Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 92
Filtrar
1.
Adv Mater ; 33(13): e2008194, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33645858

RESUMO

Oxygen-redox of layer-structured metal-oxide cathodes has drawn great attention as an effective approach to break through the bottleneck of their capacity limit. However, reversible oxygen-redox can only be obtained in the high-voltage region (usually over 3.5 V) in current metal-oxide cathodes. Here, we realize reversible oxygen-redox in a wide voltage range of 1.5-4.5 V in a P2-layered Na0.7 Mg0.2 [Fe0.2 Mn0.6 □0.2 ]O2 cathode material, where intrinsic vacancies are located in transition-metal (TM) sites and Mg-ions are located in Na sites. Mg-ions in the Na layer serve as "pillars" to stabilize the layered structure during electrochemical cycling, especially in the high-voltage region. Intrinsic vacancies in the TM layer create the local configurations of "□-O-□", "Na-O-□" and "Mg-O-□" to trigger oxygen-redox in the whole voltage range of charge-discharge. Time-resolved techniques demonstrate that the P2 phase is well maintained in a wide potential window range of 1.5-4.5 V even at 10 C. It is revealed that charge compensation from Mn- and O-ions contributes to the whole voltage range of 1.5-4.5 V, while the redox of Fe-ions only contributes to the high-voltage region of 3.0-4.5 V. The orphaned electrons in the nonbonding 2p orbitals of O that point toward TM-vacancy sites are responsible for reversible oxygen-redox, and Mg-ions in Na sites suppress oxygen release effectively.

2.
Nano Lett ; 2021 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-33570961

RESUMO

Understanding the behavior of high-entropy alloy (HEA) materials under hydrogen (H2) environment is of utmost importance for their promising applications in structural materials, catalysis, and energy-related reactions. Herein, the reduction behavior of oxidized FeCoNiCuPt HEA nanoparticles (NPs) in atmospheric pressure H2 environment was investigated by in situ gas-cell transmission electron microscopy (TEM). The reduction reaction front was maintained at the external surface of the oxide. During reduction, the oxide layer expanded and transformed into porous structures where oxidized Cu was fully reduced to Cu NPs while Fe, Co, and Ni remained in the oxidized form. In situ chemical analysis showed that the expansion of the oxide layer resulted from the outward diffusion flux of all transition metals (Fe, Co, Ni, Cu). Revealing the H2 reduction behavior of HEA NPs facilitates the development of advanced multicomponent alloys for applications targeting H2 formation and storage, catalytic hydrogenation, and corrosion removal.

3.
Nat Commun ; 11(1): 6373, 2020 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-33311508

RESUMO

Direct formation of ultra-small nanoparticles on carbon supports by rapid high temperature synthesis method offers new opportunities for scalable nanomanufacturing and the synthesis of stable multi-elemental nanoparticles. However, the underlying mechanisms affecting the dispersion and stability of nanoparticles on the supports during high temperature processing remain enigmatic. In this work, we report the observation of metallic nanoparticles formation and stabilization on carbon supports through in situ Joule heating method. We find that the formation of metallic nanoparticles is associated with the simultaneous phase transition of amorphous carbon to a highly defective turbostratic graphite (T-graphite). Molecular dynamic (MD) simulations suggest that the defective T-graphite provide numerous nucleation sites for the nanoparticles to form. Furthermore, the nanoparticles partially intercalate and take root on edge planes, leading to high binding energy on support. This interaction between nanoparticles and T-graphite substrate strengthens the anchoring and provides excellent thermal stability to the nanoparticles. These findings provide mechanistic understanding of rapid high temperature synthesis of metal nanoparticles on carbon supports and the origin of their stability.

