Field Of Energy Conversion Research Articles

Versatile Organometallic Synthesis of 0D/2D Metal@Germanane Nanoarchitectonics for Electrochemical Energy Conversion Applications.

Hydrogen-terminated 2D-Germanane (2D-GeH), a germanium-based 2D material akin to graphene, is receiving enormous attention owing to its predicted optoelectronic characteristics. However, experimental research of 2D-GeH is still in an early stage, and therefore its real implementation for task-specific applications will depend on the correct development of suitable chemical functionalization methods. Herein, a general and straightforward organometallic (OM) approach is provided for the robust functionalization of 2D-GeH with different 0D noble metal nanoparticles (M-NPs), resulting in 0D/2D M@GeH nanoarchitectonics. As a proof-of-principle, 0D/2D Pt@GeH and Au@GeH nanoarchitectonics have been successfully synthesized, characterized, and explored as unconventional electrocatalysts for boosting energy conversion reactions. While the hydrogen evolution reaction activity was evaluated for Pt@GeH, the oxygen reduction reaction was interrogated for Au@GeH. Interestingly, the implanted catalytic features of M-NPs yielded to 0D/2D M@GeH nanoarchitectonics with enhanced energy conversion activity comparing to pristine 2D-GeH counterpart. This work proves the suitability of 2D-GeH as unconventional substrates to stabilize nobleM-NPs, and the versatility of the OM approach for the custom design of a new family of 0D/2D M@GeH nanoarchitectonics to expand the implementation of monoelemental 2D materials as promising electrocatalysts in energy conversion field and beyond.

CuS-NiTe2 embedded phosphorus-doped graphene oxide catalyst for evaluating hydrogen evolution reaction.

The hydrogen evolution reaction (HER), a crucial half-reaction in the water-splitting process, is hindered by slow kinetics, necessitating efficient electrocatalysts to lower overpotential and enhance energy conversion efficiency. Transition-metal electrode materials, renowned for their robustness and effectiveness, have risen to prominence as primary contenders in the field of energy conversion and storage research. In this investigation, we delve into the capabilities of transition metals when employed as catalysts for the HER. Furthermore, we turn our attention to carbon nanomaterials like graphene, which have exhibited tremendous potential as top-performing electrocatalysts. Nevertheless, advancements are indispensable to expand their utility and versatility. One such enhancement involves the integration of phosphorus-doped graphene. Our research focuses on the synthesis of CuS-NiTe2/PrGO, a nanocomposite with a crystalline structure, through a straightforward method. This nanocomposite exhibits enhanced catalytic activity for the HER, boasting a Tafel slope of 57 mV dec-1 in an acidic environment. Consequently, our findings present a straightforward and efficient approach to developing high-performance electrocatalysts for HER.

Origin of Intrinsically Low Lattice Thermal Conductivity in Solids.

Reducing lattice thermal conductivity through external modulation techniques such as defect engineering may potentially interfere with electronic transport. Materials with intrinsically low lattice thermal conductivity have the potential to decouple the control of lattice heat transport and electronic transport, which is of great significance in the field of thermoelectric energy conversion. This paper reviews the origin of intrinsically low lattice thermal conductivity, which is directly related to three physical quantities (heat capacity, phonon group velocity, and phonon relaxation time) and is ultimately reflected in the lattice structure and bonding characteristics. An understanding of the fundamental nature of low lattice thermal conductivity can aid in guiding experimental design and theoretically enabling high-throughput prediction of novel low lattice thermal conductivity materials according to the intrinsic properties.

