Recent Advances in Carbon Nanotube Utilization in Perovskite Solar Cells: A Review

Due to their exceptional optoelectronic properties, halide perovskites have emerged as prominent materials for the light-absorbing layer in various optoelectronic devices. However, to increase device performance for wider adoption, it is essential to find innovative solutions. One promising solution is incorporating carbon nanotubes (CNTs), which have shown remarkable versatility and efficacy. In these devices, CNTs serve multiple functions, including providing conducting substrates and electrodes and improving charge extraction and transport. The next iteration of photovoltaic devices, metal halide perovskite solar cells (PSCs), holds immense promise. Despite significant progress, achieving optimal efficiency, stability, and affordability simultaneously remains a challenge, and overcoming these obstacles requires the development of novel materials known as CNTs, which, owing to their remarkable electrical, optical, and mechanical properties, have garnered considerable attention as potential materials for highly efficient PSCs. Incorporating CNTs into perovskite solar cells offers versatility, enabling improvements in device performance and longevity while catering to diverse applications. This article provides an in-depth exploration of recent advancements in carbon nanotube technology and its integration into perovskite solar cells, serving as transparent conductive electrodes, charge transporters, interlayers, hole-transporting materials, and back electrodes. Additionally, we highlighted key challenges and offered insights for future enhancements in perovskite solar cells leveraging CNTs.

Powering the Future by Iron Sulfide Type Material (FexSy) Based Electrochemical Materials for Water Splitting and Energy Storage Applications: A Review

Water electrolysis is among the recent alternatives for generating clean fuels (hydrogen). It is an efficient way to produce pure hydrogen at a rapid pace with no unwanted by-products. Effective and cheap water-splitting electrocatalysts with enhanced activity, specificity, and stability are currently widely studied. In this regard, noble metal-free transition metal-based catalysts are of high interest. Iron sulfide (FeS) is one of the essential electrocatalysts for water splitting because of its unique structural and electrochemical features. This article discusses the significance of FeS and its nanocomposites as efficient electrocatalysts for oxygen evolution reaction (OER), hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), and overall water splitting. FeS and its nanocomposites have been studied also for energy storage in the form of electrode materials in supercapacitors and lithium- (LIBs) and sodium-ion batteries (SIBs). The structural and electrochemical characteristics of FeS and its nanocomposites, as well as the synthesis processes, are discussed in this work. This discussion correlates these features with the requirements for electrocatalysts in overall water splitting and its associated reactions. As a result, this study provides a road map for researchers seeking economically viable, environmentally friendly, and efficient electrochemical materials in the fields of green energy production and storage.

Advances in Smart Photovoltaic Textiles

Energy harvesting textiles have emerged as a promising solution to sustainably power wearable electronics. Textile-based solar cells (SCs) interconnected with on-body electronics have emerged to meet such needs. These technologies are lightweight, flexible, and easy to transport while leveraging the abundant natural sunlight in an eco-friendly way. In this Review, we comprehensively explore the working mechanisms, diverse types, and advanced fabrication strategies of photovoltaic textiles. Furthermore, we provide a detailed analysis of the recent progress made in various types of photovoltaic textiles, emphasizing their electrochemical performance. The focal point of this review centers on smart photovoltaic textiles for wearable electronic applications. Finally, we offer insights and perspectives on potential solutions to overcome the existing limitations of textile-based photovoltaics to promote their industrial commercialization.

Revealing the energy paradox: Assessing the asymmetric impact of pandemic uncertainty on consumption of renewable and nonrenewable energy

Uncertainties have grown around the world during the last few decades. Pandemic uncertainty has a substantial impact on economic activities, which may have a big influence on energy consumption. The goal of this investigation is to appraise the asymmetric influence of pandemic uncertainty on nonrenewable and renewable energy consumption in the top 10 energy consumer economies of the European Union (Germany, Poland, Spain, Netherlands, France, Italy, Belgium, Sweden, Czech Republic, and Finland). Previously, panel data approaches were utilized to obtain reliable outcomes on the pandemic-energy consumption nexus, regardless of the fact that various nations did not autonomously exhibit similar relationship. This investigation, on the other hand, implements a special technique "Quantile-on-Quantile" that supports us to appraise time-series interdependence in each economy by providing international yet nation-specific perceptions of the connection among the variables. Estimates show that pandemic uncertainty reduces both nonrenewable and renewable energy consumption in most selected nations at stated quantiles of the data distribution. Nonrenewable energy consumption is much more influenced by pandemic uncertainty than renewable energy consumption. Furthermore, the rank of asymmetries across our variables differentiates by the economy, emphasizing the need for decisionmakers to pay much attention to pandemics-related uncertainty and the energy sector.

Rational Design of a High-Loading Polysulfide Cathode and a Thin-Lithium Anode for Developing Lean-Electrolyte Lithium-Sulfur Full Cells

Lithium-sulfur cells are attractive energy-storage systems because of their high energy density and the electrochemical utilization rates of the high-capacity lithium-metal anode and the low-cost sulfur cathode. The commercialization of high-performance lithium-sulfur cells with high discharge capacity and cyclic stability requires the optimization of practical cell-design parameters. Herein, a carbon structural material composed of a carbon nanotube skeleton entrapping conductive graphene is synthesized as an electrode substrate. The carbon structural material is optimized to develop a high-loading polysulfide cathode with a high sulfur loading capacity (6-12 mg cm-2 ), rate performance (C/10-C/2), and cyclic stability for 200 cycles. A thin lithium anode based on the carbon structural material is developed and exhibits long lithium stripping/plating stability for ≈2500 h with a lithium-ion transference number of 0.68. A lean-electrolyte lithium-sulfur full cell with a low electrolyte-to-sulfur ratio of 6 µL mg-1 is constructed with the designed high-loading polysulfide cathode and the thin lithium anode. The integration of all the critical cell-design parameters endows the lithium-sulfur full cell with a low negative-to-positive capacity ratio of 2.4, while exhibiting stable cyclability with an initial discharge capacity of 550 mAh g-1 and 60% capacity retention after 200 cycles.

