ChemPhysMater最新文献

Nanozymes are nanomaterials with intrinsic enzyme-mimic activity, but their large-scale application is generally limited by their low catalytic activity. Herein, we demonstrated that highly exposed Cu active sites on two-dimensional (2D) nitrogen-doped carbon (Cu_x/NC) can serve as efficient peroxidase-like (POD) catalysts with high atomic utilization. Specially, the uniformly distributed Cu active sites could react with H₂O₂ to produce singlet oxygen (¹O₂) under acidic conditions, which can efficiently oxidizes colorless 3,3′, 5,5′-tetramethylbenzidine (TMB) to blue oxidized TMB (oxTMB). Among various Cu_x/NC nanozymes studied, the Cu_0.14/NC exhibited smaller maximum catalytic velocities (V_max) and Menten constant (K_m) for TMB and H₂O₂. Benefiting from the highly active peroxidase-like activity, the Cu_0.14/NC nanozyme could be successfully applied for the hydroquinone (HQ) and ascorbic acid (AA) detection applications through the inhibitory effect of HQ and AA. More interestingly, α-glucosidase (α-Glu) detection sensing platform could be constructed based on HQ as a signal transmitter, with the detection range ranging from 0 to 12 U/L and the minimum detection limit being 0.68 U/L. This work provides not only an idea for the rational design of highly exposed Cu active sites but also fabricate an effective detection sensing platform for HQ, AA, and α-Glu detection.

The development of MXene-based heterostructures for electrocatalysis has garnered significant attention owing to their potential as high-performance catalysts that play a pivotal role in hydrogen energy. Herein, we present a multistep strategy for the synthesis of a Ti₃C₂ MXene ribbon/NiFeP_x @graphitic N-doped carbon (NC) heterostructure that enables the formation of three-dimensional (3D) Ti₃C₂ MXene ribbon networks and bimetallic phosphide nanoarrays. With the assistance of HF etching and KOH shearing, the MXene sheets were successfully transformed into 3D MXene networks with interlaced MXene ribbons. Notably, a hydrothermal method, ion exchange route, and phosphorization process were used to anchor NiFeP_x@NC nanocubes derived from Ni(OH)₂/NiFe-based Prussian blue (NiFe-PB) onto the MXene ribbon network. The resulting MXene ribbon/NiFeP_x@NC heterostructure demonstrated enhanced oxygen evolution reaction (OER) activity, characterized by a low overpotential (164 mV at a current density of 10 mA cm⁻²) and a low Tafel slope (45 mV dec⁻¹). At the same time, the MXene ribbons/NiFeP_x@NC heterostructure exhibited outstanding long-term stability, with a 12 mV potential decay after 5000 cyclic voltammetry (CV) cycles. This study provides a robust pathway for the design of efficient MXene-based heterostructured electrocatalysts for water splitting.

In view of the current study's demonstration of the synthesis of clay-doped ZnO composites, we present a low-cost method for producing clay-metal oxide (clay/ZnO). Utilizing the solution combustion technique, a composite of clay/ZnO was produced utilizing citric acid as both a fuel and a complexing agent. The hexagonal unit cell structure of the created clay/ZnO may be seen using XRD patterns. The ZnO-infused clay was visible in FE-SEM micrographs as homogenous, sphere-shaped ZnO. The possible involvement of clay/ZnO photocatalytic activity in the UV-induced photodegradation of malachite green dye was investigated. The 90% degradation rate shows the composite's outstanding photocatalytic degradation capacity. The resulting substance was electrochemically analyzed using a constructed electrode in 0.1 M KOH electrolyte. It increased its sensor capabilities, which now include chemical and biomolecule sensors, and it excelled in cyclic voltammetry-based redox potential studies. To efficiently evaluate chemically synthesized NPs for electrochemical, sensing, and photocatalytic applications, this study intends to create a solution combustion procedure for the synthesis of clay/ZnO nanocomposite using urea as fuel.