4.
Virol Sin ; 2020 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-33165771

RESUMO

Hepatitis B virus (HBV) belongs to Hepadnaviridae family and mainly infects hepatocytes, which can cause acute or chronic hepatitis. Currently, two types of antiviral drugs are approved for chronic infection clinically: interferons and nucleos(t)ide analogues. However, the clinical cure for chronic infection is still rare, and it is a huge challenge for all researchers to develop high-efficiency, safe, non-tolerant, and low-toxicity anti-HBV drugs. Antazoline hydrochloride is a first-generation antihistamine with anticholinergic properties, and it is commonly used to relieve nasal congestion and in eye drops. Recently, an in vitro high-throughput evaluation system was constructed to screen nearly 800 compounds from the Food and Drug Administration (FDA)-approved Drug Library. We found that arbidol hydrochloride and antazoline hydrochloride can effectively reduce HBV DNA in the extracellular supernatant in a dose-dependent manner, with EC50 of 4.321 µmol/L and 2.910 µmol/L in HepAD38 cells, respectively. Moreover, the antiviral effects and potential mechanism of action of antazoline hydrochloride were studied in different HBV replication systems. The results indicate that antazoline hydrochloride also has a significant inhibitory effect on HBV DNA in the extracellular supernatant of Huh7 cells, with an EC50 of 2.349 µmol/L. These findings provide new ideas for screening and research related to HBV agents.

5.
Adv Mater ; : e2003879, 2020 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-33206429

RESUMO

The potassium-selenium (K-Se) battery is considered as an alternative solution for stationary energy storage because of abundant resource of K. However, the detailed mechanism of the energy storage process is yet to be unraveled. Herein, the findings in probing the working mechanism of the K-ion storage in Se cathode are reported using both experimental and computational approaches. A flexible K-Se battery is prepared by employing the small-molecule Se embedded in freestanding N -doped porous carbon nanofibers thin film (Se@NPCFs) as cathode. The reaction mechanisms are elucidated by identifying the existence of short-chain molecular Se encapsulated inside the microporous host, which transforms to K2 Se by a two-step conversion reaction via an "all-solid-state" electrochemical process in the carbonate electrolyte system. Through the whole reaction, the generation of polyselenides (K2 Sen , 3 ≤ n ≤ 8) is effectively suppressed by electrochemical reaction dominated by Se2 molecules, thus significantly enhancing the utilization of Se and effecting the voltage platform of the K-Se battery. This work offers a practical pathway to optimize the K-Se battery performance through structure engineering and manipulation of selenium chemistry for the formation of selective species and reveal its internal reaction mechanism in the carbonate electrolyte.

6.
Sci Adv ; 6(47)2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33208378

RESUMO

To treat impairments in hard tissues or overcome pathological calcification in soft tissues, a detailed understanding of mineralization pathways of calcium phosphate materials is needed. Here, we report a detailed mechanistic study of hydroxyapatite (HA) mineralization pathways in an artificial saliva solution via in situ liquid cell transmission electron microscopy (TEM). It is found that the mineralization of HA starts by forming ion-rich and ion-poor solutions in the saliva solution, followed by coexistence of the classical and nonclassical nucleation processes. For the nonclassical path, amorphous calcium phosphate (ACP) functions as the substrate for HA nucleation on the ACP surface, while the classical path features direct HA nucleation from the solution. The growth of HA crystals on the surface of ACP is accompanied by the ACP dissolution process. The discoveries reported in this work are important to understand the physiological and pathological formation of HA minerals, as well as to engineer the biomineralization process for bone healing and hard tissue repairs.

7.
ACS Nano ; 14(11): 15669-15677, 2020 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-33147406

RESUMO

Materials storing energy via an alloying reaction are promising anode candidates in rechargeable lithium-ion batteries (LIBs) due to their much higher energy density than the current graphite anode. Until now, the volumetric expansion of such electrode particles during lithiation has been considered as solely responsible for cycling-induced structural failure. In this work, we report different structural failure mechanisms using single-crystalline bismuth nanowires as the alloying-based anode. The Li-Bi alloying process exhibits a two-step transition, that is, Bi-Li1Bi and Li1Bi-Li3Bi. Interestingly, the Bi-Li1Bi phase transition occurs not only in the bulk Bi nanowire but also on the particle surface showing its characteristic behavior. The bulk alloying kinetics favors a Bi-(012)-facilitated anisotropic lithiation, whose mechanism and energetics are further studied using the density functional theory calculations. More importantly, the protrusion of Li1Bi nanograins as a result of anisotropic Li-Bi alloying is found to dominate the surface morphology of Bi particles. The growth kinetics of Li1Bi protrusions is understood atomically with the identification of two different controlling mechanisms, that is, the dislocation-assisted strain relaxation at the Bi/Li1Bi interface and the short-range migration of Bi supporting the off-Bi growth of Li1Bi. As loosely rooted to the bulk substrate and easily peeled off and detached into the electrolyte, these nanoscale protrusions developed during battery cycling are believed to be an important factor responsible for the capacity decay of such alloying-based anodes at the electrode level.