Towards Digital Twins of the Oceans: The Potential of Machine Learning for Monitoring the Impacts of Offshore Wind Farms on Marine Environments

With an increasing number of offshore wind farms, monitoring and evaluating the effects of the wind turbines on the marine environment have become important tasks. Here we conducted a feasibility study with the focus on monitoring these effects by utilizing different machine learning methods. A multi-source dataset for a study site in the North Sea is created by combining satellite data, local in situ data and a hydrodynamic model. The machine learning algorithm DTWkNN, which is based on dynamic time warping and k-nearest neighbor, is used for multivariate time series data imputation. Subsequently, unsupervised anomaly detection is performed to identify possible inferences in the dynamic and interdepending marine environment around the offshore wind farm. The anomaly results are analyzed in terms of location, density and temporal variability, granting access to information and building a basis for explanation. Temporal detection of anomalies with COPOD is found to be a suitable method. Actionable insights are the direction and magnitude of potential effects of the wind farm on the marine environment, depending on the wind direction. This study works towards a digital twin of offshore wind farms and provides a set of methods based on machine learning to monitor and evaluate offshore wind farm effects, supporting stakeholders with information for decision making on future maritime energy infrastructures.

A Portable Triboelectric Nanogenerator Based on Dehydrated Nopal Powder for Powering Electronic Devices

Triboelectric nanogenerators (TENGs) based on organic materials can harvest green energy to convert it into electrical energy. These nanogenerators could be used for Internet-of-Things (IoT) devices, substituting solid-state chemical batteries that have toxic materials and limited-service time. Herein, we develop a portable triboelectric nanogenerator based on dehydrated nopal powder (NOP-TENG) as novel triboelectric material. In addition, this nanogenerator uses a polyimide film tape adhered to two copper-coated Bakelite plates. The NOP-TENG generates a power density of 2309.98 μW·m^-2 with a load resistance of 76.89 MΩ by applying a hand force on its outer surface. Furthermore, the nanogenerator shows a power density of 556.72 μW·m^-2 with a load resistance of 76.89 MΩ and under 4g acceleration at 15 Hz. The output voltage of the NOP-TENG depicts a stable output performance even after 27,000 operation cycles. This nanogenerator can light eighteen green commercial LEDs and power a digital calculator. The proposed NOP-TENG has a simple structure, easy manufacturing process, stable electric behavior, and cost-effective output performance. This portable nanogenerator may power electronic devices using different vibration energy sources.

Development of a Quartz-Based Photo-Mobile Polymer Film for Controlled Motion Triggered by Light or Heat

We have developed a photo-mobile polymer film, that combines organic and inorganic materials, to allow for controlled motion that can be triggered by light or heat. Our film is made using recycled quartz and consists of two layers: a multi-acrylate polymer layer and a layer containing oxidized 4-amino-phenol and N-Vinyl-1-Pyrrolidinone. The use of quartz in our film also gives it a high temperature resistance of at least 350 °C. When exposed to heat, the film moves in a direction that is independent of the heat source, due to its asymmetrical design. Once the heat source is removed, the film returns to its original position. ATR-FTIR measurements confirm this asymmetrical configuration. This technology may have potential applications in energy harvesting, due to the piezoelectric properties of quartz.

A laboratory experiment for science courses: Sedimentary microbial fuel cells

Nowadays there is a concern to improve the quality of education by including an interdisciplinary approach of concepts and their integration in the curriculum of scientific disciplines. The development of microbial fuel cells as a potential alternative for production of renewable energies gives undergraduate students the challenge of integrating interdisciplinary concepts in a hot topic of global interest as alternative energies. We present a laboratory experiment that has been part of a third-year undergraduate course in biology where students gained experience in assembling microbial fuel cells and the understanding of how they work. In this process, the students could integrate biological, biochemical, and electric concepts. In addition, the acquisition of manual skills and experimental design decisions are important for the development of future professionals.

Socio-Economic Vulnerability to Climate Change in Rural Areas in the Context of Green Energy Development-A Study of the Great Masurian Lakes Mesoregion

Green energy production has become a common and recognized method of electricity generation. Giving up reliance on non-renewable energy sources is an important trend in the economies of many countries. The paper presents an analysis of the impact of indicators like increased green energy production on the level of vulnerability to climate change. The model of the Climate Change Vulnerability Index (VCC) recommended by the Intergovernmental Panel on Climate Change (considering three aspects: exposure, vulnerability, and adaptive capacity of the studied spatial unit/society) was applied. Sensitivity analysis, spatial heterogeneity, and temporal dynamics of indicators characterizing changes in electricity consumption, renewable energy production, greenhouse gas emissions, and variability of financial losses due to extreme weather events and their number were implemented. Several findings arose. First, the vulnerability to climate change (the level of the VCC index), does not decrease after the implementation of a single action, like the development of green energy production. The level of index of vulnerability to climate change (VCC1) from the reference year (2017) relative to VCC2 (2021) has changed slightly, despite the development of RES. The variation does not exceed a 1% reduction in the value of the VCC1 index. Second, the decrease in the level of the vulnerability requires global, coordinated action. The value of the VCC3 index, reflecting, including changes in green energy production (X15), electricity consumption/inhabitant (X38), and green-house gas emissions (X14), exhibited more favorably the impact of these indicators on vulnerability to climate change, compared to the VCC1 reference value. In eleven poviats, the VCC3 index decreased between 1 and 4%. In seven of these poviats, green energy production increased, resulting in an average 10% decrease in the X15 indicator, the X14 indicator representing green-house gas emissions decreased by an average of 7%, while the X38 indicator describing electricity consumption/per capita decreased by an average of 16%. Third, harmonized and inclusive action by the population holds the potential to be the clue to reducing vulnerability to climate change.