Research on Graphitic Carbon Nitride (g-C3N4) prepared by template-based method and its photocatalytic properties

Abstract. The Graphitic Carbon Nitride (g-C3N4), a non-metallic polymer photocatalytic material, has a wide range of raw materials and a simple preparation process. Due to its unique electronic structure and excellent photocatalytic performance, g-C3N4 has attracted wide attention in the field of environmental purification and energy conversion in recent years. However, g-C3N4 faces a lot of challenges, including a wide band gap, many interlayer defects, and poor interlayer electron transport. Nevertheless, its unique semiconductor structure and chemical stability still provide the possibility to explore the effect of its piezoelectric properties on photocatalysis, which paves the way for a novel approach to environmentally friendly hydrogen production. Therefore, the paper delves into the application of different template methods in the preparation of g-C3N4 by reviewing the related literature, and analyzes the role of different template materials in the preparation. In addition, in this paper, the photocatalytic properties of g-C3N4 are explored, which are mainly reflected in the photocatalytic water separation performance and photocatalytic degradation of organic dyes. It is found that the g-C3N4 shows great potential in the fields of photocatalytic water decomposition for hydrogen production and degradation of organic pollutants due to its unique band gap, nontoxicity, low cost and wide range of sources. Future research should continue to explore more kinds of template materials and their preparation processes, with the aim of realizing further enhancement of the performance of g-C3N4 photocatalysts and promoting their practical applications in the fields of environment and energy.

Operando Reconstruction of CuO/SnO2 Nanosheets Promotes the Syngas Production from the Electrochemical CO2 Reduction Reaction.

Electrochemically reducing CO2 (CO2RR) to high-value chemical products is recognized as a promising route to simultaneously reduce the consumption of fossil fuels and carbon emission. The fabrication of syngas with an appropriate H2/CO ratio by CO2RR has been widely studied, but the dynamic evolution of the catalyst is still ambiguous. Herein, the reconstruction of CuO/SnO2 nanosheets (NSs) with a heterojunction structure in the CO2RR process was reported by an in situ X-ray diffractometer technique. The products of the CO2RR on the optimized CuO/SnO2 NSs are CO and H2, achieving a nearly 100% total Faraday efficiency. Moreover, the resulting syngas is maintained at a constant 2:1 ratio of H2/CO over a wide potential of -0.8 to -1.2 V versus the reversible hydrogen electrode. Importantly, the detailed characterizations show that Cu2+ is reduced to Cu during the CO2RR process, while the valence state of Sn remains stable. This study presents strong experimental support for the dynamic evolution process of electrocatalysts in other energy conversion fields.

Attaining a wide photoluminescence Stokes-shift of carbon dots obtained from waste biomass

Owing to the tremendous physicochemical and quantum confinement characteristics of carbon quantum dots (CQDs), they have revealed exciting and essential visions in the field of energy conversion and energy storage. However, due to their low photoluminescence quantum yield (PLQY) and/or short Stokes-shift, limits their application in photovoltaic (PV). In this regard, a novel and cost-effective method was used to synthesize the CQDs using waste biomass. Furthermore, a comprehensive study was made to explore the applicability of the CQDs as photon downconverters/downshifters in PVs. The average size of the CQDs are 5.1, 4.4, and 3.9 nm for the synthesis temperature of 160, 180, and 200 ℃, respectively. The EDS analysis revealed that C, O, Mg, Na, Cl, and K are present in all the CQDs. The PL emission peak position is blue-shifted with the rise in the synthesis temperature. The Stokes-shift is reduced with a rise in the synthesis temperature. The highest Stokes-shift was obtained at excitation wavelength of 300 nm for CQDs synthesized at 160 ℃. The PLQY increased by 3.5 and 7.2-folds for the rise in the temperature from 160 to 180 and 200 ℃, respectively. The investigation revealed that the applicability of CQDs can be enriched via the selection of the synthesis parameters.

A strategic study of interdisciplinary frontier in the field of energy conversion and utilization for the “dual carbon” goals

A strategic study of interdisciplinary frontier in the field of energy conversion and utilization for the “dual carbon” goals

Sea urchin-like Fe3O4 hollow microspheres/fatty amines composites phase change materials for highly efficient light-to-thermal conversion and heat storage

