Green Energy Sources Research Articles

Optimization of Water Hyacinth Stem-Based Oxygen-Functionalized Activated Carbon for Enhanced Supercapacitors.

In the current world, storing and converting energy without affecting the natural ecosystem are considered a sustainable and efficient green energy source production technology. Especially, using low-cost, environmentally friendly, and high-cycle stability activated carbon (AC) from the water hyacinth (Eichhornia crassipes) waste material for charge storage application is the current attractive strategy for renewable energy generation. In this study, preparation of AC from water hyacinth using a mixed chemical activation agent followed by activation time was optimized by the I-optimal coordinate exchange design model based on a 3-factor/3-level strategy under nine experimental runs. The optimum conditions to prepare AC were found to be potassium hydroxide (≈17 g) and potassium carbonate (≈11 g), and the carbonization time was approximately 1 h. Under these augmented conditions, the maximum specific capacitance suggested by the designed model was found to be ≈75.2 F/g. The regression coefficient (R 2 = 0.9979), adjusted (R 2 = 0.9917), predicted (R 2 = 0.8706), adequate precision (39.2795), and p-values (0.0062) proved the good correlation between actual and predicted values. The physicochemical and electrochemical properties of the final optimized AC were characterized by thermogravimetric/differential thermal analysis (TGA/DTA), X-ray diffractometry (XRD), Fourier transform infrared (FTIR), Brunauer-Emmett-Teller (BET), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), selected area electron diffraction (SAED), and potentiostat (CV and EIS) instruments. Finally, the optimized AC electrode after 100 cycles at a current density of 2 A g-1 retains an efficiency of 71.57%, indicating the good stability and sustainability of this material.

Conjugated diacetylene polymers with intrachain D-A block heterostructure for efficient photocatalytic hydrogen production

Solar-driven photocatalytic hydrogen production has been considered as a promising candidate technology for supplying green and sustainable energy source alternative to fossils. But its low solar-to-hydrogen conversion efficiency level hampers its practical application, and lack of effective structure for promoting charge separation is one of the accounts. Herein, intrachain heterojunction structure comprised of donor-acceptor (D-A) blocks has been proved to be one of effective structures for addressing such an issue. Utilizing the facile oxidative coupling polymerization reactions of diacetylene monomers and oligomers, a block heterojunction polymeric photocatalyst named PDTPDPA-BP bearing D-A blocked heterostructure was synthesized by first separative oligomerizations of diacetylene-functionalized dibenzothiophene sulfone (DTP) and triphenylamine (TPA) monomers and then mixed together and undergoing further polymerization. In photocatalytic hydrogen production, PDTPDPA-BP displayed a hydrogen evolution rate of 2164 μmol g−1 h−1, which is much larger than those of PDTP (1270 μmol g−1 h−1) and PTPA (57 μmol g−1 h−1) synthesized by homopolymerization of DTP and TPA monomers, respectively, and their 1:1 molar ratio physical blend (363 μmol g−1 h−1). By means of Fluorescence spectroscopy and photo-responsive measurements, it was found PDTPDPA-BP has narrower bandgap and more efficient charge separation than the other polymers. Therefore, the work highlights intrachain heterojunction structure promotes exciton dissociation into free charge carries, and thus deserves the consideration in the design of high performance organic photocatalysts.

Sustainable development through green transition in EU countries: New evidence from panel quantile regression

Sustainable development addresses global challenges by promoting practices that balance economic, social, and environmental considerations. Key factors include the shifting to green energy and the integrating of green technology in the sustainable development process. This study investigates the heterogenous effects of green technology development, green energy, R&D expenditures, FDI, economic growth, and urbanization on CO2 emissions in 25 European Union (EU) countries using panel quantile regression over the period 2000–2021. The results, based on panel quantile regression, indicate that green energy decreases CO2 emissions from the 10th to the 90th quantiles, while green technology development increases CO2 emissions at the lower quantiles (10th to 60th) and then turns negative. The robustness of the fixed effect model also confirms the findings of the study. Additionally, panel causality tests indicate no causal link between green technology development and CO2 emissions, but there is bidirectional causality between green energy and CO2 emissions. Therefore, the findings highlight that policymakers should thoroughly evaluate measures and strategies to encourage the development of green technologies and green energy sources to reduce high levels of CO2 emissions. One strategy is to provide financial aid and support technological advances to produce green energy at reduced costs.

