Depletion Of Fossil Fuels Research Articles

Effect of Annealing Temperature on the Electrochemical Behavior of Hydrothermal Assisted Bismuth Phosphate Nanostructures

: In the present scenario, society requires various energy sources due to the depletion of fossil fuels. In the current work, Bismuth Phosphate nanostructures are synthesized via the hydrothermal method at different aging periods and were further annealed at 300 These samples are abbreviated as BP6300, BP12300, BP18300, and BP24300. Further, we analyzed the synthesized samples' structural, morphological, and electrochemical behavior. X-ray Diffraction Technique is used to analyze the phase and crystal structure of all the synthesized samples. A field emission scanning electron microscope (FESEM) is used to analyze the morphology. Raman and FTIR spectra also approved the structure of materials and functional groups of all the synthesized samples. EDX spectra analysis confirmed the results quantitatively by detecting all the elements present in the synthesized material. High–resolution X-ray photoelectron spectroscopy (XPS) spectra confirmed the oxidation states of the synthesized samples. Various aging period treatments with annealing temperatures play a significant role in tuning the electrochemical behavior of working electrodes for battery or hybrid energy storage applications. The drop casting method was adopted for the fabrication of working electrodes, and all the electrochemical analysis of these electrodes was done in the 2 M KOH electrolyte solution. Cyclic Voltammetry (CV), Galvanostatic Charge Discharge (GCD), and Electrochemical Impedance Spectroscopy (EIS) of all the samples were analyzed in the 3-electrode setup and exhibited a high potential window of 1.4 V. The specific capacity is found to be maximum for BP12300 samples. The investigation revealed that synthesized material could be used as an electrode for various energy storage device applications. Keywords: Bismuth Phosphate, Cyclic Voltammetry, Galvanostatic charge-discharge, and hydrothermal method.

Facile synthesis of FeNi alloy-supported N-doped Mo2C hollow nanospheres for the oxygen evolution reaction

The rapid depletion of fossil fuels results in significant environmental pollution. Consequently, researching environmentally friendly and cost-effective electrocatalysts with exceptional oxygen evolution reaction (OER) capabilities holds immense importance in enhancing the efficient utilization of resources. In this paper, a straightforward and cost-effective method was employed to produce Fe-Ni alloy-supported N-doped carbon hollow nanospheres (FeNi/Mo2C/NC) using self-assembled molybdenum dopamine spheres (Mo-PDA-HS) as a substrate. The inclusion of iron and nickel addressed the issue of aggregation and collapse in Mo-PDA-HS nanostructures at high temperatures, while adjusting the electronic structure of the composites to achieve efficient OER activity. The composite displayed a low overpotential (η10 mA = 304 mV) and a minimal Tafel slope (41.8 mV/dec-1). This study introduces a simple strategy for constructing structurally robust and non-aggregating Mo2C nanostructures, along with a direct method for designing cost-effective and high-performance catalysts for OER.

Facile Fabrication of Nickel Supported on Reduced Graphene Oxide Composite for Oxygen Reduction Reaction.

Due to the depletion of fossil fuels, the demand for renewable energy has increased, thus stimulating the development of novel materials for energy conversion devices such as fuel cells. In this work, nickel nanoparticles loaded on reduced graphene oxide (Ni/rGO) with small size and good dispersibility were successfully prepared by controlling the pyrolysis temperature of the precursor at 450 °C, assisted by a microwave-assisted hydrothermal method, and exhibited enhanced electrocatalytic activity towards oxygen reduction reaction (ORR). Additionally, the electron enrichment on Ni NPs was due to charge transfer from the rGO support to metal nickel, as evidenced by both experimental and theoretical studies. Metal-support interactions between nickel and the rGO support also facilitated charge transfer, contributing to the enhanced ORR performance of the composite material. DFT calculations revealed that the first step (from O2 to HOO*) was the rate-determining step with an RDS energy barrier lower than that of the Pt(111), indicating favorable ORR kinetics. The HOO* intermediates can be transferred onto rGO by the solid-phase spillover effect, which reduces the chemical adsorption on the nickel surface, thereby allowing continuous regeneration of active nickel sites. The HO2- intermediates generated on the surface of rGO by 2e- reduction can also efficiently diffuse towards the nearby Ni surface or the interface of Ni/rGO, where they can be further rapidly reduced to OH-. This mechanism acts as the pseudo-four-electron path on the RRDE. Furthermore, Ni/rGO-450 demonstrated superior stability, methanol tolerance, and durability compared to a 20 wt% Pt/C catalyst, making it a cost-effective alternative to conventional noble metal ORR catalysts for fuel cells or metal-air batteries.

