Renewable Energy Conversion Research Articles

ZIF-67-derived petal-like Co(OH)2-MoO3/NF layered nanosheets as a promising electrocatalyst for oxygen evolution reaction

The development of high-performance and cost-effective electrocatalysts for oxygen evolution reactions (OER) is key to renewable energy conversion and storage technologies. In this paper, a hierarchical Co(OH)2-MoO3 nanosheets with petal-like architecture was prepared by a simple one-step hydrothermal method using ZIF-67/NF as a precursor, and it was used as a direct electrocatalyst for OER. Notably, this petal-like Co(OH)2-MoO3/NF layered nanosheets not only prevent the agglomeration of nanostructured material, but also facilitate the complete penetration and diffusion of electrolyte.In addition, due to the strong electronic interaction between Co(OH)2 and MoO3 in the Co(OH)2-MoO3/NF system, Co(OH)2-MoO3/NF exhibits excellent electrocatalytic OER performance. It has a low overpotential of 273 mV at 10 mA cm−2 and excellent stability.This study provides a simple and effective strategy for the rational design and structural evolution of MOF-derived materials to achieve inexpensive and effective electrocatalysis.

Northern Lights: Prospecting Efficiency in Europe’s Renewable Energy Sector

Northern European nations are at the forefront of renewable energy adoption but face challenges in optimizing energy conversion efficiency. There is a lack of detailed understanding of how behavioral factors affect the efficiency of renewable energy conversion in these countries. This study aims to evaluate and compare the renewable energy conversion efficiency of Northern European countries, intending to inform strategic policy making and identify best practices for technology deployment in the renewable energy sector. Employing a Data Envelopment Analysis (DEA) model, the study integrates behavioral economic parameters—specifically, the aversion loss and gain significance coefficients—to assess the efficiency of renewable energy conversion, accounting for psychological factors in decision making. A comprehensive sensitivity analysis was conducted, varying the gain significance coefficient while maintaining the aversion loss coefficient at constant levels. This experiment was designed to observe the impact of behavioral parameters on the efficiency ranking of each country. The analysis revealed that Latvia consistently ranked highest in efficiency, irrespective of the gain significance valuation, whereas Iceland consistently ranked lowest. Other countries demonstrated varying efficiency rankings with changes in gain significance, indicating different behavioral economic influences on their renewable energy sectors. Theoretically, the study enhances the DEA framework by integrating behavioral economics, offering a more holistic view of efficiency in renewable energy. Practically, it provides a benchmarking perspective that can guide policy and investment in renewable energy, with sensitivity analysis underscoring the importance of considering behavioral factors. The research offers a practical tool for policymakers and energy stakeholders to align renewable energy strategies with behavioral incentives, aiming to improve the adoption and effectiveness of these initiatives.

Application of activated carbon in renewable energy conversion and storage systems: a review

Application of activated carbon in renewable energy conversion and storage systems: a review

Structure, Synthesis, and Catalytic Performance of Emerging MXene-Based Catalysts.

As traditional fossil fuel energy development faces significant challenges, two-dimensional layered materials have become increasingly popular in various fields and have generated widespread research interest. MXene is an exceptional catalytic material that is typically integrated into functional composite materials with other substances to enhance its catalytic-reaction performance. Improving the thermal stability, electrical conductivity, and electrochemical activity, as well as enhancing the specific surface structure, can make the material an excellent catalyst for photoelectrocatalysis and energy-regeneration reactions. The article mainly outlines the structural characteristics, preparation methods, and applications of MXene in the field of catalysis. This text highlights the latest progress and performance comparison of MXene-based catalytic functional materials in various fields such as electrochemical conversion, photocatalysis, renewable energy, energy storage, and carbon capture and conversion. It also proposes future prospects and discusses the current bottlenecks and challenges in the development of MXene-based catalytic materials.

