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• An integrated CCHP system is proposed with one machine synchronously. • A prototype based on a free-piston Stirling configuration was designed and built. • The prototype can obtain the highest values of COPc and COPh of 0.26 and 1.28. • Under typical working conditions, the prototype can achieve an exergy efficiency of 49.3 %. • Compared with the traditional system, the prototype saves at least 39 % of energy consumption. Conventional combined cooling, heating, and power (CCHP) systems, involving multiple energy conversion technologies, are composed of a variety of coupled subsystems with different working principles. To solve the problems of bulky structure, operational complexity, and high initial investment cost, a novel integrated combined heating, cooling, and electricity system based on the same energy conversion technology with a triple-effect free-piston Stirling configuration was proposed. Compared with the traditional system, the novel integrated system can cool, heat, and generate power using one machine without introducing additional devices. Some verification experiments were tested on a built experimental platform to validate the feasibility of the concept of this configuration. The result shows that the system was able to obtain the highest values of COPc, COPh, and the output performance coefficient of 0.26, 1.28, and 1.54, respectively, which can save 39 % of energy consumption compared with traditional independent energy-supplying systems when providing the same cooling and heating capacity and electricity under typical working conditions. It is expected that the reported result can facilitate a practical application in decentralized CCHP systems. [ABSTRACT FROM AUTHOR]

To enhance the piezoelectric properties of poly (vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE))-based composites and prepare a piezoelectric sensor with high sensitivity, two types of potassium sodium niobate (KNN) fillers, micro-particles (MPs) and micro-rods (MRs), were individually doped into a P(VDF-TrFE) matrix to form composites using a traditional solution-casting process. Identically, the two groups of P(VDF-TrFE)-based piezoelectric composites doped with KNN MPs and KNN MRs exhibited an enhanced β -phase and typical ferroelectricity with high residual polarization (P r), which resulted in good piezoelectric constant (d 33) and sensing electrical response. In contrast, the KNN MRs/P(VDF-TrFE) composite showed better piezoelectric output performance compared to the KNN MPs/P(VDF-TrFE) composite in all test scenarios, which is attributed to its depressed dielectric permittivity owing to the ameliorative conductivity dielectric loss. An output voltage (U) of 16 V, 4 V, and 6 V were recorded using 10 g zirconium ball impacting, finger tapping, and finger bending, respectively, in the KNN MRs/P(VDF-TrFE) sensors. This research demonstrates the impact of the filler shape on the electrical performance of P(VDF-TrFE)-based piezoelectric composites, which provides a reliable reference to enhance the energy harvesting and conversion performance of self-powered electronic devices. [ABSTRACT FROM AUTHOR]

The hydrogen evolution reaction (HER) is a cathodic reaction of water splitting which is crucial in energy conversion. However, its wide-scale industrial applicability is limited by the slow reaction kinetics and complex diffusion of generated gas bubbles. In this study, we chose the readily available, low-cost stainless steel as a conductive substrate and feasibly in-situ developed the active phase ZnIn 2 S 4 and Ni-doped ZnIn 2 S 4 on it as a high-rate cathode for HER in acidic, alkaline, and neutral conditions. The Ni-doped electrocatalysts, when compared to bare ZnIn 2 S 4 , have higher electrocatalytic activity for HER, with low overpotentials of only 259 mV and 224 mV, to generate a high current density of 100 mA cm−2 in 0.5 M H 2 SO 4 and 1 M KOH, respectively, exhibiting obviously enhanced performance. The presence of Ni atoms is evident in EDS mapping, TEM analysis, and ICP technique. A detailed analysis of the electrochemical characteristics of the generated electrocatalysts was carried out to gain a better understanding of the effect of additional doping atoms. We not only demonstrate a feasible method for developing unique, stable and efficient HER electrocatalysts in all pH settings by comprehending the collaborative effect of the active phase, doped Ni atoms, and affordable stainless-steel substrate, but also point out new avenue to branch out self-standing HER electrocatalyst categories. • An appropriate large-scale industrial production method. • A simple and universal strategy for increasing HER activity. • Competitive overpotentials in a wide pH range. [ABSTRACT FROM AUTHOR]

The surface reconstruction of the electrocatalysts often occurs in the oxygen evolution reaction (OER), which inevitably leads to the deterioration of stability. Hence, Ce-doped transition metal-hydroxide organic frameworks (Ce-TMHOF) with varying molar ratios of Ce were synthesized using a simple one-step hydrothermal method. The 21%Ce-TMHOF exhibited overpotentials of 200 and 240 mV to achieve current densities of 10 and 100 mA cm−2, respectively. Moreover, it maintained a remarkable efficiency of 98.3% after 110 h of stability testing during the OER process. When incorporated into an anion exchange membrane (AEM) electrolyzer alongside commercial Pt/C electrocatalysts, the 21%Ce-TMHOF maintained an efficiency of 98.8% even after 500 h of testing. Our findings suggest that 4f orbital electron of Ce induce charge redistribution through electronic coupling with Ni and Fe, thereby mitigating surface reconstruction and improving the activity and stability of the electrocatalyst. This study sets a foundation for developing more stable and efficient electrocatalysts for energy storage and conversion applications. [ABSTRACT FROM AUTHOR]

