1,721,241 research outputs found
2025-04-09
No full textThe electrocatalytic oxidation of small organic molecules, such as ethylene glycol (EG), can be paired with the hydrogen evolution reaction (HER) to effectively lower the overall cell voltage, thereby enhancing energy efficiency for hydrogen production. Moreover, the anodic EG oxidation reaction (EGOR) can generate valuable C1 and C2 compounds, offering a sustainable approach to greener chemical production. The industrial viability of this process requires nonprecious metal electrocatalysts that demonstrate high performance at low potential and exhibit high selectivity. In this study, we report on a cost-effective electrocatalyst based on a nickel sulfide phase (Ni3S2) heterogeneously nucleated on the surface of nickel–iron-manganese layered double hydroxide (NiFeMn-LDH) nanosheet arrays and supported on nickel foam (NF), demonstrating exceptional activity for the coupled HER and EGOR in alkaline conditions. This Ni3S2@NiFeMn-LDH/NF catalyst achieves an EG-to-formate faradaic efficiency of up to 90% at 1.5 V, with glycolate and oxalate as minor byproducts. Density functional theory calculations reveal that the EGOR was facilitated by the phase-separated Ni3S2, which lowers the energy barrier of the rate-limiting step. This work presents a promising, sustainable pathway for hydrogen production alongside value-added chemical generation from the electrooxidation of EG.Peer reviewe
Supporting Information: Two-Dimensional Transition Metal Phosphides As Cathode Additive in Robust Lithium–Sulfur Batteries
No full textThe development of advanced cathode materials able to promote the sluggish redox kinetics of polysulfides is crucial to bringing lithium–sulfur batteries to the market. Herein, two electrode materials: namely, Zr2PS2 and Zr2PTe2, are identified through screening several hundred thousand compositions in the Inorganic Crystal Structure Database. First-principles calculations are performed on these two materials. These structures are similar to that of the classical MXenes. Concurrently, calculations show that Zr2PS2 and Zr2PTe2 possess high electrical conductivity, promote Li ion diffusion, and have excellent electrocatalytic activity for the Li–S reaction and particularly for the Li2S decomposition. Besides, the mechanisms behind the excellent predicted performance of Zr2PS2 and Zr2PTe2 are elucidated through electron localization function, charge density difference, and localized orbital locator. This work not only identifies two candidate sulfur cathode additives but may also serve as a reference for the identification of additional electrode materials in new generations of batteries, particularly in sulfur cathodes.Peer reviewe
Supporting Information: Heterostructured Copper–Palladium Phosphide Particles as Efficient Electrocatalysts for Ethanol Oxidation and Oxygen Reduction in Direct Ethanol Fuel Cells
No full textChemicals, material characterizations, structural characterization, electrochemical measurements, MEA fabrication and direct ethanol fuel cell performance test, theoretical modeling and calculations; additional TEM, AC-HRTEM, HRTEM, HAADF-STEM images, corresponding FFT spectrum and GPA analysis; XRD pattern; Tafel slope curve; schematic illustration of mechanism for EOR; CO-TPD and CO–DRIFTS spectra; 1H NMR spectra; work functions and electron density differences diagram; and calculation details of Faradaic efficiency, mass activity, price activityEngineering lattice strain, electronic structure, and crystallinity in palladium alloys offers a promising approach to significantly enhance their electrocatalytic performance. In this work, we present a versatile strategy to synthesize Pd-based phosphide alloys integrated with non-noble metal atoms (Pd-M-P; M = Co, Ni, Cu), characterized by expanded lattice structures and a crystalline–amorphous core–shell architecture. Catalytic performance assessments revealed that CuPdP exhibits an impressive mass activity of 7.96 A mgPd–1 for the ethanol oxidation reaction (EOR), which is 10.6 times higher than that of commercial Pd/C. This performance enhancement can be attributed to the precisely engineered lattice tensile strain and the strong p–d hybridization interaction between P and Pd. Density functional theory calculations further confirmed that these factors facilitate enhanced OH adsorption and weakened CO adsorption, thereby significantly improving EOR performance. This study presents an effective strategy for the atomic-level engineering of palladium alloy nanomaterials to achieve good electrocatalytic performance, providing a method for designing highly active catalysts.Peer reviewe
Thermoelectric Performance of Surface-Engineered Cu<sub>1.5–<i>x</i></sub>Te–Cu<sub>2</sub>Se Nanocomposites
Full text linkCu2–xS and Cu2–xSe have recently been reported as
promising thermoelectric
(TE) materials for medium-temperature applications. In contrast, Cu2–xTe, another member of the copper
chalcogenide family, typically exhibits low Seebeck coefficients that
limit its potential to achieve a superior thermoelectric figure of
merit, zT, particularly in the low-temperature range
where this material could be effective. To address this, we investigated
the TE performance of Cu1.5–xTe–Cu2Se nanocomposites by consolidating surface-engineered Cu1.5Te nanocrystals. This surface engineering strategy allows
for precise adjustment of Cu/Te ratios and results in a reversible
phase transition at around 600 K in Cu1.5–xTe–Cu2Se nanocomposites, as systematically
confirmed by in situ high-temperature X-ray diffraction combined with
differential scanning calorimetry analysis. The phase transition leads
to a conversion from metallic-like to semiconducting-like TE properties.
