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The physicochemical properties of molecules can be modulated through polariton formation under strong electromagnetic confinement. Here, we discuss the possibility of exploiting this phenomenon to increase the electron transfer rate at an electrode–electrolyte interface. Electron transfer theory under strong electromagnetic confinement can be extended to the electrode–electrolyte interface, and single-electron transfer reactions can be simulated using Gerischer's theory. Although single electron transfer in free space is well described using Marcus theory, the vacuum electric field can facilitate an additional electron transfer pathway via virtual photon excitation under cavity strong coupling conditions. Therefore, this binary reaction pathway for single electron transfer can yield a quasi-two-particle electron transfer process. This quantum behavior can dominate when the mode volume is small and when there are a large number of molecules in the vacuum electric field. Exploitation of polaritons in single electron transfer reactions can lead to enhanced electrochemical energy conversion systems. [ABSTRACT FROM AUTHOR]

High gain and large bandwidth of traveling-wave parametric amplifier exploiting the nonlinearity of Josephson Junctions can be achieved by fulfilling the so-called phase-matching condition. This condition is usually addressed by placing resonant structures along the waveguide or by periodic modulations of its parameters, creating gaps in the waveguide's dispersion. Here, we propose to employ the Josephson junctions, which constitute the centerline of the amplifier, as resonant elements for phase matching. By numerical simulations in JoSIM (and WRspice) software, we show that Josephson plasma oscillations can be utilized to create wave vector mismatch sufficient for phase matching as well as to prevent the conversion of the pump energy to higher harmonics. The proposed traveling wave parametric amplifier design has a gain of 15 dB and a 3 GHz bandwidth, which is comparable to the state-of-the-art TWPAs. [ABSTRACT FROM AUTHOR]

Modeling solvation dynamics and properties is crucial for developing electrolytes for electrochemical energy storage and conversion devices. This work reports an on-the-fly multi-objective Bayesian optimization (OTF-MOBO) method to parameterize force fields for modeling ionic solvation structures, thermodynamics, and transport properties using molecular dynamics simulations. By leveraging solvation-free energy and solvation radii as training data, we employ the data-driven OTF-MOBO algorithm to actively optimize the force field parameters. The modeling accuracy was evaluated in molecular dynamics simulations until the Pareto front in the parameter space was reached through minimized prediction errors in both solvation-free energy and solvation radii. Using transition metal redox ions (Fe3+/Fe2+, Cr3+/Cr2+, and Cu2+/Cu+) in aqueous solution as examples, we demonstrate that simple force fields combining the Lenard–Jones potential and Coulombic potential can achieve relative error below 2% in both solvation free energy and solvation radii. The optimized force fields can be further extrapolated to predict solvation entropy and diffusivities with relative error below 10% compared with experiments. [ABSTRACT FROM AUTHOR]

Solar-driven semiconductor photocatalysts are highly appealing in applications of environmental remediation and energy conversion. However, photocatalytic reactions, particularly oxygen evolution reaction (OER), are often constrained by the swift recombination of electron–hole pairs, thereby resulting in low reaction efficiency. Although it is effective to separate charge carriers by constructing heterojunctions to form built-in electric field, the lattice mismatch and inefficient interlayer charge transfer of heterojunctions in the photocatalysts limit their further development. Here, we propose a new strategy by constructing an internal electric field for OER through an individual piezoelectric two-dimensional material. The results indicate that the piezoelectric effect regulates the electronic structure, reduces bandgap, improves light absorption efficiency, and that the displacement of positive and negative charge centers is the key factor in the enhanced OER. This research indicates the feasibility of combining piezoelectric properties of two-dimensional materials with OER (1.19 eV), providing new insights and guidance for applying the piezoelectric effect in the OER and opening up a way to promote efficient separation of charge carriers. [ABSTRACT FROM AUTHOR]

Physical processes involving hot electrons, including their generation, transport, injection, and relaxation, have been an extensive area of research. The most widely utilized method for actuating the creation of hot electrons involves the excitation of plasmonic modes followed by their non-radiative decay, channeling the energy into these energetic carriers. Since plasmonics has already evolved into a mature field of scientific exploration, active plasmonic devices serve as an ideal platform to study hot-electron physics. In this Perspective article, we will provide the reader with a comprehensive outline of the physics underlying hot-electron dynamics. Emphasis will be placed on the characteristic timescales involved with the lifecycle of hot electrons, the generation and decay mechanisms of surface plasmon-induced hot electrons, and the material platforms suitable for such a study. Then, we will move on to discuss different temperature models used to explain the evolution of hot electrons and the changes in the optical properties of the materials they are generated in or injected into. Finally, we will focus on some of the interesting optical phenomena occurring at ultrafast timescales mediated by hot-carrier dynamics. Such a discussion is expected to incorporate valuable insights into our understanding of the synergistic relationship between hot-electron dynamics and active plasmonics, thereby paving the way for novel applications involving optoelectronics and energy conversion. [ABSTRACT FROM AUTHOR]

Recent developments in materials manufacturing has allowed researchers to engineer unique wave-matter interactions at the nano-scale. These interactions foster unique and coupled modes of thermal, optical, electrical, and acoustic energy transport and conversion. This study addresses the sensitivity of the static ϵ 0 and complex ϵ ~ (ω) = ϵ 1 (ω) + i ϵ 2 (ω) dielectric constant due to changes in pressure (P), volume (V), and temperature (T). General β -sensistivity relations are derived based on traditional Drude and Lorentz oscillator models. Then, these sensitivity relations are compared to literature d ln ⁡ ϵ i / d T and d ln ⁡ ϵ i / d ln ⁡ V data for various metals, dielectric insulators, and semiconductor materials. For example, the effects of isotropic strain on ϵ (ω) are found to have two common contributions: the frequency dependence of the dielectric dispersion (d ln ⁡ ϵ / d ln ⁡ ω) and key vibrational-mode Grüneisen parameters (γ i = − d ln ⁡ ω i / d ln ⁡ V). Because these sensitivity relations are dictated by the various electronic, optical, and lattice Grüneisen parameters, a comprehensive listing of mode Grüneisen parameters and coupled property data are provided for materials ranging from metals to semiconductors to polymers to dielectric insulators such as BaTiO 3. In most cases, the developed sensitivity relations are consistent with published isotropic strain derivative data. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new approach for constructing broadband rectifiers from resonant-type in-plane spin-torque diodes (STDs). The intrinsic bandwidth of such STDs constrained by the ferromagnetic resonance linewidth of the corresponding magnetic tunnel junction's is relatively narrow, which is a significant limitation. To address this issue, we propose the implementation of an array of these STDs, each with a distinct resonance frequency. By ensuring that the frequency difference between adjacent STDs is smaller than their individual bandwidths, we achieve a device capable of rectifying signals over a much wider frequency range. To verify the effectiveness of our approach, we have performed analytical calculations based on the Landau–Lifshitz–Gilbert equation with the Slonczewski term, complemented by macrospin modeling and full-scale micromagnetic simulations to account for thermal fluctuations and local magnetization inhomogeneities. Our results demonstrate that an STD array can effectively function as a broadband energy harvester, maintaining near-constant rectification efficiency across a broad frequency range. This research establishes the groundwork for the development of broadband energy harvesters based on STD arrays, with potential applications in various fields requiring efficient energy conversion across a wide frequency spectrum. [ABSTRACT FROM AUTHOR]