Pure phase change materials (PCMs) have limited photothermal conversion capabilities. To improve the photothermal conversion capability of PCMs, we developed composite phase change materials (FHS@PCMs) of sea urchin-like Fe3O4 hollow spheres (FHS) loaded with fatty amines (hexadecylamine (HDA) and octadecylamine (ODA)). The material composition and the surface nano-raised structure of FHS enable FHS@PCMs to exhibit excellent light absorption (up to 90 %, without any additional modification) and thermal conductivity. Moreover, the internal hollow spherical structure would prevent the leakage of PCM during the phase change process. Interestingly, FHS and FHS@PCMs exhibit inherent superhydrophobic properties with a water contact angle greater than 150°, thus endowing them with self-cleaning properties. FHS possesses strong magnetic properties that aid in material collection. Furthermore, the prepared FHS@PCMs exhibited exceptional thermal properties. The latent heat of FHS@HDA and FHS@ODA was 139.21 J∙g−1 and 140.13 J∙g−1, respectively. Additionally, FHS@PCMs maintained their excellent thermal properties even after 50 and 100 thermal cycles. Under one solar radiation, FHS@PCMs show a photothermal conversion efficiency of 89.63 % and 88.02 %, respectively. Taking of these advantages, the as-prepared composite phase change material may have significant potential in the fields of solar energy conversion and storage.

Strong Metal-Support Interactions in Heterogeneous Oxygen Electrocatalysis.

Molecular oxygen redox electrocatalysis involves oxygen reduction and evolution as core reactions in various energy conversion and environmental technology fields. Strong metal-support interactions (SMSIs) based nanomaterials are regarded as desirable and state-of-the-art heterogeneous electrocatalysts due to their exceptional physicochemical properties. Over the past decades, considerable advancements in theory and experiment have been achieved in related studies, especially in modulating the electronic structure and geometrical configuration of SMSIs to enable activity, selectivity, and stability. In this focuses on the concept of SMSI, explore their various manifestations and mechanisms of action, and summarizes recent advances in SMSIs for efficient energy conversion in oxygen redox electrocatalysis applications. Additionally, the correlation between the physicochemical properties of different metals and supports is systematically elucidated, and the potential mechanisms of the structure-activity relationships between SMSIs and catalytic performance are outlined through theoretical models. Finally, the obstacles confronting this burgeoning field are comprehensively concluded, targeted recommendations and coping strategies are proposed, and future research perspectives are outlined.

A Review of Wide Bandgap Semiconductors: Insights into SiC, IGZO, and Their Defect Characteristics.

Although the irreplaceable position of silicon (Si) semiconductor materials in the field of information has become a consensus, new materials continue to be sought to expand the application range of semiconductor devices. Among them, research on wide bandgap semiconductors has already achieved preliminary success, and the relevant achievements have been applied in the fields of energy conversion, display, and storage. However, similar to the history of Si, the immature material grown and device manufacturing processes at the current stage seriously hinder the popularization of wide bandgap semiconductor-based applications, and one of the crucial issues behind this is the defect problem. Here, we take amorphous indium gallium zinc oxide (a-IGZO) and 4H silicon carbide (4H-SiC) as two representatives to discuss physical/mechanical properties, electrical performance, and stability from the perspective of defects. Relevant experimental and theoretical works on defect formation, evolution, and annihilation are summarized, and the impacts on carrier transport behaviors are highlighted. State-of-the-art applications using the two materials are also briefly reviewed. This review aims to assist researchers in elucidating the complex impacts of defects on electrical behaviors of wide bandgap semiconductors, enabling them to make judgments on potential defect issues that may arise in their own processes. It aims to contribute to the effort of using various post-treatment methods to control defect behaviors and achieve the desired material and device performance.

