ChemPhysMater最新文献

Atomically dispersed single-atom catalysts (SACs) have been extensively studied over the past decade because of their high atom utilization efficiencies and specific selectivities. Although numerous strategies have been proposed to obtain SACs with high densities and stabilities, the transformation mechanism that occurs during the reaction is still unclear. This review summarizes the structural evolution of SACs in the preparation process and reaction with various electron microscopy techniques at atomic scale under environmental conditions. Current state-of-the-art environmental electron microscopy studies on SACs mainly focus on porous carbons, metals or metal oxides, and some specific composite materials. The dynamic evolution of SACs under various reaction conditions is also investigated in this study. Finally, we highlight the challenges and drawbacks of the current studies and the prospects for the future exploration of SACs with environmental strategies.

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.

The realization of long-range magnetic ordering in two-dimensional (2D) van der Waals systems significantly expands the scope of the 2D family as well as their possible spin-related phenomena and device applications. The atomically thin nature of 2D materials makes their magnetically ordered states sensitive to local environments, and this necessitates advanced characterization at the atomic scale. Here, we briefly review several representative 2D magnetic systems, namely, iron chalcogenides, chromium chalcogenides, chromium trihalides, and their heterostructures. With powerful scanning-probe microscopy, atomically resolved characterization of their crystalline configurations, electronic structures, and magnetization distributions has been achieved, and novel phenomena such as giant tunneling magnetoresistance and topological superconductivity have been observed. Finally, we discuss the challenges and new perspectives in this flourishing field.

Ultrasonic velocity measurements are used to elucidate various aspects of solvation chemistry, including solute–solute and solute–solvent interactions. Herein, an attempt is made to study a behavior of two sweeteners, D-fructose and D-sorbitol, in aqueous and non-aqueous media was attempted. D-fructose is a simple sugar found in many foods and can be consumed by diabetics and people suffering from hypoglycemia. D-Sorbitol is a sugar substitute used in diet foods, sugar-free chewing gum, mints, cough syrups, mouthwash, toothpaste etc., D-sorbitol is an excellent humectant and texturizing agent that is also used in other products such as pharmaceuticals and cosmetics. The interactions between the solute and solvent molecules are explained in terms of the solvation numbers of both aqueous and non-aqueous solutions of D-fructose and D-sorbitol. The viscosity study correlates the viscosity of the solution with solvation; here, density, ultrasonic velocity, and viscosity of aqueous and non-aqueous solutions at various concentrations are measured at different temperatures ranging from 35 to 55 °C. These parameters provide sufficient information on the interaction between molecules that may aid chemists in analyzing the mechanisms of the behavior of D-fructose and D-sorbitol in water and the water–ethanol medium through which they are consumed. The Fourier transforms infrared spectra of pure solvent, salt, and their solutions were recorded and analyzed for confirmation.

Metal-ion (Li-, Na-, Zn-, K-, Mg-, and Al-ion) batteries (MIBs) play an important role in realizing the goals of “emission peak and carbon neutralization” because of their green production techniques, lower pollution, high voltage, and large energy density. Carbon-based materials are indispensable for developing MIBs and are widely adopted as active or auxiliary materials in the anodes and cathodes. For example, carbon-based materials, including graphite, Si/C and hard carbon, have been used as anode materials for Li- and Na-ion batteries. Carbon can also be used as a conductive coating for cathodes, such as in LiFePO₄/C, to achieve better performance. In addition, as new high-valence MIBs (Zn-, Al-, and Mg-ion) have emerged, a growing number of novel carbon-based materials have been utilized to construct high-performance MIBs. Herein, we discuss the recent development trends in advanced carbon-based materials for MIBs. The impact of the structure properties of advanced carbon-based materials on energy storage is addressed, and a perspective on their development is also proposed.

TiO₂ cluster sensitivity to acetone adsorption using transition state theory is investigated. Ti₁₀O₂₀ cluster is used to perform the calculations using density functional theory with dispersion corrections. Adsorption state and transition state are calculated via thermodynamic energies, i.e., Gibbs free energy of adsorption and activation. Reaction rate, response, response time, and recovery time as a function of temperature and acetone concentration are calculated. Acetone burning in the air due to autoignition is considered using a logistic function. The results of the theory are compared with available experimental findings that revealed the quality of both theoretical and experimental results. The response time decreases with respect to acetone concentration. On the other hand, the recovery time in the desorption phase increases with acetone concentration. The temperature of maximum response is 356 °C, while the maximum response value is 2.9.