High-fidelity numerical modelling of a two-WEC array with accurate implementation of the PTO system and control strategy using DualSPHysics

In order for Wave Energy Converters (WECs) to become economically viable they will have to be installed closely together in so-called WEC arrays. When WECs are placed closely together they influence each other’s motion, which is challenging to implement in a numerical model. The accurate modelling of WECs in WEC arrays is crucial for their further development into cost-effective renewable energy converters. This paper presents the study of numerical modelling of an array of two heaving WECs (a two-WEC array) placed in close proximity of each other in order to increase their interaction effect. The numerical model uses DualSPHysics, a Smoothed Particle Hydrodynamics (SPH) based software to model wave-WEC interaction, coupled to Project Chrono for the modelling of the Power Take-Off (PTO) system and the friction. First, a series of numerical system identification tests are simulated: a free-decay test of an isolated WEC, radiation tests and an excitation test. During the radiation test one WEC is moved by an external force with a chirp-up noise signal, while the other WEC is kept still. This allows the computation of the impedance matrix, and thereby also the hydrodynamic coefficients of the two-WEC array, which has not been done before in SPH. Results were validated with experimental data from the WECfarm test campaign. Secondly, a series of numerical dynamic tests are simulated of the two-WEC array in regular and irregular waves. In the experimental test campaign a friction force caused by the motor and gearbox was counteracting the WEC’s motion, so a friction compensation (FC) force was added to cancel out this friction. This friction and FC force was numerically modelled by adding a novel implementation in Project Chrono. Furthermore, a novel global control strategy was implemented using Project Chrono, in which the PTO force on each WEC depends on the velocity of both WECs. Overall, good to very good agreement was found in terms of heave and free surface elevation when comparing numerical to experimental results.

A Perspective of Bioinspired Interfaces Applied in Renewable Energy Storage and Conversion Devices.

The natural world renders a large number of opportunities to design intriguing structures and fascinating functions for innovations of advanced surfaces and interfaces. Currently, bioinspired interfaces have attracted much attention in practical applications of renewable energy storage and conversion devices including rechargeable batteries, fuel cells, dye-sensitized solar cells, and supercapacitors. By mimicking miscellaneous natural creatures, many novel bioinspired interfaces with various components, structures, morphology, and configurations are exerted on the devices' electrodes, electrolytes, additives, separators, and catalyst matrixes, resorting to their wonderful mechanical, optical, electrical, physical, chemical, and electrochemical features compared with the corresponding traditional modes. In this Perspective, the principles of designing bioinspired interfaces are discussed with respect to biomimetic chemical components, physical morphologies, biochemical reactions, and macrobiomimetic assembly configurations. A brief summary, subsequently, is mainly focused on the recent progress on bioinspired interfaces applied in key materials for rechargeable batteries. Ultimately, a critical comment is projected on significant opportunities and challenges existing in the future development course of bioinspired interfaces. It is expected that this Perspective is able to provide a profound perception into some underlying artificial intelligent energy storage and conversion device design as a promising candidate to resolve the global energy crisis and environmental pollution.

Improvement of SnFe2O4 OER electrochemical property by Sm doping for water splitting

Electrocatalysts are crucial for achieving highly efficient renewable energy conversion and storage applications. Nevertheless, doping proves to be a successful approach in creating affordable spinel oxides that exhibit exceptional electrochemical capabilities. Our study focuses on the preparation of a samarium (Sm)-doped SnFe2O4 catalyst to expand the activity and stability of the oxygen evolution reaction (OER). However, the Sm-doped SnFe2O4 catalyst shows a highly encouraging overpotential of 179 mV at a current density of 10 mA cm−2 and a reduced Tafel slope of 32 mA dec−1. It maintains its durability for a duration of 40 h and even after undergoing 5000th cycles. The Sm-doped SnFe2O4 catalyst exhibits several positive effects, including reduced overpotential, higher catalytic current density, improved charge transfer kinetics (Rct = 0.29 Ω), and increased ECSA (111.62 cm2) value. These improved superior activity of Sm-doped SnFe2O4 catalyst can be attributed to factors such as its unique interconnected structures morphology, strong synergistic effects of Sm with Sn and Fe and the robust OH− adsorption, which are more pronounced compared to the un-doped SnFe2O4, which greatly enhanced their performance in OER activity. These findings indicate that by incorporating rare earth (Sm) dopant with a high valence state, spinel oxide can be fine-tuned to potentially enhance OER optimization for energy-producing applications.