The sluggish kinetics of the oxygen evolution reaction (OER), an essential half-reaction of water splitting, lead to high OER overpotential and low energy-conversion efficiency, hampering its industrial application. Therefore, considerable attention has been paid to the development of efficient catalysts to accelerate the OER. In this study, we synthesized the high-entropy oxides [(FeCoNiMnV)_xO] and used them as efficient OER catalysts. A simple oil-phase method was used to synthesize (FeCoNiMnV)_xO. The catalytic performances of the (FeCoNiMnV)_xO catalysts were modified by tuning the reaction temperature. The optimized (FeCoNiMnV)_xO catalyst exhibited multiple elemental interactions and abundant exposed active sites, leading to an overpotential of approximately 264 mV to reach a current density of 10 mA cm⁻² in 1 M KOH and stability of 50 h at 1000 mA cm⁻². Thus, a highly active OER catalyst was synthesized. This study provides an efficient approach for the synthesis of high-entropy oxides.

Hydrogen, a clean and versatile energy carrier, has gained significant attention as a potential solution for addressing the challenges of climate change and energy sustainability. Efficient hydrogen production relies heavily on the development of advanced materials that enable cost-effective and sustainable methods. This review article presents a comprehensive overview of cutting-edge materials used for hydrogen production, covering both traditional and emerging technologies. This article begins by briefly introducing the importance of hydrogen as a clean energy carrier and various methods used for hydrogen production. This emphasizes the critical role of these materials in enabling efficient hydrogen generation. Traditional methods, such as steam methane reforming, coal gasification, biomass gasification, and water electrolysis, are discussed, highlighting the materials used and their advantages and limitations. This review then focuses on emerging technologies that have shown promise for achieving efficient hydrogen production. Photocatalytic water splitting is explored with an emphasis on recent advancements in semiconductor-based photocatalysts and nanostructured materials for enhanced photocatalysis. Solid oxide electrolysis cells (SOEC) are examined, discussing high-temperature electrolysis materials and advancements in electrolytes and electrode materials. Biological hydrogen production and chemical looping are also discussed, highlighting the use of microorganisms, bioengineered systems, metal oxides as oxygen carriers, and catalysts for improved hydrogen generation. Advanced characterization techniques, including X-ray diffraction, spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Auger electron spectroscopy, thermogravimetric analysis, and differential scanning calorimetry, have been used to gain insight into the properties and performances of materials. This review concludes by addressing the challenges and prospects in the field of hydrogen production materials. This highlights the importance of the durability, stability, cost-effectiveness, scalability, and integration of materials into large-scale hydrogen pchiroduction systems. This article also discusses the emerging trends and potential breakthroughs that could shape the future of hydrogen production.

Hierarchical heterostructures have emerged as promising candidates for the efficient photocatalytic degradation of antibiotics owing to their matched energy levels and tunable absorption bands. Herein, we report the facile synthesis of a heterojunction photocatalyst composed of basic bismuth nitrate (BiON) and BiOCl_0.9I_0.1 using a simple room-temperature hydrolysis method. Our results demonstrate that the BiON/BiOCl_0.9I_0.1 composite exhibits superior photodegradation performance compared to pure-phase materials owing to the catalytic enhancement at the heterointerface and the effective separation of the photogenerated carriers. Moreover, the unique three-dimensional microsphere morphology of the synthesized composite enhances its specific surface area and light absorption, further enhancing its photocatalytic activity. In the tetracycline (TC) photodegradation reaction as a model reaction, the catalyst could degrade 88% of TC in just 25 min. Overall, this work provides a promising strategy for the facile and low-cost synthesis of heterogeneous photocatalytic degradation materials.

