Search Results (172)

The complex system of high-entropy materials makes it challenging to reveal the specific function of each site for oxygen evolution reaction (OER). Here, with nickel foam (NF) as the substrate, FeCoNiCrMo/NF is designed to be prepared by metal–organic frameworks (MOF) as a precursor under an argon atmosphere. XRD analysis confirms that it retains a partial MOF crystal structure (characteristic peak at 2θ = 11.8°) with amorphous carbon (peaks at 22° and 48°). SEM-EDS mapping and XPS demonstrate uniform distribution of Fe, Co, Ni, Cr, and Mo with a molar ratio of 27:24:30:11:9. Electrochemical test results show that FeCoNiCrMo/NF has excellent OER characteristics compared with other reference prepared samples. FeCoNiCrMo/NF has an overpotential of 285 mV at 100 mA cm⁻² and performs continuously for 100 h without significant decline. The OER mechanism of FeCoNiCrMo/NF further reveal that Co and Ni are true active sites, and the dissolution of Cr and Mo promote the conversion of active sites into MOOH following the lattice oxygen mechanism (LOM). The precipitation–dissolution equilibrium of Fe also plays an important role in the OER process. The study of different reaction sites in complex systems points the way to designing efficient and robust catalysts. Full article

Industrial catalysts are accelerating the global transition toward renewable energy, serving as enablers for innovative technologies that enhance efficiency, lower costs, and improve environmental sustainability. This review explores the pivotal roles of industrial catalysts in hydrogen production, biofuel generation, and biomass conversion, highlighting their transformative impact on renewable energy systems. Precious-metal-based electrocatalysts such as ruthenium (Ru), iridium (Ir), and platinum (Pt) demonstrate high efficiency but face challenges due to their cost and stability. Alternatives like nickel-cobalt oxide (NiCo₂O₄) and Ti₃C₂ MXene materials show promise in addressing these limitations, enabling cost-effective and scalable hydrogen production. Additionally, nickel-based catalysts supported on alumina optimize SMR, reducing coke formation and improving efficiency. In biofuel production, heterogeneous catalysts play a crucial role in converting biomass into valuable fuels. Co-based bimetallic catalysts enhance hydrodeoxygenation (HDO) processes, improving the yield of biofuels like dimethylfuran (DMF) and γ-valerolactone (GVL). Innovative materials such as biochar, red mud, and metal–organic frameworks (MOFs) facilitate sustainable waste-to-fuel conversion and biodiesel production, offering environmental and economic benefits. Power-to-X technologies, which convert renewable electricity into chemical energy carriers like hydrogen and synthetic fuels, rely on advanced catalysts to improve reaction rates, selectivity, and energy efficiency. Innovations in non-precious metal catalysts, nanostructured materials, and defect-engineered catalysts provide solutions for sustainable energy systems. These advancements promise to enhance efficiency, reduce environmental footprints, and ensure the viability of renewable energy technologies. Full article

The rapid recombination of photoinduced charge carriers in semiconductors remains a significant challenge for their practical application in photocatalysis. This study presents the design of a step-scheme (S-scheme) heterojunction composed of carbon nitride (g-C₃N₄) and nickel-based metal–organic framework (Ni-MOF) to achieve enhanced charge separation. The establishment of an S-scheme charge transfer configuration at the interface of the Ni-MOF/g-C₃N₄ heterostructure plays a pivotal role in enabling efficient charge carrier separation, and hence, high CO₂ photoreduction efficiency with a CO evolution rate of 1014.6 µmol g⁻¹ h⁻¹ and selectivity of 95% under simulated solar illumination. CO evolution represents an approximately 3.7-fold enhancement compared to pristine Ni-MOF. Density functional theory (DFT) calculations, supported by in situ irradiated X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) experimental results, confirmed the establishment of a well-defined and strongly bonded interface, which improves the charge transfer and separation following the S-scheme mechanism. This study sheds light on MOF-based S-scheme heterojunctions as fruitful and selective alternatives for practical CO₂ photoreduction. Full article