Progress on the Design of Electrocatalysts for Large‐Current Hydrogen Production by Tuning Thermodynamic and Kinetic Factors

AbstractElectrochemical water splitting to produce green hydrogen offers a promising technology for renewable energy conversion and storage, as well as realizing carbon neutrality. The efficiency, stability, and cost of electrocatalysts toward hydrogen evolution reaction (HER) and electrocatalytic overall water splitting (EOWS) at large current densities are essential for practical application. In this review, the key factors that determine the catalytic performance of electrocatalysts at large current densities are summarized from the angel of thermodynamic and kinetic correlation. The corresponding design strategies are presented. The electronic structure and density of active sites that affect the adsorption/desorption of intermediates are considered as the thermodynamic aspects, while charge transfer and mass transport capabilities closely associated with electrode resistance and intermediate diffusion are assigned as kinetic effects. Recent development of bifunctional and integrated electrocatalysts toward EOWS is also discussed in detail. Finally, the perspective and direction on the electrocatalytic water splitting under large current density are proposed. This comprehensive overview will offer profound insights and guidance for the continued advancement of this field.

Simultaneously Engineering the First and Second Coordination Shells of Single Iron Catalysts for Enhanced Oxygen Reduction.

The atomically dispersed Fe-N4 active site presents enormous potential for various renewable energy conversions. Despite its already remarkable catalytic performance, the local atomic microenvironment of each Fe atom can be regulated to further enhance its efficiency. Herein, a novel conceptual strategy that utilizes a simple salt-template polymerization method to simultaneously adjust the first coordination shell (Fe-N3S1) and second coordination shell (C-S-C, a structure similar to thiophene) of Fe-N4 isolated atoms is proposed. Theoretical studies suggest that this approach can redistribute charge density in the MN4 moiety, lowering the d-band center of the metal site. This weakens the binding of oxygenated intermediates, enhancing oxygen reduction reaction (ORR) activity when compared to only implementing coordination shell regulation. Based on the above discovery, a single Fe atom electrocatalyst with the optimal Fe-N3S1-S active moiety incorporated in nitrogen, sulfur co-doped graphene (Fe-SAc/NSG) is designed and synthesized. The Fe-SAc/NSG catalyst exhibits excellent alkaline ORR activity, exceeding benchmark Pt/C and most Fe-SAc ORR electrocatalysts, as well as superior stability in Zn-air battery. This work aims to pave the way for creating highly active single metal atom catalysts through the localized regulation of their atomic structure.

Hollow Ti3C2Tx MXene sphere-based ZIF-67 derived central radiative cobalt-tipped carbon nanotubes electrocatalysts for ORR and OER

