Ultrafine Nanoparticles Research Articles

Ultrafine Ni-MoOx Nanoparticles Anchored on Nitrogen-Doped Carbon Nanosheets: A Highly Efficient Noble-Metal-Free Catalyst for Ammonia Borane Hydrolysis.

The development of low-cost and high-efficiency catalysts for the hydrolytic dehydrogenation of ammonia borane (AB, NH3BH3) is still a challenging technology. Herein, ultrafine MoOx-doped Ni nanoparticles (~3.0 nm) were anchored on g-C3N4@glucose-derived nitrogen-doped carbon nanosheets via a phosphate-mediated method. The strong adsorption of phosphate-mediated nitrogen-doped carbon nanosheets (PNCS) for metal ions is a key factor for the preparation of ultrasmall Ni nanoparticles (NPs). Notably, the alkaline environment formed by the reduction of metal ions removes the phosphate from the PNCS surface to generate P-free (P)NCS so that the phosphate does not participate in the subsequent catalytic reaction. The synthesized Ni-MoOx/(P)NCS catalysts exhibited outstanding catalytic properties for the hydrolysis of AB, with a high turnover frequency (TOF) value of up to 85.7 min-1, comparable to the most efficient noble-metal-free catalysts and commercial Pt/C catalyst ever reported for catalytic hydrogen production from AB hydrolysis. The superior performance of Ni-MoOx/(P)NCS can be ascribed to its well-dispersed ultrafine metal NPs, abundant surface basic sites, and electron-rich nickel species induced by strong electronic interactions between Ni-MoOx and (P)NCS. The strategy of combining multiple modification measures adopted in this study provides new insights into the development of economical and high-efficiency noble-metal-free catalysts for energy catalysis applications.

Hydrogen‐Induced Disproportionation of Samarium‐Cobalt Intermetallics Enabling Promoted Hydrogen Evolution Reaction Activity and Durability in Alkaline Media

AbstractTransition‐metal nanoparticles hold great promise as electrocatalysts for alkaline hydrogen evolution reaction (HER), however, addressing the simultaneous challenges of ensuring sufficient active sites, promoting favorable water dissociation, and optimizing binding energy toward hydrogen intermediates remains a formidable task. To overcome these hurdles, a novel gaseous hydrogen engineering strategy is proposed by in situ embedding cobalt nanoparticles within a samarium hydride matrix (Co/SmH2) via hydrogen‐induced disproportionation of SmCo5 particles for efficient alkaline HER. The as‐designed Co/SmH2 delivered an overpotential as low as 252 mV at 100 mA cm−2, surpassing the performance of pristine Co by 100 mV. Notably, this catalyst lasts remarkably long maintaining a durability at ≈500 mA cm−2 for 120 h. A combination of in situ Raman spectroscopy, in situ X‐ray absorption spectroscopy, density functional theory calculation and post‐HER characterizations unambiguously unveiled that the surface SmH2 transforms into samarium (hydr)oxide during electrocatalysis. This transformation not only inhibits the aggregation of the ultrafine cobalt nanoparticles but also significantly enhances the water dissociation and optimizes the binding energy of active cobalt species toward hydrogen intermediate, resulting in concurrent improvement of kinetics, thermodynamics, and stability of the HER process.

Microwave-assisted ultrafine silver nanoparticle synthesis using Mitragyna speciosa for antimalarial applications

Abstract This study investigates the antiplasmodial activity of ultrafine silver nanoparticles (AgNPs, 2–5 nm) synthesized using a green approach involving the Mitragyna speciosa extract and emphasizing the microwave-assisted irradiation technique. Various synthesis parameters were optimized, resulting in the successful production of spherical AgNPs, which exhibited a characteristic surface plasmon resonance peak at around 440 nm. The synthesized AgNPs demonstrated high stability, indicated by a zeta potential value of −28 mV. The antimalarial efficacy of the microwave-assisted AgNPs against the P. falciparum strain was evaluated, demonstrating a half-maximum inhibitory concentration (IC50) value of 1.56 µg·mL−1. Further enhancement in the antimalarial performance was observed when the AgNPs were conjugated with chloroquine (CQ), a traditional antimalarial drug, achieving an impressive IC50 value of 24 ng·mL−1. Additionally, all formulations exhibited low toxicity, with a cytotoxic concentration (CC50) exceeding 800 µg·mL−1 in Vero cells. Complementing these experimental findings, specific computational studies offered insights into the interactions between silver atoms and bioactive compounds in M. speciosa, as well as shedding light on the dynamics of CQ functionalization. These experimental and computational findings emphasize the potential of a sustainable, low-toxicity, and cost-effective AgNP synthesis process, showcasing significant promise in advancing green nanotechnology for the development of effective antimalarial medications.

