- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Double Fano resonances in hybrid disk/rod artificial plasmonic molecules based on dipole-quadrupole coupling
摘要： Fano resonance can be achieved by the destructive interference between a superradiant bright mode and a subradiant dark mode. A variety of artificial plasmonic oligomers have been fabricated to generate Fano resonance for its extensive applications. However, the Fano resonance in plasmonic oligomer systems comes from the interaction of all metal particles, which greatly limits the tunability of the Fano resonance. Besides, only a single Fano resonance is supported by many existing plasmonic oligomers, while multiple Fano resonances mostly occur in complex and multilayer structures, whose fabrication is greatly challenging. Here, a simple asymmetric plasmonic molecule consisting of a central metal disk and two side-coupled parallel metal rods is demonstrated. The simulation and experimental results clearly show that double Fano resonances appear in the transmission spectrum. In addition, the two Fano peaks can be independently tuned and single/double Fano peak switching can be achieved by changing one rod length or the gap distances between the rods and the disk. The modulation method is simple and effective, which greatly increases the tunability of the structure. The proposed asymmetric artificial plasmonic molecule can have applications in multi-channel optical switches, filters and biosensors. Moreover, the controllable plasmonic field intensity in the gap between the disk and rods also provides a new control means for plasmon-induced photocatalytic reactions and biosynthesis.
关键词： plasmonic oligomers,biosynthesis,Fano resonance,filters,optical switches,biosensors,asymmetric plasmonic molecule,plasmon-induced photocatalytic reactions,double Fano resonances
更新于2025-09-23 15:19:57
-
Photocatalytic Decolorization of Cobalamin in Aqueous Suspensions of TiO2 and ZnO Under Solar Irradiation
摘要： Photolysis and photocatalysts treatments of aqueous solution of cobalamin were carried out over a suspension of titanium dioxide and zinc oxide. Heterogeneous photocatalytic processes applied under natural weathering conditions, in the presence of solar radiation show a promising degradation capability. Under solar radiation a complete removal of color was achieved in a relatively short time of about 10 minutes, when ZnO was used and in 45 min when TiO2 was used. However, in the presence of artificial UV-light, complete decolorization of cobalamin was obtained in 20 min of irradiation when ZnO was used and in 60 min, when TiO2 was used at the same temperature. The results indicate that the degree of photocatalytic decolorization of cobalamin was obviously affected by different parameters such as, catalyst mass, type of catalyst and addition of H2O2.
关键词： Titanium dioxide,Zinc oxide,Cobalamin,Solar,Photocatalytic reactions,Decolorization efficiency
更新于2025-09-09 09:28:46
-
Langmuir–Hinshelwood and Light-Intensity Dependence Analyses of Photocatalytic Oxidation Rates by Two-Dimensional-Ladder Kinetic Simulation
摘要： Though photocatalytic reactions gather enormous attention, dependences of light intensity and reactant concentration have not been concurrently expressed clearly. In the previously reported studies, a quadratic formula equation obtained from the conventional analysis using the concentration of electron?hole pairs has been modified. In this report we numerically simulated the reaction with a two-dimensional(2D)-ladder kinetics without using electron?hole concentrations. In fundamental processes, (i) photoabsorption, (ii) reduction, (iii) oxidation, and (iv) recombination, were treated as the transitions between the states of each powder characterized by the numbers of possessing negative and positive charges. Through the numerical 2D-ladder simulation with various rate constants, the light-intensity (I) dependence of the oxidation rate was found to be fully expressed by involving the square of the intrinsic quantum yield into the square root part of the well-known quadratic formula equation. The square root dependence of the reaction rate, r ∝ I1/2, could be expected only when the rate of the reduction is extremely smaller than the recombination rate at the normal light intensity. Then, the resultant equations obtained with this 2D-ladder simulation were transformed to the equation for Langmuir?Hinshelwood kinetics with two parameters, rL and KL, which correspond to the intrinsic oxidation rate and the adsorption equilibrium constant of the reactant, respectively. Light-intensity dependence of KL was expressed by adding two terms proportional to I2 to both the adsorption and desorption rate constants. The reported experimental data sets of the decomposition rates for phenol and 4-chlorophenol were fitted with the proposed equation, and then from the obtained parameter values the formation rate of (cid:129)O2? could be estimated and found to be compatible to that which has been experimentally measured. Thus, the present analytical treatment is actually the simple and useful method to understand the dependencies of reactant concentration and light-intensity on the photocatalytic oxidation rates.
关键词： reactant concentration,photocatalytic reactions,light intensity,Langmuir?Hinshelwood kinetics,two-dimensional-ladder kinetics
更新于2025-09-04 15:30:14
-
Rational design of yolk–shell nanostructures for photocatalysis
摘要： Photocatalysis is a promising route to convert solar energy into chemical energy directly, providing an alternative solution to environment and natural resource problems. Theoretically, all photocatalytic reactions are driven by charge carriers whose behavior can be divided into charge generation, separation, migration and surface reactions. Efficiencies of charge utilization in every step determine the overall performance of photocatalysis. Yolk–shell (YS) structures can provide an ideal platform for the efficient utilization of charge carriers. Typically, a YS structure is constructed from a hollow shell and an inner core, which can enhance light scattering in the hollow space and provide a large surface to create sufficient active sites, both of which can significantly improve the efficacy of charge utilization. Additionally, many strategies can be adopted to modify the YS structure for further enhancement of charge behaviors in every step. Existing reviews about YS structures mainly concentrate on the universality of the application of YSs, while the strategies to improve photocatalytic performance based on YSs have not been elaborately illustrated. This review describes the classification, synthesis, formation mechanism of YS structures and the rational regulation of the behaviors of photogenerated charge carriers, aiming at their effective utilization based on YS structures in heterogeneous photocatalytic reactions.
关键词： Charge carriers,Heterogeneous photocatalytic reactions,Solar energy conversion,Yolk–shell structures,Photocatalysis
更新于2025-09-04 15:30:14