Green Source Research Articles

Enhanced charge-carrier dynamics and efficient solar-to-urea conversion on Si-based photocathodes

Photoelectrochemical (PEC) coupling of CO2 and nitrate can provide a useful and green source of urea, but the process is affected by the photocathodes with poor charge-carrier dynamics and low conversion efficiency. Here, a NiFe diatomic catalysts/TiO2 layer/nanostructured n+p-Si photocathode is rationally designed, achieving a good charge-separation efficiency of 78.8% and charge-injection efficiency of 56.9% in the process of PEC urea synthesis. Compared with the electrocatalytic urea synthesis by using the same catalysts, the Si-based photocathode shows a similar urea yield rate (81.1 mg·h-1·cm-2) with a higher faradic efficiency (24.2%, almost twice than the electrocatalysis) at a lower applied potential under 1 sun illumination, meaning that a lower energy-consumption method acquires more aimed productions. Integrating the PEC measurements and characterization results, the synergistic effect of hierarchical structure is the dominating factor for enhancing the charge-carrier separation, transfer, and injection by the matched band structure and favorable electron-migration channels. This work provides a direct and efficient route of solar-to-urea conversion.

An Open-Air Palladium-Catalyzed Stereoselective O-Glycosylation of Glycals via in-situ Generation of gem-Disubstituted Methanols from p-Quinone Methides.

We devised a palladium-catalyzed α-stereoselective glycosylation that incorporates oxygen via in-situ generation of gem-disubstituted methanols from p-quinone methides to access 2,3-unsaturated gem-diarylmethyl O-glycosides under open-air atmosphere at room temperature. Advantages of this environmentally friendly strategy include the absence of additives and ligands, using water as the green source of oxygen, mildest, operationally simple, exhibiting a wide functional group tolerance, and compatibility with a variety of glycal progenitors in appreciable yields. A mechanistic study has been verified via H2 18 O labeling, which validates that water (moisture) is a sole source of oxygen.

Using Natural Dye Additives to Enhance the Energy Conversion Performance of a Cellulose Paper-Based Triboelectric Nanogenerator.

Green and sustainable power sources for next-generation electronics are being developed. A cellulose paper-based triboelectric nanogenerator (TENG) was fabricated to harness mechanical energy and convert it into electricity. This work proposes a novel approach to modify cellulose paper with natural dyes, including chlorophyll from spinach, anthocyanin from red cabbage, and curcumin from turmeric, to enhance the power output of a TENG. All the natural dyes are found to effectively improve the energy conversion performance of a cellulose paper-based TENG due to their photogenerated charges. The highest power density of 3.3 W/m2 is achieved from the cellulose paper-based TENG modified with chlorophyll, which is higher than those modified with anthocyanin and curcumin, respectively. The superior performance is attributed not only to the photosensitizer properties but also the molecular structure of the dye that promotes the electron-donating properties of cellulose.

Graphene and nanocomposites—Imprints on environmentally sustainable production and applications based on ecological aspects

Graphene, an innovative nanocarbon, has been discovered as a significant technological material. Increasing utilization of graphene has moved research towards the development of sustainable green techniques to synthesize graphene and related nanomaterials. This review article is basically designed to highlight the significant sustainability aspects of graphene. Consequently, the sustainability vision is presented for graphene and graphene nanocomposites. Environmentally sustainable production of graphene and ensuing nanomaterials has been studied. The formation of graphene, graphene oxide, reduced graphene oxide, and other derivatives has been synthesized using ecological carbon and green sources, green solvents, non-toxic reagents, and green routes. Furthermore, the utilization of graphene for the conversion of industrial polymers to sustainable recycled polymers has been studied. In addition, the recycled polymers have also been used to form graphene as a sustainable method. The implication of graphene in the sustainable energy systems has been investigated. Specifically, high specific capacitance and capacitance retention were observed for graphene-based supercapacitor systems. Subsequently, graphene may act as a multi-functional, high performance, green nanomaterial with low weight, low price, and environmental friendliness for sustainable engineering and green energy storage applications. However, existing challenges regarding advanced material design, processing, recyclability, and commercial scale production need to be overcome to unveil the true sustainability aspects of graphene in the environmental and energy sectors.