Organic Supercapacitors as the Next Generation Energy Storage Device: Emergence, Opportunity, and Challenges

Harnessing new materials for developing high-energy storage devices set off research in the field of organic supercapacitors. Various attractive properties like high energy density, lower device weight, excellent cycling stability, and impressive pseudocapacitive nature make organic supercapacitors suitable candidates for high-end storage device applications. This review highlights the overall progress and future of organic supercapacitors. Sustainable energy production and storage depend on low cost, large supercapacitor packs with high energy density. Organic supercapacitors with high pseudocapacitance, lightweight form factor, and higher device potential are alternatives to other energy storage devices. There are many recent ongoing research works that focus on organic electrolytes along with the material aspect of organic supercapacitors. This review summarizes the current research status and the chemistry behind the storage mechanism in organic supercapacitors to overcome the challenges and achieve superior performance for future opportunities.

Anti-Oxidation Agents to Prevent Dye Degradation in Organic-Based Host-Guest Systems Suitable for Luminescent Solar Concentrators

Luminescent solar concentrators (LSCs) have been extensively studied as they offer a practical solution to increase the efficiency of silicon-based photovoltaics (PVs). In this context, the use of natural and organic luminescent materials is desirable in order to obtain sustainable and environmentally friendly devices. Moreover, solution-processable organic host-guest systems based on Foerster Resonant Energy Transfer (FRET) processes offer the possibility to exploit a low-cost technique to obtain an efficient energy downshift from the UV-visible to red or deep red emissions in order to concentrate the radiation in the area of maximum efficiency of the PV device. Nevertheless, organic materials are subjected to photodegradation that reduces their optical properties when exposed to UV light and oxygen. In this work, we incorporated two different antioxidant molecules (i.e., octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (Octa) and L-ascorbic acid (L-Asc)) in a three-dye host-guest system and studied the corresponding optical properties after prolonged irradiation times in air. It was found that the presence of the antioxidants, especially L-Asc, slowed the system's photodegradation down whilst at the same time retaining high emission efficiencies and without interfering with the cascade Resonant Energy Transfer processes among the dyes inserted in the nanochannels of the host.

Lithium Separation from Geothermal Brine to Develop Critical Energy Resources Using High-Pressure Nanofiltration Technology: Characterization and Optimization

There is a shift from internal combustion engines to electric vehicles (EVs), with the primary goal of reducing CO₂ emissions from road transport. Battery technology is at the heart of this transition as it is vital to hybrid and fully electric vehicles' performance, affordability, and reliability. However, it is not abundant in nature. Lithium has many uses, one of which is heat transfer applications; synthesized as an alloying agent for batteries, glass, and ceramics, it therefore has a high demand on the global market. Lithium can be attained by extraction from other natural resources in igneous rocks, in the waters of mineral springs, and geothermal brine. During the research, geothermal brine was used because, from the technological point of view, geothermal brine contains higher lithium content than other resources such as seawater. The nanofiltration separation process was operated using various solutions of pH 5, 7, and 10 at high pressures. The varying pressures are 11, 13, and 15 bar. The nanofiltration method was used as the separation process. High pressure of inert nitrogen gas was used to supply the driving force to separate lithium from other ions and elements in the sample. The research results supported the selected parameters where higher pressure and pH provided more significant lithium recovery but were limited by concentration polarization. The optimal operating conditions for lithium recovery in this research were obtained at a pH of 10 under a pressure of 15 bar, with the highest lithium recovery reaching more than 75%.

Towards Green and Sustainable Healthcare: A Literature Review and Research Agenda for Green Leadership in the Healthcare Sector

The health sector is one of the keys to sustainable development. Although it is directly related to only one Sustainable Development Goal (Goal 3, "Ensuring a healthy life and promoting well-being at all ages"), the sector itself, which aims to protect health, is paradoxically at the same time the main emitter of environmental pollutants that have a negative impact on health itself. Therefore, sustainability has become a key priority for health sector organizations, and leadership in this area is essential at all levels. Scientific research plays a particular role here, helping to more clearly define the links between environmental sustainability and the health effects of a polluted environment and climate change as well as indicating the direction of actions needed and disseminating good practices that can help accelerate the adoption of efforts towards climate neutrality and sustainable development of health sector organizations. The aim of this article is to present the current state of the art and future research scenarios in the field of green and sustainable healthcare through a literature review by using the Preferred Reporting Items for Systematic Reviews Meta-Analyses (PRISMA) method to perform a bibliometric analysis of papers published in 2012-2022. The Web of Science Core Collection (WoSCC) database is used for this purpose. A total of 144 papers are included for analysis, categorized based on eight fields: author(s), title, year of publication, country, journal, scientific category, and number of citations. Based on the results, themes for future research on green leadership in the healthcare sector are identified and recommended.