The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) plays a key role in many renewable energy conversion and storage technologies. As the state-of-the-art ORR and OER electrocatalysts, noble-metal-based electrocatalysts suffer from high price, low earth abundance, single functionality, and poor stability. Developing high performance noble-metal-free ORR and OER bifunctional electrocatalysts as alternatives is highly desirable but remains a significant challenge. In this work, we reported a metal-organic-framework-engaged strategy for the fabrication of central radiative cobalt-tipped N-doped carbon nanotube/hollow Ti3C2Tx sphere composites (h-Ti3C2Tx@Co-NCNT), in which ZIF-67 particles were in situ grown on spherical structure composed of Ti3C2Tx nanosheets constructed with hard template PMMA and then were converted to cobalt-tipped N-doped carbon nanotubes through a pyrolysis process. The hollow Ti3C2Tx nanosheets sphere not only served as conductive scaffolds for the growth of Co-NCNT but also balanced the tradeoff between graphitization of carbon and the surface area. Benefiting from the abundant Co-N/C active sites, reasonably high graphitization of carbon and suitable surface areas, the optimized h-Ti3C2Tx@Co-NCNT manifested comparable ORR (half-wave potential of 0.843 V) and OER (overpotential of 323 mV) activities. In addition, the h-Ti3C2Tx@Co-NCNT assembled zinc-air battery exhibits superior performance beyond commercial Pt/C+RuO2. Certificating this strategy can provide great opportunity for its application in renewable conversion and storage technologies.

The Prospective Applications of Arising Nanostructured Dielectric Materials in Storage of Energy: A Comprehensive Review

Background: The manufacture and study of innovative materials that enable the availability of relevant technologies are vital in light of the energy demands of various human activities and the need for a substantial shift in the energy matrix. Objective: A strategy based on the creation of enhanced applications for batteries has been devised to reduce the conversion, storage, and feeding of renewable energy like fuel cells and electrochemical capacitors. Methods: Conductive polymers (CP) can be utilised instead of traditional inorganic chemicals. Electrochemical energy storage devices with similar capabilities can be built using approaches based on the production of composite materials and nanostructures. Results: CP's nanostructuring is notable for its concentration on synergistic coupling with other materials, which sets it apart from other nanostructures that have been developed in the preceding two decades. This is due to the fact that, when paired with other materials, their distinctive morphology and adaptability significantly enhance performance in areas like the suppression of ionic diffusion trajectories, electronic transport and the improvement of ion penetrability and intercalation spaces. Conclusion: The present study forecasts the wide-ranging modern applications of diverse nanostructured dielectric materials along with its future prospectives. The potential contributions of nanostructured carbon nanotubes to the development of innovative materials for energy storage devices are also critically discussed in this context, which delivers a summary of the present state of information on this emerging topic.

Biomass Carbon Anchored Co‐N4 Single‐Atom Catalyst for Efficient Hydrogen Evolution, Oxygen Evolution and Alcohol Oxidation Reaction

AbstractGreat efforts have been made to boost the performance of electrochemical catalysts by regulating the electronic and geometric structures. However, the electrochemical catalytic properties have entered the bottleneck stage only depend on these methods, especially in alkaline or neutral conditions. It is highly desired to develop new strategy to make robust electrocatalysts. In this study, an atomic Co‐N4 catalyst embedded on nitrogen‐doped 3D hierarchically porous carbon has been prepared via a facile method of calcining the coordination compound. Benefiting from the unique properties of Co single‐atoms, they are coordinated with the heteroatom nitrogen of o‐phenylenediamine and melamine and anchored on the nitrogen‐doped porous carbon carriers. The as‐synthesized Co‐N‐LPC with a maximum Co single‐atom loading of 3.82 wt % features a high specific surface area of 196.6 m2 g−1 and exhibits decently high hydrogen evolution, oxygen evolution and alcohol oxidation catalytic activities in 1.0 mol L−1 KOH electrolyte with competitive overpotentials of 131, 318 and 124 mV at 10 mA cm−2 current density respectively. This study offers a cost‐effective electrocatalyst for water splitting or alcohol oxidation that can be used instead of noble metals in various renewable energy storage and conversion applications.