Dynamic Control of Fuel Cell Powered Water Pumping Station

An efficient renewable green energy system consisting a hydrogen PEM-fuel cell as an energy sources is simulated and studied in this paper. The proposed green scheme has four separate key components. The first is the green power generation source. The second is the interfacing DC-DC converter used to connect green power generator fuel cell to the load bus. The third is a common DC interface-bus where the generated energy is collected in a DC form. The fourth comprises all interfacing error driven controllers and novel modulated green plug power filter (GPPF) used to reduce ripple variations and stabilize the common DC-Bus voltage. In this paper, the novel multi-loop error driven dynamic controller scheme is implemented for speed control of the PMDC motor. This multi-loop controller comprises three basic loops, the main supplementary dynamic momentum loop to ensure fast dynamic and minimum current and torque ripple content. The proposed fuel cell generation scheme provides efficient and optimum dynamic operation to enhance system performance and secure energy supply. The proposed integrated hybrid system with all subsystems has been simulated using the Matlab Simulink/Sim-Power software environment and validated for voltage stabilization, efficient utilizations and enhanced power quality under different operating conditions, sudden load excursions, despite the non-linear volt-ampere characteristic of the fuel cell DC generator source.

ZIF-8 induced N, P double doped porous molybdenum phosphide hydrogen evolution catalyst

Molybdenum based phosphides have gradually become the investigation frontier of hydrogen evolution catalysts due to the platinum like electronic structure. In this paper, N, P double-doped graphite carbon layers wrapped with MoP nanoparticles (P–MoP@NPC), is directly compounded by one-step high-temperature carboning PMo12-APP@ZIF-8 precursor. P–MoP@NPC possesses splendid hydrogen production reactive, in two kinds of electrolytes, when the overpotentials of P–MoP@NPC are 132 mV and 161 mV, the slope of current density reaching 10 mA cm−2, Tafel slope are 67 and 79 mV dec−1, respectively. In the bargain, P–MoP@NPC displays satisfactory durability in acid and alkaline mediums and can continue to work for more than 24 h. The wonderful hydrogen production ability of P–MoP@NPC is ascribed to the synergistic effect of MoP nanoparticles, hierarchical porous structure as well as N, P double-doped carbon layers. The confinement effect of ZIF-8 makes most of the synthesized MoP nanoparticles evenly distributed. The hierarchical porous structure caused by the volatilization of Zn atoms with high temperature can expose more active centers. The N, P double-doped graphitic carbon layers not only protect the catalyst but also adjust the electronic structure of MoP, promoting the hydrogen production capacity. This work may provide a general way to study molybdenum phosphide catalysts synthesized by APP as a green phosphorus source for energy conversion.

Life Cycle Assessment of Selected Ammonia Production Technologies From the Perspective of Ammonia as a Fuel for Heavy-Duty Vehicle

Abstract One of the promising options for the decarbonization of industry dependent on heavy-duty vehicles is to use alternative fuels such as ammonia. The study investigates the environmental impact of five selected ammonia production technologies and compares them to diesel fuel: ammonia based on hydrogen from steam methane reforming (gray), ammonia based on steam methane reforming with carbon capture and storage (blue), ammonia based on hydrogen from electrolysis with electrical energy supplied by: PV (green PV), wind (green wind), and nuclear plant (pink). Environmental impact is assessed using the ReCiPE method based on three midpoint and two endpoint categories: climate change, fossil depletion, freshwater consumption, human health, and ecosystem quality. The climate change results per 1 MJ (LHV) are as follows: gray ammonia at 0.148 kg CO2 eq., blue ammonia at 0.0701 kg CO2 eq., green ammonia PV at 0.0197 kg CO2 eq., green ammonia wind at 0.01039 kg CO2 eq., pink ammonia at 0.00565 kg CO2 eq., and diesel (including its stoichiometric combustion) at 0.0851 kg CO2 eq. The life cycle assessment (LCA) was performed using the lca for experts (GaBi) software, with Sphera's comprehensive Managed LCA Content as the primary data source for the life cycle inventory. The study indicates nuclear and renewable-based routes to be the best options in terms of the climate change and human health categories; however, their high impact on freshwater consumption and ecosystem quality is revealed. Still, ammonia is proven to be an effective solution toward decarbonization, as compared to diesel, given its blue, green, or pink source.