Thermophotovoltaic (TPV) systems can be used to harvest thermal energy for thermoelectric conversion with much improved efficiency and power density compared with traditional photovoltaic systems. As the key component, selective emitters (SEs) can re-emit tailored thermal radiation for better matching with the absorption band of TPV cells. However, current designs of the SEs heavily rely on empirical design templates, particularly the metal-insulator-metal (MIM) structure, and lack of considering the overall performance of TPV systems and optimization efficiency. Here, we utilized a deep reinforcement learning (DRL) method to perform a comprehensive design of a 2D square-pattern metamaterial SE, with simultaneous optimization of material selections and structural parameters. In the DRL method, only the database of refractory materials with gradient refraction indexes needs to be prepared in advance, and the whole design roadmap will automatically output the SE with optimal Figure-of-Merit (FoM) efficiently. The optimal SE is composed of a novel material combination of TiO2, Si, and W substrate, with its thickness and structure precisely optimized. Its emissivity spectra match well with the external quantum efficiency curve of the GaSb cell. Consequently, the overall performance of TPV is significantly enhanced with an output power density of 5.78 W/cm2, an energy conversion efficiency of 38.26%, and a corresponding FoM of 2.21, surpassing most existing designs. The underlying physics of optimal SE is explained by the coupling effect of multiple resonance modes. This work advances the practical application potential of TPV systems and paves the way for addressing other multi-physics optimization problems and metamaterial designs. [ABSTRACT FROM AUTHOR]

This study explores the enhancement of thermoelectric response in a zigzag chain through irradiation with arbitrarily polarized light. The irradiation induces changes in hopping strengths, creating an asymmetric transmission profile around the Fermi energy, which is a crucial factor for achieving a higher figure of merit (FOM). Specific light configurations result in an FOM exceeding unity. We employ the Floquet–Bloch ansatz and minimal coupling scheme to model the irradiation effect, with transport properties evaluated using Green's function technique within the Landauer–Büttiker formalism. The investigation covers electrical conductance, thermopower, and thermal conductance due to electrons and phonons. Our research deepens understanding and opens avenues for tailoring nanostructures to fine-tune thermoelectric properties, advancing highly efficient energy conversion devices exploiting irradiation effects. [ABSTRACT FROM AUTHOR]

The entropy change causing dipolar depolarization is proposed as an origin of electrical power generation in triboelectric generators using polar materials. Rubbing mechanically forces permanent dipoles in materials to become orientationally ordered, establishing a low entropy state with an initial dipolar polarization P 0. In this state, the electric field within the materials is zero, but a nonzero Helmholtz free energy F = F 0 = P 0 2 2 (C s − C ∞) arises from the entropy contribution (C s , static capacitance; C ∞ , capacitance at high frequency). Consequently, this state is energetically unstable and undergoes a spontaneous transition into a disordered high entropy state with F < F 0 , resulting in the establishment of a non-zero electric field. Through this process, the energy bounded in materials as the entropy component of free energy is converted, and the electrical energy becomes F 0 η with η = 1 − C ∞ C s (0 < η < 1). Electrical circuit analysis shows that this energy conversion process can be well represented by introducing a virtual resistance R p = τ C s − C ∞ (τ , dipolar relaxation time). This suggests that the entropy change in finite time τ serves as the origin of electrical power generators. Under the matching condition τ = C s R , the power spectrum at the load is best aligned with that at the generator, maximizing the power transmission. The results presented here serve as a basis for understanding the principle of electric power transmission in triboelectric generators through dipolar depolarization. [ABSTRACT FROM AUTHOR]

Photocurrent measurements are widely used to study the intrinsic optoelectronic properties of semiconductors, such as photocarrier generation efficiency and carrier mobility, as well as evaluate the performance of optoelectronic devices, such as solar cells and photodetectors. Interferometric spectroscopy precisely measures optical properties and gathers optical spectra information on semiconductors. Consequently, photocurrent-based interferometric measurements, with high signal-to-noise ratios, high resolution, and broad frequency bandwidths, can probe the energy distributions of low-density defects and impurities and investigate charge transport in materials and devices. Here, we demonstrate that photocurrent interference spectroscopy reveals the intrinsic properties of solar-cell materials: bulk crystals of GaAs and halide perovskite, and thin films of halide perovskite and quantum dot. We show that homodyne interference spectroscopy of photocurrent can monitor low-density localized states in semiconductors and that it can be used in combination with other spectroscopy techniques, such as photoluminescence measurements, to provide a deep understanding of photocurrent generation processes. Furthermore, we show that heterodyne interference spectroscopy of photocurrent can be used to investigate the frequency dependence of material parameters, such as the dielectric constant, absorption coefficient, and reflectance. As an application, we used interference spectroscopy of photocurrent to show the impact of multiexcitons on the photoabsorption and photocarrier generation processes in quantum dot solar cells. Finally, we used it to reveal the distinctive spectral characteristics at the band edge of a halide perovskite, which is considered to be an exceptional solar-cell material with high energy conversion efficiency. [ABSTRACT FROM AUTHOR]

The chemical flexibility of metal-organic frameworks (MOFs) offers an ideal platform to tune structure and composition for specific applications, from gas sensing to catalysis and from photoelectric conversion to energy storage. This variability gives rise to a large configurational space that can be efficiently explored using high-throughput computational methods. In this work, we investigate from first principles the structural and electronic properties of MOF-5 variants obtained by replacing Zn with Be, Mg, Cd, Ca, Sr, and Ba and by functionalizing the originally H-passivated linkers with CH3, NO2, Cl, Br, NH2, OH, and COOH groups. To build and analyze the resulting 56 structures, we employ density-functional theory calculations embedded in an in-house developed library for automatized calculations. Our findings reveal that structural properties are mainly defined by metal atoms and large functional groups, which distort the lattice and modify coordination. The formation energy is largely influenced by functionalization and enhanced by COOH and OH groups, which promote the formation of hydrogen bonds. The charge distribution within the linker is especially influenced by functional groups with electron-withdrawing properties, while the metal nodes play a minor role. Likewise, the bandgap size is crucially determined by ligand functionalization. The smallest gaps are found with NH2 and OH groups, which introduce localized orbitals at the top of the valence band. This characteristic makes these functionalizations particularly promising for the design of MOF-5 variants with enhanced gas uptake and sensing properties. [ABSTRACT FROM AUTHOR]

An analytical device physics model is presented for determining the energy conversion efficiency of semiconductor nanowire array-based radial (core–shell) p-i-n junction betavoltaic cells for two- and three-dimensional radioisotope source geometries. Optimum short-circuit current density J sc , open-circuit voltage V oc , fill factor F F , and energy conversion efficiency η are determined for various nanowire properties, including dopant concentration, nanowire length, core diameter, and shell thickness, for Si, GaAs, and GaP material systems. A maximum efficiency of 8.05 % was obtained for GaP nanowires with diameter 200 nm (p-core diameter, i-shell, and n-shell thicknesses of 24, 29.4, and 58.6 nm, respectively), length 10 μ m , acceptor and donor concentrations of 10 19 and 5 × 10 18 cm − 3 , respectively, and a 3D source geometry. [ABSTRACT FROM AUTHOR]