The electrocatalytic CO₂ reduction reaction (CO₂RR) offers an energy-saving and environmentally friendly approach to producing hydrocarbon fuels. The use of a gas diffusion electrode (GDE) flow cell has generally improved the rate of CO₂RR, while the gas diffusion layer (GDL) remains a significant challenge. In this study, we successfully engineered a novel metal–organic framework (MOF) heterojunction through the controlled coating of zeolitic imidazolate framework (ZIF-L) on ultrathin nickel—metal–organic framework (Ni-MOF) nanosheets. This innovative architecture simultaneously integrates GDL functionality and exposes abundant solid–liquid–gas triple-phase boundaries. The resulting Ni-MOF@ZIF-L heterostructure demonstrates exceptional performance, achieving a formate Faradaic efficiency of 92.4% while suppressing the hydrogen evolution reaction (HER) to 6.7%. Through computational modeling of the optimized heterojunction configuration, we further elucidated its competitive adsorption behavior and electronic modulation effects. The experimental and theoretical results demonstrate an improvement in electrochemical CO₂ reduction activity with suppressed hydrogen evolution for the heterojunction because of its hydrophobic interface, good electron transfer capability, and high CO₂ adsorption at the catalyst interface. This work provides a new insight into the rational design of porous crystalline materials in electrocatalytic CO₂RR. Full article

Carbon nanotubes (CNTs) functionalized with metal oxides exhibit synergistic properties that enhance their performance across various applications, particularly in electrochemistry. Recent advancements have highlighted the potential of CNT–metal oxide heterostructures, with a specific focus on their electrochemical properties, which are pivotal for applications in sensors, supercapacitors, batteries, and catalytic systems. Among these, nickel oxide (NiO)-modified CNTs have garnered significant attention due to their cost-effectiveness, facile synthesis, and promising gas-sensing capabilities. This study employs quantum-chemical calculations within the framework of density functional theory (DFT) to elucidate the interaction mechanisms between CNTs and NiO. The results demonstrate that the adsorption process leads to the formation of stable CNT-NiO complexes, with detailed analysis of adsorption energies, equilibrium distances, and electronic structure modifications. The single-electron spectra and density of states (DOS) of the optimized complexes reveal significant alterations in the electronic properties, particularly the modulation of the energy gap induced by surface and edge functionalization. Furthermore, the interaction of CNT-NiO composites with acetone (C₃H₆O) and carbon dioxide (CO₂) is modeled, revealing a physisorption-dominated mechanism. The adsorption of these gases induces notable changes in the electronic properties and charge distribution within the system, underscoring the potential of CNT-NiO composites for gas-sensing applications. This investigation provides a foundational understanding of the role of metal oxide modifications in tailoring the sensory activity of CNTs toward trace amounts of diverse substances, including metal atoms, inorganic molecules, and organic compounds. The findings suggest that CNT-NiO systems can serve as highly sensitive and selective sensing elements, with potential applications in medical diagnostics and environmental monitoring, thereby advancing the development of next-generation sensor technologies. Full article

Evaluating the bioaccessibility and health risks of seafood is extremely important because, although it is a significant source of vital minerals, it may also contain potentially toxic elements. This study aimed to determine the content of metals and minerals in different seafood species before and after thermal processing. Also, given the risk of overestimating the actual final concentration available in the body, a study was carried out to determine the bioaccessibility of these elements by simulating the digestion process in the gastrointestinal tract. Assessment of the potential toxic effects on consumer health in terms of exposure to heavy metals was carried out through risk analysis by Estimated Daily Intake, Hazard Index, and Cancer Risk parameters. Three bivalve mollusks, one gastropod mollusk, four cephalopod mollusks, and one crustacean species were analyzed in terms of minerals (P, S, K, Ca, and Se) and heavy metals (Cd, Pb, Ni, Cr, Fe, Zn, Co, Mn, and As) content. The lead (Pb) concentration recorded the strongest bioaccessibility increase, even reaching 100% in P. vannamei. Generally, the bioaccessibility of all metalloids dropped below 100%, which suggests that only a part of the amount of metal in the initially ingested sample can be absorbed by the human organism. Potassium and sulfur registered the greatest value, up to 23% for minerals’ bioaccessibility in the same samples. The highest intake rate of metals occurred after the consumption of M. gigas, which registered the highest Estimated Daily Intake for Cr (chromium) (0.321 mg kg⁻¹ d⁻¹), Cu (copper) (10.15 mg kg⁻¹ d⁻¹), and Zn (zinc) (12.67 mg kg⁻¹ d⁻¹). The Hazard Index values indicated no significant risk of poisoning. All calculated Cancer Risk scores remained below the acceptable threshold. Moreover, the Pearson coefficient revealed a positive correlation between the Hazard Index and the most abundant elements in the samples, Cr, Zn, and Cu. This study could provide a framework for evaluating both the nutritional benefits and toxicological concerns of seafood intake in public health applications. Full article

