Sustainable Energy Applications Research Articles

Exploring Acetogenesis in Firmicutes: From Phylogenetic Analysis to Solid Medium Cultivation with Solid-Phase Electrochemical Isolation Equipments.

This study introduces a groundbreaking approach for the exploration and utilization of electrotrophic acetogens, essential for advancing microbial electrosynthesis systems (MES). Our initial focus was the development of Solid-Phase Electrochemical Isolation Equipment (SPECIEs), a novel cultivation method for isolating electrotrophic acetogens directly from environmental samples on a solid medium. SPECIEs uses electrotrophy as a selection pressure, successfully overcoming the traditional cultivation method limitations and enabling the cultivation of diverse microbial communities with enhanced specificity towards acetogens. Following the establishment of SPECIEs, we conducted a genome-based phylogenetic analysis using the Genome Taxonomy Database (GTDB) to identify potential electrotrophic acetogens within the Firmicutes phylum and its related lineages. Subsequently, we validated the electrotrophic capabilities of selected strains under electrode-oxidizing conditions in a liquid medium. This sequential approach, integrating innovative cultivation techniques with detailed phylogenetic analysis, paves the way for further advances in microbial cultivation and the identification of new biocatalysts for sustainable energy applications.

An experimental analysis of a hybrid photovoltaic thermal system through parallel water pipe integration

The global research community has increasingly focused on sustainable energy solutions to combat the environmental challenges posed by extensive fossil fuel consumption. This paper presents a new simple approach to enhance the electric efficiency of photovoltaic (PV) panels through efficient cooling techniques using simple parallel water pipes on the back of the PV panel. Additionally, the waste heat generated during this process is harnessed as a valuable heat source for residential hot water systems. Experimental measurements were conducted on both the reference PV panels without cooling and the PV/T system equipped with cooling pipes. A comprehensive energy analysis was performed to compare their performance. The results demonstrate that the cooled PV/T system exhibits consistently higher electric efficiency due to effective cooling by about 10%, resulting in surface temperature reduction and enhanced performance. The system also demonstrates a significant improvement in waste heat recovery, making it a practical and promising choice for sustainable energy applications.

Constructing In2S3/CdS/N-rGO Hybrid Nanosheets via One-Pot Pyrolysis for Boosting and Stabilizing Visible Light-Driven Hydrogen Evolution

The construction of hybrid junctions remains challenging for the rational design of visible light-driven photocatalysts. Herein, In2S3/CdS/N-rGO hybrid nanosheets were successfully prepared via a one-step pyrolysis method using deep eutectic solvents as precursors. Benefiting from the surfactant-free pyrolysis method, the obtained ultrathin hybrid nanosheets assemble into stable three-dimensional self-standing superstructures. The tremella-like structure of hybrid In2S3/N-rGO exhibits excellent photocatalytic hydrogen production performance. The hydrogen evolution rate is 10.9 mmol·g−1·h−1, which is greatly superior to CdS/N-rGO (3.7 mmol·g−1·h−1) and In2S3/N-rGO (2.6 mmol·g−1·h−1). This work provides more opportunities for the rational design and fabrication of hybrid ultrathin nanosheets for broad catalytic applications in sustainable energy and the environment.

Core‐Shell Micro‐ and Nano‐Structures for The Modification of Light‐Surface Interactions

AbstractControlling how a material interacts with light is key to optimizing its optical properties to fit a desired function or application. The most straightforward approach is to chemically or physically modify the surface exposed to incident light. An effective method of surface modification is based on the addition of core‐shell structures at the surface. Of particular importance to many technological applications are core‐shell structures with dimensions comparable to the wavelengths of light extending from the UV up to the near‐IR region of the electromagnetic spectrum, which coincides with the major part of the solar spectrum. Surface modification approaches to tailor the optical properties of materials in this range of wavelengths are increasingly relevant in the context of materials and devices used in sustainable energy applications, such as solar cells and heat‐reflective paints. These materials are useful to mitigate the current energy and climate crises by allowing for enhanced energy harvesting and improved thermal management, respectively. Here, recent progress in the fabrication and application of core‐shell micro‐/nano‐structures for the modification of light interaction with surfaces is highlighted. Some limitations and future directions for the design of core‐shell materials are also discussed.