A universal and ultrafast method for fabricating a library of nanocellulose-supported metal nanoparticles

Using nanocatalysts to catalyze water electrolysis for hydrogen production is an ideal solution to address the energy crisis. The most well-adopted fabrication methods for nanocatalysts are tube furnace annealing, Hydrothermal method, etc., hardly satisfying the trade-off among coarsening, dispersity, and particle size due to mutual restrictions. Herein, a universal, ultrafast and facile cellulose nanometer whiskers-high temperature shock (CNW-HTS) method was reported for fabricating a library of ultrafine metal nanoparticles with uniform dispersion and narrow size distribution. The metal-anchor functional groups in CNW (i.e., –OH and –COOH) and the characteristics of the HTS method for ultrafast heating and powerful quenching synergistically contribute to the successful synthesis of metal nanoparticles. As an initial demonstration, the as-prepared Pt nanocatalyst (η10 ​mA ​cm−2 ​= ​51.8 ​mV) shows more excellent catalytic hydrogen evolution reaction (HER) performance than the Pt catalyst prepared in the tubular furnace (η10 ​mA ​cm−2 ​= ​169.4 ​mV). This rapid and universal CNW-HTS method can pave the way for nanomanufacturing to produce high-quality metal nanoparticles, thereby expanding applications of energy conversion and electrocatalysis.

Total hydrogenation of furfural on Pd/COFs under mild conditions

Total hydrogenation of furfural (FAL) is an efficient way to produce the industrially important tetrahydrofurfuryl alcohol (THFOL). However, it is a challenge to obtain highly selective catalysts for this transformation especially under mild reaction conditions. Herein, we report that the β-ketoenamine-linked covalent organic framework (TpBD COF) supported ultrafine Pd nanoparticles exhibit significantly enhanced selectivity for THFOL compared to Pd/C (95% vs. 82 %) at almost full FAL conversion. This heightened selectivity is attributed to the increased electronic density on the Pd surface, resulting from the electron-donating effect of pendant groups in the TpBD COF. Moreover, kinetic investigations reveal that the activity of total FAL hydrogenation on Pd surface is linked to the rate-determining step in its first C = O hydrogenation process. Additionally, Pd/TpBD COF could catalyse various other bio-based furanic compounds to the corresponding furan ring saturated products in high yields. This work provides guidance for the rational design catalysts to improve its tandem hydrogenation efficiency.

Efficient Host Materials for Lithium-Sulfur Batteries: Ultrafine CoP Nanoparticles in Black Phosphorus-Carbon Composite.

The pursuit of efficient host materials to address the sluggish redox kinetics of sulfur species has been a longstanding challenge in advancing the practical application of lithium-sulfur batteries. In this study, amorphous carbon layer loaded with ultrafine CoP nanoparticles prepared by a one-step in situ carbonization/phosphating method to enhance the inhibition of 2D black phosphorus (BP) on LiPSs shuttle. The carbon coating layer facilitates accelerated electron/ion transport, enabling the active involvement of BP in the conversion of soluble lithium polysulfides (LiPSs). Concurrently, the ultra-fine CoP nanoparticles enhance the chemical anchoring ability and introduce additional catalytic sites. As a result, S@BP@C-CoP electrodes demonstrate exemplary cycling stability (with a minimal capacity decay of 0.054 % over 500 cycles at 1 C) and superior rate performance (607.1 mAh g-1 at 5 C). Moreover, at a sulfur loading of 5.5 mg cm-2, the electrode maintains an impressive reversible areal capacity of 5.45 mAh cm-2 after 50 cycles at 0.1 C. This research establishes a promising approach, leveraging black phosphorus-based materials, for developing high-efficiency Li-S batteries.