The impact of climate change on paediatric dentistry

The effects of global warming and climate change are happening at a faster rate than expected, and they are going to get worse. Global climate change has already started to show the effects on environment-fast melting glaciers, accelerated sea level rise and base shifting of native flora and fauna. There has been an increase in temperature globally with a few countries already showing intense heat waves and extreme cold temperatures. The interrelation between dentistry, environmental impact and human health is still in its nascent stage, but studies in medicine show that the healthcare industry contributes to greenhouse gas emissions and climate change, poor air quality, food and water insecurity, extreme weather events and vector-borne illnesses. The concept of eco-friendly dentistry has evolved in this context for providing environmentally feasible dental solutions. Paediatric dentistry is no exception. The concept of prevention has to be promoted more in paediatric dentistry to provide a positive impact on environment. The prevention of oral diseases will lead to less travel to paediatric dental clinics, less use of dental materials, lesser energy usage, minimal use of single-use plastics and less use of nitrous oxide/general anaesthesia for behaviour management. The greenhouse gases have an effect on teeth of children in relation to early childhood caries (ECC). Here, we discuss the impact of climate change on paediatric dentistry and what changes can be made to provide environment-friendly solutions.

The Multifaceted Function of Water Hyacinth in Maintaining Environmental Sustainability and the Underlying Mechanisms: A Mini Review

Water hyacinth (Eichhornia crassipes) (WH) is a widespread aquatic plant. As a top invasive macrophyte, WH causes enormous economic and ecological losses. To control it, various physical, chemical and biological methods have been developed. However, multiple drawbacks of these methods limited their application. While being a noxious macrophyte, WH has great potential in many areas, such as phytoremediation, manufacture of value-added products, and so on. Resource utilization of WH has enormous benefits and therefore, is a sustainable strategy for its control. In accordance with the increasing urgency of maintaining environmental sustainability, this review concisely introduced up to date WH utilization specifically in pollution remediation and curbing the global warming crisis and discussed the underlying mechanisms.

Triboelectric and Piezoelectric Nanogenerators for Self-Powered Healthcare Monitoring Devices: Operating Principles, Challenges, and Perspectives

The internet of medical things (IoMT) is used for the acquisition, processing, transmission, and storage of medical data of patients. The medical information of each patient can be monitored by hospitals, family members, or medical centers, providing real-time data on the health condition of patients. However, the IoMT requires monitoring healthcare devices with features such as being lightweight, having a long lifetime, wearability, flexibility, safe behavior, and a stable electrical performance. For the continuous monitoring of the medical signals of patients, these devices need energy sources with a long lifetime and stable response. For this challenge, conventional batteries have disadvantages due to their limited-service time, considerable weight, and toxic materials. A replacement alternative to conventional batteries can be achieved for piezoelectric and triboelectric nanogenerators. These nanogenerators can convert green energy from various environmental sources (e.g., biomechanical energy, wind, and mechanical vibrations) into electrical energy. Generally, these nanogenerators have simple transduction mechanisms, uncomplicated manufacturing processes, are lightweight, have a long lifetime, and provide high output electrical performance. Thus, the piezoelectric and triboelectric nanogenerators could power future medical devices that monitor and process vital signs of patients. Herein, we review the working principle, materials, fabrication processes, and signal processing components of piezoelectric and triboelectric nanogenerators with potential medical applications. In addition, we discuss the main components and output electrical performance of various nanogenerators applied to the medical sector. Finally, the challenges and perspectives of the design, materials and fabrication process, signal processing, and reliability of nanogenerators are included.

Recent Advances in Micro-/Nanoplastic (MNPs) Removal by Microalgae and Possible Integrated Routes of Energy Recovery

Reliance on plastic has resulted in the widespread occurrence of micro-/nanoplastics (MNPs) in aquatic ecosystems, threatening the food web and whole ecosystem functions. There is a tight interaction between MNPs and microalgae, as dominant living organisms and fundamental constituents at the base of the aquatic food web. Therefore, it is crucial to better understand the mechanisms underlying the interactions between plastic particles and microalgae, as well as the role of microalgae in removing MNPs from aquatic ecosystems. In addition, finding a suitable route for further utilization of MNP-contaminated algal biomass is of great importance. The present review article provides an interdisciplinary approach to elucidate microalgae-MNP interactions and subsequent impacts on microalgal physiology. The degradation of plastic in the environment and differences between micro- and nanoplastics are discussed. The possible toxic effects of MNPs on microalgal growth, photosynthetic activity, and morphology, due to physical or chemical interactions, are evaluated. In addition, the potential role of MNPs in microalgae cultivation and/or harvesting, together with further safe routes for biomass utilization in biofuel production, are suggested. Overall, the current article represents a state-of-the-art overview of MNP generation and the consequences of their accumulation in the environment, providing new insights into microalgae integrated routes of plastic removal and bioenergy production.

Improving the Performance of Polymer Solar Cells with Benzo[ghi]perylenetriimide-Based Small-Molecules as Interfacial Layers

In this study, we prepared three benzo[ghi]perylenetriimide (BPTI) conjugated molecules as electron-transporting surface-modifying layers for polymer solar cells (PSCs). These three BPTI derivatives differed in the nature of their terminal functionalities, featuring butylamine (C₃NH₂), propylammonium iodide (C₃NH₃I), and butyldimethylamine (C₃DMA) units, respectively. We evaluated the optoelectronic properties of PTB7-Th: PC₇₁BM blends modified with these interfacial layers, as well as the performance of resulting PSCs. We used UV-Vis spectroscopy, atomic force microscopy, surface energy analysis, ultraviolet photoelectron spectroscopy, and photoelectric flow measurements to examine the phenomena behind the changes in the optoelectronic behavior of these blend films. The presence of a BPTI derivative changed the energy band alignment at the ZnO-active layer interface, leading to the ZnO film behaving more efficiently as an electron-extraction electrode. Modifying the ZnO surface with the BPTI-C₃NH₃I derivative resulted in a best power conversion efficiency (PCE) of 10.2 ± 0.53% for the PTB7-Th:PC₇₁BM PSC (cf. PCE of the control device of 9.1 ± 0.13%). In addition, modification of a PM6:Y6:PCBM PSC with the BPTI-C₃NH₃I derivative increased its PCE from 15.6 ± 0.25% to 16.5 ± 0.18%. Thus, BPTI derivatives appear to have potential as IFLs when developing high-performance PSCs, and might also be applicable in other optoelectronic devices.