Multi-synergy enabling Ni-doped MoS2@N-doped carbon composite as versatile catalysts toward hydrogen production and photovoltaics

Construction of efficient non-precious catalyst with desired chemical composition and well-defined nanostructure is of great essential to enhance the kinetics of hydrogen evolution reaction (HER) and triiodide (I3−) reduction reaction (IRR), which is conducive to promote the development of green hydrogen production and obtain impressive photovoltaic performance of dye-sensitized solar cells (DSSCs). Herein, ZIF-8 derived N-doped carbon (NC) wrapped with two-dimensional Ni-doped MoS2 nanosheets (Ni–MoS2@NC) are elaborately designed. The catalytic activity of Ni–MoS2@NC for HER and IRR are significantly improved by modifying electronic structure through heteroatom doping. The optimized Ni–MoS2@NC has lower overpotential of 122 mV at 10 mA cm−2 in comparison with counterpart. Meanwhile, the power conversion efficiency (PCE) of DSSCs based on Ni–MoS2@NC CE catalyst is comparable to that of Pt. Density functional theory (DFT) calculation is used to unveil the mechanism of Ni–MoS2@NC for alkaline HER and IRR, namely, the multi-synergy of various sites endows Ni–MoS2@NC with appropriate Gibbs free energy for H∗ adsorption and water dissociation energy, while the top and interfacial S sites of Ni–MoS2@NC are responsible for the adsorption and activation of I3−. Our work provides a feasible route to design efficient catalysts in the field of energy conversion and understand mechanism.

Bottom-up stripping of graphene with controlled oxidation behaviors towards supercapacitors energy storage

Due to its distinctive two-dimensional planar structure, room temperature quantum Hall effect, and high strength, graphene has garnered significant interest in the fields of energy storage and conversion. In order to achieve high efficiency in the production of graphene, electrochemical peeling has been extensively investigated. Nevertheless, the intermolecular forces between graphite layers are disrupted during ion intercalation in solution, leading to inconsistent bonding forces and low yields. In order to address the issues above, this study introduces a novel bottom-up electrochemical peeling method, wherein graphite expansion occurs above the electrolyte. By preventing contact between the peeled graphene and the electrolyte, the oxidation of graphene is significantly minimized, resulting in a substantial yield of 88 %. At the current density of 1.0 A g−1, the Go-QAS displayed 225.5 F g−1, and kept about 220.2 F g−1 after 500 cycles. The well-designed bottom-up peeling process leads to graphene nanosheets with reduced structural degradation, high purity, and excellent conductivity. This technique is expected to introduce innovative concepts for the field.

Optical Applications of CuInSe2 Colloidal Quantum Dots.

The distinctive chemical, physical, electrical, and optical properties of semiconductor quantum dots (QDs) make them a highly fascinating nanomaterial that has been extensively studied. The CuInSe2 (CIS) QDs demonstrates great potential as a nontoxic alternative to CdSe and PbSe QDs for realizing high-performance solution-processed semiconductor devices. The CIS QDs show strong light absorption and bright emission across the visible and infrared spectrum and have been designed to exhibit optical gain. The special characteristics of these properties are of great significance in the fields of solar energy conversion, display, and electronic devices. Here, we present a comprehensive overview of the potential applications of colloidal CIS QDs in various fields, with a particular focus on solar energy conversion (such as QD solar cells, QD-sensitized solar cells, and QD luminescence solar concentrators), solar-to-hydrogen production (such as photocatalytic and photoelectrochemical H2 production), and QD electronics (such as QD transistors, QD light-emitting diodes, and QD photodetectors). Furthermore, we offer our insights into the current challenges and future opportunities associated with CIS QDs for further research.

Impact of Surface Enhanced Raman Spectroscopy in Catalysis.

Catalysis stands as an indispensable cornerstone of modern society, underpinning the production of over 80% of manufactured goods and driving over 90% of industrial chemical processes. As the demand for more efficient and sustainable processes grows, better catalysts are needed. Understanding the working principles of catalysts is key, and over the last 50 years, surface-enhanced Raman Spectroscopy (SERS) has become essential. Discovered in 1974, SERS has evolved into a mature and powerful analytical tool, transforming the way in which we detect molecules across disciplines. In catalysis, SERS has enabled insights into dynamic surface phenomena, facilitating the monitoring of the catalyst structure, adsorbate interactions, and reaction kinetics at very high spatial and temporal resolutions. This review explores the achievements as well as the future potential of SERS in the field of catalysis and energy conversion, thereby highlighting its role in advancing these critical areas of research.

