Explore the vast range of titles available.

Direct ethanol fuel cells have been widely investigated as nontoxic and low-corrosive energy conversion devices with high energy and power densities. It is still challenging to develop high-activity and durable catalysts for a complete ethanol oxidation reaction on the anode and accelerated oxygen reduction reaction on the cathode. The materials’ physics and chemistry at the catalytic interface play a vital role in determining the overall performance of the catalysts. Herein, we propose a Pd/Co@N-C catalyst that can be used as a model system to study the synergism and engineering at the solid-solid interface. Particularly, the transformation of amorphous carbon to highly graphitic carbon promoted by cobalt nanoparticles helps achieve the spatial confinement effect, which prevents structural degradation of the catalysts. The strong catalyst-support and electronic effects at the interface between palladium and Co@N-C endow the electron-deficient state of palladium, which enhances the electron transfer and improved activity/durability. The Pd/Co@N-C delivers a maximum power density of 438 mW cm −2 in direct ethanol fuel cells and can be operated stably for more than 1000 hours. This work presents a strategy for the ingenious catalyst structural design that will promote the development of fuel cells and other sustainable energy-related technologies. It is challenging to develop high-activity and durable catalysts for both ethanol oxidation reaction on the anode and oxygen reduction reaction on the cathode. Here in this work, authors proposed Pd/Co@N-C catalyst as a model to synergistically maximize the usage of catalyst nanoparticles and active interfaces for direct ethanol fuel cells.

The microbial fuel cell (MFC) provides new opportunities for energy generation and wastewater treatment through conversion of organic matter into electricity by electrogenic bacteria. This study investigates the effect of different types and concentrations of substrates on the performance of a double chamber microbial fuel cell (DCMFC). Three mediator-less laboratory-scale DCMFCs were used in this study, which were equipped with graphite electrode and cation exchange membrane. The MFCs were fed with three different types of substrates (glucose, acetate and sucrose) at a chemical oxygen demand (COD) concentration of 1,000 mg/L. The selected substrate (acetate) was studied for three different concentrations of 500, 2,000 and 3,000 mg/L of COD. Results demonstrated that acetate was the best substrate among the three different substrates with maximum power density and COD removal of 91 mW/m2 and 77%, respectively. Concentration of 2,000 mg/L was the best concentration in terms of performance with maximum power density and COD removal of 114 mW/m2 and 79%, respectively. The polarization curve shows that ohmic losses were dominant in DCMFCs established for all three substrates and concentrations.

The focus of the study in this article is analyzing the electrochemical properties of molybdenum disulfide on miscible poly(methyl methacrylate)-poly(lactic acid) blends for supercapacitors. The interaction between molybdenum disulfide and miscible poly(methyl methacrylate)-poly(lactic acid) blends, affinity toward water, surface morphology, and mechanical properties are inspected by Fourier transform infrared spectroscopy, water contact angle, scanning electron microscopy, and universal testing machine, respectively. Among the developed membranes, 0.75 wt% of molybdenum disulfide on poly(methyl methacrylate)-poly(lactic acid) shows better electrochemical performances. It exhibits a maximum specific capacitance of 255.5 F g−1 at a current density of 1.00 mA g−1, maximum energy density of 22.7 Wh kg−1, and maximum power density of 360 W kg−1. A cycle study reveals 92% capacitance retention after 2500 cycles. The designed supercapacitor device shows a maximum specific capacitance of 1240 μF g−1 at a current density of 0.5 μA g−1, maximum energy density of 43 μWh kg−1, and maximum power density of 700 μW kg−1. Flexible membranes of molybdenum disulfide are expected to be a potent combination for supercapacitor applications.

The South China Sea is a major shipping hub between the West Pacific and Indian Oceans. In this region, the demand for energy is enormous, both for residents’ daily lives and for economic development. Wave energy and wind energy are two major clean and low-cost ocean sources of renewable energy. The reasonable development and utilization of these energy sources can provide a stable energy supply for coastal cities and remote islands of China. Before wave energy and wind energy development, however, we must assess the potential of each of these sources. Based on high-resolution and high-accuracy wave field data and wind field data obtained by ERA-Interim reanalysis for the recent 38-year period from 1979–2016, the joint development potential of wave energy and wind energy was assessed in detail for offshore and nearshore areas in the South China Sea. Based on potential installed capacity, the results revealed three promising areas for the joint development of nearshore wave energy and wind energy, including the Taiwan Strait, Luzon Strait and the sea southeast of the Indo-China Peninsula. For these three dominant areas (key stations), the directionality of wave energy and wind energy propagation were good in various seasons; the dominant wave conditions and the dominant wind conditions were the same, which is advantageous for the joint development of wave and wind energy. Existing well-known wave energy converters (WECs) are not suitable for wave energy development in the areas of interest. Therefore, we must consider the distributions of wave conditions and develop more suitable WECs for these areas. The economic and environmental benefits of the joint development of wave and wind energy are high in these promising areas. The results described in this paper can provide references for the joint development of wave and wind energy in the South China Sea.