This study investigates the effects of low-level Sr2+ substitutions on the microstructures and electrical properties of BSZT ceramics with formula (Ba 1- x Sr x)(Zr 0·025 Ti 0.975)O 3. The ability of BSZT ceramics to convert energy is assessed based on the piezoelectric coefficient, d 33 associated with the figure of merit (FOM). BSZT ceramics with 0.00 ≤ x ≤ 0.10 were sintered at 1350 °C for 2 h. The XRD measurement confirmed the formation of a single-crystalline phase in all ceramics. All ceramics stabilized in tetragonal crystal structures with progressive decline in tetragonality. It was found that the ceramic with low-level Sr2+ substitutions demonstrated excellent dielectric, piezoelectric and ferroelectric behaviours before gradually deteriorated at higher contents. Systematic deviation of Sr2+ atomic percentage signified broad dielectric curves compared to pristine Ba(Zr 0·025 Ti 0.975)O 3. A significant increase of remnant polarization, P r value (11.21 ± 0.12 μC/cm2) was recorded when x = 0.02, in line with its highest as-sintered density and tetragonality. High d 33 and low ε 33 values contributed to an optimum value of piezoelectric voltage, g 33 coefficient. Consequently, a high FOM comparable to PZT was obtained. The current work successfully demonstrated the preparation of lead-free ceramics based on BaTiO 3 with great potential for energy conversion applications. [ABSTRACT FROM AUTHOR]

For the transformation of energy conversion and photocatalytic decomposition, photocatalyst-based artificial photosynthesis for solar-to green fuels and environmental treatment has aroused great attention. Herein, a novel ternary heterojunction based on constructing an interaction between 2D-graphitic carbon nitride (CN), 3D-strontium titanate (STO) and Pt nanoparticles (NPs) (2D/3D CN/STO@Pt) is designed for the first time to greatly promote photocatalytic water cracking hydrogen (H 2) evolution in an alkalescent environment, such as triethanolamine (TEO) as well as integrating with Rhodamin B (RhB) decomposition. Under optimized conditions, the H 2 productivity over 3D/2D CN/STO@Pt-3 heterostructures (10,005 μmol h−1 g−1) with an apparent quantum yield of H 2 production approaching 47.5% is found to be ∼29.7, 8.5, 1.1, and 1.5-fold as much as that in the CN, CN/STO, CN/STO@Pt-1, and CN/STO@Pt-5 heterojunctions, respectively. An up to 2.5-fold enhancement in the photocatalytic RhB decomposition rate, obtaining 90% within 60 min under visible-light-driven is observed for 3D/2D CN/STO@Pt-3 heterostructures, surpassing that of other samples. The CN/STO@Pt-3 sample shows the highest degradation rate of 3.5 min−1, which is 1.8, 2.8, 4.27 and 4.9 -time higher than that of the CN/STO@Pt-1, CN/STO@Pt-5, CN, and STO samples, respectively. The improved photocatalytic behavior of the heterogeneous structures could be ascribed to i) the type II-heterojunction between 2D CN and 3D STO; and ii) the creation of the Schottky contacts between semiconductors and Pt NPs. The configuration of the type-II heterojunction formed by the two semiconductors of 2D g-C 3 N 4 and 3D STO contributes to improved light absorption ability, and rapid separation and transfer of photoinduced charges. At the same time, the close junction of Pt establishes the Schottky barrier to facilitate efficient electron transfer in the ternary nanostructures, impeding the quick recombination of photoexcited charge carriers, and offering abundant reactive sites, contributing multiple electron pathways for the photoreaction strategy. Increased photocurrent density from the LSV measurement and a declined in PL intensity confirmed the enhanced interfacial charge separation in the tertiary photocatalyst. Furthermore, the CN/STO@Pt-3 ternary heterostructure presents outstanding photocatalytic performance after five cycles, indicating good stability and reusability. This work gives a valuable modification pathway for the establishing multi-channel charge carrier transport for energy conversion and environmental remediation processes. The diagram showing the photocatalytic activity of CN/STO@Pt heterostructures. [Display omitted] • The novel type II-Schottky structures of CN/STO@Pt were synthesized. • The RhB decomposition obtained 90% within 60 min under visible-light-driven. • The photocatalytic H 2 evolution rates reached 10,005 μmol h−1 g−1. • The photocatalytic activity of the ternary sample remains stable after four cycles. [ABSTRACT FROM AUTHOR]