Emerging Processes for Sustainable Li‐Ion Battery Cathode Recycling

AbstractThe colossal growth in the use of Li‐ion batteries (LiBs) has raised serious concerns over the supply chain of strategic minerals, e.g., Co, Ni, and Li, that make up the cathode active materials (CAM). Recycling spent LiBs is an important step toward sustainability that can establish a circular economy by effectively tackling large amounts of e‐waste while ensuring an unhindered supply of critical minerals. Among the various methods of LiB recycling available, pyro‐ and hydrometallurgy have been utilized in the industry owing to their ease of operation and high efficiency, although they are associated with significant environmental concerns. Direct recycling, a more recent concept that aims to relithiate spent LiBs without disrupting the lattice structure of the CAMs, has been realized only in the laboratory scale so far and further optimization is required before it can be extended to the bulk scale. Additionally, significant progress has been made in the areas of hydrometallurgy in terms of using ecofriendly green lixiviants and alternate sources of energy, e.g., microwave and electrochemical, that makes the recycling processes more efficient and sustainable. In this review, the latest developments in LiB recycling are discussed that have focused on environmental and economic viability, as well as process intensification. These include deep eutectic solvent based recycling, electrochemical and microwave‐assisted recycling, and various types of direct recycling.

High-efficient removal of oxygen (O2) impurity from hydrogen (H2) flow on nickel-based oxide: effect of metal dopants

Hydrogen is considered as a green energy source, which has attracted widespread attention. Electrocatalytic hydrogen production is a promising technology for generating clean hydrogen. However, the by-product oxygen in this process would lead to a risk of explosion that should be removed before using. In this work, nickel-based oxides doped with variable proportions of Mn, Co, and Cu were used for oxygen removal through catalytic oxidation technology. The catalytic test results show that the optimized catalysts, including 4NiMn, 2Ni1.5Co, and NiCu exhibit better performance. Among all the catalysts, 4NiMn catalyst has the best catalytic performance, achieving a 90% oxygen removal rate below 100 °C. According to the results of H2-TPR, O2-TPD and H2-TPD, the catalysts with better deoxidation effect (4NiMn, 2Ni1.5Co and NiCu) exhibit a stronger oxidation-reduction ability. 4NiMn has higher amounts of adsorption surface oxygen species and overflow hydrogen, which are key factors of the promoting deoxidation effect. Overall, it can be concluded that the optimal catalytic performance of 4NiMn can be attributed to its ability to better adsorb oxygen on its surface, promote the release of overflow hydrogen and participate in oxidation-reduction reactions.

The interfacial synergy of hierarchical FeCoNiP@FeNi-LDH heterojunction for efficient alkaline water splitting

In response to the growing demand for clean, green, and sustainable energy sources, the development of cost-effective and durable high-activity overall water splitting electrocatalysts is urgently needed. In this study, the heterogeneous structure formed by the combination of FeCoNiP and FeNi-LDH was homogeneously dispersed onto CuO nanowires generated by in-situ oxidation of copper foam as a substrate using an electrodeposition method. This multilevel structure exhibits excellent bifunctional properties as an electrode material in alkaline solutions, for the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) only 206 mV and 147 mV overpotentials are needed to achieve a current density of 100 mA cm−2 respectively. Full water electrolysis is thus enabled to take place at such a low cell voltage as 1.64 V to reach the current density of 100 mA cm−2, which exhibits a long-term stability of 30 h. These improved electrocatalytic performances stem from the construction of multilevel structures. The X-ray photoelectron spectroscopy suggests that strong electron transfer occurs between heterogeneous structures, thus facilitating the OER and HER process. The dispersion of CuO nanowires not only increases the electrochemically active surface areas but also improves the overall hydrophilic and aerophobic properties. This work highlights the positive effect of multilevel structure in the design of more efficient electrocatalysts and provides a reference for the preparation of other low-cost, high-activity bifunctional electrocatalysts.

The impact of government expenditure, renewable energy consumption, and CO2 emissions on Lebanese economic sustainability: ARDL approach

Most of the recent environmental and economic studies focus on the influence of renewable energy consumption and effective government expenditure respecting global climate change in leading sustainable economic growth. The empirical studies showed variation in the relationship between these variables. Based on the Keynesian economic growth framework, this study aims to investigate the impact of government expenditure, renewable energy consumption, and carbon dioxide emissions on the sustainable economic growth of Lebanon. The study used the ordinary least square method to test the short- and long-run relationship between the model variables by employing the Autoregressive Distributed Lag Stationarity estimation. The research data are gathered from the World Development Indicators annually from 1990 to 2022. The empirical findings showed that all variables are stationary at first difference except for carbon dioxide emissions. A long-term relationship between the dependent and independent variables was shown by the model test simulation employing the bound test. The model test for model residuals showed no heteroscedasticity based on the White test. The residuals are normally distributed by applying the Shapiro-Wilk test, and the model is stable with no structural break at the period. According to the study results, government spending has a robust reverse relation with sustainable economic growth and positive significant results for both renewable energy consumption and carbon dioxide emissions. The study findings are consistent with some literature sources and raise attention to monitoring the nature of government spending and boosting green energy sources in an economy.