Efficient thermoelectric energy conversion at the nanoscale could power the Internet of Things and cool nanoelectronic circuits and improve the performance of quantum applications. Width-modulated nanowaveguides are suitable for these purposes because their thermoelectric efficiency can be geometrically tuned and integrated into the nanoelectronics industry processes. They are attracting increasing research interest stimulated by theoretical predictions for exceptional performance. To validate their potential, a better understanding of the effect of width modulation on thermoelectric efficiency is needed. So far, it is considered that (a) the thermoelectric efficiency increases monotonically with increasing width-mismatch due to decreasing phonon thermal conduction taking place without significantly affecting electron transport, (b) width-mismatch dominates the effect of width modulation in transport, and (c) phonons play the main role in increasing the thermoelectric efficiency. Here, we demonstrate counterevidence based on an investigation of the effect of width modulation on electrons so far overlooked. We reveal that (a) the thermoelectric efficiency varies non-monotonically with the modulation mismatch due to quantum effects on electron transport, (b) the modulation mismatch is quantified by the size-mismatch of the modulation rather than by the width-mismatch, and (c) it is electrons rather than phonons that play the main role in optimizing width modulation for maximum thermoelectric efficiency when quantum effects dominate. Our findings indicate that research should reorient from large width-mismatch toward optimal modulation-mismatch width-modulated nanostructures to enhance thermoelectric efficiency due to quantum effects. Our work provides new insight for designing nanowaveguides for efficient thermoelectric energy conversion at the nanoscale. [ABSTRACT FROM AUTHOR]

Roughly, 50% of primary energy worldwide is rejected as waste heat over a wide range of temperatures. Waste heat above 573 K has the highest Carnot potential (> --> 50 %) to be converted to electricity due to higher Carnot efficiency. Thermoelectric (TE) materials have gained significant attention as potential candidates for efficient thermal energy conversion devices. Silicon nanowires (SiNWs) are promising materials for TE devices due to their unique electrical and thermal properties. In this study, we report the successful fabrication of high-quality double-sided SiNW arrays using advanced techniques. We engineered the double-sided structure to increase the surface area and the number of TE junctions, enhancing TE energy conversion efficiency. We also employed non-agglomeration wire tip engineering to ensure uniformity of the SiNWs and designed effective Ohmic contacts to improve overall TE efficiency. Additionally, we post-doped the double-sided SiNW arrays to achieve high electrical conductivity. Our results showed a significant improvement in the TE performance of the SiNW array devices, with a maximum figure-of-merit (ZT) value of 0.24 at 700 K, fabricated from the single SiNW with ZT of 0.71 at 700 K in our previous work [Yang et al., Nat. Commun. 12(1), 3926(2021)]. [ABSTRACT FROM AUTHOR]

Direct thrust measurements are performed on a circular waveguide electron cyclotron resonance (ECR) thruster working at 5.8 GHz using a pendulum thrust balance with mechanically amplified displacement. Thrust levels between 1 and 3.5 mN are found for power levels in the range of 60–350 W and xenon flow rate between 2 and 8 SCCM. A maximum thrust efficiency of 3.5% is reached at 2 SCCM and 60 W. Plasma plume diagnostics are used to estimate the thruster partial efficiencies to understand the main losses, and to perform a comparative analysis between directly and indirectly measured thrust. Results suggest that the low energy conversion efficiency and propellant utilization efficiency (< 6.4 % and < 53%, respectively) are the key factors spoiling the ECR thruster performance. Finally, retarding potential analyzer measurements show the presence of energetic electrons with energy tail up to about 300 eV. [ABSTRACT FROM AUTHOR]

The choice of exchange functional is a critical factor in determining the energy bandgap of semiconductors. Ab initio calculations using different exchange functionals, including the conventional generalized-gradient approximation (GGA) functionals, meta-GGA functionals, and hybrid functionals, show significant differences in the calculated energy bandgap for semiconducting half-Heusler compounds. These compounds, which have 18 valence electrons per unit cell, are of great interest due to their thermoelectric properties, making them suitable for energy conversion applications. In addition, accounting for electronic correlations using the G W method also affects the calculated energy bandgaps compared to standard GGA calculations. The variations in calculated energy bandgaps are specific to each material when using different functionals. Hence, a detailed investigation of the electronic properties of each compound is necessary to determine the most appropriate functional for an accurate description of the electronic properties. Our results indicate that no general rules can be established and a comparison with experimental results is required to determine the most appropriate functional. [ABSTRACT FROM AUTHOR]

Pandit[1] provides a review on the application of magic angle spinning nuclear magnetic resonance (NMR) spectroscopy and related techniques, with which it is possible to access the motion of proteins, pigments, and lipids on sub-nanoseconds to millisecond timescales on very different length scales ranging from solubilized complexes to whole cells. Remarkably, the spectral density includes 50 high-frequency vibrational modes per pigment, besides a low-frequency part characterizing the pigment-protein coupling. Using this technique, excitation energy transfer between the bacteriochlorophyll a pigments of the LH2 complex of purple bacteria is studied. Two important points dealt with in the present Special Topic issue on "Photosynthetic Light-Harvesting and Energy Conversion" are the following: (i) Pigment-protein complexes undergo conformational transitions on many different timescales that include transitions between functionally relevant modes of light harvesting and photoprotection. [Extracted from the article]

An innovative electromagnetic energy harvester was developed using a compact four-ring single-resistor unit cell. To achieve efficient conversion of electromagnetic waves into electricity, we integrated the high-performance Bi2Te3 thermoelectric material onto the load resistor. Remarkably, this unit cell exhibits exceptional energy harvesting capabilities at a frequency of 5.8 GHz while maintaining polarization insensitivity. Through comprehensive analysis, we evaluated the energy harvesting efficiencies, power loss distribution, and current density distribution. Additionally, we investigated the impact of incident power on the unit cell's temperature and energy conversion efficiencies. To enhance energy concentration on the load, we ingeniously designed an "L-shaped" metal through-hole structure within the four-ring single-resistor unit cell. Our results demonstrate that the four-ring single-resistor unit cell achieves an impressive harvesting efficiency of 94.5% at 5.8 GHz, with a thermal conversion efficiency of 43.3 °C/W, an electrical conversion efficiency of 0.23 mV/°C, and an electrical response rate of 9.4 mV/W. Notably, when subjected to a power input of 7 W, the unit cell produces an output voltage of 65.9 mV, and its theoretical maximum output power reaches 180 mW. [ABSTRACT FROM AUTHOR]

The Chemical Communications journal, published by The Royal Society of Chemistry, features articles on recent advances in various chemical fields. Topics covered include functionalization of corroles, transmembrane transporters, electrocatalysts for energy conversion, and synthesis of various compounds. The journal aims to connect the global chemistry community and invest profits back into the field. [Extracted from the article]

The advancement of cutting-edge energy conversion technologies offers significant potential for addressing environmental challenges, enhancing energy security, improving economic competitiveness, and promoting resource conservation. This progress necessitates the development of advanced electrocatalysts. WOx demonstrates high intrinsic catalytic activity, excellent conductivity, an abundance of active sites, and remarkable stability, positioning it as a promising candidate for electrocatalytic reactions. Recently, there has been swift advancement in the development of WOx-based catalysts for various energy-conversion reactions. This review provides a thorough summary of recent developments in WOx-based catalysts for electrocatalytic reactions, emphasizing their multifunctional roles as active species, electron-transfer carriers, hydrogen spillover carriers, and microenvironment regulators. Moreover, it highlights the applications of WOx-based catalysts across different electrocatalytic reactions, with particular focus on the structure–activity relationship. Finally, the review discusses the challenges and future directions of these technologies, as well as key research areas necessary for achieving large-scale applications. [ABSTRACT FROM AUTHOR]