In thermophotovoltaic (TPV) systems, it is crucial that the selective emitters can tailor emission spectrum to match the bandgap of photovoltaic (PV) cells and largely enhance the system efficiency. In this work, a metamaterial emitter based on the metal-insulator-metal (MIM) structure is proposed to obtain the high energy conversion efficiencies. The geometric parameters of MIM emitter have been investigated to obtain an excellent radiation spectrum of emitter composed of W and HfO2. The excellent emission performance of MIM emitter is attributed to the excitation of surface plasmon polariton (SPP) and cavity resonance, and the structure of MIM emitter is insensitive for different polarization modes. The 21 material combinations of MIM emitters have been screened to obtain the optimal emitter matching GaSb and InGaAsSb cells. This work identifies the crucial role of structure and materials into the emitter of a TPV system. In the evaluation of MIM emitter and TPV System, when the operating temperature of emitter increases from 1400 K to 2000 K, the system efficiency of optimal W/HfO2/W MIM emitter increases from 20.26% to 30.41%, while the output electric power increases from 3.59 kW/m2 to 42.48 kW/m2. The phenomenon indicates that the MIM emitter with the optimal material combinations and geometric parameters can significantly improve the matching degree with GaSb and InGaAsSb cells. Our results will be helpful to expand the optimization scope of metamaterial emitters in TPV systems. [ABSTRACT FROM AUTHOR]

In the field of research on renewable energy conversion and storage methods, the development of catalysts with excellent properties and outstanding stability for oxygen evolution reaction (OER) acting at various pH values has become a much-anticipated research focus. RuO 2 as a benchmark OER catalyst, its wide application has always been limited by slow reaction kinetics and limited persistence. In this paper, Mn-doped RuO 2 material was developed and the optimum doping ratio was identified for using as an OER electrocatalyst under general purpose pH media. Mn 0.1 Ru 0.9 O 2 exhibited a lower overpotential value of 224 mV in acidic environment with a Tafel slope value of 51.62 mV dec−1. Moreover, in alkaline and neutral environments, overpotentials of 231 mV and 376 mV were required to obtain a current density of 10 mA cm−2, respectively. In addition, through continuous stability testing over 24 h in alkaline, acidic and neutral solutions, it has been further demonstrated that the Mn-doped RuO 2 material exhibits extremely high stability. The advancements in this research offer crucial insight into the rational development of efficient and durable RuO 2 -based catalysts. [Display omitted] • Mn 0.1 Ru 0.9 O 2 is successfully synthesized by a facile sol-gel method. • Mn doping modulates the electronic structure of RuO 2. • The catalyst exhibits enhanced OER activity and stability in pH-Universal media. [ABSTRACT FROM AUTHOR]

With the energy revolution and the proposal of "double carbon" background, hydrogen energy with rich reserves, clean and low carbon and broad application prospects has gradually become a global hot spot. The combination of seawater hydrogen production and offshore wind power is undoubtedly the focus of research in this field. However, this new research field is not yet mature and is still in its infancy, so in order to reduce unnecessary losses, it is crucial to identify the key risks and prevent them. Secondly, the adaptability of a single model is no longer reliable for the risk assessment of this emerging field, especially the conversion from offshore wind to electric energy to hydrogen energy. Based on the above, this paper first considers the ambiguity and uncertainty of information, as well as the risk attitude of decision makers in the evaluation process, and develops a novel evaluation model. The reliability and optimization of the model are verified by sensitivity analysis and comparative analysis, and a case is introduced for practical analysis. The final results show that the key risks of hydrogen production from offshore wind power are seawater electrolysis technology, hydrogen energy storage technology and high-quality wind energy resources. The overall risk is 0.4198, which is medium risk. Decision-making managers can make targeted risk prevention to reduce losses and promote the stable operation of offshore wind power hydrogen production. [Display omitted] • Offshore wind power combined with seawater hydrogen production. • An improved model based on spherical fuzzy theory and cumulative prospect theory. • Taking China 's first large-scale offshore wind power hydrogen production project as a case study. • Key risks: seawater electrolysis technology, hydrogen storage technology and wind energy resources. • The quantitative result of the overall risk assessment was 0.4198. [ABSTRACT FROM AUTHOR]