Bi/Bi2O3/TiO2 heterojunction photocathode for high-efficiency visible-light-driven lithium-sulfur batteries: Advancing light harvesting and polysulfide conversion

Integrating solar-electrical energy conversion and electrical-chemical energy storage functions within a single device offers a promising strategy for efficient light harvesting, conversion, and storage of renewable solar energy. Herein, we develop visible-light-driven photoelectrochemical Li2S6-based lithium-sulfur batteries (VPLSBs) for simultaneous energy conversion and storage, employing a versatile Bi/Bi2O3/TiO2 photocathode as both a light harvester and redox catalyst. The narrowed band gap of photocathode minimizes photoelectron-hole recombination, enabling efficient light-to-electrical energy conversion. Its energy level alignment with Li-S electrochemical potentials facilitates the photocarriers’ participation in polysulfide conversions, supporting electrical-to-chemical energy storage. Under visible light, the Bi/Bi2O3/TiO2 photocathode exhibits a photoelectrocatalysis effect, enhancing interfacial charge transfer, reducing Li2S deposition resistance, and ensuring stable Li2S plating/stripping. Additionally, the bare photo-charging process achieves an overall energy conversion-storage efficiency of 2.58 %. The VPLSB demonstrates an exceptional specific capacity of 1484 mA h g−1 over 900 cycles, maintaining an apparent energy efficiency of 100.2 % at 0.2 mA cm−2.

Mechanism and kinetics of self‐sensitized photocycloaddition of cyclohexenone and norbornene

AbstractSolar‐driven conversion of renewable biomass resources into high‐density hydrocarbon fuels can effectively realize biomass valorization and renewable energy conversion. In this work, an efficient self‐sensitized [2 + 2] photocycloaddition process is explored to develop highly strained fuel with high yield using norbornene and biomass‐derived cyclohexenone as feedstocks. The enhancement mechanism is revealed by phosphorescent measurement and theoretical calculation, and a reasonable reaction path for self‐sensitized [2 + 2] co‐cycloaddition is proposed. When using methanol as solvent, the apparent activation energy of co‐cycloaddition is 21.37 W/mol, which is lower than that of self‐cycloaddition (31.57 W/mol). Importantly, the jet‐fuel‐range highly strained fuel has high density (0.986 g/cm3) and high volumetric net heat of combustion (41.14 MJ/L), which are 5.34% and 4.39% higher than those of JP‐10, respectively. This work proposes a green and effective pathway for the preparation of high‐performance hydrocarbon fuel with polycyclic‐asymmetric structure.

Facile one-step solid-state synthesis of CuO nanoparticles finely decorated over carbon sheets for improved OER activity

Renewable energy storage and conversion in electrochemical fuel cells require highly efficient and cost-effective noble metal free electrocatalysts for oxygen evolution reaction (OER). Downscaling of a material to nanoscale morphology can lead to enhancement in its surface activities affecting its physical and chemical properties which can well serve the purpose. In lieu to this, it could be one of the first reports to tune the morphology of CuO particles to 10–25 nm finely trapped inside non-graphitic carbon sheets using a novel single step solid state reaction. XRD, SEM, TEM, XPS, and Raman analyses confirm the structural and morphological attributes. The synergistic effect from carbon and copper oxide resulted in the attainment of best-in-class electrode material for oxygen evolution reaction (OER). The as-prepared CuO/C shows an excellent OER activity with a low overpotential of 454 mV (vs. Ag/AgCl) at a current density of 10 mA cm−2 with a low Tafel slope of 74.9 mV dec−1. The amount of carbon is optimized to get optimal performance from the CuO nanopowder.

Operando imaging in electrocatalysis: insights into microstructural materials design.

Electrocatalysis plays a pivotal role in renewable energy conversion and associated chemical production, enabling a variety of emerging sustainability technologies with societal impacts. Achieving marked improvement in electrocatalytic performance relies on a deep understanding of catalyst microstructures and catalytic mechanisms, with a particular emphasis on the detailed, spatiotemporally resolved characterizations of the underlying fundamental electrocatalytic processes. This fundamental need drives the development of operando imaging techniques, which improve the ability to detect dynamic structural changes in electrocatalysts and establish clear structure-performance relationships for morphologically complex, hierarchically structured catalytic materials. This review aims to highlight significant advancements in the application of operando imaging techniques to develop a deeper understanding of important heterogeneous electrocatalytic reactions critical for emerging sustainability technologies. We summarize the up-to-date key mechanistic insights regarding these reactions achieved through a range of operando imaging techniques, including electron microscopies, X-ray imaging techniques, scanning probe microscopies, and optical microscopies. We conclude by pointing out emerging directions and future prospects within the field of operando imaging in electrocatalysis.