Traffic-Aware Secured Cooperative Framework for IoT-Based Smart Monitoring in Precision Agriculture

In recent decades, networked smart devices and cutting-edge technology have been exploited in many applications for the improvement of agriculture. The deployment of smart sensors and intelligent farming techniques supports real-time information gathering for the agriculture sector and decreases the burden on farmers. Many solutions have been presented to automate the agriculture system using IoT networks; however, the identification of redundant data traffic is one of the most significant research problems. Additionally, farmers do not obtain the information they need in time, such as data on water pressure and soil conditions. Thus, these solutions consequently reduce the production rates and increase costs for farmers. Moreover, controlling all agricultural operations in a controlled manner should also be considered in developing intelligent solutions. Therefore, this study proposes a framework for a system that combines fog computing with smart farming and effectively controls network traffic. Firstly, the proposed framework efficiently monitors redundant information and avoids the inefficient use of communication bandwidth. It also controls the number of re-transmissions in the case of malicious actions and efficiently utilizes the network's resources. Second, a trustworthy chain is built between agricultural sensors by utilizing the fog nodes to address security issues and increase reliability by preventing malicious communication. Through extensive simulation-based experiments, the proposed framework revealed an improved performance for energy efficiency, security, and network connectivity in comparison to other related works.

Multifunction Web-like Polymeric Network Bacterial Cellulose Derived from SCOBY as Both Electrodes and Electrolytes for Pliable and Low-Cost Supercapacitor

In this work, bacterial cellulose (BC)-based polymer derived from a symbiotic culture of bacteria and yeast (SCOBY) are optimized as both electrodes and electrolytes to fabricate a flexible and free-standing supercapacitor. BC is a multifunction and versatile polymer. Montmorillonite (MMT) and sodium bromide (NaBr) are used to improve mechanical strength and as the ionic source, respectively. From XRD analysis, it is found that the addition of MMT and NaBr has reduced the crystallinity of the electrolyte. Most interaction within the electrolyte happens in the region of the OH band, as verified using FTIR analysis. A maximum room temperature conductivity of (1.09 ± 0.02) × 10⁻³ S/cm is achieved with 30 wt.% NaBr. The highest conducting SCOBY-based electrolytes have a decompose voltage and ionic transference number of 1.48 V and 0.97, respectively. The multiwalled carbon nanotube is employed as the active material held by the fibrous network of BC. Cyclic voltammetry shows a rectangular shape CV plot with the absence of a redox peak. The supercapacitor is charged and discharged in a zig-zag-shaped Perspex plate for 1000 cycles with a decent performance.

Recent Progress of Nanogenerators for Green Energy Harvesting: Performance, Applications, and Challenges

Natural sources of green energy include sunshine, water, biomass, geothermal heat, and wind. These energies are alternate forms of electrical energy that do not rely on fossil fuels. Green energy is environmentally benign, as it avoids the generation of greenhouse gases and pollutants. Various systems and equipment have been utilized to gather natural energy. However, most technologies need a huge amount of infrastructure and expensive equipment in order to power electronic gadgets, smart sensors, and wearable devices. Nanogenerators have recently emerged as an alternative technique for collecting energy from both natural and artificial sources, with significant benefits such as light weight, low-cost production, simple operation, easy signal processing, and low-cost materials. These nanogenerators might power electronic components and wearable devices used in a variety of applications such as telecommunications, the medical sector, the military and automotive industries, and internet of things (IoT) devices. We describe new research on the performance of nanogenerators employing several green energy acquisition processes such as piezoelectric, electromagnetic, thermoelectric, and triboelectric. Furthermore, the materials, applications, challenges, and future prospects of several nanogenerators are discussed.

Climate Change Impact of the Development in Household Waste Management in China

The potential climate change impacts of the development in Chinese household waste management, with less landfilling, more incineration with energy recovery, and source-separated food waste treated in biorefineries, were assessed through a life cycle assessment. When the waste management system interacts with a fossil-based energy system, landfilling produces a load of 144 kg CO₂-eq/ton wet waste, while incineration shows a saving of 36 kg CO₂-eq/ton wet waste. The introduction of food waste source separation lowers climate change impacts by an additional 33 kg CO₂-eq/ton at a 60% sorting efficiency. As the Chinese energy system lowers its climate change impact over the next 30 years, energy recovery from waste treatment will change its relative contribution to climate change. In nonfossil energy systems, landfilling is estimated to have a climate change load of 180-240 kg CO₂-eq/ton wet waste, while incineration, including combinations with the source-separation of food waste, will have a load of 310-540 kg CO₂-eq/ton wet waste. These large intervals are due to waste composition uncertainty. However, considering a 20 year CH₄ characterization factor representing a shorter time perspective, the impacts from landfilling are more dramatic due to the large methane release. This significant climate change impact calls for an increased focus on the developments in Chinese household waste management. The key issues identified may also apply to other countries.