Rock brittleness and brittle failure play significant roles in deep underground space stability, unconventional gas extraction drilling, hydraulic fracturing efficiency, and coal mining disaster prevention, and these rock engineering processes involve cyclic loading conditions. However, nearly all the existing rock brittleness indices (BIs) are conducted with monotonic loading, and the variation in brittleness with cyclic loading has not been comprehensively studied. This study rearranged energy evolution and conversion based on stress–strain curves to investigate the existing energy-based rock BIs. Monotonic and cyclic triaxial compression experiments were conducted on red sandstone specimens to investigate the differences in the mechanical properties. This paper proposes a BI based on post-peak energy conversion to evaluate rock brittleness under monotonic and cyclic loadings. This index is defined as the ratio of the extra inputted/released energy to the fracture energy. The results showed that the variations in mechanical parameters in the two types of experiments were consistent at the pre-peak stage and different at the post-peak stage. The value of the proposed BI revealed that rock brittleness under cyclic loading was lower, which conformed with the qualitative analysis of stress–strain curves and macroscopic failure plane. The proposed BI strongly correlated with the mechanical parameters under monotonic and cyclic loading. The applicability verification, compared with the existing energy-based BIs for different rock types, confining pressures, and inclination angles of bedding planes, showed that the novel BI exhibited an excellent linear correlation with the strength parameters and had broad applicability. [ABSTRACT FROM AUTHOR]

Poling parameters and barium titanate (BT) content significantly affect the piezoelectric and dielectric properties of poly(vinylidene fluoride) (PVDF). Selecting the best possible values for these process parameters is indeed a significant challenge. In this study, piezoelectric nanocomposites for high-energy conversion were prepared by mixing PVDF with BT. The dependence of piezoelectric and dielectric properties on process parameters was investigated. The input parameters, including poling temperature, time and voltage, and BT mass fraction, were considered as input variables. A Box-Behnken Design was used to design and analyze the experiments. ANOVA was performed to study the significance of poling parameters and BT mass fraction. An Artificial Neural Network was used to model PVDF-based nanocomposite properties as a function of the four process parameters. A genetic algorithm was applied to search for the optimal poling conditions and BT mass fraction. The optimal combination leads to a d33 coefficient of 25.259 pC/N, a permittivity of 24.282, and a β-phase fraction (F(β)) of 95.435%. These results were experimentally validated, and the errors were 9.789, 0.338, and 0.305%, respectively. Following the optimization, a PVDF-based nanocomposite with excellent piezoelectric and dielectric properties (d33 = 28pC/N, permittivity = 24.2, F(β) = 95.7%) was fabricated for energy conversion applications. [ABSTRACT FROM AUTHOR]

The collapse behaviour of granular materials is influenced by many factors, such as aspect ratio and inter-particle friction. However, the specific impact of basal to grain friction on column collapse remains poorly understood. In this study, we systematically analyse the effect of basal friction on gravity-driven granular column collapse using a validated smoothed particle hydrodynamics (SPH) model. The results show that such the basal friction coefficient does influence deposit geometry, deposit morphology, and energy conversion. To predict the run-out distance, we propose a modified formula that incorporates the basal friction coefficient, considering two extreme cases, i.e., μ = 0 and + ∞. The basal friction also exerts an influence on the final height, with higher friction coefficients resulting in greater final heights. As the friction coefficient increases, the aspect ratio corresponding to the maximum final height also increase. However, we observe a convergence of the effect of basal friction on the final height when μ > 0.5. Furthermore, the competition mechanism between the initial column aspect ratio and basal friction coefficient reveals two transition zones between the three main deposit regimes (regime I, regime II, and regime III). This suggests that the deposit regime can be influenced by basal friction. Additionally, an analysis of energy conversion supports many of the conclusions provided in the text and exhibits the interplay between pressure gradient and base friction. Our findings show the clear influence of basal friction on the collapse behaviour of granular materials and therefore should be carefully considered in future studies. [ABSTRACT FROM AUTHOR]