Application of Underwater Constant Pressure Compressed Air Energy Storage Technology in The Direction of Hydrogen Production

With the growing global demand for renewable energy to cope with climate change and energy security issues, underwater compressed air energy storage technology has gradually attracted attention. At the same time, hydrogen production process, as an important support for green energy transition, is becoming one of the key links to achieve clean energy generation and storage. This paper aims to explore the connection between underwater compressed air energy storage technology and hydrogen production process, and put forward a device combining underwater compressed air energy storage and hydrogen production, so as to solve the problems of low efficiency and serious pollution in the traditional hydrogen production industry. In the past, scholars focused on microcosmic research in the direction of hydrogen production, and tended to the direction of catalyst. Based on this, this paper will study the case of underwater compressed air energy storage device, and conceive a new hydrogen production device to promote the collaborative application of sustainable energy and improve the integration efficiency and reliability of energy system.

Synergistic doping with Ag, CdO, and ZnO to overcome electron-hole recombination in TiO2 photocatalysis for effective water photo splitting reaction.

This manuscript is dedicated to a comprehensive exploration of the multifaceted challenge of fast electron-hole recombination in titanium dioxide photocatalysis, with a primary focus on its critical role in advancing the field of water photo splitting. To address this challenge, three prominent approaches-Schottky barriers, Z-scheme systems, and type II heterojunctions-were rigorously investigated for their potential to ameliorate TiO2's photocatalytic performance toward water photo splitting. Three distinct dopants-silver, cadmium oxide, and zinc oxide-were strategically employed. This research also delved into the dynamic interplay between these dopants, analyzing the synergetic effects that arise from binary and tertiary doping configurations. The results concluded that incorporation of Ag, CdO, and ZnO dopants effectively countered the fast electron-hole recombination problem in TiO2 NPs. Ag emerged as a critical contributor at higher temperatures, significantly enhancing photocatalytic performance. The photocatalytic system exhibited a departure from Arrhenius behavior, with an optimal temperature of 40°C. Binary doping systems, particularly those combining CdO and ZnO, demonstrated exceptional photocatalytic activity at lower temperatures. However, the ternary doping configuration involving Ag, CdO, and ZnO proved to be the most promising, surpassing many functional materials. In sum, this study offers valuable insights into how Schottky barriers, Z-scheme systems, and type II heterojunctions, in conjunction with specific dopants, can overcome the electron-hole recombination challenge in TiO2-based photocatalysis. The results underscore the potential of the proposed ternary doping system to revolutionize photocatalytic water splitting for efficient green hydrogen production, significantly advancing the field's understanding and potential for sustainable energy applications.

Effect of precursor concentration on the electrochemical properties of nickel cobalt phosphate for high-performance electrochromic supercapacitors

This research focuses on developing a high-performance electrode material for sustainable energy applications. The study explores the electrochemical deposition of a nickel-cobalt phosphate composite (NCPC) on a conductive glass substrate. A systematic investigation is conducted to analyze the influence of precursor concentrations, including nickel chloride hexahydrate (NiCl2·6H2O), cobalt chloride hexahydrate (CoCl2·6H2O), and disodium hydrogen phosphate (Na2HPO4), on the electrochromic and energy storage properties of NCPC. Utilizing Design Expert (DoE) software, the optimization process results in a predictive quadratic model with a residual standard error below 5 %, effectively capturing the relationship between independent variables and specific capacitance (Csp). Under optimized conditions (0.1 M NiCl2·6H2O, 0.3 M CoCl2·6H2O, and 0.4 M Na2HPO4), NCPC exhibits remarkable attributes, including a high Csp of 878 F/g (equivalent to 439 mAh/g) for energy storage and an impressive coloration efficiency of 62 cm2/C for electrochromic applications. These exceptional outcomes are attributed to the synergistic effects of NCPC, enhancing electrical conductivity, active site availability, and surface area, collectively contributing to superior electrochemical performance. An electrochromic energy storage device (NCPC//AC) is made, utilizing the optimized NCPC as the positive electrode and activated carbon (AC) as the negative electrode. The NCPC//AC device demonstrates notable performance features, including a high Csp of 135 F/g at a 5 mV/s scan rate, specific power of 750 W/kg, and specific energy of 11 Wh/kg, showcasing an exceptional power-to-weight ratio. Moreover, the NCPC//AC device exhibits excellent stability, retaining 78 % of its capacitance after 5000 charge-discharge cycles, highlighting its durability and long-term viability. In summary, this study emphasizes the exceptional electrochemical properties and performance of the NCPC//AC device, positioning it as a promising sustainable energy technology aligned with SDG 7 of ensuring access to affordable, reliable, sustainable and modern energy for all.