Ultrasonic in-situ reduction preparation of SBA-15 loaded ultrafine RuCo alloy catalysts for efficient hydrogen storage of various LOHCs

SBA-15-loaded RuCo alloy nanoparticle catalysts (RuxCoy/S15-SU) for the efficient catalysis of hydrogen storage by various liquid organic hydrogen carriers (LOHCs) were prepared via strong electrostatic adsorption (SEA)-ultrasonic in-situ reduction (UR) technology. The above prepared catalysts were subjected to a series of characterization, such as XPS, H2-TPD/TPR, N2 adsorption–desorption, ICP, CO-chemisorption, FT-IR, XRD and TEM. Ru3+ and Co2+ were evenly anchored on the surface of SBA-15 by SEA, and ultrafine RuCo alloy nanoparticles were formed by UR without any chemical reducing or stabilizing agents. The addition of Co enhanced the dispersion and antioxidant capacity of the RuCo alloy NPs with an average particle size of 2.07 nm and increased the number of catalytically active sites. The synergistic effect of ultrafine particle size and electron transfer between Co and Ru improved the catalytic performance of monobenzyltoluene (MBT) for hydrogen storage. SEA-UR technology strengthened the coordination effect between RuCo alloy NPs and Si-OH, which enhanced the catalytic stability. H2-TPD and H2-TPR indicated that the addition of Co led to more activated H2 to produce hydrogen overflow. For the hydrogenation of MBT, the produced Ru2Co1/S15-SU showed excellent catalytic performance. The hydrogen storage efficiency of MBT was 99.98 % under 110 °C and 6 MPa H2 for 26 min, and the TOF was 145 min−1, which is significantly superior to that of Ru/S15-SU catalyst and that reported in the literature. The hydrogen storage efficiency was still as high as 99.7 % after ten cycles, which was much better than that of Ru/S15-SU and commercial 5 wt% Ru/Al2O3. Ru2Co1/S15-SU is also suitable for efficiently catalyzing hydrogen storage of N-ethylcarbazole, dibenzyltoluene and acenaphthene.

Synergistic catalysis of Ru0-Ru3+ in MOF supported ultrafine Ru nanoparticles catalyst promotes ethyl levulinate to γ-valerolactone

Synthesis of bifunctional catalysts is very important for the hydrogenation of biomass to advanced biofuels, but its efficient regulation is difficult. In this work, a tunable bifunctional Ru/LaQS catalyst with Lewis acid and metal hydrogenation sites was prepared by stable MOFs (LaQS) supported ultrafine Ru nanoparticles (NPs). When the optimal Ru2/LaQS catalyst catalyzed bio-based ethyl levulinate (EL) to γ-valerolactone (GVL), the EL conversion and GVL selectivity reached 99.9% under mild conditions of 100 °C. The excellent catalytic performance is mainly attributed to the synergistic effect of Ru0-Ru3+ on ultrafine Ru NPs with only 1.60 nm generated by metal-support interaction, which is proved by experimental characterization and theoretical calculation. Moreover, the electron density of hydrogenation active site Ru0 and the content of acidic site Ru3+ can be modulated by Ru loading. Among them, the activation of H2 was promoted by the high electron density of Ru0 generated through metal-support electronic interactions. The enhanced medium-strong acidic site Ru3+ not only improved the activation of EL, but also promoted the intramolecular dealcoholization of the intermediate to GVL. The synergistic catalytic mechanism of Ru0-Ru3+ on ultrafine Ru NPs was speculated. The excellent stability was mainly attributed to the metal-support interaction stabilizing the ultrafine Ru NPs, which prevents the agglomeration and loss of Ru NPs during cycling. This work provides an in-depth understanding of the bifunctional catalytic mechanism, which is of guiding significance for the design and preparation of MOFs-based catalysts for biomass hydrogenation.

