Capacitive deionization (CDI) is an emerging technology for energy-efficient water desalination, and attracts more and more attention in recent years. It has been concluded that CDI technology shows ...competitiveness and perspectives on seawater desalination and wastewater treatment. The ionic adsorption mechanism can be clarified by electric double-layer capacitive adsorption and pseudocapacitive adsorption. The performance of CDI depends on both device and materials. The adsorption capacity and energy efficiency was improved significantly with fast growth of researches on material and novel energy storage techniques. This review summarizes researches on CDI technologies with an emphasis on electrode material design and improved adsorption performance.
This review outlines the ion storage mechanisms and electrode materials of capacitive deionization. Display omitted
•Electrochemical extraction of ions from seawater/brine was reviewed systematically.•An emphasis on electrode material design thought has been analyzed.•The performance of various extraction devices has been summarized and compared.•Future challenge on this technology has been clarified.
A new strategy has been developed to block the defect sites of the Pt NWs catalyst using Rh atoms, which can effectively adjust the structure of the defect sites, resulting in regulation of the ...catalytic activity and optimization of the reaction pathway.
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Anodic electrocatalyst plays the core role in direct alcohol fuel cells (DAFCs), while traditional Pt-catalysts suffer from limited catalytic activity, high over potential and severe CO poisoning. Herein, by selectively depositing Rh atoms on the defective-sites of Pt nanowires (NWs), we developed a new Pt@Rh NW electrocatalyst that exhibited enhanced electrocatalytic performance for both methanol oxidation (MOR) and ethanol oxidation (EOR). Both cyclic voltammetry (CV) and in-situ infrared spectroscopy revealed that the presence of Rh atoms suppressed the generation of poisonous intermediates and completely oxidized alcohols molecule into CO2. Atomic resolusion spherical aberration corrected high-angle annular dark field scanning transmission electron microscopy (CS-HAADF-STEM) and energy-dispersive X-ray spectroscopy (EDS) mapping analysis revealed that Rh atoms were primarily deposited on the defective sites of Pt NWs. Meanwhile, the presence of Rh atoms also modified the electronic state of Pt atoms and therefore lowered the onset potential for alcohols oxidation potential. This work gives the first clear clue on the role of the defective sites of Pt nanocatalyst poisoning, and propose that selectively blocking these sites with trace amount of Rh is an effective strategy in designing advantageous electrocatalysts.
Unmanned Aerial Vehicles (UAVs) with mobility and flexibility enhance wireless transmission performance in various mobile communication scenarios by acting as a mobile base station or relay. However, ...the high-speed movement of UAV results in the difficulties of channel estimation because of the fast time-varying channel. In this paper, we propose a novel channel estimation algorithm based on Long Short-Term Memory (LSTM) for UAV air-to-ground transmission to obtain Channel State Information (CSI). To estimate the current slot CSI, we construct the input, forget, and output gates to learn the time correlation of UAV channel. We also define a memory function to formulate the useful information retained by the forget and the input gates, in which the forget gate discards the previous slot CSI and the input gate updates received signal of the current slot. The current slot CSI is estimated through the memory function and output gate. Compared with Least Square (LS) and Minimum Mean Square Error (MMSE) algorithm, the simulation results show that the proposed algorithm obtains more accurate CSI and higher robustness in different UAV mobile scenarios.
A new designed core-satellite gold nanoassembly was constructed by forming borate ester, and it could be used for high sensitive colorimetric detection of benzoyl peroxide residues in real food ...samples.
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Here, a new designed core/satellite gold nanoprobe was developed for detecting trace mount of benzoyl peroxide (BPO) based on its deboronation. This gold nanoassembly (the BE-AuNPs12/65) was constructed via borate ester formation between large 4-mercaptophenylboronic acid (MPBA) modified AuNPs (the MPBA-AuNPs65, as cores) and small dopamine modified AuNPs (the DPA-AuNPs12, as satellites). Particularly, upon addition of BPO, it would trigger the deboronation for the BE-AuNPs12/65 probes accompanying with distinct color changes from blue, purple to wine red, which implied the disassembly of the core/satellite nanostructure after the breakage of carbon to boron chemical bond. By measuring the absorbance ratio at 665 nm and 545 nm, quantification of BPO was achieved in the range of 10.0–100.0 nmol/L, which could also be easily observed by naked eyes. The nanoprobe utilized a boronate deprotection mechanism and the LSPR properties of AuNPs to provide high selectivity for detecting BPO over similar ROS/RNS with the limit of detection as low as 7.2 nmol/L. The practical applicability of this assay was verified through successful determining BPO in flour samples, which demonstrated its great potentials in food safety field.