Synthesis of biodiesel from an unique potential oil reserve Delonix regia using a novel biocatalyst bamboo stem – A comparative study by RSM and ANN

Establishing sustainable energy sources is now necessary due to the depletion of fossil fuels and the rising global need for energy. On the other side, burning fossil fuels releases dangerous pollutants into the atmosphere, such as particulates and oxides of carbon, sulfur, and nitrogen. People all over the world are accepting a sustainable, renewable, and cost-effective source for the development of biofuels. Identification of a native reserve is a crucial part to hunt a suitable resource for biodiesel production due to its commercial transmission. Biodiesel is a prominent clean energy substitute due to its positive environmental concerns. In this work, a local potential source Delonix regia seeds are used for oil extraction and converted it into biodiesel directly due to its low free fatty acid content. A newly developed bio-nanocatalyst bamboo stem powder was facilitate as a catalyst and characterized by various spectroscopic techniques for efficient biodiesel conversion. Response surface methodology and Artificial Neural Network were employed to predict the optimized process parameters and maximum of around 97% biodiesel yield was achieved utilizing methanol/oil ratio - 0.25 v/v, catalyst dosage - 4 wt%, mixing speed - 950 rpm, reaction temperature - 65ºC and processing time - 95 min. Then, the biodiesel was characterized by gas chromatography to find the fatty acid combination and the properties were analysed for further processing in the automobiles. Moreover, the catalyst reusability was evaluated for economical biodiesel production was established effectively.

A literature review: Wind energy within the scope of MCDM methods

Renewable energy sources (RES) are vital for environmental sustainability. With the depletion and damage of fossil fuels to nature, energy production from clean and inexhaustible RES has become widespread. Wind energy, one of the RES, is a clean energy source that does not emit any harmful waste to the environment. Wind energy is a low-cost energy source that is mostly used for electricity generation. Criteria such as wind speed, turbine structure and the characteristics of the areas where the wind turbines will be located are effective on the amount of energy to be produced. In this study, a comprehensive review of the studies using MCDM methods related to wind energy is made. In the manner of the statistical data obtained from the 97 studies examined, it has been observed that the wind energy investments and the scientific publications made in these countries do not progress linearly with each other. The fact that countries have different wind energy potentials and the difference in the countries' interest in RES is thought to be effective in this regard. While there are articles in the literature in which studies on RES are discussed together with MCDM methods, there is no comprehensive review study in which wind energy and MCDM methods are discussed together. According to our best knowledge, this is the first study to comprehensively evaluate wind energy studies in terms of MCDM methods. With this study, a framework has been presented for subsequent studies on the application of MCDM methods in wind energy.

Strategy planning for sustainable biodiesel supply chain produced from waste animal fat

The rapid depletion of fossil fuels and the adverse environmental effects of combustion has growing concerns about the sustainability of fossil fuel and the world turns its focus on cleaner energy sources. Animal fat-based biodiesel is a sensible alternative to non-renewable energy sources as it's produced from inedible, affordable, and easily available biomass. The effective design of a biodiesel supply chain is pivotal for making it more advantageous than fossil fuels from a social, economic, and environmental standpoint. This model reduces the biodiesel supply chain cost while minimizing its environmental impact and maximizing its social impact. It is planned to have multi-supply sites for providing beef, chicken, and mutton fat, and numerous biorefineries, rendering factories, and distribution depots. The augmented ϵ-constraint approach combined with the lexicographic optimization technique is used to solve the multi-objective optimization model. A numerical example is analyzed, and the results show that the environmental impact of establishing biodiesel production facilities is 99.5% of the environmental impact of the entire biodiesel supply chain and that the cost of installing biodiesel production plants is 99% of the cost of the entire biodiesel supply chain. A heterogeneous fleet of trucks is incorporated to distribute the material throughout the supply chain whereby the impact of transportation on the environment is 0.0007% of the total environmental impact of the biodiesel supply chain and transportation cost amount to 0.0014% of the total costs of the biodiesel supply chain. The model demonstrates the biodiesel supply chain network under a sustainability framework and addresses the environmental and social impact based on the life cycle assessment which accelerates the transition to a renewable energy future.

