A gold-doped MOF-79 composite was synthesized and subsequently applied as an electrochemical sensing material for the determination of quercetin in seawater. Considering that quercetin is widely used as a pharmaceutical compound and may pose potential ecological risks when released into aquatic environments, the development of a simple and reliable detection method was of practical significance. To this end, a novel Au@MOF-79 composite was prepared via a hydrothermal route and was characterized by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The obtained Au@MOF-79 was drop-cast onto a glassy carbon electrode to fabricate the Au@MOF-79/GCE sensor. Electrochemical measurements demonstrated that the Au@MOF-79/GCE exhibited enhanced electrocatalytic activity toward quercetin oxidation and enabled its quantitative determination using differential pulse voltammetry. A good linear relationship between the oxidation peak current and quercetin concentration was obtained in the range of 3.04 × 10⁻⁵ to 1.196 × 10⁻³ M, with a detection limit of 6.0 × 10⁻⁶ M. Furthermore, the sensor showed good repeatability and short-term operational stability, and maintained satisfactory analytical performance in seawater samples. The improved sensing performance was attributed to the synergistic effect between the porous MOF-79 framework and uniformly dispersed Au nanoparticles, which facilitated analyte enrichment and electron transfer. These results indicated that the Au@MOF-79-modified electrode had potential for the electrochemical detection of quercetin in complex aqueous environments.
Orbital hybridization effect, an electronic structural characteristic arising from the linear combination of atomic orbitals, has emerged as a crucial strategy for tuning the electronic structure of catalysts. Despite significant progress, fully understanding the structure-activity relationship between orbital hybridization, electronic structure, and catalytic performance remains a major challenge, particularly in the field of electrocatalysis. This review summarizes the latest advances in the coupling regulation of d-orbital hybridization in transition metal catalysts (TMCs) and systematically elucidates their pivotal role in electrocatalytic reaction mechanisms. This review first discusses the basic concepts and various types of d-orbital hybridization in TMCs, including d-d, d-p, d-f, and d-p-f hybridization, emphasizing their influence on intermediate adsorption, electron transfer, and orbital interactions. Additionally, the review systematically summarizes key orbital hybridization engineering strategies, including alloying, doping, dual-atom sites, support-assisted methods, and interface engineering, and elucidates specific approaches for precisely tuning the electronic configuration of TMC active sites to optimize intermediate adsorption behavior. Building on this, it further analyzes several typical catalytic reaction mechanisms, highlighting the advantages of d-orbital hybridization in enhancing catalytic performance. Finally, it addresses the main challenges of orbital hybridization regulation in TMC electrocatalysis and offers new insights and perspectives for its future development in other catalytic applications.
To address the increased energy consumption of electric vehicles (EVs) owing to tire rolling resistance at low temperatures, this research explored the changes in EV tire rolling resistance and energy consumption at various driving speeds, environmental temperatures, tire pressures, road properties, and other conditions. The effectiveness of the developed model was validated through tire grounding and tensile experiments, and finite element simulations were performed using ABAQUS software. The results revealed that at an ambient temperature of -10 ℃, a 1.4
The purpose of this paper is to investigate the issue of the exponential stability in pth (p-ES) moment for neutral Markov switching stochastic delay systems (NMSSDSs). A generalized Halanay inequality with the state-dependent time-varying coefficients is established and the presence of a perturbation term is considered. Based on the improved Halanay inequality, we derive novel theorems for p-ES of NMSSDSs. Moreover, we overcome the difficulties posed by the neutral term for stability analysis. Finally, two examples are offered to show the reliability of our theory results.
In severe cold regions, there is an urgent need for innovative energy-saving heating solutions for office buildings due to the limitations of existing systems, which often rely on a single heat source and incur high operating cost. With the advent of the “carbon peak and carbon neutrality” initiative, maximizing the use of renewable energy has become a crucial strategy for reducing power consumption and mitigating environmental pollution in buildings. This study introduced a novel phase change energy storage solar assisted heat pump (PCES-SAHP) system. It explored the system’s performance and identified key optimization objectives, including the annual cost, unit heating cost, unit solar fraction cost, and unit system coefficient of performance (COP) cost. The Hooke-Jeeves (HJ) algorithm was employed for parameter optimization, encompassing the solar collector (SC) area, SC slope angle, SC azimuth angle, phase change energy storage (PCES) tank volume, and the rated heating capacity of the air source heat pump (ASHP). The findings revealed that a range of optimization techniques led to a substantial enhancement in performance when contrasted with the original design, all the while upholding indoor thermal comfort. The investigation also evaluated the energy-conserving, ecological, and financial advantages of various optimization techniques, determining that the optimization strategy centered on unit system COP cost proved highly effective for office buildings in severe cold climates.