A self-assembly method was performed to construct S-scheme NiO/C 3 N 5 (NOCN) heterojunction, which exhibited the high efficiencies for visible-light-responsive photocatalytic H 2 and H 2 O 2 generation due to the synergistic effects of increased light harvesting capacity, S-scheme heterojunction and photothermal effect. [Display omitted] • NiO/C 3 N 5 (NOCN) heterojunction was prepared by a facile self-assembly method. • The role of NiO loading in boosting photocatalysis was discussed over NOCN. • S-scheme NOCN heterojunction showed improved photocatalytic efficiencies. • NOCN has the photothermal effect for facilitating the charge carrier transfer. • Photocatalytic mechanism for H 2 and H 2 O 2 evolution was proposed over NOCN. Heterostructured visible-light-responsive photocatalysts represent a prospective approach to achieve efficient solar-to-chemical energy conversion. Herein, we propose a facile self-assembly technique to synthesize NiO nanoparticles/C 3 N 5 nanosheets (NOCN) heterojunctions for hydrogen (H 2) evolution catalysis and hydrogen peroxide (H 2 O 2) production under visible light. In this regard, the black NiO nanoparticles (NPs) were tightly anchored on the surface of C 3 N 5 nanosheets (CNNS) to construct S-scheme NOCN heterojunction, enabling efficient charge separation and high redox capability. Obtained results elucidated that the incorporated NiO NPs significantly promote light-harvesting efficiency and photo-to-thermal capacity over the NOCN composites. The enhanced photothermal effect facilitates the charge carrier transfer rate across the heterojunction and boosts the surface reaction kinetics. Accordingly, the photocatalytic performances of CNNS for H 2 release and H 2 O 2 production can be manipulated by introducing NiO NPs. The modified photocatalytic properties of NOCN composites are ascribed to the synergistic effects of all integrated components and the S-scheme heterojunction formation. Impressively, the high H 2 evolution photocatalysis efficiency of NOCN nano-catalysts in seawater certifies their potential environmental applicability. Among all, the 12-NOCN nano-catalyst exhibits a higher photocatalytic efficiency for H 2 release (112.2 μmol∙g−1∙h−1) and H 2 O 2 production (91.2 μmol∙L−1∙h−1). Besides, the 12-NOCN nano-catalyst reveals excellent recyclability and structural stability. Additionally, the possible mechanism for photothermal-assisted photocatalysis is proposed. This work affords a feasible pathway to design photothermal-assisted S-scheme heterojunctions for diverse photocatalytic applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multi-interfacial bridging engineering was used to prepare the flexible MXene film. • Highly efficient electromagnetic shielding capability is achieved through a dense multiple conductive network. • The total EMI shielding effectiveness can be increased by 27 % with the highest value of 67.9 dB. • The infrared emissivity is as low as 0.173 within the 8–14 μm. • The mechanism of the shielding and photothermal compatibility along with the durability are proposed. Accompanied by the progressive development of electronic equipment, excellent electromagnetic interference (EMI) shielding materials display a satisfying prospect in protecting electronic devices against electromagnetic pollution/radiation, while integrating energy conversion. Heretofore, it remains a conundrum to availably construct thin films with multi-interfacial bridging engineering as multifunctional shielding devices. To effectively achieve electromagnetic wave attenuation and integrate energy conversion, a co-mixed vacuum-assisted filtration strategy is designed to synthesize Au@MXene/cellulose nanocrystal/dodecylbenzenesulfonic acid-doped polyaniline (AMCP) films. Profited from the interfacial engineering, the total EMI shielding effectiveness (SE) can be increased by 27 % with the highest value of 67.9 dB. MXene with localized surface plasmon resonance characteristics gives the composite films good energy conversion performance, that is, the composite film can be rapidly heated up to 100 °C under the irradiation of an infrared lamp, and its surface temperature remains stable after continuous irradiation. Additionally, the infrared emissivity is as low as 0.173 within the 8–14 μm, which is necessary to adapt various application scenarios. Therefore, it is reliable that the AMCP films constructed by multicomponent offer a facile strategy for MXene-based EMI shielding devices with integration characteristics. [ABSTRACT FROM AUTHOR]

[Display omitted] Carbon nanostructures derived from human hair biowaste are incorporated into polyvinylidene fluoride (PVDF) polymer to enhance the energy conversion performance of a triboelectric nanogenerator (TENG). The PVDF filled with activated carbon nanomaterial from human hair (AC-HH) exhibits improved surface charge density and photoinduced charge generation. These remarkable properties are attributed to the presence of graphene-like nanostructures in AC-HH, contributing to the augmented performance of PVDF@AC-HH TENG. The correlation of surface morphologies, surface charge potential, charge capacitance properties, and TENG electrical output of the PVDF composites at various AC-HH loading is studied and discussed. Applications of the PVDF@AC-HH TENG as a power source for micro/nanoelectronics and a movement sensor for detecting finger gestures are also demonstrated. The photoresponse property of the fabricated TENG is demonstrated and analyzed in-depth. The analysis indicates that the photoinduced charge carriers originate from the conductive reduced graphene oxide (rGO), contributing to the enhanced surface charge density of the PVDF composite film. This research introduces a novel approach to enhancing TENG performance through the utilization of carbon nanostructures derived from human biowaste. The findings of this work are crucial for the development of innovative energy-harvesting technology with multifunctionality, including power generation, motion detection, and photoresponse capabilities. [ABSTRACT FROM AUTHOR]

