Carbon-Supported High-Entropy Oxide Nanoparticles as Stable Electrocatalysts for Oxygen Reduction Reactions

Nanoparticles supported on carbonaceous substrates are promising electrocatalysts. However, achieving good stability for the electrocatalysts during long-term operations while maintaining high activity remains a grand challenge. Herein, a highly stable and active electrocatalyst featuring high-entropy oxide (HEO) nanoparticles uniformly dispersed on commercial carbon black is reported, which is synthesized via rapid high-temperature heating (≈1 s, 1400 K). Notably, the HEO nanoparticles with a record-high entropy are composed of ten metal elements (i.e., Hf, Zr, La, V, Ce, Ti, Nd, Gd, Y, and Pd). The rapid high-temperature synthesis can tailor structural stability and avoid nanoparticle detachment or agglomeration. Meanwhile, the high-entropy design can enhance chemical stability to prevent elemental segregation. Using oxygen reduction reaction as a model, the 10-element HEO exhibits good activity and greatly enhances stability (i.e., 92% and 86% retention after 12 and 100 h, respectively) compared to the commercial Pd/C electrocatalyst (i.e., 76% retention after 12 h). This superior performance is attributed to the high-entropy compositional design and synthetic approach, which offers an entropy stabilization effect and strong interfacial bonding between the nanoparticles and carbon substrate. The approach promises a viable route toward synthesizing carbon-supported high-entropy electrocatalysts with good stability and high activity for various applications.     

Recovery of hesperidin and narirutin from waste Citrus unshiu peel using subcritical water extraction aided by pulsed electric field treatment

The objective of this study was to identify whether the efficacy of extracting hesperidin and narirutin from Citrus unshiu peel by-products can be increased by combining pulsed electric field (PEF) and subcritical water extraction (SWE). The samples were treated with a PEF at a strength of 3 kV/cm for 60 and 120 s. Subsequent SWE was conducted at extraction temperatures of 110–190 °C for 3–15 min. The concentration of hesperidin was highest at 46.96 ± 3.37 mg/g peel (dry basis) after PEF treatment at 120 s, combined with SWE at 150 °C for 15 min, while that of narirutin peaked at 8.76 ± 0.83 mg/g after PEF treatment at 120 s, integrated with SWE at 190 °C for 5 min. The concentrations of both hesperidin and narirutin increased with PEF treatment time. The PEF increased the amounts of hesperidin and narirutin extracted by 22.1% and 33.6%, respectively. This study demonstrate the potential of PEF pretreatment for enhancing the SWE of flavonoids from C. unshiu peel.     

Endogenous Shared Punishment Model in Threshold Public Goods Games

Computational Economics - Population growth and greater human well-being imply increased use of scarce resources, which makes innovative proposals for fair redistribution policies necessary. The...     

Risk Taking Behaviors Using Public Wi-Fi™

Information Systems Frontiers - Dramatic increases in public Wi-Fi? (hereafter referred to as Wi-Fi) availability have occurred over the last decade. Although Wi-Fi provides convenient...     

High-amylose and Tongil type Korean rice varieties: physical properties,cooking behaviour and starch digestibility

Food Science and Biotechnology - The National Institute of Crop Science, Rural Development Administration (RDA) of Korea is presently developing new rice varieties suitable for producing Western...     

Evaluation of survival rates of airborne microorganisms on the filter layers of commercial face masks

After the WHO designated COVID-19 a global pandemic, face masks have become a precious commodity worldwide. However, uncertainty remains around several details regarding face masks, including the potential for transmission of bioaerosols depending on the type of mask and secondary spread by face masks. Thus, understanding the interplay between face mask structure and harmful bioaerosols is essential for protecting public health. Here, we evaluated the microbial survival rate at each layer of commercial of filtering facepiece respirators (FFRs) and surgical masks (SMs) using bacterial bioaerosols. The penetration efficiency of bacterial particles for FFRs was lower than that for SMs; however, the microbial survival rate for all tested masks was >13%, regardless of filtration performance. Most bacterial particles survived in the filter layer (44%–77%) (e.g., the core filtering layer); the outer layer also exhibited significant survival rates (18%–29%). Most notably, survival rates were determined for the inner layers (<1% for FFRs, 3%–16% for SMs), which are in contact with the respiratory tract. Our comparisons of the permeability and survival rate of bioaerosols in each layer will contribute to bioaerosol-face mask research, while also providing information to facilitate the establishment of a mask-reuse protocol.     

Accurate evaluation of hydrogen crossover in water electrolysis systems for wetted membranes

In fuel cell and electrolysis systems, hydrogen crossover is a phenomenon where hydrogen molecules (H₂) permeate through a membrane, lowering the overall process efficiency and generating a potential safety risk. Many works have been reported to mitigate this undesired phenomenon, but it is yet difficult to accurately measure the rate of hydrogen crossover, particularly when the membrane is fully wetted in water. In this work, we investigated the pressure decay method as a simple, convenient, and low-cost method to characterize hydrogen crossover through wetted membranes for water electrolysis systems. Three different ion exchange membranes were analyzed: Nafion 212, Nafion 115, and in-house sulfonated poly(arylene ether sulfone). We rigorously confirmed our method and data by comparing it to the ANSI dataset with the current state-of-the-art equations of state (EOS) to account for the nonideality of high pressure hydrogen systems. The error from the gas non-ideality was less than 0.03%. As expected, the rate of hydrogen crossover showed high dependency on the temperature; more importantly, hydrogen crossover increased significantly when the membrane was fully soaked in water. For dry membranes, the proposed pressure decay method corroborated well with the literature data measured using other known methods. Moreover, for wetted membranes, the obtained data showed high similarity compared to the GC method which is currently the most reliable method in the literature. We attempted to predict the hydrogen permeability of wetted membranes using the solution diffusion model. The model based on the given thermodynamic parameters overestimated the hydrogen permeability, which can be used to estimate the ion channel tortuosity.     

Multi-period design and planning model of shale gas field development

Long-term design and planning of shale gas field development is challenging due to the complex development operations and a wide range of candidate locations. In this work, we focus on the multi-period shale gas field development problem, where the shale gas field has multiple formations and each well can be developed from one of several alternative pads. The decisions in this problem involve the design of the shale gas network and the planning of development operations. A mixed-integer linear programming (MILP) model is proposed to address this problem. Since the proposed model is a large-scale MILP, we propose a solution pool-based bilevel decomposition algorithm to solve it. Results on realistic instances demonstrate the value of the proposed model and the effectiveness of the proposed algorithm.     

Effect of powder milling routes on the sinterability and optical properties of transparent Y2O3 ceramics

In ceramic processing, the size distribution of the starting powder to a certain degree is inevitable. It is prerequisite to control the size distribution, which influences the fabrication of a sound green body featuring both smaller pores and a narrower pore structure for full-density sintering facilitated by the easier elimination of pores. The milling process was systematically investigated here to elucidate the effect of powder characteristics on the sinterability and transmittance of Y₂O₃ ceramics. Three types of powder sets having different width of particle size distribution (W_PSD) while keeping the same median size (D₅₀) were prepared by changing the milling condition. By means of narrowing the W_PSD in this research, pore free transparent polycrystalline Y₂O₃ with average grain size of 730 nm was successfully fabricated by hot-pressing at 1500℃, which is 100℃ lower than the previously lowest known sintering temperature.