Ru Cluster Incorporated NiMoO(P)4 Nanosheet Arrays as High-Efficient Bifunctional Catalyst for Wind/Solar-To-Hydrogen Generation Systems.

Developing cost-efficient bifunctional water splitting catalysts is crucial for sustainable hydrogen energy applications. Herein, ruthenium (Ru)-incorporated and phosphorus (P)-doped nickel molybdate (Ru-NiMoO(P)4 ) nanosheet array catalysts are synthesized. Due to the synergy of Ru clusters and NiMoO(P)4 by the modulated electronic structure and the rich active sites, impressively, Ru-NiMoO(P)4 exhibits superior OER (194mV @ 50mA cm-2 ) and HER (24mV @ 10mA cm-2 ) activity in alkaline media, far exceeding that of commercial Pt/C and RuO2 catalysts. Meanwhile, as bifunctional catalyst, to drive the overall water splitting at the current density of 10mA cm-2 , Ru-NiMoO(P)4 requires only 1.45V and maintaining stable output for 100h. Furthermore, Ru-NiMoO(P)4 also possesses excellent capability for seawater electrolysis hydrogen production. Moreover, the successful demonstration of wind and solar hydrogen production systems provide the feasibility of the ultra-low Ru loading catalyst for large-scale hydrogen production in the future.

Effects of quenching on the microstructure and magnetic properties of MnBi nanopowders synthesized by low-oxygen induction thermal plasma

Fine and magnetically hard MnBi powders with limited surface oxidation were unprecedentedly synthesized with a high-throughput low-oxygen induction thermal plasma (LO-ITP) system for rare-earth-free permanent magnets (REF-PMs) application. Furthermore, by inducing quenching during the LO-ITP process, one can effectively reduce the as-processed Mn-Bi particle size from 63.9 to 49.8 nm and promote the formation of magnetic hard low-temperature phase of MnBi (LTP-MnBi, 72 to 84 wt%) with enhanced surface diffusion during post-annealing. The dominant LTP-MnB in the quenched and post-annealed MnBi powders was confirmed with detailed microstructure analysis. With higher weight fraction of LTP-MnBi, the quenched and post-annealed MnBi powders showed improved magnetic properties with a higher saturation magnetization (56.7 vs. 60.1 Am2/kg) and stronger coercivity (188.4 vs. 371.0 kA/m) than the powders without quenching. This work paved a new path for the mass production of high-purity and fine LTP-MnBi powders for synthesizing REF-PMs and/or related sustainable energy and automotive applications.

Understanding Photophysical Properties of Molecules Relevant in Organic Semiconductor Laser Diodes from Electron Localization Function-Tuned and Solvent-Tuned Range-Separated Functionals.

Organic semiconductor laser diodes (OSLDs) are prevalent in optoelectronics because of their sustainable energy applications. Organic molecules used in such diodes are usually large; hence, their studies are computationally challenging with high-end benchmark methods. Computational methods with reliable accuracy and efficiency are always indispensable. In the present work, we have applied our computationally inexpensive, nonempirically tuned [electron localization function (ELF*) and solvent (Sol*)] range-separated (RS) functionals to study five molecules used in OSLDs. The emission energies in three different environments [toluene, CBP (4,4'-bis(n-carbazolyl)-1,1'-biphenyl) film, and gas] have been computed with the tuned functionals and compared with the experimental emission energies. ELF* and Sol* functionals can accurately reproduce emission energies in toluene and CBP film environments. On the other hand, both ELF* and IP-tuned functionals with excited-state geometry (IP*) perform better in the gas phase. In addition, a comparative study is performed between time-dependent density functional theory and the Tamm-Dancoff approximation. Along with the emission energy, oscillator strength values have also been reported. Different IP-tuned RS parameters were obtained with the ground- and excited-state geometries. Interestingly, it has been observed that the optimally tuned RS parameter with excited-state geometry (IP*) performs better compared to that with ground-state geometries (IP). Fractional occupation calculations show that the tuned functionals exhibit less localization and delocalization error. The study envisages that ELF* and Sol* functionals can be used to design future candidates for OSLDs.