Ferroelectric photovoltaic cells have attracted particular interest owing to their potential applications in the green energy field. But there are two drawbacks: weak polarization and wide bandgap, which make them suffer from the limitation of energy conversion efficiency. In this study, the key issue is solved in Ag2O nanoparticle-dispersed Bi5Ti3FeO15 composites. In order to clarify the mechanism, performances of the bandgap, polarization-dependent J–V curves, dielectric response, and switchable photocurrents were investigated. The Maxwell–Wagner polarization effect is confirmed by permittivity Cole–Cole plots with two or more semicircles overlapping. The spatial polarization gradient matrices can reduce the effective mass of the electron–hole pairs and further promote their separation via the Maxwell–Wagner polarization effect. The synchronous mobility of the separated carriers is enhanced. An improved ferroelectric photovoltaics is achieved in Bi5Ti3FeO15⋅3%Ag2O composites, and the key parameters are as follows: VOC ∼ −3.1 V, energy converse efficiency 9.2 × 10−4%. Furthermore, this work shows the first step toward polarization gradient composites for application in ferroelectric photovoltaic cells. [ABSTRACT FROM AUTHOR]

Vibrational relaxation of H2O(v2,v13) molecules by collisions with Ar was studied at 298 K (v2 denotes the bending vibrational mode and v13 denotes the sum of the symmetric, v1, and asymmetric, v3, vibrational modes). The H2O molecules from 14 different exothermic reactions of H-atom abstraction by OH radicals were observed by infrared emission from a fast flow reactor as a function of Ar pressure and reaction time. Numerical kinetic calculations were used to obtain rate constants for stretch-to-bend energy conversion, (v2,v13) → (v2 + 2,v13 − 1), and pure bend relaxation, (v2,v13) → (v2 − 1,v13). Rate constants for states up to v13 = 4 were based on the average values from all reactions. The rate constant for the (2,0) → (1,0) bending relaxation is in agreement with the published values from laser-induced fluorescent experiments; the rate constants for higher levels increase with v2. Our average rate constant for the (0,1) → (2,0) stretch-to-bend conversion is somewhat smaller but falls within the uncertainty limit of the published value. The average rate constants for the stretch-to-bend process for (01), (02), (03), and (04) stretching states are (4.3 ± 0.8) × 10−14, (7.7 ± 1.1) × 10−14, (14.3 ± 4.2) × 10−14, and (20.6 ± 6.2) × 10−14 cm3 molecule−1 s−1, respectively. [ABSTRACT FROM AUTHOR]

Lithium niobate (LiNbO3) single crystal is one of the pyroelectric materials, which can be applicable in energy storage and conversion devices. A theoretical and experimental study of the sinusoidal temperature variation of a single crystal of LiNbO3 with ultra-low frequency of 1–80 mHz is presented here. The previously unreported phenomenon of the optimal frequency range with the maximum amplitude of pyroelectric current oscillations is shown. It is noted that the observed effect is very sensitive to the thermal properties of the material. The impact of thermal properties of the crystal on the optimal frequency range is discussed. The accurate calculations of the pyroelectric coefficient using sinusoidal temperature variation are introduced. The observed phenomenon can be applied in pyroelectric energy converters and storage devices having a cycle time of 10–1000 s. [ABSTRACT FROM AUTHOR]

We determine the zero-frequency charge current noise in a metal–molecule–metal junction embedded in a thermal environment, e.g., a solvent, dominated by sequential charge transmission described by a classical master equation, and we study the dependence of specific model parameters, i.e., the environmental reorganization energy and relaxation behavior. Interestingly, the classical current noise term has the same structure as its quantum analog, which reflects a charge correlation due to the bridging molecule. We further determine the thermodynamic uncertainty relation (TUR) defininig a bound on the relationship between the average charge current, its fluctuation, and the entropy production in an electrochemical junction in the Marcus regime. In the second part, we use the same methodology to calculate the current noise and the TUR for a protoype photovoltaic cell in order to predict its upper bound for the efficiency of energy conversion into useful work. [ABSTRACT FROM AUTHOR]

The strong coupling between fluid and electromagnetic field in the annular linear induction pump (ALIP) can gradually amplify small disturbance in the fluid field into large-scale vortices. The appearance of the vortices seriously affects the efficiency and reliability of the pump. An active flow control method based on the modification of the driving electromagnetic field is proposed to improve the flow stability. A simplified numerical model of the ALIP is established to simulate the threedimensional flow in the annular flow channel, and the internal electromagnetic field is modified by using the modulated surface current. The influences of the active flow control method on the flow behavior, pressure pulsation, and energy conversion are, respectively, investigated based on the simulation results. The results show that the modulated surface current can accelerate the vortical evolution. The size and strength of the vortices are suppressed in the modified electromagnetic field. The pressure pulsation low frequency at the ALIP's outlet is significantly reduced when the modulated surface current density reaches a certain level. The surges in the processes of energy conversion become more gentle within the control method, and the overall energy efficiency is slightly reduced even at the highest modulated surface current density. [ABSTRACT FROM AUTHOR]

