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Ceramic-based conductive coatings were prepared by sol–gel method with artificial graphite (CGM) as conductive fillers and methyltrimethoxysilane (MTMS) and silica sol as dispersion medias. The gra...

Effectively addressing global warming requires a rapid transformation of the ways in which energy is consumed, and nuclear power produces very low lifecycle carbon emissions. Efficient uranium extraction from unconventional uranium ore sources, such as the ocean, can provide a stable and long-term supply of nuclear fuel for nuclear power plants. Herein, we report an interconnected open-pore architecture poly(amidoxime) (PAO) fiber with PAO nanoparticles and a nano-channel structure (AO-OpNpNc) using a top-down design. A high uranium adsorption capacity of 17.57 mg-U per g-adsorbent in natural seawater and ultra-long service life of at least 30 cycles were obtained, which are the highest values among currently available adsorbents to our knowledge. Extended X-ray absorption fine structure (EXAFS) fits and density functional theory (DFT) computational studies suggest that PAO-bound uranyl is a cooperative chelating model. More importantly, uranium production costs could be reduced to $80.70–86.25 per kg of uranium with this fiber, which is similar to the uranium spot price of $86.68 per kg of uranium and lower than the costs of all currently available adsorbents. The exceptional durability of the AO-OpNpNc fibers suggests the possibility of economically producing nuclear fuel from the ocean.

A new amidoxime-functionalized ultrahigh molecular weight polyethylene fibrous adsorbent (UHMWPE-g-PAO) was used for the recovery of Au(III) from acid aqueous solution. The maximum experimental absorption capacity of UHMWPE-g-PAO fiber was found to be approximately 220.0 mg·g−1. Au adsorption on UHMWPE-g-PAO was characterized by synchrotron radiation-based microcomputed tomography (SR-μ-CT), transmission electron microscopy (TEM), X-ray absorption near-edge structure spectroscopy (XANES) and synchrotron radiation-based Fourier transform infrared microspectroscopy (SR-FTIR). The SR-μ-CT and TEM results showed the distribution features of gold particles on the fiber. The mechanism of Au(III) recovery from aqueous solutions by UHMWPE-g-PAO was based on the adsorbed Au(III) ions, which were reduced to metallic zero-valent gold (Au(0)) by amino groups (–NH2) in the amidoxime (AO) groups during the adsorption process, as confirmed by high-resolution TEM (HRTEM) and XANES analyses. X-ray diffraction (XRD) results indicated that the incineration ashes contained metallic zero-valent gold. In conclusion, this amidoxime-functionalized fibrous adsorbent is a promising material for recovering gold from aqueous solution.

Designing and fabrication of highly active single-atom catalysts (SACs) with maximized atomic efficiency is highly desirable but still remains a great challenge. Herein, highly active and stable cobalt single-atoms with a Co–N4 moiety were uniformly anchored on a porous porphyrinic triazine-based framework (CoSAs/PTF) by a simple ionothermal method. Due to the abundant single-atom Co–N4 species, the hierarchical porous structure and the good conductivity, the resultant catalyst is highly active for the electrocatalytic oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). For the ORR, a more positive half-wave potential of 0.808 V (vs. RHE) was achieved, compared with commercial benchmark Pt/C (0.806 V). Furthermore, a small onset potential of 21 mV and a low Tafel slope of 50 mV per decade were obtained for the HER. The porphyrin-like structure was found to stabilize the CoSAs effectively, thus leading to long-term durability and a remarkable methanol-tolerant behavior. This bifunctional single-atom catalyst might be a promising candidate to replace Pt-based electrocatalysts in electrolysers and fuel cells.

The in situ growth of one-dimensional magnetite (Fe3O4) nanowire (NW) arrays with deterministic and tunable control over their orientation and morphology on a wide range of flexible and low heat resistance substrates is still a challenge. Herein, a facile method of controlling the orientation of Fe3O4 NW arrays on a polypropylene (PP) nonwoven fabric surface (PP-g-PAO/Fe3O4) through simultaneous radiation induced graft polymerization and coprecipitation processes was realized. We demonstrated a control over the orientation and geometric properties of coprecipitated Fe3O4 NWs via complex iron ion using amidoxime groups, which not only endow the material with high durability but also lead to the oriented growth of Fe3O4 NWs. The results showed that Fe3O4 NWs were only grown on the surface of the PP nonwoven fabric (length:diameter ratio ≈ 10), whereas the Fe3O4 produced in the solution exhibited a spherical structure under identical conditions. The PP-g-PAO/Fe3O4 composite presented a good saturated magneti...

Water electrolysis in alkaline electrolyte is an attractive way toward clean hydrogen energy via the hydrogen evolution reaction (HER), whereas the sluggish water dissociation impedes the following hydrogen evolution. Noble metal oxides possess promising capability for catalyzing water dissociation and hydrogen evolution; however, they are never utilized for the HER due to the instability under the reductive potential. Here it is shown that compressive strain can stabilize RhO2 clusters and promote their catalytic activity. To this end, a strawberry-like structure with RhO2 clusters embedded in the surface layer of Rh nanoparticles is engineered, in which the incompatibility between the oxide cluster and the metal substrate causes intensive compressive strain. As such, RhO2 clusters remain stable at a reduction potential up to -0.3 V versus reversible hydrogen electrode and present an alkaline HER activity superior to commercial Pt/C.