Biodiesel production via transesterification reaction

Global warming, climate change, local air pollution, ozone depletion, acid rain and depletion of fossil fuel are the major global environmental issues. Presently, non-renewable fossil fuels meet up to 80% of the world’s energy demand. Rapid consumption of fossil fuels as well as rising environmental pollution caused by extreme CO2 emissions, sulphur dioxide, and aromatic hydrocarbons has become crucial in searching for a clean and renewable energy source such as biodiesel. With continuous growth in the world’s population, rapid industrialization, urbanization, and economic growth, fossil fuel consumption is escalating to meet the global energy demand. Biodiesel is renewable, non-toxic, environment-friendly and an economically feasible options to tackle the depleting fossil fuels and its negative environmental impact. Biodiesel is an alternative fuel made by transesterification reaction of oil and alcohol under the influence of catalyst. Biodiesel is an alcoholic ester of various fatty acids, also known as FAME (Fatty Acid Methyl Esters). In the process of transesterification, the performance of the catalyst is the key factor of the biodiesel yield. Catalysts used in biodiesel production are classified as homogeneous, heterogeneous, and enzymatic catalysts. The incorporation of a catalysis-based transesterification reaction generally increases the rate of reaction and enhances the yield of the end product. In case of homogeneous catalysts, there are problems of catalyst poisoning and contamination. Heterogeneous acid catalysis has a lesser toxic effect and gives rise to fewer environmental problems compared to the homogeneous mode. The cost of each specific catalyst depends on various factors, including the source, synthesis method, and its reusability. Generally, using waste or biomass as sources of catalysts may reduce the price of commercially available solid catalysts.

Biodiesel production: An updated review of evidence

This review paper highlights the production of biodiesel from different plant based feedstocks via the transesterification process. Biodiesel is a renewable, non-toxic, environment-friendly and an economically feasible option to tackle the depleting fossil fuels and its negative environmental impact. Biodiesel in general possess higher kinematic viscosity and density than conventional diesel. However, because of food security concerns, the use of edible oil in biodiesel production is criticized globally. Non-edible plant oils, waste cooking oils, and edible oil industry byproducts are suggested as effective biodiesel feedstocks because nonedible feedstock does not compete with food from human consumption. High-potential second-generation feedstock for biodiesel production uses waist cooking oil, acid oil, and animal tallow. Non edible crops in India as a feedstock for biodiesel production are yellow oleander oil (Cascabela thevetia), Pongamia (Pongamia pinnata), Jatropha curcas, Mahua (Madhuca longifolia), Candlenut (Aleurites moluccanus), Rubber (Hevea brasiliensis), Soapnut (Sapindus mukorossi), Jojoba (Simmondsia chinensis), Tobacco (Nicotiana tabacum), Neem (Azadirachta indica), Karanja (Millettia pinnata), Castor (Ricinus communis), Polanga (Calophyllum inophyllum L), Cotton (Gossypium), Kusum (Carthamus tinctorius), Yellow oleander (Cascabela thevetia), Sea mango (Cerbera odollam), Tung (Vernicia fordii), and Bottle tree (Brachychiton rupestris). Biodiesel is a sustainable liquid bio-energy resource that might be used to replace diesel fuel. Despite having numerous advantages over conventional diesel, the biodiesel industry is still struggling in India because of various reasons and challenges like availability, high feedstock pricing, operational hurdles, and supply-chain management challenges.