Designing low cost, highly active and efficient non-noble metal bifunctional electrocatalysts with remarkable operational reliability for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is indispensable for large-scale water electrolysis and the development of clean energy conversion technologies. Herein, we decorated a two-dimensional (2D) selenium-blended zirconium dioxide (Se-ZrO2) on the surface of a nitrogen-doped carbon heterostructure (Se-ZrO2@NC), which was derived from Zr–metal–organic frameworks (Zr-MOFs), and loaded it on a stainless-steel mesh electrode. Accordingly, phenomenal electrocatalytic performance was observed for the Se-ZrO2@NC-loaded electrode with a minimum overpotential of 48 mV for the HER and 251 mV for the OER at 10 mA cm−2 current density in acidic and alkaline mediums, respectively. Moreover, a complete cell set up was constructed, where the OER and HER were studied at the anode and cathode, respectively, with a cell potential of 1.58 V to reach a current density of 10 mA cm−2 together with an exciting long-term stability of over 48 h. The developed Se-blended 2D transition metal dioxides on the 2D nitrogen-doped carbon heterostructure extended to a variety of catalytically active materials that would provide highly active and stable electrocatalysts for alkaline water splitting studies. [ABSTRACT FROM AUTHOR]

The microwave-to-plasma energy conversion efficiency and the ease of plasma self-ignition are critical factors affecting the applications for microwave plasma sources (MPSs). This study presents a novel MPS utilizing dielectric wedges for self-ignition and improved energy conversion. Firstly, we crafted a dielectric wedge with a gradient refractive index, guiding the electric field from air to dielectric materials and facilitating microwave propagation along the dielectric in a waveguide. Through electromagnetic simulation, we explored how the size and permittivity of the dielectric wedge affect the electric field distribution. Then, the MPS based on the dielectric wedge was designed. In this configuration, a dielectric tube encloses the discharge tube, connecting to dielectric wedges to guide electromagnetic waves to the plasma. We analyzed the MPS performance using the Drude model, evaluating microwave energy conversion efficiency across various electron densities and collision frequencies. The results were compared with a commonly used MPS based on a tapered waveguide, demonstrating the proposed MPS has wider applicability across different operation conditions. Finally, experiments under low pressures were conducted using various gases, showing an average energy conversion efficiency of approximately 40% higher than the tapered waveguide MPS. The experiments also indicate the proposed MPS has a greater capability of self-ignition at lower power levels. These findings highlight the efficacy of incorporating dielectric wedges to enhance MPS performance, making it conducive for broader industrial applications. [ABSTRACT FROM AUTHOR]

Osmotic energy from the ocean has been thoroughly studied, but that from saline‐alkali lakes is constrained by the ion‐exchange membranes due to the trade‐off between permeability and selectivity, stemming from the unfavorable structure of nanoconfined channels, pH tolerance, and chemical stability of the membranes. Inspired by the rapid water transport in xylem conduit structures, we propose a horizontal transport MXene (H‐MXene) with ionic sequential transport nanochannels, designed to endure extreme saline‐alkali conditions while enhancing ion selectivity and permeability. The H‐MXene demonstrates superior ion conductivity of 20.67 S m−1 in 1 M NaCl solution and a diffusion current density of 308 A m−2 at a 10‐fold salinity gradient of NaCl solution, significantly outperforming the conventional vertical transport MXene (V‐MXene). Both experimental and simulation studies have confirmed that H‐MXene represents a novel approach to circumventing the permeability‐selectivity trade‐off. Moreover, it exhibits efficient ion transport capabilities, addressing the gap in saline‐alkali osmotic power generation. [ABSTRACT FROM AUTHOR]

The development of active, stable, and more affordable electrocatalysts for acidic oxygen evolution reaction (OER) is of great importance for the practical application of electrolyzers and the advancement of renewable energy conversion technologies. Currently, IrO2 is the only catalyst with high stability and activity, but a high cost. Further optimization of the catalyst is limited by the lack of understanding of catalytic behaviors at the acid‐IrO2 interface. Here, in strong interaction with the experiment, we develop an explicit model based on grand‐canonical density function theory (GC‐DFT) calculations to describe acidic OER over IrO2. Compared to the explicit models reported previously, hydronium cations (H3O+) are introduced at the electrochemical interface in the current model. As a result, a variation in stable IrO2 surface configuration under the OER operating condition from previously proposed complete *O‐coverage to a mixture coverage of *OH and *O is revealed, which is well supported by in situ Raman measurements. In addition, the accuracy of predicted overpotential is increased in comparison with the experimentally measured. More importantly, an alteration of the potential limiting step from previously identified *O→*OOH to *OH→*O is observed, which opens new opportunities to advance the IrO2‐based catalysts for acidic OER. [ABSTRACT FROM AUTHOR]

Proton-conducting solid oxide fuel cells (H–SOFCs) are promising devices for efficient chemical-to-electrical energy conversion at low temperatures. Extensive research has focused on enhancing the catalytic activity of cathodes. In this study, we employ a Sn doping strategy to modify the Ruddlesden-Popper structured La 2 NiO 4+δ (LNO) cathode. Experimental results demonstrate that Sn doping significantly improve the oxygen reduction reaction (ORR) activity and protonation capability of the cathode. First-principles calculations further reveal that the La 2 Ni 1-x Sn x O 4+δ (LNSOx) cathode exhibits a lower oxygen vacancy formation energy compared to bare LNO. The peak power density of H–SOFCs with Sn-doped LNO reaches 1563 mW cm−2 at 700 °C, notably higher than previously reported LNO-based H–SOFCs. These findings confirm the potential of Sn-doped LNO as an effective cathode material for H–SOFCs. • Sn Doping significantly improve the oxygen reduction reaction (ORR) activity. • A peak power density of 1563 mW cm−2 is reached at at 700 °C. • Sn Doping effectively reduces the extent of CO 2 chemical adsorption. [ABSTRACT FROM AUTHOR]

This study presents and analyses three plant configurations of the Ocean Thermal Energy Conversion (OTEC) technology. All the solutions are based on using the OTEC system to obtain hydrogen through an electrolyzer. The hydrogen is then compressed and stored. In the first and second layouts, a Rankine cycle with ammonia and a mixture of water and ethanol is utilised respectively; in the third layout, a Kalina cycle is considered. In each configuration, the OTEC cycle is coupled with a polymer electrolyte membrane (PEM) electrolyzer and the compression and storage system. The water entering the electrolyzer is pre-heated to 80 °C by a solar collector. Energy, exergy, and exergo-economic studies were conducted to evaluate the cost of producing, compressing, and storing hydrogen. A parametric analysis examining the main design constraints was performed based on the temperature range of the condenser, the mass flow ratio of hot and cold resource flows, and the mass fraction. The maximum value of the overall exergy efficiency calculated is equal to 93.5% for the Kalina cycle, and 0.524 €/kWh is the minimum cost of hydrogen production achieved. The results were compared with typical data from other hydrogen production systems. [Display omitted] • An OTEC based offshore hydrogen production system is analysed by exergo-economics. • Three different OTEC cycles are compared: two Rankine and Kalina. • System includes OTEC, electrolyzer, H 2 compression, water desalination and heating. • Kalina cycle is the best performing, with 93.5 %, 83–87% for Rankine. • The cost of H 2 from Kalina OTEC is estimated at 17.3 €/kg (0.52 €/kWh). [ABSTRACT FROM AUTHOR]