Chitosan–sodium Tripolyphosphate–CuO Biopolymer–nanocomposite as an Efficient Electrocatalyst for Water Splitting

Background: Fossil fuels have been used extensively as primary energy sources, which has resulted in nearly depleted reserves, a contaminated environment, and a variety of negative health effects globally. Hydrogen has been proposed by researchers as an effective “carbon neutral” fuel. Large-scale hydrogen production through electrochemical water splitting necessitates the use of inexpensive, extremely effective, and earth-abundant electrocatalysts. Method: In this study, chitosan–sodium tripolyphosphate (TPP) nanoparticles are combined with CuO nanostructures to produce chitosan–TPP–CuO (CT/CuO) nanocomposite. Chitosan–TPP nanoparticles were first synthesized using the ionic gelation method. These nanoparticles were then extracted, and CuO was synthesized in situ in polymer nanoparticles using a simple chemical precipitation method. Chitosan and CuO are abundantly available and are environmentally beneficial materials. The porous structure and open channels within the chitosan polymer matrix host the CuO nanostructures, which promote electrolyte penetration, mass transport, and charge transfer, while the metal-oxide nanostructures act as catalytic centers. The structural and morphological properties of the CT/CuO nanocomposite were investigated using XRD, HRSEM, and HRTEM. The band gap and functional groups in the material were measured by UV–Vis DRS and FTIR methods, respectively. Elemental analysis was conducted utilizing EDS, HRSEM, and XPS. Thermal characteristics of the CT/CuO nanocomposite were investigated using TG-DTA and DSC methods. Electrochemical techniques were used to investigate the activities of HER and OER. Results: The XRD examination of the CT/CuO nanocomposite revealed semi-crystalline chitosan peaks and a monoclinic CuO structure. HRSEM and HRTEM pictures indicated that chitosan–TPP nanoparticles and CuO nanostructures were evenly spread and clustered to create a nanoparticulate matrix. UV–Vis DRS indicated that the CT/CuO nanocomposite had a direct band gap of 1.702 eV. The FTIR and XPS studies revealed the various bonds and oxidation states of the nanocomposite. Thermal analyses demonstrated that the inclusion of CuO increased the thermal stability of the CT/CuO nanocomposite. CT/CuO nanocomposite exhibited excellent OER and HER activity, requiring a low overpotential of 444 mV and 379 mV at 10 mA cm−2 and -10 mA cm−2, respectively. Conclusion: Biopolymer metal-oxide nanocomposites could potentially be used as electrocatalysts in water splitting, energy conversion, storage devices, sensors, and several other fields.

Modulation performance of terahertz waves by titanium disulfide nanosheets towards 6G

AbstractThe TiS2 compound has attracted considerable attention among researchers in the fields of energy storage and conversion, as well as semiconductor materials. This is due to its remarkable capability to incorporate various elements into its van der Waals gap, as well as its potential to adjust the carrier concentration within the material to optimize its electrically relevant properties. In our study, we employed a terahertz (THz) time‐domain spectroscopy system to measure the spectra of TiS2 within the THz frequency range. Through this analysis, we examined the optical parameters, such as transmittance and refractive index, of the TiS2 samples. Additionally, we conducted optical pumping correlation experiments using THz detection technology to investigate the optical pumping effects on TiS2. By analyzing the THz energy transmission process in different states, we were able to calculate and fit the carrier recombination time. The findings of our research hold significant implications for the advancement of THz devices operating in the 6G frequency band.