In this study we report, for the first time, the synthesis of Co-doped NiO microspheres assembled by two-dimension nanosheets using a facile solvothermal method. The H₂S gas-sensing performance of the as-prepared samples was systematically investigated. The result demonstrates that the Co–NiO sensor with Co/Ni molar ratio of 1% (1% Co–NiO) exhibits high response (12.9) and rapid response speed (110 s) to 20×10⁻⁶ H₂S at 200 °C in comparison with the pure NiO sensor. Moreover, excellent selectivity, repeatability, and stability were achieved. The sensing mechanism illustrates that the superior gas-sensing properties can be attributed to two factors. (1) The hierarchical microspherical construction with an ultrahigh specific surface area of 163.1 m² g⁻¹ provides adequate active sites for H₂S gas adsorption, porous structures, and an interlayer gap that accelerates the diffusion of H₂S gas, resulting in improved sensitivity and response speed of the sensor. (2) Co-doping results in a decrease in the particle sizes (ca. 4 nm) and increase in the number of adsorbed ionized oxygen species, which improves sensitivity and selectivity. Therefore, this study provides a facile approach for the synthesis of hierarchical Co–NiO microspheres with enhanced H₂S gas-sensing performance.

Poor electron conductivity is the key issue influencing the rate capability of NaTi₂(PO₄)₃ (NTP). Hence, herein, polyacrylonitrile (PAN) was utilized as a NTP modifier by simply mixing NTP in a liquid PAN suspension, followed by sintering at 850 °C for 5 h. The product with a PAN/NTP mass ratio of 0.3 delivered splendid rate capabilities (achieving lithiation capacities of 282.9, 243.0, 207.1, 173.1, 133.5, and 257.5 mAh g⁻¹ at 0.1, 0.2, 0.4, 0.8, 1.6, and 0.1 A⁻¹, respectively) and excellent long cycling life (capacity retention of 165.5 mAh g⁻¹ after 1200 cycles at 0.5 A g⁻¹). Based on detailed structural and compositional characterizations, as well as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), the uniform N-doped carbon coating stemming from PAN carbonization around the NTP particles promoted electron transfer, while the oxygen vacancies induced by N-doping in NTP facilitated Li⁺ diffusion. The boosted and well matched electronic and ionic conductivities give rise to the optimized electrochemical performance.

All-inorganic perovskites are rapidly emerging as novel optoelectronic functional materials owing to their fluorescence properties. However, the stability of these materials has always been the biggest challenge for their applications in photoelectric devices. Therefore, this study focuses on developing phosphor-aluminosilicate-based CsPbX₃ (X = Cl, Br, and I) glass with a low reaction temperature by adding CsCO₃, PbX_2, and NaX to the raw materials in order to improve the stabilities. The glass network intermediates of SiO₂ and Al₂O₃ doping in the raw material enhanced the stability of the pure phosphate glass network structure and devitrification while decreasing the melting temperature. Full chromatographic CsPbX₃ quantum dots (QDs) encapsulated in phosphate-based glass were found to increase the fluorescence properties and quantum efficiency (>59%). Notably, the high water stability of CsPbX₃ QDs glasses, with the maintenance of 90% luminous intensity, emerged when soaked in water. In addition, the excellent thermal stability and anti-ion exchange properties of the CsPbX₃ QDs glasses were revealed. Benefiting from the above, multicolor light-emitting diode (LED) devices were assembled with a mixture of phosphors of CsPbX₃ QDs glasses and commercial red-emission K₂SiF₆:Mn⁴⁺ phosphor spread on an InGaN chip, demonstrating bright light with superior luminous properties. Phosphor-aluminosilicate-based CsPbX₃ QDs glass with high stability and low formation temperature would provide new methods for applications in lighting and displays.

Ferroelectric domain engineering with infrared femtosecond laser pulses has been a powerful technique to achieve a spatially modulated second-order nonlinear coefficient in three dimensions. However, studies regarding the influence of laser writing conditions on the light-induced ferroelectric domain inversion remain limited. Herein, an experimental study to reveal the role of laser polarization in light-induced domain inversions is discussed. The dependence of the optical threshold and maximal writing depth of inverted domains on light polarization is experimentally investigated. The results are explained by considering the second-order nonlinear optical properties and birefringence-induced focus splitting in the crystal. These findings are useful in fabricating high-quality and large-scale ferroelectric domain structures for applications in optics, electronics, and quantum technologies.