Dipolarization fronts (DFs) are widely believed to host energy conversion processes. However, which mechanism is responsible for the energy conversion is still obscure. Using data from the Magnetospheric Multiscale mission, a current sheet is observed at a DF. This current sheet is caused by interchange instability bending the edge of the DF. Inside the current sheet, Hall electromagnetic field, super Alfvénic electron jets, demagnetization of ions and electrons, strong energy conversion, and steady ion flow and temperature are observed, indicating an electron‐only reconnection at the DF. The duskward plasma flow, which may be deflected by the DF, compresses the bent edges of the DF. As a result, the width of the current sheet between two adjacent bent edges of the DF reduces, and then reconnection begins. Our observations give direct evidence that magnetic reconnection results in energy conversion at a DF. Plain Language Summary: Magnetic reconnection is an explosive phenomenon in space, which can rapidly convert energy from magnetic field to particles. Dipolarization fronts are essential carriers of mass and energy from the magnetotail to the Earth. Strong energy conversion, considered to be even more significant than magnetic reconnection, is usually observed at dipolarization fronts. However, the specific mechanism responsible for the energy conversion at a dipolarization front is elusive. Using data from the Magnetospheric Multiscale mission, we present direct evidence of magnetic reconnection at a dipolarization front, leading to strong energy conversion. The reconnection occurs in the current sheet at the dipolarization front. The duskward diverted flow compresses the bent dipolarization front induced by interchange instability, resulting in reconnection. Key Points: A current sheet with strong energy conversion is found at a DFThe strong energy conversion at this DF is mainly caused by the magnetic reconnectionThe duskward diverted flow compresses the bent DF caused by interchange instability, leading to the reconnection [ABSTRACT FROM AUTHOR]

For the advancement of electrochemical energy conversion and storage technologies, bifunctional electrocatalysts are crucial for efficiently driving both the oxygen evolution (OER) and reduction reactions (ORR). Cobalt‐based spinel oxides are a class of promising bifunctional electrocatalysts. However their low electrical conductivity and stability may hinder further improvement. A novel composite material composed of NiCo2O4 nanoparticles integrated with emerging two dimensional MXene nanosheets (NiCo2O4/MXene) was developed. The successful integration of NiCo2O4 with MXene brings about a number of attractive structural features. This includes synergistic effects between NiCo2O4 and MXene, highly accessible surface areas, complete exposure of numerous active sites, and excellent electronic conductivity, all of which collectively contribute to the desirability of composite material for OER and ORR. The synthesized NiCo2O4/MXene composite showed extraordinary OER electrocatalytic activity with a lower overpotential of 360 mV at a current density of 10 mA/cm2, and a small Tafel slope of 64 mV/dec compared to NiCo2O4, MXene and NiCo2O4+MXene (physically mixed). Additionally, NiCo2O4/MXene displays an ORR limiting current density of −4 mA/cm2 and exhibited highest onset potential and half wave potential of 0.92 V and 0.72 V vs. RHE, respectively, for the ORR in alkaline media compared to NiCo2O4, MXene and NiCo2O4+MXene (physically mixed). [ABSTRACT FROM AUTHOR]

Nanofluidic channels with tailored ion transport dynamics are usually used as channels for ion transport, to enable high-performance ion regulation behaviors. The rational construction of nanofluidics and the introduction of external fields are of vital significance to the advancement and development of these ion transport properties. Focusing on the recent advances of nanofluidics, in this review, various dimensional nanomaterials and their derived homogeneous/heterogeneous nanofluidics are first briefly introduced. Then we discuss the basic principles and properties of ion transport in nanofluidics. As the major part of this review, we focus on recent progress in ion transport in nanofluidics regulated by external physical fields (electric field, light, heat, pressure, etc.) and chemical fields (pH, concentration gradient, chemical reaction, etc.), and reveal the advantages and ion regulation mechanisms of each type. Moreover, the representative applications of these nanofluidic channels in sensing, ionic devices, energy conversion, and other areas are summarized. Finally, the major challenges that need to be addressed in this research field and the future perspective of nanofluidics development and practical applications are briefly illustrated. [ABSTRACT FROM AUTHOR]

Designing low-dimensional nanomaterials is vital to address the energy and environmental crisis by means of electrocatalytic conversion reactions. Bimetallenes, as an emerging class of 2D materials, present promise for electrocatalytic conversion reactions. By leveraging atomically thin layers, bimetallenes present unsaturated surface coordination, high specific surface area and high conductivity, which are all indispensable features for heterogeneous electrochemical reactions. However, the intrinsic activity and stability of bimetallenes needs to be improved further for bimetallene electrocatalysts, due to the higher demands of practical applications. Recently, many strategies have been developed to optimize the chemical or electronic structure to accommodate transfer of reactants, adsorption or desorption of intermediates, and dissociation of products. Considering that most such work focuses on adjusting the structure, this review offers in-depth insight into recent representative strategies for optimizing bimetallene electrocatalysts, mainly including alloying, strain effects, ligand effects, defects and heteroatom doping. Moreover, by summarizing the performance of bimetallenes optimized using various strategies, we provide a means to understand structure–property relationships. In addition, future prospects and challenges are discussed for further development of bimetallene electrocatalysts. [ABSTRACT FROM AUTHOR]