The electrocatalytic reduction of CO2 (CO2ER) to liquid fuels is important for solving fossil fuel depletion. However, insufficient insight into the reaction mechanisms renders a lack of effective ...regulation of liquid product selectivity. Here, in situ surface-enhanced Raman spectroscopy (SERS) empowered by 13C/12C isotope exchange is applied to probing the CO2ER process on nanoporous silver (np-Ag). Direct spectroscopic evidence of the preliminary intermediates, *COOH and *OCO–, indicates that CO2 is coordinated to the catalyst via diverse adsorption modes. Further, the relative Raman intensities of the above intermediates vary notably on np-Ag modified by Cu or Pd, and the liquid product selectivity also changes accordingly. Combined with density functional theory calculations, this study demonstrates that the CO2 adsorption configuration is a critical factor governing the reaction selectivity. Meanwhile, *COOH and *OCO– are key targets in the initial stage regulating liquid product selectivity, which could facilitate future selective catalyst design.
In view of the problem that radar-type anti-aircraft missiles are affected by the multipath effect when intercepting ultra-low-altitude targets, the radar seeker looks down to detect the target, ...which seriously reduces the tracking accuracy, and the method of controlling the radar grazing angle near the Brewster’s angle can reduce the interference of sea clutter, minimize the intensity of sea clutter, and improve the guidance accuracy. In this paper, by constructing the sea clutter model, using the ballistic design method of segmented design, the guidance method of five key guidance sections in the trajectory is studied and analyzed, a special ballistic scheme for radar-type anti-aircraft missiles to intercept ultra-low-altitude targets is comprehensively designed, and simulation is verified. The simulation results show that the ballistic performance is good, which can effectively reduce the interference of sea clutter, meet the overall requirements of high interception, high guidance accuracy and high enemy
Understanding the reactive site/CO2/electrolyte interfacial behaviors is very crucial for the design of an advantageous CO2 electrocatalytic reduction (CO2ER) system. One important but unrevealed ...question is how the CO2ER process is influenced by the high concentration of HCO3 –, which is deliberately added as electrolyte or from the inevitable reaction between dissolved CO2 and OH–. Here, we provide unambiguous in situ spectroscopic evidence that on Ag-based catalysts, HCO3 – is apt to facilitate *OCO– generation and therefore rebalances CO2ER pathways. By employing an alternative acid electrolyte to restrict the exchange between CO2 and HCO3 – and eliminating the effect of solution pH, we reveal that HCO3 – can decrease the onset potential of *OCO– and promote further formate production. Theoretical calculations indicate HCO3 – can stabilize the adsorption of *OCO– instead of *COOH. The renewed understanding of the role of HCO3 – could facilitate the judicious selection of electrolytes to regulate the CO2ER pathway and product distribution.
Electrochemical reduction (ER) is a promising approach to safely remove pollutants. However, sluggish reaction kinetics and significant side reactions considerably limit the applicability of this ...green process. Herein, we uncovered the previously ignored role of interfacial hydrophilicity in determining the ER performance through electron microscopy observations, contact angle (CA) analysis, and electrochemical measurements. A Pd/C electrocatalyst forms dense nanopores on the electrode surface, rendering it highly hydrophobic and achieving a CA of up to 145°. This imposes a large mass-transfer barrier for the diffusion of water and pollutants into Pd sites. Moreover, the release of H2 is suppressed, which changes the solid–liquid (Pd–polluted water) interface into a solid–gas (H2)–liquid interface. This further slows down mass transfer and the decontamination process. This dilemma can be easily alleviated by adding hydrophilic polymers like polyethylene glycol to increase hydrophilicity and improve mass transfer. By this way, the activity and Faraday efficiency of Pd/C in the electrochemical hydrodehalogenation of 2,4-dichlorophenol could be increased by 4–5 times. Moreover, this interfacial microenvironment modulation strategy is parallel to other approaches, such as Pd structural engineering, and therefore these strategies can be combined to further increase the electrochemical decontamination performance of electrocatalysts.
Catalyzed reduction processes have been recognized as important and supplementary technologies for water treatment, with the specific aims of resource recovery, enhancement of ...bio/chemical-treatability of persistent organic pollutants, and safe handling of oxygenate ions. Palladium (Pd) has been widely used as a catalyst/electrocatalyst in these reduction processes. However, due to the limited reserves and high cost of Pd, it is essential to gain a better understanding of the Pd-catalyzed decontamination process to design affordable and sustainable Pd catalysts. This review provides a systematic summary of recent advances in understanding Pd-catalyzed reductive decontamination processes and designing Pd-based nanocatalysts for the reductive treatment of water-borne pollutants, with special focus on the interactions and transformation mechanisms of pollutant molecules on Pd catalysts at the atomic scale. The discussion begins by examining the adsorption of pollutants onto Pd sites from a thermodynamic viewpoint. This is followed by an explanation of the molecular-level reaction mechanism, demonstrating how electron-donors participate in the reductive transformation of pollutants. Next, the influence of the Pd reactive site structure on catalytic performance is explored. Additionally, the process of Pd-catalyzed reduction in facilitating the oxidation of pollutants is briefly discussed. The longevity of Pd catalysts, a crucial factor in determining their practicality, is also examined. Finally, we argue for increased attention to mechanism study, as well as precise construction of Pd sites under batch synthesis conditions, and the use of Pd-based catalysts/electrocatalysts in the treatment of concentrated pollutants to facilitate resource recovery.