Catalytic Enantioselective Nucleophilic α-Chlorination of Ketones with NaCl.

Catalytic enantioselective α-chlorination of ketones is a highly desirable process. Different from the conventional approaches that employ corrosive electrophilic chlorination reagents, the process disclosed here employs nucleophilic chloride, aqueous NaCl solution, and even seawater, as green inexpensive chlorine sources. This mechanistically distinct and electronically opposite approach provides facile access to diverse highly enantioenriched acyclic α-chloro ketones that are less straightforward by conventional approaches. With a chiral thiourea catalyst, a range of racemic α-keto sulfonium salts underwent enantioconvergent carbon-chlorine bond formation with high efficiency and excellent enantioselectivity under mild conditions. The sulfonium motif plays a crucial triple role by permitting smooth dynamic kinetic resolution to take place via a chiral anion binding mechanism in a well-designed phase-transfer system. This protocol represents a new general platform for the asymmetric nucleophilic α-functionalization of carbonyl compounds.

Ag‐Nanocatalysts Based on Porous Organic Polymers in Chemical Fixation of CO2 for the N‐Methylation and N‐Formylation of Amines

AbstractChemical fixation of CO2 for the synthesis of valuable chemicals is very demanding in the context of green and sustainable chemistry. Herein, we report highly efficient silver‐loaded porous organic polymer catalysts for the exclusive N‐formylation and N‐methylation of amines under ambient reaction conditions using CO2 as a green C1 source. By adjusting the solvent and temperature of the reaction, the successful production of formamides and methylamines could be accomplished with high levels of selectivity and efficiency. POP‐based materials Ag@TTP‐1 and Ag@PAN‐T are utilized as low‐cost catalysts for both the N‐methylation and N‐formylation of primary and secondary amines and the product yields up to 98 % could be achieved. Ag@TTP‐1 demonstrated superior catalytic efficiency compared to Ag@PAN‐T in the N‐methylation and N‐formylation reactions. This result suggests that the grafting of Ag nanoparticles onto POP surface with a high surface area plays a crucial role in these CO2 fixation reactions. The above‐mentioned catalysts (Ag@TTP‐1 and Ag@PAN‐T) are characterized through powder XRD, FT IR spectroscopy, FE‐SEM, TEM, thermogravimetric techniques, N2 sorption and XPS analysis. Ag‐nanocatalysts demonstrated heterogeneous nature and high recycling efficiency for several cycles in this CO2 fixation reaction.

Harnessing Cyanobacteria's Bioactive Potential: A Sustainable Strategy for Antioxidant Production.

Unsaturated diacylglycerols are a class of antioxidant compounds with the potential to positively impact human health. Their ability to combat oxidative stress through radical scavenger activity underscores their significance in the context of preventive and therapeutic strategies. In this paper we highlight the role of Anabaena flos-aquae as a producer of unsaturated mono and diacylglycerols, and then demonstrate the antioxidant activity of its methanolic extract, which has as its main components a variety of acylglycerol analogues. This finding was revealed using a sustainable strategy in which the One Strain Many Compounds (OSMAC) cultivation in microscale was coupled with a bioinformatic approach to analyze a large dataset of mass spectrometry data using the molecular networking analyses. This strategy reduces time and costs, avoiding long and expensive steps of purification and obtaining informative data on the metabolic composition of the extracts. This study highlights the role of Anabaena as a sustainable and green source of novel bioactive compounds.