The effect of metal surface nanomorphology on the output performance of a TENG

In this work, the effect of charge density and nanomorphology of a metal tip on the output performance of a triboelectric nanogenerator (TENG) is studied. The basic working principle of the TENG is charge transfer after separation of a metal and a polymer. There are different charge densities on different kinds of metal surface nanomorphology, which significantly influences the output performance of the TENG. Copper samples with different nanomorphology were obtained by controlling pH value, current density, electrolyte concentration, and temperature during the electrodeposition of copper. The samples were characterized using XRD and SEM. The output performance of the TENG is closely related to the size, charge density distribution, and shape of the metal nanoparticles.

p-n Junction Based Direct-Current Triboelectric Nanogenerator by Conjunction of Tribovoltaic Effect and Photovoltaic Effect

Triboelectric nanogenerators (TENGs) have attracted much interest in recent years, due to its effectiveness and low cost for converting high-entropy mechanical energy into electric power. The traditional TENGs generate an alternating current, which requires a rectifier to provide a direct-current (DC) power supply. Herein, a dynamic p-n junction based direct-current triboelectric nanogenerator (DTENG) is demonstrated. When a p-Si wafer is sliding on a n-GaN wafer, carriers are generated at the interface and a DC current is produced along the direction of the built-in electric field, which is called the tribovoltatic effect. Simultaneously, an UV light is illuminated on the p-n junction to enhance the output. The results indicate that the current increases 13 times and the voltage increases 4 times under UV light (365 nm, 28 mW/cm²) irradiation. This work demonstrates the coupling between the tribovoltaic effect and the photovoltaic effect in DTENG semiconductors, promoting further development for energy harvesting in mechanical energy and photon energy.

Triboelectric Nanogenerator from Used Surgical Face Mask and Waste Mylar Materials Aiding the Circular Economy

Apart from claiming the lives of more than 3.2 million people, the COVID-19 pandemic is worsening the global plastic pollution every day, mainly with the overflux of single-use polypropylene (PP) face masks. In this scenario, as an innovative solution to mitigate plastic pollution as well as to meet the rising electrical energy demand, we are introducing an all-flexible and facile waste material-based triboelectric nanogenerator (WM-TENG), aiding toward the circular economy. The WM-TENG operating in contact separation mode is fabricated using the PP from a used face mask in combination with recovered Mylar sheets from solid wastes as triboelectric contact layers and a flexible supporting structure. After detailed investigation and trials to study the effect of various disinfection mechanisms of PP materials on the energy output of WM-TENG, UV-C radiation is selected for disinfecting the used masks owing to the retention of electrical energy output. Under a tapping force of 3 N, the WM-TENG having an active area of 6 cm² delivers an open-circuit voltage of 200 V and a short-circuit current density of 0.29 mA/m², respectively. The WM-TENG also delivered a maximum power density of 71.16 mW/m² under 10⁸ Ω load. Additionally, the WM-TENG is demonstrated for powering electronic gadgets such as a calculator, digital thermometer, and LCD clock. This flexible and low-cost nanogenerator without any complex fabrication steps is a sustainable solution for the alarming plastic pollution as well as the rising energy demands.

Biohybrid generators based on living plants and artificial leaves: influence of leaf motion and real wind outdoor energy harvesting

Plants translate wind energy into leaf fluttering and branch motion by reversible tissue deformation. Simultaneously, the outermost structure of the plant, i.e. the dielectric cuticula, and the inner ion-conductive tissue can be used to convert mechanical vibration energy, such as that produced during fluttering in the wind, into electricity by surface contact electrification and electrostatic induction. Constraining a tailored artificial leaf to a plant leaf can enhance oscillations and transient mechanical contacts and thereby increase the electricity outcome. We have studied the effects of wind-induced mechanical interactions between the leaf of a plant (Rhododendron) and a flexible silicone elastomer-based artificial leaf fixed at the petiole on power output and whether performance can be further tuned by altering the vibrational behavior of the artificial leaf. The latter is achieved by modifying a concentrated mass at the tip of the artificial leaf and observing plant-generated current and voltage signals under air flow. In this configuration, the plant-hybrid wind-energy converters can directly power light-emitting diodes and a temperature sensor. Detailed output analysis has revealed that, under all conditions, an increase in wind speed leads to nearly linearly increased voltages and currents. Accordingly, the cumulative sum energy reaches its highest values at the highest wind speed and resulting oscillations of the plant-artificial leaf system. The mass at the tip can, in most cases, be used to increase the voltage amplitude and frequency. Nevertheless, this behavior was found to depend on the individual configuration of the system, such as the leaf morphology. Analysis of these factors under controlled conditions is crucial for optimizing systems meant to operate in unstructured outdoor scenarios. We have established, in a first approach, that the artificial leaf-plant hybrid generator is capable of autonomously generating electricity outdoors under real outdoor wind conditions, even at a low average wind speed of only 1.9 m s^-1.

Wind Booster Optimization for On-Site Energy Generation Using Vertical-Axis Wind Turbines

Large cities have a significant area of buildings with roofs that are not used most of the time. Vertical-axis wind turbines are suitable for this kind of on-site renewable energy generation. Since wind speeds are not high in these cities, a suitable solution to improve energy generation is to add a Wind Booster. This paper presents a methodology useful for selecting and optimizing the main components of a Wind Booster. As a case of study, we present this methodology in a Wind Booster for a Vertical Axis Wind Turbine (VAWT) that considers the wind flow’s specific behavior in a particular city. The final Wind Booster design is state of the art and makes use of Computational Fluid Dynamics (CFD) and Design of Experiments (DOE) techniques. We experimented with the conditions of Mexico City, obtaining a 35.23% increase in torque with the optimized Wind Booster configuration. The results obtained show the potential of this methodology to improve the performance of this kind of system. Moreover, since wind behavior is very different in each city, our proposal could be beneficial for researchers looking to implement the best possible wind turbine in their locality.