NiFe₂O₄ and TiO₂ are widely studied for photoelectrochemical (PEC) applications due to their unique properties. Nitrogen-doped graphene (NG) and metal–organic frameworks (MOFs), such as MIL-100(Fe) (where MIL stands for Materials of Lavoisier Institute), are commonly incorporated to enhance PEC performance by offering a high surface area and facilitating efficient charge transport. Composite systems are commonly employed to overcome the limitations of individual PEC catalysts. In this study, a highly efficient NiFe₂O₄/NG@MIL-100(Fe)/TiO₂ photoanode was developed to enhance photoelectrochemical water-splitting performance. The composite was synthesized via a hydrothermal method with a two-step heating process. X-ray diffraction confirmed the expected crystal structures, with peak broadening in NiFe₂O₄ indicating reduced crystallite size and increased lattice strain. X-ray photoelectron spectroscopy of the Ni 2p and Fe 2p regions validated the successful integration of NiFe₂O₄ into the composite. Electrochemical analysis demonstrated excellent performance, with linear sweep voltammetry achieving a peak photocurrent density of 3.5 mA cm⁻² at 1.23 V (vs RHE). Electrochemical impedance spectroscopy revealed a reduced charge-transfer resistance of 50 Ω, indicating improved charge transport. Optical and electronic properties were evaluated using UV-Vis spectroscopy and Tauc plots, revealing a direct bandgap of 2.1 eV. The composite exhibited stable photocurrent under amperometric J-t testing for 2000 s, demonstrating its durability. These findings underscore the potential of NiFe₂O₄/NG@MIL-100(Fe)/TiO₂ as a promising material for renewable energy applications, particularly in photoelectrochemical water splitting. Full article

Metal–organic frameworks (MOFs) are regarded as advanced supercapacitor materials owing to their high surface area, redox-active sites, and porosity. However, their insufficient charge carrier mobility remains a critical limitation for practical application. Integrating MOFs with conductive carbon substrates is an effective strategy to break through this limitation. However, conventional carbon materials often require complex preparation methods and pre-activation steps for use in MOF composites. Herein, multilayer graphene (MLG) mechanically exfoliated from expandable graphite is employed as a substrate, and a van der Waals force-assisted chemical deposition method is developed to directly anchor Ni-MOF onto its surface without requiring pre-activation treatment. To optimize the composite, Ni-MOFs with various mass loadings are synthesized on MLG surface. The morphological characteristics and energy storage performance of these composites are thoroughly characterized. Ni-MOF/MLG-0.30 (with a 70.8% Ni-MOF loading on MLG) features a porous stacking structure of well-crystalline Ni-MOF parallelogram nanosheets on MLG, exhibiting optimal electrochemical performance. The composite achieves 1071.4 F·g⁻¹ at 1 A·g⁻¹, and a capacitance retention of 64.9% at the elevated current density of 10 A·g⁻¹. Meanwhile, the composite maintains 63.2% of its initial capacitance after 5000 charge/discharge cycles at 4 A·g⁻¹. A hybrid supercapacitor is fabricated using Ni-MOF/MLG-0.30 cathode and activated carbon anode, delivering 27.9 Wh·kg⁻¹ energy density at 102.5 W·kg⁻¹ power output. Full article