Developing green energy to be applied in green cities has received much attention. The Internet of energy (IoE) effectively improves networking of distributed green energies through extending smart grids with bidirectional transmission of energy and distributed renewable energy facilities. Previous works on the IoE focused on decisions of IoE operators or optimization of the whole system. However, few considered optimal decisions of a single end user in the IoE. Therefore, this work creates a mixed-integer linear programming (MILP) model for a single end user that considers green energy generation, an energy storage, an electric vehicle, and an IoE-based energy trading platform to reduce energy waste. This model considers a complete system of charging control of multiple facilities of a single end user in the IoE, and allows the end user to purchase energy and sell green energy through the IoE, in which the energy prices of the electrical grid and the IoE platform are set by the power company and the energy market, respectively. Because MILP is NP complete and the proposed model involves a large number of variables and constraints, this paper further proposes a genetic algorithm for this problem, in which a repairing scheme is proposed to handle solution infeasibility of all constraints. By simulation, the proposed algorithm is verified to effectively reduce energy waste.

The rational design of highly efficient, low-cost, and durable electrocatalysts to replace platinum-based electrodes for oxygen reduction reaction (ORR) is highly desirable. Although atomically dispersed supported metal catalysts often exhibit excellent catalytic performance with maximized atom efficiency, the fabrication of single-atom catalysts remains a great challenge because of their easy aggregation. Herein, a simple ionothermal method was developed to fabricate atomically dispersed Fe–Nx species on porous porphyrinic triazine-based frameworks (FeSAs/PTF) with high Fe loading up to 8.3 wt %, resulting in highly reactive and stable single-atom ORR catalysts for the first time. Owing to the high density of single-atom Fe–N4 active sites, highly hierarchical porosity, and good conductivity, the as-prepared catalyst FeSAs/PTF-600 exhibited highly efficient activity, methanol tolerance, and superstability for oxygen reduction reaction (ORR) under both alkaline and acidic conditions. This work will bring ...

A new functionalized ultrahigh molecular weight polyethylene-based chelating fiber (UHMWPE-AM) for trace uranium extraction from wastewater was synthesized by preirradiation grafting modification. Adsorption behavior of adsorbent was examined under varying conditions like solution pH, contact time, initial ion concentration and adsorbent dose. The results showed the maximum removal of U(VI) was 99.7% at pH 4. Adsorption isotherm was in agreement with Langmuir isotherm equation with the maximum monolayer adsorption capacity of 16.56 mg/g, and the pseudo-second-order model can well describe the kinetics process. The dominant coordination mechanism of U(VI) on the UHMWPE-AM fibers was ascribed to inner-sphere surface complexation.

M-N-C single-atom electrocatalysts recently have received significant attention because of high catalytic activity and maximal atom utilization. Here, it is firstly reported that macrocycle cucurbit[6]uril (CB[6]) self-assembly was employed as precursor to fabricate M-N-C single-atom electrocatalysts for the Zn-air battery (ZAB). This template-free method using CB[6] self-assembly acquires the holey N-doped matrixes with hierarchical micro/mesoporous structure. The Fe loaded N-doped holey carbon single-atom electrocatalyst (Fe-NHC) exhibited high activity with the half-wave potential (E1/2) of 0.89 V versus reversible hydrogen electrode (RHE) for oxygen reduction reaction (ORR) in alkaline condition, which was better than those of Co or Ni loaded catalyst and commercial Pt/C (E1/2 = 0.83 V). Moreover, the ZAB employing Fe-NHC catalyst achieved higher power and energy density with longer-term stability than those of Pt/C + Ir/C catalyst. This work provided a promising strategy to design stable and highly efficient catalyst for long-life electrochemical storage devices.

In Industry 4.0, various types of IoT sensors which are installed on machines to collect data for predictive maintenance. As the collected data increases, there are more missing values and noisy data. Related studies have already proposed various methods to solve the problems in big data. Among them, most studies focused on either feature selection or instance selection for data preprocessing before training forecast models. Metaheuristic algorithm is one of the mainstream methods in data preprocessing. However, most of these studies rarely considered feature and instance selection simultaneously. In addition, they seldom focused on noisy data. Therefore, this work combines the UCI datasets with noisy data to simulate the real situation. Memetic algorithm (MA) has excellent performance in machine learning of data selection, and variable neighborhood search (VNS) was also proved to be widely applied to the systematic change of local search algorithms. This work proposes a hybrid MA and VNS to find a new subset that maximizes the accuracy of the classifier while preserving the minimum amount of data by feature and instance selection simultaneously. Experimental results show that the proposed method can efficiently reduce the amount of data and the ratio of noisy data. By comparison with other metaheuristic algorithms, the proposed method has good performance by an excellent balance between exploration and exploitation.

It is imperative to develop efficient and robust electrocatalysts for CO2 reduction reaction (CO2RR) that would overcome the sluggish kinetics and exhibit high current density. Porous carbon nanotubes with highly delocalized electrons and tubular structure are promising candidates for CO2RR due to it is favorable for the accessible of substrates to active sites. However, there are rare reports of using carbon nanotubes to stabilize single-atom active sites for CO2RR. Herein, a self-sacrificial template method is developed to disperse single atomic Ni sites on N-doped carbon nanotubes from metal-organic frameworks (MOFs) for highly efficient CO2RR. Compared with the corresponding other N-doped carbon stabilized Ni single-atom catalysts, the obtained hierarchically porous Ni/NCTs exhibited enhanced selectivity and activity for the electrochemical reduction of CO2 to CO with Faradaic efficiency of 98 %, turnover frequency (TOF) of 9366 h−1 and CO current density of 34.3 mA cm-2 at the applied potential of -1.0 V.