Bright Nanocomposites based on Quantum Dot‐Initiated Photocatalysis

Integrating quantum dots (QDs) into polymer matrix to form nanocomposites without compromising the QD photoluminescence (PL) is crucial to emerging QD light‐emitting and solar energy conversion fields. However, the most widely‐used bulk polymerization technique, where monomers serve as the QD solvent, usually leads to QD PL quenching caused by radical initiators. Here we demonstrate high‐brightness nanocomposites with near‐unity PL quantum yield (QY), through a novel QDs‐catalyzed (‐initiated) bulk polymerization without using any radical initiators. Different from previous reports where QDs were designed as photo‐sensitizers/catalysts (always with cocatalysts) and hence non‐emissive in catalytic conditions, our QDs combine high brightness with highly effective catalysis, a combination that was previously considered to be hardly possible. In our case, apart from emitting light (at a large probability), the photoexcited QDs act as ‘overall reaction’ catalysts by simultaneously employing photoexcited electrons and holes to produce active radicals without the need of any sacrificial agents. These active radicals, though with a small amount, are sufficient to initiate effective chain reaction‐dominated bulk polymerization, eliminating the requirement of extra radical initiators. This study provides new insights for understanding and development of QDs for energy applications.

Bright Nanocomposites based on Quantum Dot-Initiated Photocatalysis.

Integrating quantum dots (QDs) into polymer matrix to form nanocomposites without compromising the QD photoluminescence (PL) is crucial to emerging QD light-emitting and solar energy conversion fields. However, the most widely-used bulk polymerization technique, where monomers serve as the QD solvent, usually leads to QD PL quenching caused by radical initiators. Here we demonstrate high-brightness nanocomposites with near-unity PL quantum yield (QY), through a novel QDs-catalyzed (-initiated) bulk polymerization without using any radical initiators. Different from previous reports where QDs were designed as photo-sensitizers/catalysts (always with cocatalysts) and hence non-emissive in catalytic conditions, our QDs combine high brightness with highly effective catalysis, a combination that was previously considered to be hardly possible. In our case, apart from emitting light (at a large probability), the photoexcited QDs act as 'overall reaction' catalysts by simultaneously employing photoexcited electrons and holes to produce active radicals without the need of any sacrificial agents. These active radicals, though with a small amount, are sufficient to initiate effective chain reaction-dominated bulk polymerization, eliminating the requirement of extra radical initiators. This study provides new insights for understanding and development of QDs for energy applications.

Advancements in Energy Storage and Conversion: The Role of High‐Energy Irradiation Technology

AbstractContemporary challenges have emerged concerning the capability and safety of secondary batteries in the energy storage field. Additionally, catalysts employed in the energy conversion confront issues including inadequate stability and elevated costs. In addition to its traditional use, high‐energy irradiation has found extended application in controlled manipulation of materials for electrochemical energy storage and conversion, due to its unique advantages of no secondary pollution, convenience, and efficiency. This review article shows the recent progress of the application of high‐energy irradiation technology in the field of energy storage and conversion for the first time. The mechanism of material modification via high‐energy irradiation was elaborated, and the application of high‐energy irradiation in tailoring materials for battery components and catalysts was discussed in detail. Finally, challenges for future research of high‐energy irradiation technology in the field of energy storage and conversion were proposed. This review article will provide important significance for subsequent research on high‐energy irradiation technology in the field of energy storage and conversion.

Manipulating Electron Delocalization of Metal Sites via a High-Entropy Strategy for Accelerating Oxygen Electrode Reactions in Lithium-Oxygen Batteries.

High-entropy perovskite oxides, in which the B-type metal site of perovskite oxides (ABO3) is occupied by over five kinds of transition metal ions, show promising applications in energy storage and conversion fields. Herein, high-entropy perovskite oxides (LaSr(5TM)O3) composed of Cr, Mn, Fe, Co, and Ni at the B-type metal site are prepared as oxygen electrocatalysts for Li-O2 batteries. The presence of compressive strain in LaSr(5TM)O3 effectively regulates the 3d orbit occupancy of the active Co site (Co2+ → Co3+) and lifts the energy level of the Co d-band center, thus leading to enhanced adsorption toward the LiO2 intermediate on Co sites. Furthermore, the high electron-drawing capability of Cr sites ensures sufficient electron exchange and further strengthens the adsorption of LiO2. As expected, the Li-O2 battery with a LaSr(5TM)O3 electrode delivers a low overpotential (0.79 V) and superior cyclability (226 cycles). This study provides a meaningful strain strategy to improve the electrocatalytic activity of multicomponent oxides via fabricating high-entropy materials.