Hydrogen energy plays an important role in clean energy system and is considered the core energy source for future technological development owing to its lightweight nature, high calorific value, and clean combustion products. The electrocatalytic conversion of water into hydrogen is considered a highly promising method. An electrocatalyst is indispensable in the electrocatalytic process, and finding an efficient electrocatalyst is essential. However, the current commercial electrocatalysts (such as Pt/C and Ru) are expensive; therefore, there is a need to find an inexpensive and efficient electrocatalyst with high stability, corrosion resistance, and high electrocatalytic efficiency. In this study, we developed a cost-effective bifunctional electrocatalyst by incorporating molybdenum into nickel sulfide (Ni₃S₂) and subsequently tailoring its structure to achieve a one-dimensional (1D) needle-like configuration. The hydrogen production efficiency of nickel sulfide was improved by changing the ratio of Mo doping. By analyzing the electrochemical performance of different Mo-doped catalysts, we found that the Ni₃S₂-Mo-0.1 electrocatalyst exhibited the best electrocatalytic effect in 1 M KOH; at a current density of 10 mA cm⁻², it exhibited overpotentials of 120 and 279 mV for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively; at a higher current density of 100 mA cm⁻², the HER and OER overpotentials were 396 and 495 mV, respectively. Furthermore, this electrocatalyst can be used in a two-electrode water-splitting system. Finally, we thoroughly investigated the mechanism of the overall water splitting of this electrocatalyst, providing valuable insights for future hydrogen production via overall-water-splitting.

Lithium–oxygen batteries (LOBs) have extensive applications because of their ultra-high energy densities. However, the practical application of LOBs is limited by several factors, such as a high overpotential, poor cycle stability, and limited rate capacity. In this paper, we describe the successful uniform loading of Mn₃O₄ nanoparticles onto multi-walled carbon nanotubes (Mn₃O₄@CNT). CNTs form a conductive network and expose numerous catalytically active sites, and the one-dimensional porous structure provides a convenient channel for the transmission of Li⁺ and O₂ in LOBs. The electronic conductivity and electrocatalytic activity of Mn₃O₄@CNT are significantly better than those of MnO@CNT because of the inherent driving force facilitating charge transfer between different valence metal ions. Therefore, the Mn₃O₄@CNT cathode obtains a low overpotential (0.76 V at a limited capacity of 1000 mAh g⁻¹), high initial discharge capacity (16895 mAh g⁻¹ at 200 mA g⁻¹), and long cycle life (97 cycles at 200 mA g⁻¹). This study provides evidence that transition metal oxides with mixed-valence states are suitable for application as efficient cathodes for LOBs.

Covalent organic frameworks (COFs) have emerged as an interesting class of crystalline porous materials with desirable properties (such as highly ordered porosity, structural versatility, high chemical and thermal stabilities, and facile surface modification) and a broad range of potential applications. This critical review is aimed at providing insight into design strategies and synthetic methodologies for COFs. Unlike previous reviews on COFs, this article also focuses on the characterization of COFs, which is important for understanding the physical and chemical properties of COFs that are essential for practical applications. Furthermore, this review highlights the applications of COFs in various fields, including catalysis, photovoltaic devices, sensors, supercapacitors, wastewater treatment, biomedicine, chromatographic and spectroscopic analyses, and gas separation and storage. Lastly, perspectives on future directions and challenges associated with COFs are provided.

Self-assembly has been extensively studied in chemistry, physics, biology, and materials engineering and has become an important “bottom-up” approach in creating intriguing structures for different applications. Using dissipative self-assembly to construct fuel-dependent, energy-consuming, and dynamic nonequilibrium systems is important for developing intelligent life-like materials. Furthermore, dissipative self-assembly has become a research hotspot in materials chemistry, biomedical science, environmental chemistry, and physical chemistry. An in-depth understanding of the process and mechanism provides useful insights to the researchers for developing materials using dissipative self-assembly and also helps guide future innovation in material fabrication. This critical review comprehensively analyzes various chemical fuel input and energy consumption mechanisms, supported by numerous illustrative examples. Versatile transient assemblies, including gels, vesicles, micelles, and nanoparticle aggregates, have been systematically studied in our and other laboratories. The relationship between the molecular structure of precursors and temporal assemblies in dissipative self-assemblies is discussed from the perspective of physical chemistry. Using dissipative self-assembly methods to construct functional assemblies provides important implications for constructing high-energy, nonequilibrium, and intelligent functional materials.