatial confinement, the Pt elements were mainly distributed on the exposed TiO 2 , thus generating the Pt/10EG-TiO 2 –10 catalyst. The best CO oxidation activity with the excellent resistance to H 2 O and SO 2 was obtained over the Pt/10EG-TiO 2 –10 catalyst: CO conversion after 36 hr of the reaction was ca. 85% under the harsh condition of 10 vol.% H 2 O and 100 ppm SO 2 at a high gaseous hourly space velocity (GHSV) of 400,000 hr−1. Physicochemical properties of the catalysts were characterized by various techniques. The results showed that the electrostatic adsorption, which riveted the Pt elements mainly on the exposed TiO 2 of the support surface, reduced the dispersion of Pt NPs on EG and achieved the effective dispersion of Pt NPs, hence significantly improving CO oxidation activity over the Pt/10EG-TiO 2 –10 catalyst. The 10 wt.% EG doped in TiO 2 caused the TiO 2 support to form a more hydrophobic surface, which reduced the adsorption of H 2 O and SO 2 on the catalyst, greatly inhibited deposition of the TiOSO 4 and formation of the PtSO 4 species as well as suppressed the oxidation of SO 2 , thus resulting in an improvement in the resistance to H 2 O and SO 2 of the Pt/10EG-TiO 2 –10 catalyst. 10 wt% EG-TiO 2 nanocomposites were first prepared using the high shear method, and then Pt NPs were loaded on EG-TiO 2 to generate the Pt/10EG-TiO 2 –10 catalyst. Pt/10EG-TiO 2 –10 shows high CO oxidation activity at low temperatures and good resistance of H 2 O and SO 2. The doping of EG increases the hydrophobicity of TiO 2 , thus reducing the adsorption of H 2 O and the oxidation of SO 2 by the catalyst. [Display omitted] [ABSTRACT FROM AUTHOR]

A Gaussian approximation machine learning interatomic potential for platinum is presented. It has been trained on density-functional theory (DFT) data computed for bulk, surfaces, and nanostructured platinum, in particular nanoparticles. Across the range of tested properties, which include bulk elasticity, surface energetics, and nanoparticle stability, this potential shows excellent transferability and agreement with DFT, providing state-of-the-art accuracy at a low computational cost. We showcase the possibilities for modeling of Pt systems enabled by this potential with two examples: the pressure–temperature phase diagram of Pt calculated using nested sampling and a study of the spontaneous crystallization of a large Pt nanoparticle based on classical dynamics simulations over several nanoseconds. [ABSTRACT FROM AUTHOR]