Exploring novel benzene sulfonamide derivatives: Synthesis, ADME studies, anti-proliferative activity, docking simulation, and emphasizing theoretical investigations

In this investigation, we elucidated the different heterocyclic containing benzenesulphonamide utilizing Microwave irradiation as a green energy source. Firstly the synthesis of (E)-N-(4-(3-(4-bromophenyl)acryloyl)phenyl)-4-methylbenzene sulfonamide (4) from the nucleophilic substitution reaction between 4-methylbenzenesulfonyl chloride and 1-(4-aminophenyl)ethan-1-one in pyridine, yielding N-(4-acetylphenyl)-4-methylbenzenesulfonamide (3), then the aldol condensation with bromobenzaldehyde in basic condition to afford the corresponding benzene sulfonamide chalcone 4 which is building block for different heterocycles. So its reactivity with different active methylene derivatives such as ethyl cyanoacetate and acetylacetone and nitrogen nucleophiles such as hydrazine hydrate and hydroxylamine using microwave irradiation in excellent yield. All synthesized compounds were investigated through spectral analysis such as FT-IR, 1HNMR, 13C NMR, and mass spectrum. Moreover, the synthesized compounds were screened through their ADME properties and were tested for antitumor activity against HepG2 hepatocellular carcinoma and MCF-7 breast cancer, exhibiting excellent efficacy compared to standard drugs, especially the heterocycles 6,8, 10, and 13 compared with Doxorubicin drug Furthermore, Molecular simulations with different proteins confirmed these results with PDBID:4hdq and 5H38. Additionally, the DFT analysis of optimized structures investigated their physical descriptors, Frontier Molecular Orbitals (FMO) which correlated them with the biological evaluation and showed the stabilities of these compounds.

The Age of Buried Carbon Changes the Greenhouse Gas Budget of a Dam

AbstractDams are a globally relevant source of greenhouse gases (GHG), which impairs their function as a source of green energy. High burial rates of organic carbon (OC) in dam sediments may partly or fully offset the emissions. We argue that only the burial of carbon fixed in the timespan of dam operation changes the GHG balance. Here, we took sediment cores from a temperate dam. We analyzed radiocarbon age and OC molecular composition by laser desorption ionization mass spectrometry in the bulk OC and in four chemical extract fractions. The bulk samples contained modern OC, fixed after 1950. However, the extracted OC was of different ages (modern to 1900 years BP). Fractions with OC measured as old (>960 years BP) accounted for 57% of total sediment OC. Correlations of molecular composition with extract age suggest that these older fractions contained insignificant amounts of modern OC. We conclude that a substantial proportion of buried carbon did not originate from the contemporary atmosphere and cannot be offset against recent GHG emissions.

Heterogeneous alkaline catalyst synthesized from local bovine bone wastes for transesterification of palm oil into biodiesel

Abstract Local bovine bone wastes, which are abundant in Aceh Province, have been successfully used as biomineral sources to produce heterogeneous catalysts that result in alkaline oxide. This study aimed to produce alkaline oxides by employing a high heat breakdown approach on local bovine bone particles at atmospheric pressure. The physicochemical analysis of the obtained inorganic particles revealed that the predominant component of those obtained inorganic oxide particles was calcium oxides (CaO). Furthermore, the produced alkaline oxide was employed as an alkali oxide catalyst for the transesterification of palm oil (RPDPO) with methanol, yielding methyl ester compounds, which are well recognized as a sustainable and green diesel energy source.