The design and construction of stable and inexpensive bifunctional catalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) present a challenge in electrocatalytic water splitting. In this study, we utilized zeolitic imidazolate frameworks-8 (ZIF-8) as the precursor to fabricate ZnS-ZIF-8 via facile sulfidation processes. The ZnS-ZIF-8 nanostructures were anchored on the surface of the nickel nanowire (denoted as Ni NWs@ ZnS-ZIF-8 nanocomposite) and their catalytic activity for HER, OER, and overall water splitting were studied. The prepared Ni NWs@ ZnS-ZIF-8 revealed a low overpotentials value of 90 and 260 mV at 10 mA cm−2 for HER and OER in 1.0 M KOH solution, respectively. The alkaline electrolyzer assembled by Ni NWs@ ZnS-ZIF-8 provides a low cell voltage of 1.61 V at 10 mA cm−2 current density to boost the overall water splitting and robust stability for 15 h. The superior electrocatalytic activity of Ni NWs@ ZnS-ZIF-8 is owing to the facile and effective electron transport of Ni NWs, accessible active sites of ZnS-ZIF-8, and as well as the synergistic effect of the nanocomposite structures. This finding presents a viable methodology for synthesizing a proficient noble-metal-free catalyst for energy conversion and storage. [Display omitted] • Ni NWs@ S-ZIF8 composite was synthesized. • The as-prepared Ni NWs@ S-ZIF8 exhibits stability over 24 h. • The electrocatalyst revealed overpotentials of 90 and 260 mV at 10 mA cm−2 for HER and OER. [ABSTRACT FROM AUTHOR]

Crystalline and soluble 1D linear conjugated polymers (LCPs) have garnered considerable interest as cost‐effective and efficient metal‐free electrocatalysts for the oxygen reduction reaction (ORR) due to their high exposure of catalytic sites and ease of processing. However, difficulties remain in achieving excellent ORR performance for 1D LCPs by conventional molecular design. Herein, it is demonstrated the utilization of quinoidal units as a promising strategy to develop 1D LCPs for ORR. The incorporation of quinoidal unit not only results in polymers with strong inter‐ and intra‐molecular interactions and low‐lying LUMO (lowest unoccupied molecular orbital) energy levels, but also provides polymers with good crystallinity and commendable charge carrier mobilities. The electronic properties of these polymers are fine‐tuned through the introduction of additional heteroatoms and/or substituents in the monomers and comonomers to understand and optimize their ORR catalytic activity. Evaluation of their catalytic performances reveals a remarkable half‐wave potential and limiting current density of up to 0.74 V (vs reversible hydrogen electrod) and 7.50 mA cm−2, respectively. Notably, these performances are achieved without the addition of carbon nanomaterials as support. This study offers a new insight into the design of highly efficient metal‐free organic electrocatalysts. [ABSTRACT FROM AUTHOR]

Sub-ion-scale magnetic holes (MHs) are ubiquitous structures in plasmas across a wide range of environments. Despite previous observational and modeling efforts, the three-dimensional (3D) electric field in MHs has yet to be adequately resolved. In this study, utilizing high-resolution measurements of an MH (∼0.08 ρ i × 0.14 ρ i ) from the Magnetospheric Multiscale mission in Earth's turbulent magnetosheath, we report this 3D electric field and unveil its roles and generation mechanism. A model is established to quantify the impacts of E ∥ on increasing the loss cone of trapped electrons. The electric field is attributed to electron convection and pressure gradient terms of generalized Ohm's law. The MH, primarily coupling to the electron, is accompanied by electron jets. These electron jets can be interpreted as different segments of an electron vortex. These electron jets combined with nonideal electric fields not only lead to strong energy conversion ( j · ( E + v e × B ) ∼ 40 nW m−3) from the electromagnetic field to electrons but also enable energy conversion between different electron motion directions. Our study significantly clarifies the physical image of kinetic-scale MHs. [ABSTRACT FROM AUTHOR]

Reversible solid oxide cells (RSOCs) are highly efficient energy conversion devices for electricity generation and hydrogen production. However, their commercialization is significantly hindered by the slow oxygen reduction/evolution reaction (ORR/OER) activity of oxygen electrodes and the insufficient durability of the RSOCs. Herein, an active and durable PrBa 0.8 Ca 0.2 Co 1.5 Fe 0.5 O 5+ δ –Ce 0.8 Gd 0.2 O 2-δ (PBCCF–GDC) composite oxygen electrode with mediate thermal expansion is developed, achieving a low polarization resistance of 0.058 Ω cm2 at 750 °C. The PBCCF–GDC oxygen electrode has been applied and evaluated in both the button cell (Φ = 20 mm) and large-area cell (10 × 10 cm2), respectively. When utilized as an oxygen electrode in button cell, it achieves a peak power density of 0.88 W cm−2 in the fuel cell (FC) mode, and a current density of −1.51 A cm−2 at 1.3 V with 70% H 2 O in the electrolysis cell (EC) mode at 750 °C, and favorable stability in the both FC and EC modes. When utilized in large-area cell, it exhibits a power of 29.5 W and good stability over 330 h, and an impressive electrolysis current of −27A at 1.3 V with 70% H 2 O at 750 °C. The results indicate that PBCCF–GDC is a promising oxygen electrode material for RSOCs. [Display omitted] • Button and large-area cells with PBCCF–GDC composite oxygen electrode are prepared. • The PBCCF–GDC oxygen electrode exhibits excellent ORR/OER activity. • The large-area cells exhibit good durability in both FC and EC modes at 750 °C. • The scalability of PBCCF–GDC oxygen electrode in large-area RSOCs is proved. [ABSTRACT FROM AUTHOR]

The advancement of energy storage and conversion technologies critically depends on developing superior electrode materials characterized by high specific capacitance and exceptional electrocatalytic properties. In this study, we successfully synthesized a novel ZnCo 2 O 4 @NiCo-LDH nanoelectrode material using the hydrothermal method. This composite exhibited an impressive specific capacitance of 1118 C g−1 at a current density of 1 A g−1. The resulting supercapacitor demonstrated a high energy density of 15.56 μWh cm−2 at a power density of 0.825 mW cm−2. Notably, after 10000 cycles, the material retained 79.7% of its initial capacity, underscoring its substantial cyclic stability and potential for supercapacitor applications. Furthermore, the ZnCo 2 O 4 @NiCo-LDH material displayed excellent electrocatalytic properties, with an overpotential of 54.2 mV for the Hydrogen Evolution Reaction (HER) at a current density of 10 mA cm−2 and a Tafel slope of 48.69 mV dec−1. For the Oxygen Evolution Reaction (OER), it showed an overpotential of 296.1 mV and a Tafel slope of 24.13 mV dec−1. These results indicate that the ZnCo 2 O 4 @NiCo-LDH nanoelectrode material is highly promising for high-performance supercapacitors and electrocatalytic water splitting applications, paving the way for new developments in energy storage and conversion technologies. • Composite: High specific capacitance of 1118 C g−1 at 1 A g−1 current density. • Supercapacitor: 15.56 μWh cm−2 energy density at 0.825 mW cm−2 power density. • For HER, the overpotential is 54.2 mV with a Tafel slope of 48.69 mV dec−1. • For OER, the overpotential is 296.1 mV with a Tafel slope of 24.13 mV dec−1. • ZnCo 2 O 4 @NiCo-LDH: High performance for supercapacitors and water splitting. [ABSTRACT FROM AUTHOR]