Novel green protocols for the synthesis of tetrahydropyrazolopyrazolones

1,3 – Dipolar cycloadditions represent an important method for obtaining novel bicyclic heterocycles which is of great importance due to their medicinal application and diverse bioactivity such as antitumor, antibacterial and etc. The most suitable way for the synthesis of bicyclic heterocycles such as pyrazolopyrazolones is based on dipolar cycloaddition of azomethine imines and enones. This reaction was explored to develop more sustainable protocols by using less toxic chemicals and different sources of energy. Herein novel green protocols for the synthesis of tetrahydropyrazolopyrazolones are presented. These green protocols avoid hazardous AlCl3 and CH2Cl2 which were used until now, and implement green sources of irradiation. In this research, acetic acid has proved itself as a great catalyst for this type of reaction. Different azomethine imines and enones were submitted to the reaction in the presence of acetic acid for 12 h. A series of ten tetrahydropyrazolopyrazolones is successfully synthesized. The impact of ultrasound and microwave irradiation was also investigated. Three novel protocols for the synthesis of tetrahydropyrazolopyrazolones were established. The best results with significant improvement in yield, reaction time, and cleaner reaction conditions were observed when acetic acid and microwave irradiation were used. These novel protocols for the synthesis of pyrazolopyrazolones based on the usage of acetic acid as a catalyst and ultrasound and microwave irradiation represent a noteworthy advancement in research of sustainable methods for obtaining heterocycles.

Green Banking Practices and Green Financing of Listed Deposit Money Banks in Nigeria

This study examined the nexus between green banking practices and green financing sources of listed deposit money banks in Nigeria. The study anchored on the institutional theory and cross sectional survey research design was adopted with a population consisting of listed banks in Nigeria. The study used stratified random sampling of seven hundred and fifty (750) bank employees with questionnaire as the primary source of data collection from the respondents while only five hundred (500) were used for data analysis using univairate, bivariate and multivariate methods of data analysis. The results from the regression analysis disclosed that banks’ employee-related practices of green banking positively and significantly influence sources of green financing of deposit money banks in Nigeria; banks’ daily operations-related practices of green banking positively and significantly affect sources of green financing of deposit money banks in Nigeria; banks’ customers-related practices of green banking positively but significantly influence sources of green financing of deposit money banks in Nigeria; banks’ policy-related practices of green banking positively and significantly influence sources of green financing of deposit money banks in Nigeria and banks’ green investment related practices of green banking positively and significantly impact on sources of green financing of deposit money banks in Nigeria. Consequently, on the basis of the findings the study concluded that green banking practices positively influences the sources of green financing of deposit money banks in Nigeria. Therefore, the study recommends amongst others that banks’ in Nigeria should adopt contemporary banking practices that are ecofriendly as a means of enhancing the sources of green financing in Nigeria.

Silver nanoparticles synthesis from Crinum moorei: Optimization, characterization, kinetics and catalytic application

Nanotechnology has been developing tremendously since the 1970s. Various types of nanoparticles such as carbon, metal, bio-originated, etc. have been synthesized by a variety of physical, chemical and biological methods. Biological methods which employ bacteria, fungi and plants for the synthesis of metal nanoparticles are found to be a sustainable and eco-friendly approach. Among biological methods, plants being a cleaner and greener source are widely accepted. The present work includes screening the synthesis of silver nanoparticles using the roots and leaves extract of 15 different Indian Crinum species, optimization, characterization and kinetic studies of silver nanoparticles. Among all the species, the highest synthesis was observed by Crinum moorei which was detected by apeak at 390 nm in UV–visible spectrophotometry. The optimization of silver nanoparticle synthesis from C. moorei roots was performed based on extract concentration (1 %), salt concentration (1.5 mM), pH (9) and temperature (30°C). The kinetics study of silver nanoparticles showed a rate constant of 0.0609 h−1. Furthermore, the characterization of synthesized silver nanoparticles was conducted using TEM, SEM, FTIR, XRD, NTA and DLS. These synthesized AgNPs exhibited catalytic activity for Congo red dye decolorization, which could serve as an initiative for the further studies to control the environmental pollution caused by dyes and colorants.