Applying finite time thermodynamics theory and the non-dominated sorting genetic algorithm-II (NSGA-II), thermodynamic analysis and multi-objective optimization of an irreversible Diesel cycle are performed. Through numerical calculations, the impact of the cycle temperature ratio on the power density of the cycle is analyzed. The characteristic relationships among the cycle power density versus the compression ratio and thermal efficiency are obtained with three different loss issues. The thermal efficiency, the maximum specific volume (the size of the total volume of the cylinder), and the maximum pressure ratio are compared under the maximum power output and the maximum power density criteria. Using NSGA-II, single-, bi-, tri-, and quadru-objective optimizations are performed for an irreversible Diesel cycle by introducing dimensionless power output, thermal efficiency, dimensionless ecological function, and dimensionless power density as objectives, respectively. The optimal design plan is obtained by using three solution methods, that is, the linear programming technique for multidimensional analysis of preference (LINMAP), the technique for order preferences by similarity to ideal solution (TOPSIS), and Shannon entropy, to compare the results under different objective function combinations. The comparison results indicate that the deviation index of multi-objective optimization is small. When taking the dimensionless power output, dimensionless ecological function, and dimensionless power density as the objective function to perform tri-objective optimization, the LINMAP solution is used to obtain the minimum deviation index. The deviation index at this time is 0.1333, and the design scheme is closer to the ideal scheme.

Triboelectric nanogenerators (TENGs) have emerged as a promising technology to harvest electrical energy from natural motions such as human movement, wind, and water flow. Although TENGs show significant potential in small-scale applications, developing large-scale TENGs capable of generating high power remains a significant challenge. Several factors that can affect the performance of large-scale TENGs are being investigated to overcome this challenge, including the size and configuration of dielectric materials. This study optimizes dielectrics regarding surface area, thickness, and multicell configuration to improve harvested electrical power density in large-scale TENGs. In the studies, glass fiber was used as the positive dielectric, and multipurpose white silicone was used as the negative dielectric because of their high tribo-potential, durability, and easy accessibility. In the size optimization phase, dielectric thicknesses and surface areas that provide the maximum power density were determined. Subsequently, horizontal and vertical multicell configurations were examined to efficiently integrate size-optimized dielectrics. The results reveal that large-scale TENGs with vertical multicell configurations can achieve high and usable energy density for electronics. The findings provide valuable insight into the development of large-scale TENGs with advanced power generation capabilities.

Nickel copper cobalt oxide (NiCuCoO) ternary metal oxide nanoparticles were synthesized by employing the hydrothermal method. NiCuCoO electrode demonstrates a specified capacity of 596 C g −1 at 1 A g −1 , high capacitance retaining of 99% even if 1000 sequences at the density of current 10 A g −1 , and significant extended cyclic strength over 1000 sequences. The gathered asymmetric supercapacitor (ASC) tool via NiCuCoO as the cathode and activated carbon as anode materials achieve a specified capacity of 168 C g −1 at a current density of 1 Ag −1 , an excellent capacity retaining of 95% even later than 5000 sequences at a density of current 10 A g −1 . The fabricated device exhibits a high density of energy and power is 96 Wh kg −1 and 841 W kg −1 . The prepared material confirms an excellent capacitance routine, so this work represents for a next-generation energy storage device.

Based on the established model of the irreversible rectangular cycle in the previous literature, in this paper, finite time thermodynamics theory is applied to analyze the performance characteristics of an irreversible rectangular cycle by firstly taking power density and effective power as the objective functions. Then, four performance indicators of the cycle, that is, the thermal efficiency, dimensionless power output, dimensionless effective power, and dimensionless power density, are optimized with the cycle expansion ratio as the optimization variable by applying the nondominated sorting genetic algorithm II (NSGA-II) and considering four-objective, three-objective, and two-objective optimization combinations. Finally, optimal results are selected through three decision-making methods. The results show that although the efficiency of the irreversible rectangular cycle under the maximum power density point is less than that at the maximum power output point, the cycle under the maximum power density point can acquire a smaller size parameter. The efficiency at the maximum effective power point is always larger than that at the maximum power output point. When multi-objective optimization is performed on dimensionless power output, dimensionless effective power, and dimensionless power density, the deviation index obtained from the technique for order preference by similarity to an ideal solution (TOPSIS) decision-making method is the smallest value, which means the result is the best.

This work deals with the development of Combined Energy Pattern & Power Density Method (CEPPDM) to evaluate the two parameters needed to define Weibull distribution. Five years (2015–2019) wind data recorded each 60-minutes interval at eleven representative sites in Pakistan was used and efficiency of CEPPDM was compared with Energy Pattern Factor Method (EPFM) and Power Density Method (PDM) with the help of MAPE, MSE and R². Analysis showed that CEPPDM is the most efficient method while EPFM is the least efficient. Furthermore, it was found that RYK is the most lucrative site and Layyah is the weakest site regarding wind potential. Wind rose plots were drawn which showed that the wind mainly blows in the range of 200°–270°.

Congo red is an azo dye widely used as a colouring agent in textile industries. It is a serious threat due to its carcinogenic effects. Its degradation has been challenging due to its complex yet stable structure. The present study was aimed to investigate the effective degradation of Congo red by bioremediating bacteria isolated from different environments. To investigate predominant microorganisms that degrade Congo red and its functions in microbial fuel cells (MFCs), strains isolated from cow dung (Enterococcus faecalis SUCR1) and soil (Pseudomonas aeruginosa PA1_NCHU) were used as a co-culture inocula. The remarkable results establish that E. faecalis as an excellent microbial source for the biological degradation of dye-contaminated wastewater treatment alongside bioactive treating wastewater with varied concentrations of congo red dye. The highest efficiency percentage of dye degradation was 98% after 3 days of incubation at pH 7 and 37 °C, whereas findings have shown that the decolorization at pH 5 and 6 was lower at 66% and 83.3%, respectively, under the same incubation conditions. Furthermore, the co-culture of E. faecalis SUCR1 and P. aeruginosa at a 1:1 ratio demonstrated improved power generation in MFCs. The maximum power density of 7.4 W/m3 was recorded at a 150 mg L−1 concentration of Congo red, indicating that the symbiotic relation between these bacterium resulted in improved MFCs performance simultaneous to dye degradation.