The technological implementation of electrochemical energy conversion and storage necessitates the acquisition of high-performance electrocatalysts and electrodes. Carbon encapsulated nanoparticles have emerged as an exciting option owing to their unique advantages that strike a high-level activity–stability balance. Ever-growing attention to this unique type of material is partly attributed to the straightforward rationale of carbonizing ubiquitous organic species under energetic conditions. In addition, on-demand precursors pave the way for not only introducing dopants and surface functional groups into the carbon shell but also generating diverse metal-based nanoparticle cores. By controlling the synthetic parameters, both the carbon shell and the metallic core are facilely engineered in terms of structure, composition, and dimensions. Apart from multiple easy-to-understand superiorities, such as improved agglomeration, corrosion, oxidation, and pulverization resistance and charge conduction, afforded by the carbon encapsulation, potential core–shell synergistic interactions lead to the fine-tuning of the electronic structures of both components. These features collectively contribute to the emerging energy applications of these nanostructures as novel electrocatalysts and electrodes. Thus, a systematic and comprehensive review is urgently needed to summarize recent advancements and stimulate further efforts in this rapidly evolving research field. [ABSTRACT FROM AUTHOR]

Photocatalysts for hydrogen evolution reaction (HER) have widely been explored but fine-tuning and engineering multiphase photocatalyst components are still challenging. Among catalysts, ZnIn 2 S 4 has shown promise but maximizing the use of ZnIn 2 S 4 -photogenerated carriers and enhancing quantum yield still require further investigation. One way to achieve this is by enhancing the photon utilization and reducing the recombination of shallow carriers in ZnIn 2 S 4. Accordingly, novel ZnIn 2 S 4 /g-C 3 N 4 /MoS 2 type-II heterojunction composites with 2D/2D/2D structures (abbreviated ZIS/CN/MS) were synthesized in the present work by simple thermal condensation-solvothermal method. The optimized ZIS/CN/MS exhibited a photocatalytic hydrogen evolution rate of 13.6 mmol g−1 h−1 under visible light (λ ≥ 420 nm) irradiation, a value much higher than those of pure-phases ZIS and CN, as well as the binary composite of ZIS/CN. The apparent quantum efficiency of the optimized ZIS/CN/MS at a wavelength of 420 nm reached 27.0 % coupled with excellent cycling stability. The significantly improved photocatalytic performance and the excellent stability can mainly be attributed to the unique 2D/2D/2D arrangement of the ternary components of ZIS, CN, and MS in ZIS/CN/MS photocatalyst, providing a large number of close interfacial contacts between the components for shortened migration distance of photogenerated charges and more pathways for electron separation and transport in type-II heterostructures. Overall, the proposed methodology and ZIS/CN/MS composites with type-II heterojunction and 2D/2D/2D structures have great potential for use in solar-to-hydrogen energy conversion and can be extended to the preparation of other photocatalysts. [Display omitted] • 2D/2D/2D ZnIn 2 S 4 /g-C 3 N 4 /MoS 2 hybrid junction enhances dielectric properties. • New structure provides close interfacial contact and pathway for electron separation. • Unique 2D/2D/2D arrangement improves photocatalytic performance and stability. [ABSTRACT FROM AUTHOR]

Metal oxides have attracted much attention due to their potential in electromagnetic wave absorption. However, the inherent energy dissipation capabilities of low-entropy metal oxides pose challenges in designing materials with optimal entropy levels. The regulation of entropy structure is anticipated to facilitate the development of novel electromagnetic functional materials featuring abundant active sites, adjustable specific surface area, stable crystal structure, unique geometric compatibility, and distinctive electronic structure. This study compared the electromagnetic loss performance of low, medium, and high entropy metal oxides in carbon matrices. As entropy increases, the number of phases expands, leading to enhanced interface polarization losses and improved impedance matching. However, further increases in entropy result in performance decline due to lattice distortions and mismatches in dielectric constant and magnetic permeability. Experimental data and theoretical analysis reveal that performance enhancement in medium-to high-entropy metal oxides is attributed to their unique morphology and the synergistic effects of multiple metal components, which enhance interfacial and defect polarization mechanisms. Heterogeneous interfaces and lattice defects provide additional polarization sites, aiding in the conversion of electromagnetic energy into heat. The presence of intermediate phases effectively absorbs and dissipates electromagnetic waves, thereby enhancing the overall absorption capability. [ABSTRACT FROM AUTHOR]

Anion exchange membrane fuel cells (AEMFCs) are advantageous for reducing or even eliminating the dependency on platinum resources, as the alkaline environment allows the use of non‐precious metal catalysts for oxygen reduction reaction at the cathode. However, the intrinsic activity of hydrogen oxidation reaction (HOR) catalysts in alkaline environments is 2 to 4 orders of magnitude lower than in acidic environments, which becomes the major challenge for AEMFCs. This review examines the current developments in the intrinsic activity of alkaline HOR catalysts and systematically summarizes the hydrogen activation mechanism with a focus on potential influencing factors and enhancement strategies. Furthermore, it offers insights into the prospects for developing more efficient alkaline HOR catalysts. [ABSTRACT FROM AUTHOR]

The practical capacity of lithium-oxygen batteries falls short of their ultra-high theoretical value. Unfortunately, the fundamental understanding and enhanced design remain lacking, as the issue is complicated by the coupling processes between Li2O2 nucleation, growth, and multi-species transport. Herein, we redefine the relationship between the microscale Li2O2 behaviors and the macroscopic electrochemical performance, emphasizing the importance of the inherent modulating ability of Li+ ions through a synergy of visualization techniques and cross-scale quantification. We find that Li2O2 particle distributed against the oxygen gradient signifies a compatibility match for the nucleation and transport kinetics, thus enabling the output of the electrode's maximum capacity and providing a basis for evaluating operating protocols for future applications. In this case, a 150% capacity enhancement is further achieved through the development of a universalizing methodology. This work opens the door for the rules and control of energy conversion in metal-air batteries, greatly accelerating their path to commercialization. To realize the theoretical energy density of lithium-oxygen batteries, this work uses the relationship between microscopic phenomena and macroscopic performance. By adjusting lithium-ion concentration, alignment of transport and nucleation kinetics improves and discharge capacity of the electrodes maximized. [ABSTRACT FROM AUTHOR]

The relentless increase in global energy consumption, coupled with the detrimental effects of over‐reliance on non‐renewable fossil fuels, has necessitated a paradigm shift in the energy industry towards sustainable energy sources. Thermoelectric materials have emerged as a promising avenue for harnessing waste heat, offering a viable solution to the dual challenges of energy scarcity and environmental pollution. Compared with traditional electronic thermoelectric materials, ionic thermoelectric (i‐TE) materials have received increasing attention. This review provides an overview of the recent advancements in i‐TE materials based on the thermodiffusion effect, including an in‐depth analysis of the fundamental principle, material design, and potential applications. The significance of material selection is highlighted, with types of i‐TE materials ranging from liquid to quasi‐solid and solid states, each presenting unique advantages and challenges. The innovative microstructural engineering and regulating interactions are identified as key strategies to enhance the thermoelectric performance of i‐TE materials. Furthermore, the applications in capacitors and generators and sensing devices are summarized, demonstrating their potentials in varieties of scenarios. Encouraged by the recent rapid progresses, it is believed that the ionic i‐TE materials and related technology are expected to generate practical impacts in the future solutions for sustainable energy. [ABSTRACT FROM AUTHOR]