Self-supportive Pd0.2Ni58Fe30O11.8 nanowires for solar-driven self-powered water/seawater splitting with large current density

Solar-driven water/seawater splitting system is a significant renewable technology for obtaining hydrogen fuel, while the drawbacks of sunlight with intermittent and unstable limit their widespread practical applications. It is an efficient and renewable way to add an energy storage module between the photovoltaic system and electrolyzer to operate a self-powered and uninterrupted electrolyzer for improving the development of solar-driven water/seawater splitting. Herein, we develop an efficient and stable trifunctional electrocatalyst of self-supportive Pd0.2Ni58Fe30O11.8 nanowires for Zn-air batteries and overall seawater splitting, which connect with photovoltaic cells to assemble solar-driven self-powered electrocatalytic water splitting system. It is noticed that the obtained self-supportive Pd0.2Ni58Fe30O11.8 nanowires show a special 3D network structure connected by nanowires with a hierarchical structure, improving the charge and mass transfer on their surface. Furthermore, the self-supportive Pd0.2Ni58Fe30O11.8 nanowires displayed low overpotentials of 77 and 233 mV to deliver current densities of 100 mA cm−2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) processes, which is at the top level of great prospects for industrialization. A highly efficient and stable 24-hour integral water exchange system was successfully established with a circuit output voltage of 1.88 V and constant and stable current density throughout the system. The solar-powered uninterrupted overall water-splitting systems open up exciting opportunities for fully renewable and sustainable energy applications.

Membraneless Hydrogen Peroxide Fuel Cells as a Promising Clean Energy Source.

In an in-depth investigation of membraneless hydrogen peroxide-based fuel cells (H2O2 FCs), hydrogen peroxide (H2O2), a carbon-neutral compound, is demonstrated to undergo electrochemical decomposition to produce H2O, O2, and electrical energy. The unique redox properties of H2O2 position it as a viable candidate for sustainable energy applications. The proposed membraneless design addresses the limitations of conventional fuel cells, including fabrication complexities and design challenges. A novel three-dimensional electrode, synthesized via electroplating techniques, is introduced. Constructed from Au-electroplated carbon fiber cloth combined with Ni-foam, this electrode showcases enhanced electrochemical reaction kinetics, leading to an increased power density for H2O2 FCs. The performance of fuel cells is intricately linked to the pH levels of the electrolyte solution. Beyond FC applications, such electrodes hold potential in portable energy systems and as high surface area catalysts. This study emphasizes the significance of electrode engineering in optimizing the potential of H2O2 as an environmentally friendly energy source.

Defect Driven Opto-Critical Phases Tuned for All-Solar Utilization.

Materials imbued with uniformly dispersed, photo-responsive nanoparticles are instrumental in sustainable energy and photonic applications. Conventional methods, however, constrain their all-solar response. An innovative alternative is proposed: submerged photo-synthesis of crystallites (SPsC). It is shown that strategic doping with copper and oxygen vacancies can induce opto-critical phases from the non-stoichiometric tungstic acids (WO3 ·H2 O). These opto-critical phases enable a dynamic equilibrium shift in lattice defect stabilization, facilitating an unprecedented a whole solar wavelength response. This response manifests as photothermal, photo-assisted water evaporation, and photo-electrochemical characteristics. Harnessing all-solar energy, this one-pot SPsC strategy may steer the design and development of advanced oxide materials, enhancing functionality across diverse application domains. This article is protected by copyright. All rights reserved.