A Causality Perspective: Investments in Green Energy Business vs. Conventional Business

Abstract At the level of the European Union numerous sustainability programs are being created. Considering these the main role f the research is to explore the potential of green energy production along with its limitations. Studies have found that by combining multiple sources of green energy and harnessing technological advances, there is the possibility to believe that one can reduce human’s dependence on fossil fuels. The aim of this study is to create a stock market analysis in order to identify future investment trends by assessing whether there is greater interest in investing in renewable electricity companies. The current paper explores the impact of investing in renewable electricity companies versus investing in the stock market of fossil fuel-based energy companies. The dataset includes closing stock price data for two major companies, one of which is the British-Dutch company SHELL.L Global (known in the oil industry as well as the energy sector) and the other company is Vestas Wind Systems (a Danish company that manufactures wind turbines for renewable energy parks around the world). This dataset covers the period 3rd of January 2011 to 24th of November 2023 and is used together with time series statistical tests. The purpose is to highlight the main objective of this article: to demonstrate through Granger causality whether investment in the renewable electricity market affects investment in the conventional energy market. This result will shed light on whether long-term investments in fossil fuel-based businesses are worth investors’ attention going forward. While the major purpose of the paper is the research mentioned above, there is also a secondary objective, that of carrying out a descriptive analysis of the two listed companies and their evolution in order to identify the key periods that led to significant fluctuations in the series temporal.

Vertical Takeoff and Landing for Distribution of Parcels to Hospitals: A Case Study about Industry 5.0 Application in Israel’s Healthcare Arena

To gain a sustained competitive advantage, organizations such as UPS, Fedex, Amazon, etc., began to seek for industry 5.0 innovative autonomous delivery options for the last mile. Autonomous unmanned aerial vehicles are a promising alternative for the logistics industry. The fact that drones are propelled by green renewable energy source fits the companies’ need to become sustainable, replacing their fuel truck fleets, especially for traveling to remote rural locations to deliver small packages, but a major obstacle is the necessity for charging stations which is well documented in the literature. Therefore, the current research embarks on devising a novel yet practical piece of technology adopting the simplicity approach of direct flights to destinations. The analysis showcases the application for a network of warehouses and hospitals in Israel while controlling costs. Given the products in the case study are medical, direct flight has the potential to save lives when every moment counts. Hydrogen cell technology allows long-range flying without refueling, and it is both vibration-free which is essential for sensitive medical equipment and environmentally friendly in terms of air pollution and silence in urban areas. Importantly, hydrogen cells are lighter, with higher energy density than batteries, which makes them ideal for drone usage to reduce weight, maintain a longer life, and enable faster charging, all of which minimize downtime. Also, hydrogen sourcing is low-cost and unlimited compared to lithium-ion material which needs to be mined. The case study investigates an Israeli entrepreneurial company, Gadfin, which builds a vertical takeoff-and-landing-type of drone with folded wings that enable higher speed for the delivery of refrigerated medical cargo, blood, organs for transplant, and more to hospitals in partnership with the Israeli medical logistic conglomerate, SAREL. An analysis of shipping optimization (concerning the number and type of drone) is conducted using a mixed-integer linear programming technique based on various types of constraints such as traveling distance, parcel weight, the amount of flight controllers and daily number of flights allowed in order to not overcrowd the airspace. Importantly, the discussion assesses the ecosystem’s variety of risks and commensurate safety mechanisms for advancing a newly shaped landscape of drones in an Israeli tight airspace to establish a network of national routes for drone traffic. The conclusion of this research cautions limitations to overcome as the utilization of drones expand and offers future research avenues.

A Novel Ag-MgFe2O4 nanocomposite based hydroelectric cell: Green energy source illuminating the future

Hydroelectric cells demonstrate their capacity to produce electricity via the dissociation of water molecules, eliminating the requirement of electrolytes. The objective of this research is to synthesize Ag-MgFe2O4 nanocomposite using low-cost method and to study the green electricity generation by hydroelectric cell via the dissociation of water molecules. The nanocomposite displayed a cubic crystalline structure with an average crystallite size of about 29 nm, as determined by XRD. The lattice strain and crystal defects resulted from the insertion of the Ag in spinel ferrite from the W-H plot. The theoretical porosity of 54 % was further evaluated by XRD analysis and visually confirmed by FESEM imaging. The FTIR spectroscopy revealed functional groups present in ferrite observed from 428 cm−1 to 3450 cm−1 spectra. Strong water absorption near 3450 cm−1 showed materials sensitivity to water. FESEM imaging displayed the morphology, revealing porous grains with an average size of 93 nm. BET analysis of the prepared nanocomposite confirmed mesoporosity within the nanocomposite. Photoluminescence study confirmed radiative defects and oxygen deficiencies, as evidenced by emitted light maximum at 483 nm and broad peak from 456 nm to 526 nm. The voltage-current (V-I) polarization diagram for the Ag- MgFe2O4 nanocomposite-based hydroelectric cell showed an offload current of 18 mA, an open circuit voltage of 1.404 V, and an output power of 25.27 mW. In this context, the hydroelectric cell based on Ag- MgFe2O4 nanocomposite demonstrated increased porosity, radiative defects, and oxygen vacancies, all contributing to efficient water molecule dissociation for power generation. This represents a significant development in sustainable energy and highlights the practical possibilities of clean and renewable resources.