Li‐CO2 batteries, as a novel type of secondary battery, show great potential for energy conversion and storage. However, challenges such as large electrode polarization and poor cycling performance, stemming from difficulties in decomposing discharge products, limit their practical application. Here, Ferrocene‐based nickel metal–organic framework (Ni‐Fc) nanosheets structure to act as cathode catalysts, prepared via a one‐pot solvothermal reaction. X‐ray absorption fine structure (XAFS) analysis shows that Ni metal forms abundant catalytic active centers with O coordination of carboxylic acid groups in ferrocene units. The Ni‐Fc‐based battery demonstrates a high discharge capacity of 18636 mAh g−1 and exhibits a cycle life exceeding 2000 h at a current of 200 mA g−1. Density functional theory (DFT) calculations indicate that the stronger interaction of Ni‐Fc with discharge intermediates and enhanced Li adsorption accelerate battery reaction kinetics. This study introduces novel catalyst design concepts aimed at achieving high‐performance CO2 reduction and oxidation, thereby advancing Li‐CO2 batteries toward practical application. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have emerged as promising platforms for the construction of single-atom and dual-atom catalysts (SACs and DACs), owing to their well-defined structures, tunable pore sizes, and abundant active sites. In recent years, the development of COF-based SACs and DACs as highly efficient catalysts has witnessed a remarkable surge. The synergistic interplay between the metal active sites and the COF has established the design and fabrication of COF-based SACs and DACs as a prominent research area in electrocatalysis. These catalytic materials exhibit promising prospects for applications in energy storage and conversion devices. This review summarizes recent advances in the design, synthesis, and applications of COF-based SACs and DACs for oxygen catalysis. The catalytic mechanisms of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are comprehensively explored, providing a comparative analysis to elucidate the correlation between the structure and performance, as well as their functional attributes in battery devices. This review highlights a promising approach for future research, emphasizing the necessity of rational design, breakthroughs, and in-situ characterization to further advance the development of high-performance COF-based SACs and DACs for sustainable energy applications. [ABSTRACT FROM AUTHOR]

A novel nanohybrid architecture comprising an N -doped carbon hollow nanorod housing a semi-coherent Co-Ni/Co 6 Mo 6 C heterojunction was developed for reversible oxygen catalysis. [Display omitted] • N -doped carbon nanorod housing a semi-coherent Co-Ni/Co 6 Mo 6 C heterojunction. • The introduction of Ni sites facilitates directed charge migration. • The semi-coherent interface provides efficient pathways for charge transfer. To achieve high-performance Zn-air batteries (ZABs), the development of bifunctional air electrodes capable of efficiently mediating both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) is imperative. In this study, we present an N -doped carbon hollow nanorod encapsulating a semi-coherent Co-Ni/Co 6 Mo 6 C heterojunction, tailored for reversible oxygen catalysis. This nanohybrid demonstrated an ORR half-wave potential of 0.907 V alongside an OER overpotential of η 10 = 352 mV. When incorporated into ZABs, this catalyst exhibited extraordinary performance metrics, including a high-power density of 343.7 mW/cm2, a specific capacity of 681 mAh/g Zn , and enhanced durability. The distinctive electric field within the heterojunction facilitated electron transfer across the semi-coherent interface during reversible oxygen electrocatalysis, enhancing the adsorption and release of active intermediates. Thus, this heightened ORR-OER catalytic efficiency culminated in superior ZABs performance. Our findings afford a pivotal design paradigm for the advancement of productive bifunctional catalysts within the field of energy conversion technologies. [ABSTRACT FROM AUTHOR]

A layer-by-layer strategy is developed to fabricate transition metal silicates/C architecture to enhance their electrochemical properties. [Display omitted] • Layer-by-layer rGO@NiSiO@NiO/C is rationally designed and fabricated. • The rGO@NiSiO@NiO/C shows fast electron/mass transfer kinetics. • The rGO@NiSiO@NiO/C delivers improved electrochemical performances. • The hybrid supercapacitor device achieves the energy density of 26.7 Wh kg−1 at 343.8 W kg−1. In the wake of the carbon–neutral era, the exploration of innovative materials for energy storage and conversion has garnered increasing attention. While nickel silicates have been a focal point in energy storage research, their application in supercapacitors (SCs) has been relatively underreported due to poor conductivity. A newly designed architecture, designated as rGO@NiSiO@NiO/C (abbreviated for reduced graphene oxide (rGO), nickel silicate (NiSiO), nickel oxide/carbon (NiO/C)), has been developed to enhance the electrochemical performance of NiSiO. The incorporation of inner rGO provides structural support for NiSiO, enhancing conductivity, while the outer NiO/C layer not only boosts conductivity but also safeguards NiSiO from structural degradation and electrolyte dissolution. This architecture eliminates multi-phase mixtures, facilitating rapid electron/mass transfer kinetics and accelerating electrochemical reactions, resulting in exceptional electrochemical properties. The rGO@NiSiO@NiO/C architecture achieves a specific capacitance of 324F·g−1 at 0.5 A·g−1, with a superb cycle performance of ∼ 91 % after 10,000 cycles, surpassing state-of-the-art nickel silicates. Furthermore, the hybrid supercapacitor (HSC) device incorporating the rGO@NiSiO@NiO/C electrode attains an areal capacitance of 159 mF·cm−2 at 2.5 mA·cm−2, a retention ratio of ∼ 98 % after 10,000 cycles, and an energy density of 0.68 Wh·m−2 (26.7 Wh·kg−1) at 3.4 W·m−2 (343.8 W·kg−1). This study presents a layer-by-layer approach for constructing transition metal silicates/C architectures to enhance their electrochemical performance. [ABSTRACT FROM AUTHOR]

The laser-regulated mixed-phase TiO 2 efficiently enhances the hydrogenation or hydroxylization of nitrogen to form NH*/NOxOH*, thereby promoting electrochemical overall nitrogen fixation. [Display omitted] • Laser synthesis has achieved the fabrication of TiO 2 integrated electrodes with controllable phase sites. • The optimized mixed-phase TiO 2 can serve as both anode and cathode, achieving good nitrogen reduction and oxidation activity. • The rutile phase promotes nitrogen adsorption activation, while the anatase phase provides protons and reactive oxygen species. • A dual-electrode coupled system constructing by mixed-phase TiO 2 achieves a breakthrough in overall electrocatalytic nitrogen fixation. Traditional oxide electrocatalytic materials encounter significant challenges associated with sluggish reaction kinetics and formidable energy barriers for NH intermediates formation in electrocatalytic nitrogen fixation. The implementation of phase control emerges as an effective strategy to address these challenges. Herein, leveraging the energy localization of laser, this work achieved precise phase control of TiO 2. In the optimized material system, the rutile phase TiO 2 facilitates nitrogen adsorption, while the anatase phase TiO 2 provides proton sources and active oxygen species. The synergistic effect of the two phases effectively enhances the electrocatalytic activity for nitrogen reduction and oxidation, with an ammonia yield reaching ∼22.3 μg h-1 cm-2 and a nitrate yield reaching ∼60.9 μg h-1 cm-2. Furthermore, a coupled dual-electrode system with mixed-phase titanium dioxide as both the anode and cathode successfully achieved a breakthrough in electrochemical overall nitrogen fixation. This laser precision control strategy for manipulating phase sites lays the groundwork for designing efficient catalysts for energy conversion and even energy storage nanomaterials. [ABSTRACT FROM AUTHOR]