Stability study of AC grid-connected quasi-Z-source inverter-based photovoltaic power systems

The presence of photovoltaic power systems is currently increasing as green power sources, and quasi-Z-source inverters are commonly used to connect them to AC grids. However, stability concerns can appear due to inverters. Several studies address these concerns but they are not completely solved yet. This paper contributes with a simulation study about stability of AC grid-connected quasi-Z-source inverter-based photovoltaic power systems. The study is based on the PSCAD/EMTDC model of these systems and analyzes the influence of system parameters on subsynchronous and harmonic instabilities. Several solutions to improve these instabilities are discussed.

Evaluation of green laser source additive manufacturing technology for accelerator applications with ultra-high vacuum requirements

Additive Manufacturing (AM) offers different benefits such as efficient material usage, reduced production time and design freedom. Moreover, with continuous technological developments, AM expands in versatility and different material usage capabilities. Recently new energy sources have been developed for AM – green wavelength lasers, which provide better energy absorption for pure copper. Due to high thermal and electrical conductivity of copper, this novel AM technology is highly promising for various industries, particularly, there is a huge interest to use it for accelerator applications. In particular, these AM produced accelerator components should reach the associated Ultra High Vacuum (UHV) requirements. In this study, vacuum membranes of pure copper were produced by AM using a green laser source, in different thicknesses and built angles. Furthermore, a vacuum membrane helium leak tightness test was performed at room temperature by using a high-sensitivity mass spectrometer. Comparison of these test results was performed with previously established results. Through this study, novel knowledge and initial results are provided for green laser source AM technology usage for applications for UHV accelerator components.

Biomass derived sulfonated carbon catalysts: efficient catalysts for green chemistry

BDSCCs, known as efficient solid acid catalysts with easy preparation and a green source, are anticipated to play a role in advancing circular and economic development in various sectors.

Micron-sized iron particles as energy carrier: Cycling experiments in a fixed-bed reactor

Iron is a promising energy carrier with the potential to store substantial amounts of energy over extended time periods with minimal losses. For instance, the energy from green hydrogen sources can be used to reduce iron oxides, be stored or transported, and thus be regained by exothermic oxidation of the iron. This work explores the influence of oxygen partial pressure and temperature on the oxidation process in a fixed-bed reactor. Furthermore, the analysis extends to the reduction of oxidized iron particles at varying temperatures. The experimental findings highlight that both oxidation and reduction progress through the fixed-bed reactor as distinct reaction fronts. In the oxidation process, the speed of the reaction front increases with rising oxygen content and temperature, resulting in a higher reaction rate and a correspondingly increased heat release. Conversely, the reaction rate for reduction experiences a notable decrease for 600°C and 700°C. The reprocessability of the iron powder was validated for up to 16 cycles under the optimal reaction conditions established. Furthermore, it was demonstrated that the performance improves with an increasing number of cycles. This improvement is attributed to the formation of pores due to density changes and the subsequent creation of a larger surface area, mitigating the negative effects of sintering and agglomeration.

An optimal power flow solution for a power system integrated with renewable generation