Emerging Technology for a Green, Sustainable Energy-Promising Materials for Hydrogen Storage, from Nanotubes to Graphene-A Review

The energetic and climate crises should pose a challenge for scientists in finding solutions in the field of renewable, green energy sources. Throughout more than two decades, the search for new opportunities in the energy industry made it possible to observe the potential use of hydrogen as an energy source. One of the greatest challenges faced by scientists for the sake of its use as an energy source is designing safe, usable, reliable, and effective forms of hydrogen storage. Moreover, the manner in which hydrogen is to be stored is closely dependent on the potential use of this source of green energy. In stationary use, the aim is to achieve high volumetric density of the container. However, from the point of view of mobile applications, an extremely important aspect is the storage of hydrogen, using lightweight tanks of relatively high density. That is why, a focus of scientists has been put on the use of carbon-based materials and graphene as a perspective solution in the field of H₂ storage. This review focuses on the comparison of different methods for hydrogen storage, mainly based on the carbon-based materials and focuses on efficiently using graphene and its different forms to serve a purpose in the future H₂-based economy.

Pilot Scale Elimination of Phenolic Cellulase Inhibitors From Alkali Pretreated Wheat Straw for Improved Cellulolytic Digestibility to Fermentable Saccharides

Depleting supplies of fossil fuel, regular price hikes of gasoline and environmental deterioration have necessitated the search for economic and eco-benign alternatives of gasoline like lignocellulosic biomass. However, pre-treatment of such biomass results in development of some phenolic compounds which later hinder the depolymerisation of biomass by cellulases and seriously affect the cost effectiveness of the process. Dephenolification of biomass hydrolysate is well cited in literature. However, elimination of phenolic compounds from pretreated solid biomass is not well studied. The present study was aimed to optimize dephenoliphication of wheat straw using various alkalis i.e., Ca(OH)₂ and NH₃; acids i.e., H₂O₂, H₂SO₄, and H₃PO₄; combinations of NH₃+ H₃PO₄ and H₃PO₄+ H₂O₂ at pilot scale to increase enzymatic saccharification yield. Among all the pretreatment strategies used, maximum reduction in phenolic content was observed as 66 mg Gallic Acid Equivalent/gram Dry Weight (GAE/g DW), compared to control having 210 mg GAE/g DW using 5% (v/v) combination of NH₃+H₃PO₄. Upon subsequent saccharification of dephenoliphied substrate, the hydrolysis yield was recorded as 46.88%. Optimized conditions such as using 1%+5% concentration of NH₃+ H₃PO₄, for 30 min at 110°C temperature reduced total phenolic content (TPC) to 48 mg GAE/g DW. This reduction in phenolic content helped cellulases to act more proficiently on the substrate and saccharification yield of 55.06% was obtained. The findings will result in less utilization of cellulases to get increased yield of saccharides by hydrolyzing wheat straw, thus, making the process economical. Furthermore, pilot scale investigations of current study will help in upgrading the novel process to industrial scale.

Fiduciary Responsibility and the Green Energy Act, 2009 (Ontario, Canada)

Analyses of the Green Energy Act (2009) have stated that the act had numerous shortcomings concerning the environmental impacts of the energy projects initiated within its purview. This account addresses the core points of divergence in the policy's creation that are responsible for the problematic effects. The crux of these problems comes from the ambiguity of the concept of green energy within the act due to its lack of a formal definition. The reasons for this anomaly originate from the Legislative Assembly of Ontario's address on the topic and their decision to let it remain ambiguous. This stance raises questions of whether they are fulfilling their fiduciary duties to an acceptable level. Although these questions of duty and obligation are both delicate and necessary when talking about projects that involve Canada's indigenous peoples, it is not limited to them due to the scope of the effects. Ultimately, although the policy was repealed in January 2019, there are many lessons that can be learned from the missteps of the Act.

Effects of Fabrication Methods on the Performance of Luminescent Solar Concentrators Based on Doped Polymer Optical Fibers

In this work, we detail two types of fabrication processes of four polymer optical fibers doped with lumogen dyes. The fiber preforms have been manufactured with two different methods: extrusion and casting. We have compared the performance of the two types of fibers as luminescent solar concentrators by calculating their optical efficiencies and concentration factors. The obtained results show better performance for those fibers manufactured by the casting process. We have also studied the photostability of the two types of fibers doped with the dye lumogen red under solar light radiation. A high thermal stability of the doped fibers has been observed.

A New Methodology to Design Sustainable Archimedean Screw Turbines as Green Energy Generators

Current energy demand and climate target plans are leading to green energy facilities which are efficient and sustainable. Archimedean screw turbines (ASTs) are used to generate hydroelectricity in low heads. They have been manufactured and installed worldwide. However, there is a lack of knowledge about how to design them efficiently. In this study, the performance of ASTs is analyzed using an analogy between ASTs and bucket elevators. Based on this analogy, a theoretical hypothesis on how to produce efficient ASTs is proposed. The new methodology for the design of ASTs is based on two considerations: the filling level of the AST buckets must be 85% and the increase of leakage losses must be minimized. This hypothesis is numerically and experimentally studied. Two experimental prototypes were developed and installed in the north of Spain. The numerical and experimental results are provided. A discussion comparing the results of this work and other results from the literature is presented. Finally, conclusions are drawn from this work that contribute to the improvement of AST technology as a sustainable facility to generate green energy.

Characterization of Double-Doped Polymer Optical Fibers as Luminescent Solar Concentrators

This work reports on a diameter dependence analysis of the performance as luminescent solar concentrators of three self-fabricated polymer optical fibers (POFs) doped with a hybrid combination of dopants. The works carried out include the design and self-fabrication of the different diameter fibers; an experimental analysis of the output power, of the output irradiance and of the fluorescent fiber solar concentrator efficiency; a comparison of the experimental results with a theoretical model; a study of the performance of all the fibers under different simulated lighting conditions; and a calculation of the active fiber length of each of the samples, all of them as a function of the fiber core diameter. To the best of our knowledge, this paper reports the first analysis of the influence of the POF diameter for luminescent solar concentration applications. The results obtained offer a general perspective on the optimal design of solar energy concentrating systems based on doped POFs and pave the way for the implementation of cost-effective solar energy concentrating devices.