8.
ACS Cent Sci ; 6(10): 1827-1834, 2020 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-33145419

RESUMO

In spite of the great potential in leading next-generation energy storage technology, Li-S batteries suffer rapid capacity decay arising from the shuttling effect of lithium polysulfides (LiPSs), a major concern that must be addressed before commercialization can be realized. To tackle this challenge, we demonstrate a facile approach to fabricate a hierarchically structured composite of Fe2P@nitrogen, phosphorus codoped carbon (Fe2P@NPC) by direct biological recycling of iron metal from electroplating sludge using bacteria. This material, featuring uniform dispersion of Fe2P nanoparticles (NPs) in porous NPC matrix, effectively adapts volume variation of sulfur upon cycling and simultaneously provides multiple channels for efficient lithium ion transport. In addition, Fe2P NPs with strong adhesion properties of tightly anchored soluble LiPSs formed during discharge can significantly facilitate the decomposition of Li2S during the subsequent charging process. The Li-S cell built on this cathode architecture delivers high specific capacity (1555.7 mAh g-1 at 0.1 C), appreciable rate capability (679.7 mAh g-1 at 10 C), and greatly enhanced cycling performance (761.9 mAh g-1 at 1.0 C after 500 cycles).

9.
Angew Chem Int Ed Engl ; 59(51): 22978-22982, 2020 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-33017504

RESUMO

Lithium-oxygen (Li-O2 ) batteries have attracted extensive research interest due to their high energy density. Other than Li2 O2 (a typical discharge product in Li-O2 batteries), LiOH has proved to be electrochemically active as an alternative product. Here we report a simple strategy to achieve a reversible LiOH-based Li-O2 battery by using a cation additive, sodium ions, to the lithium electrolyte. Without redox mediators in the cell, LiOH is detected as the sole discharge product and it charges at a low charge potential of 3.4 V. A solution-based reaction route is proposed, showing that the competing solvation environment of the catalyst and Li+ leads to LiOH precipitation at the cathode. It is critical to tune the cell chemistry of Li-O2 batteries by designing a simple system to promote LiOH formation/decomposition.

10.
ACS Nano ; 14(11): 15131-15143, 2020 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-33079522

RESUMO

Although high-entropy alloys (HEAs) have shown tremendous potential for elevated temperature, anticorrosion, and catalysis applications, little is known on how HEA materials behave under complex service environments. Herein, we studied the high-temperature oxidation behavior of Fe0.28Co0.21Ni0.20Cu0.08Pt0.23HEA nanoparticles (NPs) in an atmospheric pressure dry air environment by in situ gas-cell transmission electron microscopy. It is found that the oxidation of HEA NPs is governed by Kirkendall effects with logarithmic oxidation rates rather than parabolic as predicted by Wagner's theory. Further, the HEA NPs are found to oxidize at a significantly slower rate compared to monometallic NPs. The outward diffusion of transition metals and formation of disordered oxide layer are observed in real time and confirmed through analytical energy dispersive spectroscopy, and electron energy loss spectroscopy characterizations. Localized ordered lattices are identified in the oxide, suggesting the formation of Fe2O3, CoO, NiO, and CuO crystallites in an overall disordered matrix. Hybrid Monte Carlo and molecular dynamics simulations based on first-principles energies and forces support these findings and show that the oxidation drives surface segregation of Fe, Co, Ni, and Cu, while Pt stays in the core region. The present work offers key insights into how HEA NPs behave under high-temperature oxidizing environment and sheds light on future design of highly stable alloys under complex service conditions.