Oxalate-mediated synthesis of hybrid nickel cobalt-based nanostructures for boosting water and urea electrooxidation efficiency

The utilization of urea during electrolysis presents an appealing option for anodic oxidation, offering environmental benefits by converting waste into energy. The present work focuses on synthesizing mixed transition metal oxide (MMO) nanostructures composed of nickel rich nickel cobaltite electrode materials. Interesting, cobalt rich nickel cobaltite have been widely studied; however, the nickel-rich nickel cobaltite remains relatively unexplored. For stabilization of nickel rich nickel cobaltite, we have designed a process for synthesizing three-dimensional (3D) Ni-Co oxalate as a precursor via the coprecipitation method using diammonium oxalate monohydrate as a precipitating agent. The as obtained precursor was further subjected to thermal decomposition which results in the formation of Ni2CoO4. Microstructural analysis of Ni-Co oxalate indicates that oxalate-assisted synthesis leads to anisotropic ultrafine nanoparticle growth, forming hierarchically arranged 3D microflowers. Interestingly, the use of NaOH as a precipitating agent induces a significant change in the morphology of Ni2CoO4, (nanoparticles). Furthermore, the effect of morphology changes over the electrochemical performance was investigated. Ni2CoO4 microflower demonstrates an overpotential of 330 mV@25 mA/cm2 for O2 and −190 mV@10 mA/cm2 for H2 production during water oxidation in 1 M KOH, exhibiting excellent stability for up to 24 h. During urea oxidation, the potential required by Ni2CoO4 microflowers was 1.31 V@10 mA/cm2. Ni2CoO4 nanoparticles' performance is significantly poor during water and urea oxidation compared to the microflower counterpart. Therefore, this work provides detailed insights into designing MMOs with high porosity, increased exposed active sites, and unique structural features that enhance electrocatalytic activity.

Revolutionizing plasmonic platform via magnetic field-assisted confined ultrafast laser deposition of high-density, uniform, and ultrafine nanoparticle arrays

The remarkable capabilities of 2D plasmonic surfaces in controlling optical waves have garnered significant attention. However, the challenge of large-scale manufacturing of uniform, well-aligned, and tunable plasmonic surfaces has hindered their industrialization. To address this, we present a groundbreaking tunable plasmonic platform design achieved through magnetic field (MF) assisted ultrafast laser direct deposition in air. Through precise control of metal nanoparticles (NPs), with cobalt (Co) serving as the model material, employing an MF, and fine-tuning ultrafast laser parameters, we have effectively converted coarse and non-uniform NPs into densely packed, uniform, and ultrafine NPs (∼3 nm). This revolutionary advancement results in the creation of customizable plasmonic ‘hot spots,’ which play a pivotal role in surface-enhanced Raman spectroscopy (SERS) sensors. The profound impact of this designable plasmonic platform lies in its close association with plasmonic resonance and energy enhancement. When the plasmonic nanostructures resonate with incident light, they generate intense local electromagnetic fields, thus vastly increasing the Raman scattering signal. This enhancement leads to an outstanding 2–18 fold boost in SERS performance and unparalleled sensing sensitivity down to 10−10 M. Notably, the plasmonic platform also demonstrates robustness, retaining its sensing capability even after undergoing 50 cycles of rinsing and re-loading of chemicals. Moreover, this work adheres to green manufacturing standards, making it an efficient and environmentally friendly method for customizing plasmonic ‘hot spots’ in SERS devices. Our study not only achieves the formation of high-density, uniform, and ultrafine NP arrays on a tunable plasmonic platform but also showcases the profound relation between plasmonic resonance and energy enhancement. The outstanding results observed in SERS sensors further emphasize the immense potential of this technology for energy-related applications, including photocatalysis, photovoltaics, and clean water, propelling us closer to a sustainable and cleaner future.