Feasibility study on application of low-grade fuels (naphtha and ethanol) in blended-fuel- and convergence-combustion modes

Since electrification is difficult in the sector where heavy-duty diesel engines are used, research is still needed to improve air pollutants. In addition, it is necessary to search for fuel to solve the depletion of fossil fuels and to study appropriate combustion methods according to fuel characteristics. In this study, naphtha or ethanol was selected as a fuel that could replace a certain fraction of diesel fuel. This study aims to compare both methods of supplying and burning naphtha or ethanol with diesel. The method of supplying naphtha or ethanol blended directly with diesel and burning it is suitable for naphtha. Since ethanol has a lower heating value, blended-fuel combustion mode with ethanol reduces IMEPnet. However, this method of separate injection and burning is only suitable for ethanol. When naphtha is utilized in convergence combustion, a wetting phenomenon arises due to its limited evaporation characteristics, leading to a reduction in fuel delivery. The NOx reduction rate was higher in the convergence combustion mode than that in the blended-fuel combustion mode. However, both the combustion methods led to an increase in the THC and CO emissions.

Solar-Powered Water Electrolysis Using Hybrid Solid Oxide Electrolyzer Cell (SOEC) for Green Hydrogen—A Review

The depletion of fossil fuels in the current world has been a major concern due to their role as a primary source of energy for many countries. As non-renewable sources continue to deplete, there is a need for more research and initiatives to reduce reliance on these sources and explore better alternatives, such as renewable energy. Hydrogen is one of the most intriguing energy sources for producing power from fuel cells and heat engines without releasing carbon dioxide or other pollutants. The production of hydrogen via the electrolysis of water using renewable energy sources, such as solar energy, is one of the possible uses for solid oxide electrolysis cells (SOECs). SOECs can be classified as either oxygen-ion conducting or proton-conducting, depending on the electrolyte materials used. This article aims to highlight broad and important aspects of the hybrid SOEC-based solar hydrogen-generating technology, which utilizes a mixed-ion conductor capable of transporting both oxygen ions and protons simultaneously. In addition to providing useful information on the technological efficiency of hydrogen production in SOEC, this review aims to make hydrogen production more efficient than any other water electrolysis system.

Increase power output and radiation in photovoltaic systems by installing mirrors

Renewable energy sources are becoming increasingly popular today due to the depletion of fossil fuels. Solar energy is a sustainable and environmentally benign energy source that exploits renewable resources, thereby contributing to creating employment opportunities in a number of fields. Output power and irradiance are two important parameters for photovoltaic production systems. The use of affordable mirrors is a promising approach to reflecting and concentrating linear sunlight. In this article, the implementation of mirrors to increase the power output and irradiance of solar panels is presented. TRNSYS does not have any components for the mirror. Therefore, in this study, the EES tool is used to create mirror components. On the other hand, two software tools, TRNSYS and EES, have joined together. The results show that power and irradiance are the main parameters that increase with the installation of mirrors in the PV system.

Controlling the output current of a SEPIC H-bridge inverter

The rapid depletion of fossil fuels and humanity's increasing dependence on electricity drive us to adopt renewable energy-based power generation. However, using renewable energy requires a system to maximize the results of converting renewable energy into electrical energy. An inverter is a DC-to-AC power conversion device. Inverters have two types: buck and boost. In closed-loop control, it can be controlled using current or voltage control. Current-controlled inverters sent to the grid have constraints, such as the inverter input voltage value must exceed the voltage on the grid. This study suggests using an H-bridge inverter and an AC-AC SEPIC to generate a voltage value more significant than the input voltage value. The proposed converter uses a single DC source and bases grid current injection on the regulated output current approach. The proposed converter satisfies the IEEE Std 519-2014 requirement of less than 5% and has a Total Harmonic Distortion (THD) of 4.6%.