<abstract> <p>Integrating Green Renewable Energy Sources (GRES) as substitutes for fossil fuel-based energy sources is essential for reducing harmful emissions. The GRES are intermittent and their integration into the conventional IEEE 30 bus configuration increases the complexity and nonlinearity of the system. The Grey Wolf optimizer (GWO) has excellent exploration capability but needs exploitation capability to enhance its convergence speed. Adding particle swarm optimization (PSO) with excellent convergence capability to GWO leads to the development of a novel algorithm, namely a Grey Wolf particle swarm optimization (GWPSO) algorithm with excellent exploration and exploitation capabilities. This study utilizes the advantages of the GWPSO algorithm to solve the optimal power flow (OPF) problem for adaptive IEEE 30 bus systems, including thermal, solar photovoltaic (SP), wind turbine (WT), and small hydropower (SHP) sources. Weibull, Lognormal, and Gumbel probability density functions (PDFs) are employed to forecast the output power of WT, SP, and SHP power sources after evaluating 8000 Monte Carlo possibilities, respectively. The multi-objective green economic optimal solution consisted of 11 control variables to reduce the cost, power losses, and harmful emissions. The proposed method to address the OPF problem is validated using an adaptive IEEE bus system. The proposed GWPSO algorithm is evaluated by comparing it with PSO and GWO optimization algorithms in terms of achieving an optimal green economic solution for the adaptive IEEE 30 bus system. This evaluation is conducted within the confines of the same test system using identical system constraints and control variables. The integration of a small SHP with WT and SP sources, along with the proposed GWPSO algorithm, led to a yearly cost reduction ranging from <bold>$\$$19,368</bold> to <bold>$\$$30,081</bold>. Simulation findings endorsed that the proposed GWPSO algorithm executes fruitfully compared to alternative algorithms regarding a consistent convergence curve and robustness, proving its potential as a viable choice for achieving cost-effective solutions in power systems incorporating GRES.</p> </abstract>

Delayed tunneling of charges to deep traps in a ZnO impurity containing Cr3+ doped Zn2TiO4 inverse spinel.

Herein, the structural, optical and thermoluminescence properties of Cr doped Zn2TiO4 are explored extensively for a possible application in bioimaging. All the samples show prominent luminescence at wavelengths 712 and 716 nm, which correspond to Cr R and N2-lines, respectively. These R and N2 lines correspond to the presence of Cr3+ in undistorted and distorted sites. The excitation spectra of all the samples possess at least five different bands at 616, 440, 388, 330 and 283 nm. The persistent luminescence is observed upon excitation at all these wavelengths, suggesting the existence of both localized and delocalized mechanisms. The charges can be easily stored in deeper traps (trap depth > 1.0 eV) upon localized excitation with green and red light sources. However, upon excitation at wavelengths 254 and 365 nm, these traps were found empty when thermoluminescence glow curves were recorded immediately after excitation. Furthermore, it was observed that the trapping in these deeper traps through the delocalized band is possible when a delay in the thermoluminescence measurement is pursued. We attribute the possible reason for such delayed tunneling to the higher probability of retrapping than the recombination process.

Unveiling the total catechin profile in tea leaves: a novel one-step extraction method empowered by UPLC-IDX-Orbitrap mass spectrometry.

More catechins are found in green tea than in any other type of tea, with its predominant production taking place in Asian nations. Consumption of green tea has been strongly correlated with a reduced risk of many diseases. This study introduces a new, efficient, and reliable method for extracting total catechins using ultra-high-performance liquid chromatography coupled with an ID-X-Orbitrap Mass spectrometer (UHPLC-IDX-Orbitrap-MS). The method was then applied to quantify the catechin content in green tea, yielding results comparable to previously published studies. Among the various sources of green tea analyzed, the lowest average catechin content was observed in Vietnam, Japan (2: Matcha), and Morocco, ranging between 346 and 322 mg/L. Conversely, the highest average catechin content (between 424 and 422 mg/L) was found in Sri Lanka and Japan (1: Sencha). For the remaining green tea extracts, the catechin levels ranged from 367 to 410 mg/L, exhibiting similar values. These findings demonstrate the high reproducibility of the proposed extraction procedure, with a relative standard deviation (RSD) error of less than 15% for the catechin standard. Additionally, the limit of detection for catechins was determined to be 1 ng mL-1. This study serves as a pilot investigation for extracting catechins from various green tea sources. Future research will focus on identifying all active compounds present. Furthermore, it is worth noting that this study aligns with the goals set forth in Saudi Vision 2030, which aims to diversify the country's economy and promote scientific advancements in various fields, including healthcare and agriculture.