Directionally assembled FeCO3 nanoparticles wrapped with rGO enabled by the synergy of tartaric and ascorbic acids for lithium/sodium storage

Ferrous carbonate (FeCO3) particles synthesized by conventional routes generally possess large-size bulk structures with the drawbacks of low conductivity and easy pulverization, thereby limiting their promising application as high-capacity anodes for lithium/sodium ion batteries (LIBs/SIBs). Herein, a robust strategy via the synergy of tartaric and ascorbic acids (TA/AA) is developed to craft FeCO3 dumbbells that are directionally assembled by ultrafine nanoparticles and uniformly encapsulated in reduced graphene oxide matrixes (denoted FeCO3 NADs-rGO). It is noteworthy that TA serves as a capping agent to inhibit the overgrowth of FeCO3 nanoparticles and guide their directional assembly into dumbbells. Concurrently, AA functions as a reductant to prevent the oxidation of Fe2+ and initiate the reduction of GO. Remarkably, benefiting from the efficient synergy of hierarchical architecture and rGO encapsulation, FeCO3 NADs-rGO delivers highly-reversible lithium and sodium storage capacities of 1853 and 641 mAh/g in the 1200th and 100th cycles at 100 and 20 mA g−1, respectively, which are 2.1 and 3.9-fold over FeCO3 micron peanut kernels-rGO (884 and 163 mAh/g) fabricated without introducing TA. As revealed by experimental investigations and theoretical calculations, FeCO3 nanoparticles shorten the ion transfer distance and rGO accelerates the electron conduction to boost the electrochemical kinetics for high-rate capability. More importantly, the ample mesopores of FeCO3 NADs accommodate the inward stress and the rGO buffer the outward expansion of lithiated/sodiated FeCO3 NADs to strengthen the electrode durability. As such, FeCO3 NADs-rGO may stand out as a superior LIB/SIB anode, and the implementation of facile capping and reductant co-regulators (e.g., TA and AA) could synergistically render the creation of various rGO-based nanocomposites with outstanding mechanical flexibility and electrochemical activity for advanced energy storage.

Interface regulation of micro-sized sintered Ag-10Al composite based on in-situ surface modification and enhanced microstructure stability in power electronic packaging

The increasing demand for high-power SiC semiconductors necessitate the development of a die attachment material that combines high-temperature resistance, reliability, and cost-effectiveness. In this study, a novel micro-sized composite, Ag-10Al paste, containing 10 wt% Al particles, was designed. A remarkable phenomenon, the ejection of ultrafine Ag nanoparticles from micron-sized Ag flakes, was observed for the first time. The phenomenon was utilized for the in-situ surface modification of Al. Subsequently, the microstructure and mechanical properties of the sintered Ag-10Al/direct bonded copper (DBC) joints were studied. Results indicated that the Ag-10Al composite exhibited superior microstructure stability compared to sintered Ag. The Ag/Al interface was systematically analyzed, revealing a unique Ag/nano Ag2O/Al2O3 amorphous/Al structure. This structure was formed through the Ag nanoparticle jetting effect of Ag flakes, achieving effective bonding between nano Ag2O and Al2O3 amorphous phases through mutual dissolution at the atomic level. Moreover, the sintered Ag-10Al joint demonstrated enhanced mechanical performance stability over the sintered Ag joint. After 1000 h aging at 300 ℃, the shear strength of the sintered Ag-10Al joint reached 34.1 MPa, meeting the requirements for power semiconductor packaging. In conclusion, the Ag-10Al composite paste was thoughtfully designed, excelling in both performance and cost-effectiveness.

CoS2 nanoparticles embedded in N-doped hollow carbon nanotubes as anode materials for high performance lithium-ion battery

CoS2 nanoparticles are effectively incorporated into N-doped hollow carbon nanotubes (CoS2@HC) through a combination of a straightforward oil bath method and a high-temperature sulfurization process. The CoS2@HC composite demonstrates exceptional electrochemical performance as an anode material in Li-ion batteries. The outstanding performance of this system can be attributed to the ingeniously designed hollow carbon nanotubes. These nanotubes not only possess high electrical conductivity, thus facilitating efficient electron transfer, but also provide ample space to accommodate volume changes. Furthermore, the ultrafine CoS2 nanoparticles embedded within the hollow carbon nanotubes offer a large surface area for effective electrolyte wetting and rapid ion diffusion during the cycling process. As a result, the CoS2@HC composite delivers a high capacity of 356.2 mAh·g−1 at 2000 mA·g−1 even after 1500 cycles, demonstrating remarkable cyclic stability.