Lattice oxygen activation and local electric field enhancement by co-doping Fe and F in CoO nanoneedle arrays for industrial electrocatalytic water oxidation

Oxygen evolution reaction (OER) is critical to renewable energy conversion technologies, but the structure-activity relationships and underlying catalytic mechanisms in catalysts are not fully understood. We herein demonstrate a strategy to promote OER with simultaneously achieved lattice oxygen activation and enhanced local electric field by dual doping of cations and anions. Rough arrays of Fe and F co-doped CoO nanoneedles are constructed, and a low overpotential of 277 mV at 500 mA cm−2 is achieved. The dually doped Fe and F could cooperatively tailor the electronic properties of CoO, leading to improved metal-oxygen covalency and stimulated lattice oxygen activation. Particularly, Fe doping induces a synergetic effect of tip enhancement and proximity effect, which effectively concentrates OH− ions, optimizes reaction energy barrier and promotes O2 desorption. This work demonstrates a conceptual strategy to couple lattice oxygen and local electric field for effective electrocatalytic water oxidation.

Optimizing Lead-Free Chalcogenide Perovskite Solar Cells: A Path to High Efficiency and Stability for Renewable Energy Conversion

Optimizing Lead-Free Chalcogenide Perovskite Solar Cells: A Path to High Efficiency and Stability for Renewable Energy Conversion

Porous Ni Electrodes for Hydrogen Production from Water Electrolysis

Hydrogen has been seen as one of the most valuable options regarding renewable energy storage and conversion. However, its production is still mostly based on fossil fuels, in part because of the high cost of alternative production routes, as is the case of water electrolysis for example. This fact is explained by the energy consumed during the process of hydrogen evolution from water. Nevertheless, the research on water electrolysis is justifiable by the advantages that the process offers, as high produced hydrogen purity, possible association with other renewable energy sources such as solar, hydro and wind power generation, no CO2 emissions during the evolution, simplicity of the process, as so many others. With the purpose of increasing the hydrogen-producing device (electrolysers) performance, great scientific efforts have been directed to the electrodes base materials and their surface technology. In this way, the present work propose powder metallurgy based processes as production routes of nickel porous electrodes, i.e., relatively low cost and high active superficial area electrodes for hydrogen production.

The thermophysical properties of a promising composite adsorbent based on multi-wall carbon nanotubes for heat storage

AbstractThe use of energy from alternative energy sources as well as the use of waste heat are key elements of an efficient energetics. Adsorption heat storage is a technology that allows solving such problems. For the successful operation of an adsorption heat accumulator, it is necessary to analyze the thermophysical characteristics of the system under the conditions of the operating cycle: heat transfer coefficient adsorbent-metal (α2), overall (U) and global (UA) heat transfer coefficients of heat exchanger. Multi-walled carbon nanotube (MWCNT) composites are very promising for adsorption-based renewable energy storage and conversion technologies. In this work at the stage of heat release, α2 was measured by the large pressure jump (LPJ) method, at the stage of heat storage by large temperature jump method (LTJ), which made it possible to obtain thermophysical characteristics that corresponded to the implementation of the real working cycle as much as possible. The heat transfer coefficients for a pair of adsorbent LiCl/MWCNT—methanol are measured for the first time under the conditions of a daily heat storage cycle both at the sorption stage (α2 = 190 W/m2K) and at the desorption stage (α2 = 170 W/m2K).