Weld Zone Analysis Based on FCAW Mechanical Characteristics and Heat Transfer Analysis of 316L Stainless Steel for Liquefied Hydrogen Tanks.

The International Maritime Organization (IMO) is currently rolling out more restrictive regulations in order to achieve net-zero GHG emissions by 2050. In response, the shipping industry is planning to pivot to green energy sources such as hydrogen fuel. However, since hydrogen has an extremely low boiling point (-253 °C), materials for storing liquid hydrogen must be highly resistant to low-temperature brittleness and hydrogen embrittlement. A 316L stainless steel is a typical material that meets these requirements, and various welds have been studied. In this study, 3 pass butt welding was performed by applying the FCAW (flux cored arc welding) process to 10 mm thick ASTM-A240M-316L stainless steel, with the size of the fusion zone and HAZ investigated by mechanical testing and heat transfer FE analysis according to process variables, such as heat input, welding speed, and the number of passes. In all cases, the yield and tensile strengths were about 10% and 3% higher than the base metal, respectively. Furthermore, heat transfer FE analysis showed an average error rate of 1.3% for penetration and 10.5% for width and confirmed the size of the HAZ, which experienced temperatures between 500 °C and 800 °C.

Advancing sustainability in mechanical engineering: Integration of green energy and intelligent manufacturing

Efficient energy utilization and waste reduction are imperative for sustainable mechanical engineering practices. This paper explores the integration of green energy sources and intelligent manufacturing techniques to enhance sustainability in the mechanical engineering sector. Through quantitative analysis and case studies, the efficacy of energy-efficient technologies, waste reduction strategies, and the adoption of green energy sources are examined. Additionally, the role of smart process automation and digital twin simulation in optimizing resource utilization and operational efficiency is discussed. The findings underscore the potential of integrating sustainable practices into mechanical engineering processes, contributing to environmental conservation, cost savings, and competitiveness.

Optimal sizing of a proposed stand-alone hybrid energy system in a remote region of southwest Egypt applying different meta-heuristic algorithms

Hybrid energy system (HES) is considered a solution to the energy supply issue, particularly in rural areas to achieve their sustainable development goals. The rise in energy consumption has increased the appeal of renewable resources, because of their potential to supply consumers with competitive, carbon-free electricity. This paper suggests strategies for managing energy and the most recently published optimizers for designing a stand-alone HES positioned in a remote region of southwest Egypt. This HES includes two green energy sources (wind and solar) and a storage system for energy (battery) as the first backup in addition to a second backup (diesel). The most recent sizing techniques employing the Chernobyl disaster optimizer, dynamic control cuckoo search (DCCS), and gold rush optimizer have been suggested to obtain the optimal design of the utilized HES. Furthermore, an in-depth evaluation of the applied optimization approaches has been achieved based on a comparative study. A detailed analysis of the studied algorithms aims to identify the optimum algorithm that provides the lowest possible cost at the highest level of reliability for the proposed HES. The simulation results verified that, the DCCS algorithm outperformed other algorithms, indicating its potential for achieving promising solutions.

Cross-Domain Knowledge Transfer for Sustainable Heterogeneous Industrial Internet-of-Things Networks.

In this article, a novel cross-domain knowledge transfer method is implemented to optimize the tradeoff between energy consumption and information freshness for all pieces of equipment powered by heterogeneous energy sources within smart factory. Three distinct groups of use cases are considered, each utilizing a different energy source: grid power, green energy source, and mixed energy sources. Differing from mainstream algorithms that require consistency among groups, the proposed method enables knowledge transfer even across varying state and/or action spaces. With the advantage of multiple layers of knowledge extraction, a lightweight knowledge transfer is achieved without the need for neural networks. This facilitates broader applications in self-sustainable wireless networks. Simulation results reveal a notable improvement in the 'warm start' policy for each equipment, manifesting as a 51.32% increase in initial reward compared to a random policy approach.