Composite catalysts combining a metal–organic framework (MOF) with its derivatives have attracted significant attention in electrocatalysis due to their unique properties. In this study, we report the synthesis of a Ni-doped Co-1,4-benzenedicarboxylate (defined as Co₃Ni₁BDC) metal–organic framework via a straightforward solvothermal method, aiming to enhance oxygen evolution reaction (OER) activity. The introduction of Ni modulated the electronic structure, yielding high catalytic activity with an overpotential (η₁₀₀) of 300 mV and excellent stability for the OER. The Co₃Ni₁BDC material was further encapsulated with Co₂P nanoparticles via a controlled phosphating annealing process, forming a hybrid electrocatalyst (Co₃Ni₁BDC@Co₂P) to boost hydrogen evolution reaction (HER) performance. The Co₃Ni₁BDC@ Co₂P catalysts exhibited superior HER performance with low overpotentials of η₁₀ = 20 mV and η₁₀₀ = 127 mV, outperforming the Co₃Ni₁BDC precursor. An alkaline electrolyzer assembled with Co₃Ni₁BDC//Co₃Ni₁BDC@Co₂P achieved a cell voltage of 1.70 V at a current density of 20 mA cm⁻². This work provides a valuable idea for designing efficient electrocatalysts for overall water splitting. Full article

Doping undermines fairness in sports and threatens athlete health, while conventional detection methods like LC-MS and GC-MS face challenges such as complex procedures, matrix interferences, and lengthy processing times, limiting on-site applications. Two-dimensional (2D) materials, including graphene, MoS₂, and metal–organic frameworks (MOFs), offer promising solutions due to their large surface areas, tunable electronic structures, and special interactions with doping agents, such as hydrogen bonding, π-π stacking, and electrostatic forces. These materials enable signal transduction through changes in conductivity or fluorescence quenching. This review highlights the use of 2D materials in doping detection. For example, reduced graphene oxide–MOF composites show high sensitivity for detecting anabolic steroids like testosterone, while NiO/NGO nanocomposites exhibit strong selectivity for stimulants like ephedrine. However, challenges such as environmental instability and high production costs hinder their widespread application. Future efforts should focus on improving material stability through chemical modifications, reducing production costs, and integrating these materials into advanced systems like machine learning. Such advancements could revolutionize doping detection, ensuring fairness in sports and protecting athlete health. Full article

Developing efficient bifunctional oxygen reduction (ORR) and oxygen evolution (OER) electrocatalysts is critical for renewable energy technologies. Noble metal catalysts face limitations in cost, scarcity, and bifunctional compatibility. Herein, we report the synthesis of nickel nanoparticles encapsulated in nitrogen-doped carbon nanosheets (Ni@NC-T) via a solvothermal polymerization and pyrolysis process using a Ni-hexamine coordination framework (NiHMT) as a precursor. The Ni@NC-900 catalyst exhibits superior ORR and OER activity under alkaline conditions, with an ORR performance (half-wave potential = 0.86 V) comparable to commercial Pt/C and an OER overpotential of only 430 mV at 10 mA cm⁻². Structural analysis indicates that the hierarchical porous structure and high specific surface area (409 m² g⁻¹) of Ni@NC-900 facilitate the exposure of active sites and enhance mass transport. The surface-doped nitrogen species, predominantly in the form of pyridinic N and graphitic N, promote electron transfer during the ORR. Furthermore, its application as a bifunctional cathode in rechargeable zinc-air batteries results in a high power density of 137 mW cm⁻², surpassing the performance levels of many existing carbon-based bifunctional catalysts. This work highlights a facile strategy for the fabrication of transition metal-based catalysts encapsulated in MOF-derived carbon matrices, with promising potential for energy storage and conversion devices. Full article

Furfural (FAL), a platform molecule derived from biomass through acid-catalyzed processes, holds significant potential for producing various value-added chemicals. Its unique chemical structure, comprising a furan ring and an aldehyde functional group, enables diverse transformation pathways to yield products such as furfuryl alcohol, furan, tetrahydrofuran, and other industrially relevant compounds. Consequently, optimizing catalytic processes for FAL conversion has garnered substantial attention, particularly in selectivity and efficiency. The liquid-phase hydrogenation of FAL has demonstrated advantages, including enhanced catalyst stability and higher product yields. Among the catalysts investigated, mesoporous materials have emerged as promising candidates because of their high surface area, tunable pore structure, and ability to support highly dispersed active sites. These attributes are critical for maximizing the catalytic performance across various reactions, including FAL hydrogenation. This review provides a comprehensive overview of recent advances in mesoporous catalyst design for FAL hydrogenation, focusing on synthesis strategies, metal dispersion control, and structural optimization to enhance catalytic performance. It explores noble metal-based catalysts, particularly highly dispersed Pd systems, as well as transition-metal-based alternatives such as Co-, Cu-, and Ni-based mesoporous catalysts, highlighting their electronic structure, bimetallic interactions, and active site properties. Additionally, metal–organic frameworks are introduced as both catalysts and precursors for thermally derived materials. Finally, key challenges that require further investigation are discussed, including catalyst stability, deactivation mechanisms, strategies to reduce reliance on external hydrogen sources, and the impact of solvent effects on product selectivity. By integrating these insights, this review provides a comprehensive perspective on the development of efficient and sustainable catalytic systems for biomass valorization. Full article