11.
Adv Sci (Weinh) ; 7(17): 2001207, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32995126

RESUMO

The development of advanced rechargeable batteries provides a great opportunity for basic and applied researchers to collectively overcome challenging scientific and technological barriers that directly address a critical need for energy storage. In addition to novel battery chemistries often scientifically reviewed, advanced battery structures via technological innovations that boost battery performance are also worthy of attention. In this context, bipolar electrodes (BEs) are capable of improving the specific power, simplifying cell components, and reducing manufacturing costs for rechargeable batteries. By focusing on the fundamentals and applications of BEs in rechargeable batteries, the rational utilization of BEs from an academic perspective is considered. The progress and challenges of BEs are discussed and summarized in detail. Key techniques and materials for enabling BEs are highlighted and an outlook for the future directions of BEs that involve emerging concepts, such as wearable devices, all-solid-state batteries, fast spraying fabrication, and recyclable secondary batteries, is also presented.

12.
Adv Mater ; 32(32): e2002292, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32613698

RESUMO

Mechanically stable and foldable air cathodes with exceptional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activities are key components of wearable metal-air batteries. Herein, a directional freeze-casting and annealing approach is reported for the construction of a 3D honeycomb nanostructured, N,P-doped carbon aerogel incorporating in situ grown FeP/Fe2 O3 nanoparticles as the cathode in a flexible Zn-air battery (ZAB). The aqueous rechargeable Zn-air batteries assembled with this carbon aerogel exhibit a remarkable specific capacity of 648 mAh g-1 at a current density of 20 mA cm-2 with a good long-term durability, outperforming those assembled with commercial Pt/C+RuO2 catalyst. Furthermore, such a foldable carbon aerogel with directional channels can serve as a freestanding air cathode for flexible solid-state Zn-air batteries without the use of carbon paper/cloth and additives, giving a specific capacity of 676 mAh g-1 and an energy density of 517 Wh kg-1 at 5 mA cm-2 together with good cycling stability. This work offers a new strategy to design and synthesize highly effective bifunctional air cathodes to be applied in electrochemical energy devices.

13.
Adv Mater ; 32(31): e2002403, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32584489

RESUMO

Li2 S holds a promising role as a high-capacity Li-containing cathode, circumventing use of metallic lithium in constructing next-generation batteries to replace current Li-ion batteries. However, progress of Li2 S cathode has been plagued by its intrinsic drawbacks, including high activation potentials, poor rate performance, and rapid capacity fading during long cycling. Herein, a series of Li2 S/transition metal (TM) nanocomposites are synthesized via a lithiothermic reduction reaction, and it is realized that the presence of TMs in Li2 S matrix can transform electrochemical behaviors of Li2 S. On the one hand, the incorporation of W, Mo, or Ti greatly increases electronic and ionic conductivity of Li2 S composites and inhibits the polysulfide dissolution via the TMS bond, effectively addressing the drawbacks of Li2 S cathodes. In particular, Li2 S/W and Li2 S/Mo exhibit the highest ionic conductivity of solid-phase Li-ion conductors ever-reported: 5.44 × 10-2 and 3.62 × 10-2 S m-1 , respectively. On the other hand, integrating Co, Mn, and Zn turns Li2 S into a prelithiation agent, forming metal sulfides rather than S8 after the full charge. These interesting findings may shed light on the design of Li2 S-based cathode materials.

14.
ACS Nano ; 14(7): 9117-9124, 2020 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-32584544

RESUMO

Sodium-ion batteries have attracted widespread attention for cost-effective and large-scale electric energy storage. However, their practical deployment has been largely retarded by the lack of choice of efficient anode materials featuring large capacity and electrochemical stability and robustness. Herein, we report a durian-inspired design and template-free fabrication of a robust sodium anode based on triangular pyramid arrays of Bi0.75Sb0.25 alloy electrodeposited on Cu substrates. The Bi0.75Sb0.25 arrays exhibit an appreciable electrochemical robustness for sodium storage, sustaining a reversible capability 335 mAh g-1 at a high rate of 2.5 A g-1 and 87% of the initial capacity over 2000 cycles. We further demonstrate the applicability of the Bi0.75Sb0.25 array anode in sodium full cells by pairing it with a Na3V2(PO4)3/C cathode. This full cell achieves a high specific energy of 203 Wh kg-1 (based on both active electrodes). Such an enhanced performance is attributed to the thorny-durian-like architecture and bimetallic alloy composition. The pyramid tip induces ion enrichment for rapid charge-transfer reaction, while the alloy design reduces the electrode volume swelling for stable Na cycling.