Developing and optimizing a new cogeneration cycle to produce hydrogen from seawater

Global warming and the depletion of fossil fuels have driven countries to develop alternative fuel strategies. As an alternative fuel, hydrogen is very attractive since it has a high thermal energy and near-zero emissions. This paper proposes a new arrangement of the cogeneration cycle for hydrogen production from seawater is proposed and optimized via the multi-objective swarm optimization (MOPSO) algorithm. In this survey, hydrogen is produced through the electrochemical cycle Copper-Chloride (Cu-Cl), using the heat and electricity provided via waste heat recovery of a gas cycle. A reverse osmosis system provides drinking water for the Cu-Cl cycle. This cycle can produce 256 GWh of electricity and 23616 tons/year of hydrogen during a year. This cycle's first and second law efficiencies are 35.3 % and 7.2 %. Based on the financial aspects, this cycle's investment return time equals 4.1 years. By using MOPSO algorithm, the exergy efficiency of the cogeneration system is improved by 22.7 %, while the payback is decreased by around 33.3 %.

Life cycle assessment of SBS modified bitumen waterproofing membrane

Building waterproofing membranes constitute essential components of construction materials. This study utilizes the life cycle assessment (LCA) methodology to develop a comprehensive life cycle inventory and conduct an environmental impact assessment of typical styrene-butadiene-styrene (SBS) modified bitumen waterproofing membrane products. The main research objective of this paper is to identify the key factors influencing the environmental impact of products and to provide data for the selection of green materials in the construction industry. The results reveal that the production of raw materials for SBS-modified bitumen waterproofing membranes contributes the most to all environmental impact categories, followed by the transportation and energy production stages, while the production stage of the membranes exhibits a relatively smaller contribution. Within the raw material production stage, the bitumen production process exhibits the highest contribution to fossil fuel depletion (FFP) environmental impact, surpassing 50%. The production process of polyester tire cloth demonstrates the greatest influence on human toxicity potential (HTPc), global warming potential (GWP), freshwater eutrophication (FEP), marine eutrophication potential (MEP), and mineral resource scarcity potential (SOP), accounting for 54.63%, 32.86%, 68.55%, 72.41%, and 61.69%, respectively. Additionally, the production process of base oil exhibits the most significant contribution to fine particulate matter formation (PMFP) and terrestrial acidification potential (AP) among the environmental impact indicators. Variations in the quantities of polyester tire cloth and base oil exhibit the most notable influence on the environmental indicators of the product. Specifically, the sensitivity analysis reveals that polyester tire cloth has the greatest impact on mineral resource scarcity potential (SOP); base oil exhibits the highest sensitivity to fossil fuel depletion (FFP).

Numerical investigation for enhancing HCCI combustion characteristics in DI-CI engine fueled with butanol/diesel blends

The fast depletion of fossil fuels and the hazardous emissions associated with the use of fossil fuels in IC engines is driving the research in the area of renewable fuels. Homogeneous charge combustion ignition (HCCI) is a new mode of engine combustion technology, used for reducing the emissions without compromising the engine performance. The combination of HCCI and alcohol/diesel blends has the potential to simultaneously address the twin problems of depletion of fossil fuels and engine emissions. Butanol is an attractive biofuel, which is produced from agriculture wastes such as sugar cane bagasses and corn stalk etc. This paper presents numerical and modeling analysis on the emission and performance characteristics of a direct injection- compression ignition (DI-CI) engine operated with butanol/diesel blends. Numerical analysis was carried out using CONVERGE CFD software. Response surface methodology (RSM) was used in developing the response models for three output parameters, viz., nitrogen oxides (NOx), soot emissions and indicated specific fuel consumption (ISFC), in terms of the four input parameters, viz., compression ratio (CR), start of injection (SOI), fuel injection pressure (FIP) and exhaust gas recirculation (EGR). Numerical experiments were conducted by varying these four input parameters, i.e., CR from 14 to 19, FIP from 200 to 280 bar, EGR from 0% to 30% and SOI from 17° to 29° CA bTDC, and with four butanol/diesel blends (0, 20%, 30% and 40% of butanol-by volume, designated as Bu00, Bu20, Bu30 and Bu40). The optimum combination of the input parameters for the four test fuels were found with the objective of minimizing the three output parameters (i.e., ISFC, soot and NOx) using desirability approach. The homogeneity of the air-fuel mixture was estimated using equivalence ratio distribution index, i.e., Target fuel distribution index (TFDI). From the numerical analysis, it was found that the TFDI improved for the optimized case by 20.5%, 21.5%, 24.4% and 27.2% for Bu00, Bu20, Bu30 and Bu40 respectively as compared to their respective baseline configuration.