Additionally, a layer of Cu2Se generated around Cu1.5–xTe nanoparticles effectively inhibits
Cu1.5–xTe grain growth, minimizing
thermal conductivity and decreasing hole concentration. These properties
indicate that copper telluride based compounds have a promising thermoelectric
potential, translated into a high dimensionless zT of 1.3 at 560 K
Supplementary Information: Metal Doping Activation of Anion-Mediated Electron Transfer in Catalytic Reactions
No full textExperimental section; additional electrochemical measurements; material characterizations; and theoretical calculationsPeer reviewe
Supporting information: Ligand-Mediated Tailoring of Self-Supported MnxOy@Ni(OH)2 Nanoheterostructures with Enhanced OER Performance
No full textSEM images and EDS spectra of MnxOy@Ni(OH)2 electrodes; DFT-calculated adsorption energies on NiOOH, Mn3O4, and NiOOH/Mn3O4–MnO2 surfaces; CV curves and scan rate-dependent behavior; analysis of diffusion and kinetic parameters; post-CV XPS spectra of Mn and Ni; chronoamperometric stability tests and LSV curves before/after operation; optimized structures of OER intermediates (*OH, *O, *OOH) under AEM and LOM pathways; ICP-OES analysis of Mn/Ni ratios; thermodynamic, kinetic, and electrochemical parameters for OER; XPS quantification of surface states pre- and postcycling; benchmarking of overpotential performance versus literatureWe report a colloidal synthesis strategy for producing MnxOy@Ni(OH)2 nanoheterostructures under mild conditions, i.e., low temperature and ambient pressure. The role of carboxylic acid ligands in directing the synthesis is systematically explored, revealing that lower ligand concentrations along with low-molecular weight molecules favor the formation of well-defined MnxOy@Ni(OH)2 heterostructures. Electrochemical characterization demonstrates that the resulting nanocomposites exhibit significantly enhanced electrochemical surface area and oxygen evolution reaction (OER) activity compared to their single-component counterparts. Specifically, MnxOy@Ni(OH)2 achieves a low overpotential of 299 mV at 10 mA cm–2, a Tafel slope of 61 mV dec–1, and a low charge transfer resistance of 9 Ω. The improved OER performance is attributed to the synergistic effect between the Ni(OH)2 nanosheets, which facilitate *OOH intermediate formation, and the MnO2 component, known for its intrinsic catalytic activity. Additionally, Mn3O4 serves as a stabilizing phase and precursor to MnO2, contributing to the overall durability and structural integrity of the catalyst.Peer reviewe
Performance of oil sorbents based on reduced graphene oxide–silica composite aerogels
Full text linkClean-up of crude-oil spills ranks among the major environmental remediation issues and demands for sorbents with high and stable oleophilic and hydrophobic features. Here, aerogels with durable hydrophobicity are produced by incorporating reduced graphene oxide (rGO) in highly porous silica matrices. By a sol-gel protocol, high rGO loadings are achieved by exploiting highly dispersible hydrophilic graphene oxide as rGO precursor. Homogeneous rGO-silica composite monoliths are obtained with tunable loading up to 10 wt%, enabling a detailed analysis of the sorption behaviour towards oil spills. Composite aerogels demonstrate an excellent performance towards oil sorption with oil uptake from ∼7 to ∼10 times the aerogel mass. Although the sorption ability is lower than for plain hydrophobic silica, composites with a minimum loading of 5 wt% exhibit very high oil selectivity and show a durable and reliable behaviour over time, providing longer shelf-life than plain SiO2 aerogels. The synergetic effect of rGO towards long-term hydrophobicity and oil selectivity on silica composite aerogels allows for the implementation of such composite materials in real water remediation processes
Palladium Hydride on C<sub>2</sub>N to Boost Formate Oxidation
No full textThe
lack of electrocatalysts for the formate oxidation reaction
(FOR) hampers the deployment of direct formate fuel cells (DFFCs).
To overcome this limitation, herein, we detail the production of palladium
hydride particles supported on C2N (PdH0.58@C2N) via a facile method. PdH0.58@C2N
displays excellent FOR performance, reaching current densities up
to 5.6 A·mgPd–1 and stable cycling
and chronoamperometric operation. The Pd lattice expands due to the
hydrogen intercalation. Besides, an electronic redistribution associated
with the distinct electronegativity of Pd and H is observed. Both
phenomena modify the electron energy levels, enhancing the activity
and stability of the composite catalyst. More specifically, differential
functional theory calculations show H intercalation to downshift the
Pd d-band center in Pd0.58@C2N, weakening adsorbate
binding and accelerating the FOR rate-determining step
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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