15.
Nano Lett ; 20(6): 4681-4686, 2020 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-32426983

RESUMO

Metal-air batteries have attracted extensive research interests due to their high theoretical energy density. However, most of the previous studies were limited by applying pure oxygen in the cathode, sacrificing the gravimetric and volumetric energy density. Here, we develop a real sodium-"air" battery, in which the rechargeability of the battery relies on the reversible reaction of the formation of sodium peroxide dihydrate (Na2O2·2H2O). After an oxygen evolution reaction catalyst is applied, the charge overpotential is largely reduced to achieve a high energy efficiency. The sodium-air batteries deliver high areal capacity of 4.2 mAh·cm-2 and have a decent cycle life of 100 cycles. The oxygen crossover effect is largely suppressed by replacing the oxygen with air, whereas the dense solid electrolyte interphase formed on the sodium anode further prolongs the cycle life.

16.
ACS Nano ; 14(6): 6673-6682, 2020 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-32463691

RESUMO

Slow kinetics of polysulfide conversion reactions lead to severe issues for lithium-sulfur (Li-S) batteries, for example, low rate capability, polysulfide migration, and low Coulombic efficiencies. These challenges hinder the practical applications of Li-S batteries. In this study, we proposed a rational strategy of tuning the d-band of catalysts to accelerate the conversion of polysulfides. Nitrogen vacancies were engineered in hexagonal Ni3N (space group P6322) to tune its d-band center, leading to the strong interaction between polysulfides and Ni3N. Because of the greater electron population in the lowest occupied molecular orbital of Li2S4, the terminal S-S bonds were weakened for breaking. Temperature-dependent experiments confirm that Ni3N0.85 demonstrates a much low activation energy, thereby accelerating the conversion of polysulfides. A Li-S cell using Ni3N0.85 can deliver a high initial discharge capacity of 1445.9 mAh g-1 (at 0.02 C) and low decay per cycle (0.039%). The Ni3N0.85 cell can also demonstrate an initial capacity of 1200.4 mAh g-1 for up to 100 cycles at a high loading of 5.2 mg cm-2. The high efficiency of rationally designed Ni3N0.85 demonstrates the effectiveness of the d-band tuning strategy to develop low-activation-energy catalysts and to promote the atomic understanding of polysulfide conversion in Li-S batteries.

17.
Adv Mater ; 32(29): e2000952, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32468648

RESUMO

Lithium (Li) metal electrode cannot endure elevated temperature (e.g., >200 °C) with the regular battery configuration due to its low melting point (180.5 °C) and high reactivity, which restricts its application in high-temperature Li metal batteries for energy storage and causes safety concerns for regular ambient-temperature Li metal batteries. Herein, this work reports a Li5 B4 /Li composite featuring a 3D Li5 B4 fibrillar framework filled with metallic Li, which maintains its initial structure at 325 °C in Ar atmosphere without leakage of the liquid Li. The capillary force caused by the porous structure of the Li4 B5 fibrillar framework, together with its lithiophilic surface, restricts the leakage of liquid metallic Li and enables good thermal tolerance of the Li5 B4 /Li composite. Thus, it can be facilely operated for rechargeable high-temperature Li metal batteries. Li5 B4 /Li electrodes are coupled with a garnet-type ceramic electrolyte (Li6.5 La3 Zr0.5 Ta1.5 O12 ) to fabricate symmetric cells, which exhibit stable Li stripping/plating behaviors with low overpotential of ≈6 mV at 200 °C using a regular sandwich-type cell configuration. This work affords new insights into realizing a stable Li metal anode for high-temperature Li metal batteries with a simple battery configuration and high safety, which is different from traditional molten-salt Li metal batteries using a pristine metallic Li anode.