Analyzing the factors influencing the wind energy adoption in Bangladesh: A pathway to sustainability for emerging economies

The future of energy security has become a prominent concern for emerging economies due to the inevitable depletion of fossil fuels and the ongoing disruptions in their supply. The crippling effect of complete dependence on expensive fossil fuel imports is magnified by the ineffective policy response to the enduring energy crisis, impeding progress across various sectors and thwarting efforts to meet the demands of population growth and industrialization amid acute electricity shortages. Amidst the economic growth of a prominent emerging economy, Bangladesh, wind energy emerges as a transformative solution to effectively tackle the mounting challenges of electricity demand, environmental pollution, greenhouse gas emissions, and the depleting reserves of fossil fuels. Therefore, this study utilizes an integrated multi-criteria decision-making (MCDM) approach combining the inter-valued type 2 intuitionistic fuzzy (IVT2IF) theory with the decision-making trial and evaluation laboratory (DEMATEL) method aiming to identify, prioritize, and investigate the relationships among the factors that impact the sustainable adoption and growth of wind energy in an emerging economy like Bangladesh. Initially, the factors were derived from reviewing existing literature. After subsequent expert validation, sixteen factors were selected for analysis using the IVT2IF DEMATEL method. The findings of the study indicate that "Fossil fuel supply disruption," "Stable financial investment and resource mobilization," and "Geographical region" are the most significant factors influencing the adoption of wind energy for national grid support with prominence value 4.415, 4.406 and 4.339 respectively. Moreover, "Fossil fuel supply disruption" is also the most significant causal factor with a causal weight of 1.274, which is followed by "Stable financial investment and resource mobilization" and "Geographical region" with a causal weight of 1.029 and 0.794. The study's findings have the potential to aid decision-makers and policymakers in formulating long-term strategies and investment decisions to improve the sustainability of the national grid and achieve carbon neutrality.

Effect on minor addition of aromatic (benzyl alcohol) and diethyl ether in Calophyllum inophyllum blended diesel fuel in a CI engine operates by hydrogen energy as a secondary fuel

Strict regulations on vehicle emissions are in place to lessen pollution and environmental damage. The depletion of fossil fuels also threatens energy security. Renewable, cleaner-burning and sustainable fuels could aid the researcher in solving these problems. Because of their limited supply, renewable fuels cannot resolve the issue independently. Therefore, much research is being done on enhanced combustion technologies, such as dual-fuel engines, homogenous charge compression ignition, and low-temperature combustion. The Calophyllum inophyllum oil (P20) mixed with diesel, diethyl ether, and aromatic alcohol (benzyl alcohol) was tested in this study using a dual-fuel engine. Hydrogen gas is added to the air intake manifold as a second energy source. Aromatic alcohol is an organic fuel that can be produced naturally by hydrolysis of lignin. The OH hydroxyl group is attached to the aromatic ring and promotes free radical propagation. Minor addition of oxygenates affects the performance, combustion, and emission of engines operating on various loads. Maximum brake thermal efficiency and lower brake-specific fuel consumption were observed with 20 % aromatic alcohol, 32.45 %, and 0.2 kg/kW-hr, respectively. Brake thermal efficiency improved to 6.54 % compared to neat diesel. Reduction in brake-specific fuel consumption by 28 % compared to diesel fuel. Compared to other blends, aromatic alcohol additions are linked to reduced smoke, HC, and CO emissions. However, using aromatic alcohol results in slightly increased nitrogen oxide emissions compared to diesel. Blends of biofuel and benzyl alcohol have shown favorable effects in terms of enhanced combustion, reduced emissions, and increased efficiency.