With the rapid expansion of electronic information technology and rising material safety needs, the creation of composite materials that perform both electromagnetic microwave absorption (EMA) and flame retardancy has arisen as a materials science research hotspot. Metal–organic frameworks (MOFs) have great potential for developing novel multifunctional composite materials due to their unique structural characteristics and customizable functions. This work presents a comprehensive assessment of the most recent research findings on MOF-based EMA-flame retardant dual-functional composites. The fundamental mechanisms of EMA and flame retardancy are covered, including dielectric loss, magnetic loss, and both condensed-phase and gas-phase flame retardancy mechanisms. The development of composites based on Fe-MOF, Co-MOF, Ni-MOF, and polymetallic MOF in terms of EMA and flame retardancy is highlighted. These materials offer exceptional EMA performance and strong flame retardancy effects thanks to their unique structural designs and component regulations. In addition, some materials have great infrared stealth, thermal insulation, hydrophobic, and mechanical qualities. Ultimately, the problems of MOF-based dual-functional composites and their development possibilities are reviewed, giving valuable references for the development of new multifunctional composite materials. Full article

To achieve the “double carbon” goal, it is urgent to reform the energy system. The oxygen evolution reaction (OER) is a vital semi-reaction for many new energy-storage and conversion devices. Metal nanoparticles embedded in heteroatom-doped carbon materials prepared by the pyrolyzing of metal–organic frameworks (MOFs) have been a key route to obtain high-performance electrochemical catalysts. Herein, a nanocatalyst embedding Ni nanoparticles into S- and N-co-doped carbon nanoplate (Ni NPs@SN-CNP) has been synthesized by pyrolysis of a Ni-MOF precursor. The prepared Ni NPs@SN-CNP exhibits superior oxygen evolution performance with an overpotential of 256 mV to attain 10 mA cm⁻² and a low Tafel slope value of 95 mV dec⁻¹. Moreover, a self-assembled overall-water-splitting cell with Ni NPs@SN-CNP/NF||Pt-C/NF achieves a low potential of 1.56 V at 10 mA cm⁻² and a high cycling stability for at least 10 h. The improvement in this performance is benefit from its large surface area, unique morphology, and the nanostructure of the electrocatalyst. This study presents a novel and simple approach to designing high-performance OER catalysts. Full article

This study explores the electrochemical properties of additive-free NiCo₂O₄ derived from NiCo–metal–organic frameworks (MOFs) as a high-performance anode material for lithium-ion batteries (LIBs), excluding the effect of additives. NiCo-MOF was synthesized via an ultrasonic-assisted method and deposited on stainless steel foils using alternating current electrophoretic deposition (AC-EPD). The resulting thin films exhibited outstanding cycling stability and rate performance, maintaining a specific capacity of ~1200 mAh/g over 250 cycles at a high current density of 2.35 A/g, with nearly 100% Coulombic efficiency. Differential capacity analysis revealed enhanced redox activity at 0.8 V and 1.7 V during lithiation and delithiation, attributed to the decomposition of NiCo₂O₄ into metallic Ni and Co, followed by their oxidation to Ni²⁺ and Co³⁺, respectively. The gradual activation of electroactive sites, coupled with improved electrode kinetics and structural adjustments, contributed to the observed capacity increase over cycles. These findings underscore the potential of NiCo₂O₄ as a robust and efficient anode material for next-generation LIBs. Full article