To improve the combustion performance and energy conversion, a dual-inlet combustor is proposed for H 2 /NH 3 powered generator. Effects of the dual-inlet employment, equivalence ratio, and H 2 /NH 3 blending ratios on combustion characteristics and thermal performance are analyzed under different conditions. And the maximum error between simulation and experiment is 58 K. Results indicate that the dual-inlet significantly alters the reactions, flame regime and enhances heat transfer. Furthermore, a small proportion of H 2 /NH 3 /air from secondary inlet cause a noticeable increase of OH radical to promote reactions at the burner downstream, forming of the weak flame and increasing gas temperature. The burner achieves optimal radiation performance at m NH3 = 30%. The dual-inlet burner consistently outperforms the single-inlet burner, and the highest radiant power 74.5 W is obtained at V f = 800 mL/min and m NH3 = 30% with 5% premixed reactants from the second inlet, while the highest energy efficiency 56.3% is achieved at V f = 600 mL/min. [Display omitted] • A micro planar with dual-inlets are proposed for zero carbon combustion. • Optimal H 2 /NH 3 mixing ratios and fuel/air ratios at each inlet are selected for enhanced energy efficiency. • Radiant power and efficiency are calculated and analyzed for micro power generation. [ABSTRACT FROM AUTHOR]

Clean energy production is now the main challenge for sustainable future which can be addressed by introducing renewable energy sources. Fuel cells are critical in providing sustainable energy solutions by enabling efficient energy conversion in microgrids. To enhance the performance of fuel cell-based microgrids, advanced controllers and inverters are necessary to manage power quality and stability. One of the key benefits of this fuel cell is the separation of energy conversion and management, which allows independent optimization for each function of microgrid's performance, cost, or other installation considerations. The ability to individually control of each component of a microgrid can significantly impact various applications positively. Beyond their technological and economic advantages, fuel cells are highly sensitivity to microgrid's characteristics such as current quality and harmonics which creates difficulties for their design and management. Therefore, the entire microgrid must be managed by an effective energy management strategy and integration of advanced inverter topologies. This study aims to improve fuel cell efficiency and power quality within the microgrid through an advanced energy management (AEM) strategy. The proposed AEM structure is developed focusing on two key components: a self-regulated controller (SRC) and a switched capacitor multilevel inverter (SCMLI). These elements work together to mitigate the disturbances and enhance the power quality of the system. The methodology includes simulation and hardware-in-the-loop (HIL) testing under non-linear load conditions. Initial grid-side current total harmonic distortion (THD) of 28.38% was reduced to 2.19% through the proposed system. An impact analysis is also presented to demonstrates that reducing current harmonics and voltage imbalance have improved the efficiency of fuel cell to 50.18% and fuel utilization to 98.05%. The findings show that the proposed scheme significantly reduces current harmonics and improves the overall performance benchmark of the microgrid and fuel cell. • An advanced energy management (AEM) is proposed for fuel cell-based microgrid. • A self-regulated controller (SRC) is utilized to reduce computational burden. • Power quality is improved utilizing a 7-level switched capacitor multilevel inverter. • Fuel cell's performance is improved due to improved power quality of the system. [ABSTRACT FROM AUTHOR]

Understanding the origin of ultralow lattice thermal conductivity κL of halide perovskites is of great significance in the energy conversion field. The soft phonon modes and the large anharmonicity corresponding to the dynamic rotation of halogen atoms play an important role in limiting the thermal transport of halide perovskites. The dynamic rotation has long been thought to originate from the electrostatic repulsion of lone pairs around halogen atoms. Here, by studying the layered perovskite Cs3Bi2I6Cl3, it is found that the interaction between the lone pairs contributed by the s bands of halogen atoms is short‐range, and the dynamic rotation is really driven by the occupied p‐band electrons. It dominates Cs3Bi2I6Cl3 with ultralow κL, < 0.2 W mK−1 at 300 K. Moreover, soft optical phonons are presented ≈1 and 2.2 THz that constitute relatively flat and dense bands due to the rattling Cs and Cl atoms, contributing a large glass‐like component to the κL. The results have important implications for understanding the origin of the ultralow κL in halide perovskites and for designing novel perovskites to serve the energy conversion field. [ABSTRACT FROM AUTHOR]

Zn‐air battery (ZAB)‐driven water splitting holds great promise as a next‐generation energy conversion technology, but its large overpotential, low activity, and poor stability for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) remain obstacles. Here, a trifunctional graphene‐sandwiched, heterojunction‐embedded layered lattice (G‐SHELL) electrocatalyst offering a solution to these challenges are reported. Its hollow core‐layered shell morphology promotes ion transport to Co3S4 for OER and graphene‐sandwiched MoS2 for ORR/HER, while its heterojunction‐induced internal electric fields facilitate electron migration. The structural characteristics of G‐SHELL are thoroughly investigated using X‐ray absorption spectroscopy. Additionally, atomic‐resolution transmission electron microscopy (TEM) images align well with the DFT‐relaxed structures and simulated TEM images, further confirming its structure. It exhibits an approximately threefold smaller ORR charge transfer resistance than Pt/C, a lower OER overpotential and Tafel slope than RuO₂, and excellent HER overpotential and Tafel slope, while outlasting noble metals in terms of durability. Ex situ X‐ray photoelectron spectroscopy analysis under varying potentials by examining the peak shifts and ratios (Co2+/Co3+ and Mo4+/Mo6+) elucidates electrocatalytic reaction mechanisms. Furthermore, the ZAB with G‐SHELL outperforms Pt/C+RuO2 in terms of energy density (797 Wh kg−1) and peak power density (275.8 mW cm−2), realizing the ZAB‐driven water splitting. [ABSTRACT FROM AUTHOR]

Over the last decade, there has been significant effort dedicated to both fundamental research and practical applications of biomass-derived materials, including electrocatalytic energy conversion and various functional energy storage devices. Beyond their sustainability, eco-friendliness, structural diversity, and biodegradability, biomass-derived materials provide additional benefits, including naturally organized hierarchical structures, rich surface properties, and an abundance of heteroatoms. These characteristics make them appealing candidates for effective energy storage and electrocatalytic energy conversion applications. This review explores the recent advancements in biomass-derived materials for energy storage system (ESS), including supercapacitors and electrocatalytic reactions. We also address the scientific and technical hurdles associated with these materials and outline potential avenues for future research on biomass-based energy conversion applications. By emphasizing the significance of controllable structural designs and modifications, we highlight their crucial roles in advancing this field. Article Highlights: Biomass-derived materials offer sustainable solutions for energy storage & conversion. Challenges include fabrication of high-quality biomass-derived carbon materials. Future research directions aim to optimize structural designs for enhanced performance. [ABSTRACT FROM AUTHOR]

Electrocatalysis can synthesize kinds of valuable chemicals and plays vital role in developing clean and renewable energy storage and conversion devices. In the traditional electrocatalytic systems, researchers try to synthesize one type of valuable chemical at cathode or anode independently. Recently, electrocatalytic bipolar synthesis of valuable chemicals at both cathode and anode simultaneously becomes popular and attracts much attention. In this minireview, we summarize the latest processes on innovative strategies for electrocatalytic bipolar synthesis of various chemicals. We will discuss the findings according to the categories of the products, including bipolar hydrogen production, bipolar formate production and bipolar hydrogenation. And the associated catalysts optimization, reaction mechanism, and design principles are well introduced. Moreover, the challenges and prospects are highlighted for future developments. This review is timely and will guide others pay more attention to this novel electrocatalytic bipolar synthesis systems. [ABSTRACT FROM AUTHOR]