A Secure, Energy- and SLA-Efficient (SESE) E-Healthcare Framework for Quickest Data Transmission Using Cyber-Physical System

: Due to advances in technology, research in healthcare using a cyber-physical system (CPS) opens innovative dimensions of services. In this paper, the authors propose an energy- and service-level agreement (SLA)-efficient cyber physical system for E-healthcare during data transmission services. Furthermore, the proposed phenomenon will be enhanced to ensure the security by detecting and eliminating the malicious devices/nodes involved during the communication process through advances in the ad hoc on-demand distance vector (AODV) protocol. The proposed framework addresses the two security threats, such as grey and black holes, that severely affect network services. Furthermore, the proposed framework used to find the different network metrics such as average qualifying service set (QSS) paths, mean hop and energy efficiency of the quickest path. The framework is simulated by calculating the above metrics in mutual cases i.e. without the contribution of malevolent nodes and with the contribution of malevolent nodes over service time, hop count and energy constraints. Further, variation of SLA and energy shows their expediency in the selection of efficient network metrics.

Integration of Green Energy and Advanced Energy-Efficient Technologies for Municipal Wastewater Treatment Plants

Wastewater treatment can consume a large amount of energy to meet discharge standards. However, wastewater also contains resources which could be recovered for secondary uses under proper treatment. Hence, the goal of this paper is to review the available green energy and biomass energy that can be utilized in wastewater treatment plants. Comprehensive elucidation of energy-efficient technologies for wastewater treatment plants are revealed. For these energy-efficient technologies, this review provides an introduction and current application status of these technologies as well as key performance indicators for the integration of green energy and energy-efficient technologies. There are several assessment perspectives summarized in the evaluation of the integration of green energy and energy-efficient technologies in wastewater treatment plants. To overcome the challenges in wastewater treatment plants, the Internet of Things (IoT) and green chemistry technologies for the water and energy nexus are proposed. The findings of this review are highly beneficial for the development of green energy and energy-efficient wastewater treatment plants. Future research should investigate the integration of green infrastructure and ecologically advanced treatment technologies to explore the potential benefits and advantages.

Freshwater ecosystems could become the biggest losers of the Paris Agreement

Securing access to energy for a growing population under the international commitment of reduction of greenhouse emissions requires increasing the contribution of renewable sources to the global share. Hydropower energy, which accounts for >80% of green energy, is experiencing a boom fostered by international investment mainly in developing countries. This boom could be further accelerated by the recent climate agreement reached in Paris. Despite its flexibility, hydropower production entails social, economic and ecological risks that need to be carefully considered before investing in the development of potentially thousands of planned hydropower projects worldwide. This is especially relevant given the weak or nonexistent legislation that regulates hydropower project approval and construction in many countries. I highlight the need for adequate policy to provide the Paris Agreement with new financial and planning mechanisms to avoid further and irreversible damage to freshwater ecosystem services and biodiversity.

Bifunctional Manganese Ferrite/Polyaniline Hybrid as Electrode Material for Enhanced Energy Recovery in Microbial Fuel Cell

Microbial fuel cells (MFCs) are emerging as a sustainable technology for waste to energy conversion where electrode materials play a vital role on its performance. Platinum (Pt) is the most common material used as cathode catalyst in the MFCs. However, the high cost and low earth abundance associated with Pt prompt the researcher to explore inexpensive catalysts. The present study demonstrates a noble metal-free MFC using a manganese ferrite (MnFe2O4)/polyaniline (PANI)-based electrode material. The MnFe2O4 nanoparticles (NPs) and MnFe2O4 NPs/PANI hybrid composite not only exhibited superior oxygen reduction reaction (ORR) activity for the air cathode but also enhanced anode half-cell potential upon modifying carbon cloth anode in the single-chambered MFC. This is attributed to the improved extracellular electron transfer of exoelectrogens due to Fe(3+) in MnFe2O4 and its capacitive nature. The present work demonstrates for the first time the dual property of MnFe2O4 NPs/PANI, i.e., as cathode catalyst and an anode modifier, thereby promising cost-effective MFCs for practical applications.

Cobinamide production of hydrogen in a homogeneous aqueous photochemical system, and assembly and photoreduction in a (βα)8 protein

Components of a protein-integrated, earth-abundant metal macrocycle catalyst, with the purpose of H2 production from aqueous protons under green conditions, are characterized. The cobalt-corrin complex, cobinamide, is demonstrated to produce H2 (4.4 ± 1.8 × 10(-3) turnover number per hour) in a homogeneous, photosensitizer/sacrificial electron donor system in pure water at neutral pH. Turnover is proposed to be limited by the relatively low population of the gateway cobalt(III) hydride species. A heterolytic mechanism for H2 production from the cobalt(II) hydride is proposed. Two essential requirements for assembly of a functional protein-catalyst complex are demonstrated for interaction of cobinamide with the (βα)8 TIM barrel protein, EutB, from the adenosylcobalamin-dependent ethanolamine ammonia lyase from Salmonella typhimurium: (1) high-affinity equilibrium binding of the cobinamide (dissociation constant 2.1 × 10(-7) M) and (2) in situ photoreduction of the cobinamide-protein complex to the Co(I) state. Molecular modeling of the cobinamide-EutB interaction shows that these features arise from specific hydrogen-bond and apolar interactions of the protein with the alkylamide substituents and the ring of the corrin, and accessibility of the binding site to the solution. The results establish cobinamide-EutB as a platform for design and engineering of a robust H2 production metallocatalyst that operates under green conditions and uses the advantages of the protein as a tunable medium and material support.