18.
Nat Commun ; 11(1): 2016, 2020 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-32332743

RESUMO

High-entropy alloy nanoparticles (HEA-NPs) are important class of materials with significant technological potential. However, the strategies for synthesizing uniformly dispersed HEA-NPs on granular supports such as carbon materials, γ-Al2O3, and zeolite, which is vital to their practical applications, are largely unexplored. Herein, we present a fast moving bed pyrolysis strategy to immobilize HEA-NPs on granular supports with a narrow size distribution of 2 nm up to denary (MnCoNiCuRhPdSnIrPtAu) HEA-NPs at 923 K. Fast moving bed pyrolysis strategy ensures the mixed metal precursors rapidly and simultaneously pyrolyzed at high temperatures, resulting in nuclei with a small size. The representative quinary (FeCoPdIrPt) HEA-NPs exhibit high stability (150 h) toward hydrogen evolution reaction with high mass activity, which is 26 times higher than the commercial Pt/C at an overpotential of 100 mV. Our strategy provides an improved methodology for synthesizing HEA-NPs on various supports.

19.
Ocul Immunol Inflamm ; : 1-7, 2020 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-32275172

RESUMO

Purpose: To explore the performance of ultrasound biomicroscopy (UBM) and color Doppler flow imaging (CDFI) in the diagnosis of primary lacrimal canaliculitis.Methods: Subjects with relevant symptoms of canaliculitis were prospectively recruited. UBM and CDFI were performed for presumptive diagnosis. Microbiology and histopathology were performed for definitive diagnosis.Results: A total of 37 cases were recruited, including 25 cases of canaliculitis and 12 cases of non-canaliculitis. Pathogens were isolated in 13 canaliculitis cases, and the leading pathogens were Actinomyces (4 cases) and Streptococcus (4 cases). UBM and CDFI identified 24 canaliculitis cases (sensitivity = 96%) and 11 non-canaliculitis cases (specificity = 92%). The predictive factors for canaliculitis were lumen wall thickness >0.25 mm (P = .019) and intracanalicular concretions (P = .010). Other typical features were enlarged lumen (2.16 ± 0.25 mm) and hot-wheel sign-on CDFI (84%). These image findings were congruent with histopathologic changes.Conclusion: Ultrasonography is a valuable tool to assist the diagnosis of canaliculitis.(Clinical trial registration number: ChiCTR1900025411).

20.
ACS Nano ; 14(4): 4074-4086, 2020 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-32283933

RESUMO

The decoration of two-dimensional (2D) substrates with nanoparticles (NPs) serve as heterostructures for various catalysis applications. Deep understanding of catalyst degradation mechanisms during service conditions is crucial to improve the catalyst durability. Herein, we studied the sintering behavior of Pt and bimetallic Au-core Pt-shell (Au@Pt core-shell) NPs on MoS2 supports at high temperatures under vacuum, nitrogen (N2), hydrogen (H2), and air environments by in situ gas-cell transmission electron microscopy (TEM). The key observations are summarized as effect of environment: while particle migration and coalescence (PMC) was the main mechanism that led to Pt and Au@Pt NPs degradation under vacuum, N2, and H2 environments, the degradation of MoS2 substrate was prominent under exposure to air at high temperatures. Pt NPs were less stable in H2 environment when compared with the Pt NPs under vacuum or N2, due to Pt-H interactions that weakened the adhesion of Pt on MoS2. Effect of NP composition: under H2, the stability of Au@Pt NPs was higher in comparison to Pt NPs. This is because H2 promotes the alloying of Pt-Au, thus reducing the number of Pt at the surface (reducing H2 interactions) and increasing Pt atoms in contact with MoS2. Effect of NP size: The alloying effect promoted by H2 was more pronounced in small size Au@Pt NPs resulting in their higher sintering resistance in comparison to large size Au@Pt NPs and similar size Pt NPs. The present work provides key insights into the parameters affecting the catalyst degradation mechanisms on 2D supports.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...