Silver Nanoparticle Decorated Perforated Graphene: An Efficient and Low-Cost Catalyst for Hydrogen Evolution Reaction

Recently, the fabrication of noble-metal-free, Earth-abundant, inexpensive, and efficient electrocatalysts for hydrogen evolution reaction (HER) has become a challenge for clean and sustainable energy applications. This report details the one-step pyrolysis method for producing perforated graphene (PG) using dead Bougainvillea bracts (natural waste) without activating agents. The properties of the as-prepared PG are studied through basic and electrochemical characterizations. In addition, silver nanoparticles (Ag NPs) are attached to it in weight ratios of 1:5 and 1:8, resulting in a composite catalyst that exhibits notable activity towards HER. The electrochemical performances of the catalysts reveal that PG:Ag 1:5 displays superior electrocatalytic HER activity in an acidic medium, with an onset potential of approximately −143 mV, an overpotential of 327 mV to achieve a current density of 10 mA cm−2, and a Tafel slope of around 125 mV dec−1. In order to assess its stability, the optimized catalyst was subjected to a chronoamperometric study for a duration of 104 s. This study presents a simple and effective way to produce hydrogen sustainably from electrochemical water splitting, using efficient, stable, environmentally friendly, abundant, and low-cost catalysts.

Unveiling the Potential of MnxCo3–xS4 Electrocatalyst in Triiodide Reduction for Dye-sensitized Solar Cells

The development of a low-cost and high-efficiency Pt-free counter electrode is an important goal to improve the performance of dye-sensitized solar cells. In this study, we successfully synthesized a MnxCo3-xS4-based counter electrode by a facile solvothermal synthesis technique. The electrocatalyst was directly deposited on a fluorine doped titanium oxide (FTO) coated glass substrate. Various characterization techniques such as Xray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy were employed to analyze the obtained MnxCo3-xS4 counter electrode material. The photovoltaic measurements performed on the dye-sensitized solar cells showed a remarkable improvement in energy conversion efficiency with the MnxCo3-xS4 counter electrode (8.60 %) compared to the conventional Pt (8.11 %). Moreover, the MnxCo3-xS4counter electrode exhibited excellent stability, further highlighting its potential as an efficient and durable alternative to Pt in dye-sensitized solar cells. Overall, our results contribute to the further development of Pt-free counter electrode materials for sustainable solar energy applications.

Achieving Solar-Thermal-Electro Integration Evaporator Nine-Grid Array with Asymmetric Strategy for Simultaneous Harvesting Clean Water and Electricity.

Water evaporation is a ubiquitous and spontaneous phase transition process. The utilization of solar-driven interface water evaporation that simultaneously obtains clean water and power generation can effectively alleviate people's concerns about fresh water and energy shortages. However, it remains a great challenge to efficiently integrate the required functions into the same device to reduce the complexity of the system and alleviate its dependence on solar energy to achieve full-time operation. In this work, a multifunctional device based on reduced graphene oxide (RGO)/Mn3 O4 /Al2 O3 composite nanomaterials is realized by an asymmetric strategy for effective solar-thermal-electro integration that can induce power generation by water evaporation in the presence/absence of light. Under one sun irradiation, the solar-driven evaporation rate and output voltage are 1.74kgm-2 h-1 and 0.778V, respectively. More strikingly, the nine-grid evaporation/power generation array integrated with multiple devices in series has the advantages of small volume, large evaporation area, and high power generation, and can light up light-emitting diodes (LEDs), providing the possibility for large-scale production and application. Based on the high photothermal conversion efficiency and power production capacity of the RGO/Mn3 O4 /Al2 O3 composite evaporation/generator, it will be a promising energy conversion device for future sustainable energy development and applications.

3D black g-C3N4 isotype heterojunction hydrogels as a sustainable photocatalyst for tetracycline degradation and H2O2 production

The sustainable visible light active g-C3N4 hydrogel is synthesized and employed for water reclamation and H2O2 production. In this study, citric acid-assisted chemically functionalized black g-C3N4 isotype heterojunction (BCN) hydrogel was prepared using the blend-crosslinking method. The comprehensive characterization of the BCN hydrogels affirmed its tuned optical bandgap with effective visible light utilization, greater separation efficiency, and restricted recombination ratio of electrons and holes. The BCN hydrogels exhibited a phenomenal photocatalytic efficiency towards tetracycline degradation (86% in 40 min) and H2O2 production (987 µmol in 60 min). The superoxide, holes, and singlet oxygen demonstrated a synergistic role in photocatalytic activity through the effective migration of electrons. As an immobilized system, the predominant advantages of BCN hydrogel beads include ease of recovery and remarkable reusability up to 7 cycles. This study provides insights into systematically modifying g-C3N4 toward sustainable energy and environmental applications.