The impact of cleaner energy sources, advanced technology firms, and economic expansion on ecological footprints is critical in sustainable development

The environmental degradation accompanying economic growth, despite the potential mitigating effects of technological advancements and cleaner energy sources. This study examines the critical impact of cleaner energy sources, advanced technology firms, and economic expansion on ecological footprints within the context of sustainable development, focusing on the period between 2010 and 2022. By comparing the E7 (emerging seven) and G7 (Group of Seven) economies, the research aims to delineate how these factors collectively influence environmental sustainability in both developing and developed nations. Utilizing a robust panel estimation technique, the study systematically explores the relationship between the adoption of renewable energy technologies, the growth of high-tech industries, and macroeconomic expansion, alongside their respective effects on the ecological footprint, a key indicator of environmental impact. Our statistical analysis reveals significant differences between the E7 and G7 countries. For the G7, investments in cleaner energy and technology sectors have shown a more pronounced effect in reducing ecological footprints, attributed to higher efficiency standards and greater public awareness. In contrast, the E7 countries exhibit a delayed response, owing to varying stages of economic development and technological adoption, although promising trends are emerging. Notably, the G7 demonstrates a more pronounced inclination towards financial imperialism (0.043), while the E7 is significantly influenced by green energy sources (0.258). Policy implications drawn from the findings suggest that targeted investments in green technologies and renewable energy sources, coupled with robust policies supporting economic expansion in a sustainable manner, are crucial for both groups of countries. For the E7, accelerating technology transfer and adopting stricter environmental regulations are key, while the G7 should focus on innovation and the continuous improvement of energy efficiency standards. This dual approach is essential for mitigating the environmental impacts of economic growth and steering the global economy towards a more sustainable trajectory.

Spray Characterization of Direct Hydrogen Injection as a Green Fuel with Lower Emissions

A viable green energy source for heavy industries and transportation is hydrogen. The internal combustion engine (ICE), when powered by hydrogen, offers an economical and adaptable way to quickly decarbonize the transportation industry. In general, two techniques are used to inject hydrogen into the ICE combustion chamber: port injection and direct injection. The present work examined direct injection technology, highlighting the need to understand and manage hydrogen mixing within an ICE’s combustion chamber. Before combusting hydrogen, it is critical to study its propagation and mixture behavior just immediately before burning. For this purpose, the DI-CHG.2 direct injector model by BorgWarner was used. This injector operated at 35 barG and 20 barG as maximum and minimum upstream pressures, respectively; a 5.8 g/s flow rate; and a maximum tip nozzle temperature of 250 °C. Experiments were performed using a high-pressure and high-temperature visualization vessel available at our facility. The combustion mixture prior to burning (spray) was visually controlled by the single-pass high-speed Schlieren technique. Images were used to study the spray penetration (S) and spray volume (V). Several parameters were considered to perform the experiments, such as the injection pressure (Pinj), chamber temperature (Tch), and the injection energizing time (Tinj). With pressure ratio and injection time being the parameters commonly used in jet characterization, the addition of temperature formed a more comprehensive group of parameters that should generally aid in the characterization of this type of gas jets as well as the understanding of the combined effect of the rate of injection on the overall outcome. It was observed that the increase in injection pressure (Pinj) increased the spray penetration depth and its calculated volume, as well as the amount of mass injected inside the chamber according to the ROI results; furthermore, it was also observed that with a pressure difference of 20 bar (the minimum required for the proper functioning of the injector used), cyclic variability increased. The variation in temperature inside the chamber had less of an impact on the spray shape and its penetration; instead, it determined the velocity at which the spray reached its maximum length. In addition, the injection energizing time had no effect on the spray penetration.

Cobalt-Based Nanoscale Material: An Emerging Electrocatalyst for Hydrogen Production.

Modern civilization has been highly suffering from energy crisis and environmental pollutions. These two burning issues are directly and indirectly created from fossil fuel consumption and uncontrolled industrialization. The above critical issue can be solved through the proper utilization of green energy sources where no greenhouse gases will be generated upon burning of such materials. Hydrogen is the most eligible candidate for this purpose. Among various methods of hydrogen generation, electrocatalytic process is one of the most efficient methods because of easy handling and high efficiency. In these aspects Co-based nanomaterials are considered to be extremely significant as they can be utilized as efficient, recyclable and ideal catalytic system. In this article a series of Co-based nano-electrocatalysts has been discussed with proper structure-property relationship and their medium dependency. Therefore, such type of stimulating summary on recently reported electrocatalysts and their activity may be helpful for scientists of the corresponding field as well as for broader research communities. This can be inspiration for materials researchers to fabricate active catalysts for the production of hydrogen gas in room temperature.