Remarkable dye adsorption capabilities in CaO-Doped-Zirconia systems

The realm of dye adsorption involving zirconia systems remains an untapped frontier, awaiting the unveiling of its complete prowess. The present work investigates the adsorption potentials of CaO-doped ZrO2 nanoparticles with varying doping of CaO (0, 7, 10, and 16 mol.%). With the highest adsorption capacity (of 760 mg/g) reported ever for any zirconia system, the 16 mol.% CaO-doped ZrO2 (16CaSZ) ultrafine nanoparticles portrayed fastest kinetics of dye (Congo red) removal. Along with effect of different pHs (in the presence of different anions such as Cl-, NO3–, SO42- and the mixture of them), a simulated wastewater (comprising urea, different salts, dye, sand, grass, engine oil etc.) was made to examine the efficacy of our nano-adsorbent. The 16CaSZ nanoparticles depicted excellent adsorption (∼99 %) in simulated industrial effluent and duplicated the same performance for pHs ranging from 2 to 10. Multitude of factors (e.g., phase-pure cubicity, highest oxygen vacancy content, pronounced surface area etc.) were credited for this chemisorption-based (R-SO3- interactions, as revealed by the structural and spectroscopic investigations on the post-adsorption products) remarkable adsorption process.

In-situ exsolved ultrafine Ni nanoparticles from CeZrNiO2 solid solution for efficient photothermal catalytic CO2 reduction by CH4

CO2 reduction by CH4 (CRM) to produce fuel is of great significance for solar energy storage and eliminating greenhouse gas. Herein, the catalyst of ultrafine Ni nanoparticles supported on CeZrNiO2 solid solution (Ni@CZNO) was synthesized by the sol-gel method. High yield of H2 and CO (58.0 and 69.8 ​mmol ​min−1 ​g−1) and excellent durability (50 ​h) were achieved by photothermal catalytic CRM merely under focused light irradiation. Structural characterization and DFT calculations reveal that CZNO has rich oxygen vacancies that can adsorb and activate CO2 to produce reactive oxygen species. Oxygen species are transferred to ultrafine Ni nanoparticles through the rich Ni-CZNO interface to accelerate carbon oxidation, thereby maintaining the excellent catalytic stability of the catalyst. Moreover, the experimental results reveal that light irradiation can not only enhance the photothermal catalytic CRM activity through photothermal conversion and molecular activation, but also improve the stability by increasing the concentration of oxygen vacancies and inhibiting CO disproportionation.

Strong Metal‐Support Interaction‐Induced Regulation of Hydrogen Adsorption Behavior of Uniform Ru Nanoparticles Integrated with CoP Nanosheets for High‐Efficiency Electrochemical Hydrogen Production

AbstractThe ingenious modification of the hydrogen adsorption state of ruthenium (Ru) for achieving high‐efficiency electrocatalytic performance is of vital importance for water electrolysis technology. Herein, a novel heterostructured catalyst composed of highly dispersed ultrafine Ru nanoparticles immobilized on CoP nanosheet (denoted as Ru/CoP hereafter) is developed through a feasible “impregnation‐phosphorization” strategy. Experimental results and density functional theory (DFT) simulations collectively indicate that the strong metal‐support interaction (SMSI) effect between Ru nanoparticles and CoP nanosheet substrate can dramatically tailor the electronic configurations of active centers, thus accelerating the charge transfer rate and regulating the hydrogen binding energy. Consequently, the Ru/CoP electrocatalyst with optimal Ru loading content demonstrates prominent HER performance in alkaline solution with a low overpotential of 36 mV to afford a current density of 10 mA cm−2 and a small Tafel slope of 73.0 mV dec−1, which can almost compete with that of commercial Pt/C. This work provides a new inspiration for the elaborate modification of intermediate adsorption capacity and enhancement of electrocatalytic performance for high‐efficiency electrocatalysts in energy conversion fields.