Oxygen evolution catalyzed by Ni-Co-Nb ternary metal sulfides on plasma-activated Ni-Co support

As a four-electron–proton coupled reaction, the oxygen evolution reaction (OER) requires a high overpotential for electrocatalytic water splitting. Most of the reported OER catalysts still need higher overpotentials than the thermodynamic water decomposition potential (1.23 V). Therefore, developing the efficient and cost-effective OER electrocatalysts remains a challenge in the electrocatalysis filed. Herein, multiphase Ni-Co-Nb sulfides (NiCoNbSx) are in-situ engineered on the plasma-activated nickel–cobalt foam (PNCF), and the synthesized NiCoNbSx/PNCF exhibits rich heterointerfaces and active sites, causing a high OER performance in an alkaline medium. The NiCoNbSx/PNCF catalyst features the low overpotentials of 48 and 382 mV for delivering the current densities of 10 (j10) and 1000 mA cm−2 (j1000), with a good electrocatalytic stability. The theoretical calculations reveal that the heterojunction interface of NiS (401)-Co9S8 (440) acts as the active center for OER. These results provide a new effective surface modification approach and insights into catalytic processes enabling water electrolysis pursued for clean and sustainable energy applications.

Multi-objective control and optimization of a stand-alone photovoltaic power conversion system with battery storage energy management

This paper addresses the problem of controlling a stand-alone photovoltaic (PV) energy conversion system integrated with a battery energy storage system. The study focuses on a series association of PV panels, a DC/AC converter, a Li-ion battery, and a DC load. The intermittent nature of PV power and frequent variations in load demand decrease battery lifetime and its charging performance. To mitigate these issues, an efficient battery charge controller is proposed to instantaneously balance the PV power flow delivered to the DC load and the battery, ensuring optimal utilization of PV power and appropriate battery charging. Based on available solar power, battery state of charge (SOC), and DC load demand The controller adapts to three charging modes, namely, maximum power point tracking (MPPT) charging mode, constant current (CC) charging mode, and constant voltage (CV) charging mode. Additionally, a novel energy management algorithm is designed to ensure battery safety and determine the system’s mode of operation, considering weather conditions and load demand variations. Interestingly, no solar irradiation or battery SOC sensors are required for the implementation of the control system. Nonlinear and robust controllers are developed to provide the necessary control input laws for the management algorithm. The robustness and stability of the system are verified using the Lyapunov theory. Furthermore, the paper quantifies the performance of the proposed strategy through a comparative analysis using integral of absolute error (IAE) indices against two conventional control approaches. Simulation results validate the effectiveness of the proposed controller strategy, demonstrating its high performance and ability to meet the specified objectives. This work presents an innovative approach to enhance the efficiency and reliability of stand-alone PV energy conversion systems with battery storage, offering promising prospects for sustainable energy applications.

Conduction Band Tuning by Controlled Alloying of Fe into Cs2AgBiBr6 Double Perovskite Powders

AbstractHalide double perovskite semiconductors such as Cs2AgBiBr6 are widely investigated as a more stable, less toxic alternative to lead‐halide perovskites in light conversion applications including photovoltaics and photoredox catalysis. However, the relatively large and indirect bandgap of Cs2AgBiBr6 limits efficient sunlight absorption. Here, it is shown that controlled replacement of Bi3+ with Fe3+ via mechanochemical synthesis results in a remarkable tunable absorption onset between 2.1 and ≈1 eV. First‐principles density functional theory (DFT) calculations suggest that this bandgap reduction originates primarily from a lowering of the conduction band upon the introduction of Fe3+, and predict a direct bandgap when >50% of Bi3+ is replaced with Fe3+. The tunability of the conduction band energy is found and reflected in the photoredox activity of these semiconductors. These findings open new avenues for enhancing the sunlight absorption of double perovskite semiconductors and for harnessing their full potential in sustainable energy applications.