G-C3N4/Bromocobaloxime nanocomposites as multi-functional electrocatalysts for water splitting and energy storage

The depletion of fossil fuels necessitates the search for alternative sources of energy and energy storage for long-term usage. Recently graphitic carbon nitride (g-C3N4) based materials have gained attention due to their enhanced activity compared to previously tested materials. But the poor electron mobility of g-C3N4 continues to cause a significant energy loss in the electrocatalytic processes. Herein we report the synthesis and characterization of g-C3N4/Bromocobaloxime composites and their electrocatalytic applications towards hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and energy storage. Bromocobaloximes [BrCo(dpgH)2B] (B1-B4) containing diphenylglyoxime [dpgH] as the equatorial ligand and functionalized neutral bases such as Isonicotinic acid (1), Pyridine-3,5-dicarboxylic acid (2), Indole-2-carboxylic acid (3) and p-Aminobenzoic acid (4) were synthesized using the standard procedure. The g-C3N4/Cobaloxime nanocomposites (g-C3N4/B1, g-C3N4/B2, g-C3N4/B3 and g-C3N4/B4) were prepared using g-C3N4 nanosheets by solvothermal method. The prepared nanocomposites were characterized by FT-IR, UV-DRS, XRD, SEM, EDAX, TEM and XPS analysis. The electrochemical HER studies of the synthesized nanocomposites showed low overpotentials in the range of 51 to 228 mV at −10 mAcm−2 and the OER studies exhibited overpotentials in the range of 310 to 460 mV at 10 mAcm−2. Among them nanocomposite g-C3N4/B2 showed a lower Tafel slope of 45 mV/dec for HER and 112 mV/dec for OER. The supercapacitance studies indicated that among the nanocomposites, g-C3N4/B1 showed a good specific capacitance of 302 F/g at 0.5 A/g. The increased electrochemical performance of the synthesized nanocomposites is due to the incorporation of cobaloximes containing carboxylic acid functionalized neutral bases into the g-C3N4 nanosheets, which increases the electron mobility. This will lead to explore the applications of g-C3N4/metal complexes towards energy conversion by tuning the ligands in the metal complexes.

Development of a spherical solar collector with a cylindrical receiver

Solar energy can be used for substitution of the depleting fossil fuels in thermal applications and electricity generation through thermal route. For medium and high temperature applications, a system for collecting solar energy at high temperatures was developed and built in this research work. The system, built at the center of development of renewable energy of the Algiers, consists of a 2=60°C included angle, R0=0.90 m diameter spherical reflector with a cylindrical receiver filled with water, tracking reflector which moves into the focus following the sun's movement. The system is capable of heating water or other fluids to temperatures above 350 °C, thus making it possible to obtain process heat for domestic use and to store solar energy in a compact and economical way. An analysis of the system's optical characteristics was performed to aid in the design of the spherical reflector and cylindrical receiver. The thermal performance of the system was analyzed. The effects of mirror reflection, concentration ratio, heat transfer to the fluid (water), incidence angle, size and form of the cylindrical receiver, environmental conditions (wind, ambient temperature), have been studied by means of thermal model. The performance of the spherical reflector was tested by the temperature of the water. Total efficiencies (solar to thermal) of = 60% - 70% were obtained for a wide range of temperatures up to 350 °C. The results of the present study show that it is possible to use the spherical reflector for systems requiring process heat and make possible substantial utilization of solar energy and considerable savings relative to fossil energy in the sunny countries of the world.

Adaptively optimal energy management for integrated hydrogen energy systems

AbstractIntegrated hydrogen energy systems (IHESs) have become attractive alternatives to cope with the depletion of fossil fuels and increasingly severe climate change problems. This paper proposes an adaptively optimal energy scheduling method based on deep deterministic policy gradient (DDPG) to improve the operational efficiency of IHES. The optimal scheduling problem is formulated as a Markov decision process problem with action space, environmental states, and action‐value function. The DDPG‐based optimal energy management algorithm with actor‐critic structure is proposed based on policy gradients and neural networks. Through actor‐critic network training and policy iteration, the energy management scheme can be adaptively optimized according to the dynamic responses of IHES. The benefits of the proposed algorithm are analysed through time‐domain simulations, and the scheduling robustness under different uncertain conditions is verified.