Towards an Improved Understanding of the Evolution of the Size Distribution of Ultrafine Nanoparticles Produced by a Rapidly Quenched Vapor Source

Towards an Improved Understanding of the Evolution of the Size Distribution of Ultrafine Nanoparticles Produced by a Rapidly Quenched Vapor Source

Rhombohedral platinum-copper intermetallic compound: A high phosphate tolerance electrocatalyst for HT-PEMFC

In high-temperature proton exchange membrane fuel cells (HT-PEMFC), phosphate anions act as a poisonous 'spectator species', binding strongly to the Pt surface through PtO bonds similarly to O2. This blocks the Pt active sites, resulting in slow ORR kinetics. Herein, we synthesized ultrafine L11-PtCu intermetallic compound nanoparticles (O-PtCu/S-C) loaded on an S-doped carbon support with an average size of about 3 nm through wet impregnation followed by hydrogen annealing, which showed high resistance to phosphate poisoning. The introduction of S notably improved the metal-support interaction and prevented particle growth during annealing, which is beneficial for the uniform distribution of nanoparticles and prevents detachment and agglomeration during ADT. The pronounced Cu-Pt electronic interaction in O-PtCu/S-C induced electron transfer from Cu to Pt, which effectively modified the electronic structure of Pt and weakened the adsorption energy of phosphate anions on the catalyst surface. In addition, the phosphate poisoning test results from both room temperature RDE and high-temperature RDE demonstrate that O-PtCu/S-C possesses excellent phosphate tolerance, superior ORR activity, and remarkable stability. It exhibits a superior peak power density of 800.5 mW cm−2 in 160°C H2-O2 HT-PEMFC with Pt loading of 0.5 mg cm−2. This research offers a novel approach to designing phosphate-resistant electrocatalysts for HT-PEMFC.

Boosting the catalytic activity of Pd-nanocatalysts by anchoring transition metal atoms on carbon supports for formic acid dehydrogenation

Liquid formic acid (FA) dehydrogenation, which needs high-performance catalysts to generate green hydrogen at room temperature, is a promising chemical hydrogen storage technology that can replace fossil fuels in energy-related devices. In this work, a novel nanocatalyst with ultrafine palladium nanoparticles (Pd NPs) immobilized on a transition metal atom-decorated carbon support was synthesized for the dehydrogenation of liquid FA. Via a hydrothermal of glucose and carbonitride with a following Co doping through a heat treatment process, porous carbons with evenly dispersed Co-sites on it were strategically achieved, which could be used as a support for immobilizing Pd NPs. The obtained Pd/NC-Co1% catalyst exhibited much superior catalytic activities to those samples without Co doping on the support (Pd/NC and PdCo1%/NC), showing an impressive turnover frequency of 3045 h−1 at 50 °C for FA dehydrogenation. Other transition metal species such as Fe- and Ni-decorated carbon nanocatalysts also showed an improved catalytic activity for FA dehydrogenation. This work not only provides an efficient method to synthesize nanocatalysts with ultrafine metal NPs but also demonstrates that highly dispersed metal atoms on the support can effectively affect the immobilized NPs, resulting in an enhancement of catalytic performance.

Enhanced electrochemical oxygen generation from sillenite phase of bismuth iron oxide (Bi24Fe2O39) ultrafine particles stabilised at room temperature

Recently, lot of research is going on in development of clean energy-based technology to address the issue of exponentially increasing energy demands. Electrochemical water splitting is a clean and efficient process for generation of H2 and O2. Water electrolysis produces hydrogen and oxygen on cathode and anode respectively as separate half-cell reactions is one of the most important clean alternative processes. This work reports synthesis of Bi24Fe2O39 ultrafine crystalline nanoparticles via facile room temperature chemical method for the first time. Bi24Fe2O39 shows a spherical morphology with an average size of 8 nm. As obtained Bi24Fe2O39 acts as an electrocatalyst for electrochemical oxygen evolution reaction (OER). Electrochemical oxygen generation studies confirm the overpotential of 420 mV in 1 M KOH solution at a current density of 10 mA/cm2. Tafel slope and EIS studies give further insight of oxygen generation process. The results show that Bi24Fe2O39 exhibits low Tafel slope of 63 mV dec−1 and a very low charge transfer resistance of ∼10 Ω. This study paves a new way for future research into bismuth based sillenite structure for various energy related applications.