Owing to their remarkable and adjustable optoelectronic properties, halide perovskites (HPs) have been regarded as a class of promising materials for various optoelectronic applications based on different energy conversion reactions, including photovoltaic cell, photocatalysis, electrocatalysis, and photoelectrochemical (PEC) systems. However, the low stability of HPs upon exposure to ambient conditions (e.g., water, heat, light, electricity) greatly hinders the practical applications of HPs. In the past few years, significant efforts have been devoted to enhancing the eventual stability of the perovskite‐based optoelectronic systems, mainly focusing on delivering improvements in the stabilities of halide perovskite materials and the relevant operation conditions of optoelectronic systems, which deserve in‐depth and systematic summaries. In this comprehensive review, the in‐depth environment‐induced decomposition mechanisms of typical HPs are elucidated. Simultaneously, the strategies for addressing the instability issues of halide perovskite materials are critically reviewed, including dimension control, compositional engineering, ligand passivation, and encapsulation engineering. Furthermore, the photoelectric applications based on the modified HPs and operation conditions are discussed systematically. In the last part of this review, future perspectives and outlooks toward the stability of HPs and their photoelectric applications are envisaged respectively. [ABSTRACT FROM AUTHOR]

Ion‐selective membrane embedded in a reverse electrodialysis system can achieve the conversion of osmotic energy into electricity. However, the ingenious design and development of pure polymer membranes that simultaneously satisfy excellent mechanical strength, long‐term stability, high power density, and increased testing area is a crucial challenge. Here, high‐strength, thin PBO nanofiber membranes (PBONM) with 3D nanofluidic channels and a thickness of 0.81 µm are prepared via a simple vacuum‐assisted filtration technology. The thin PBONM exhibits excellent mechanical properties: stress of 235.8 MPa and modulus of 16.96 GPa, outperforming the state‐of‐the‐art nanofluidic membranes. The obtained PBONM reveals surface‐charge‐governed ion transport behavior and high ion selectivity of 0.88 at a 50‐fold concentration gradient. The PBO membrane‐based generator delivers a power density of 7.7 and 40.2 W m−2 at 50‐fold and 500‐fold concentration gradient. Importantly, this PBONM presents excellent stability in response to different external environments including various saline solutions, pH, and temperature. In addition, the maximum power density of PBONM reaches up to 5.9 W m−2 under an increased testing area of 0.79 mm2, exceeding other membrane‐based generators with comparable testing areas. This work paves the way for constructing high‐strength fiber nanofluidic membranes for highly efficient osmotic energy conversion. [ABSTRACT FROM AUTHOR]

Proton‐conducting solid oxide cells (P‐SOCs) as energy conversion devices for power generation and hydrogen production have attracted increasing attention recently. The lack of efficient proton‐conducting air electrodes is a huge obstacle to developing high‐performance P‐SOCs. The currently widely used air electrode material is Co/Fe based perovskite oxide, however, there is still no systematic research on studying and comparing the roles of diversiform elements at the B site for Co/Fe based perovskite oxide. Here, a machine learning (ML) model with eXtreme Gradient Boosting (XGBoost) algorithm is built to quickly and accurately predict the proton absorption amount of Co/Fe based perovskite oxides with 27 elements dopant at B site. Hereafter, La(Co0.9Ni0.1)O3 (LCN91) is screened by a combination of the ML model and the density functional theory calculation. Finally, LCN91 is applied to the air electrode of P‐SOC, and the cell exhibits excellent electrochemical performances in fuel cell and electrolysis modes. The current study not only provides a useful model for screening air electrodes of P‐SOC, but also extends the application of ML in exploring the key materials for P‐SOCs and other fuel cells/electrolyzers. [ABSTRACT FROM AUTHOR]

Proton-exchange membrane fuel cells are one of the most promising energy conversion technologies for both automotive and stationary applications. Scientists are testing a number of solutions to increase the durability of cells, especially catalysts, which are the most expensive component. These solutions include, among others, the modification of the composition and morphology of supported nanoparticles, the platinum–support interface, and the support itself. A detailed understanding of the mechanism of platinum degradation and the subsequent improvement of the durability of the entire cell requires the development of methods for effectively monitoring the behavior of catalytic nanoparticles under various cell operating conditions. The Identical-Location Transmission Electron Microscopy (IL-TEM) method makes it possible to visually track structural and morphological changes in the catalyst directly. Because the tests are performed with a liquid electrolyte imitating a membrane, they provide better control of the degradation conditions and, consequently, facilitate the understanding of nanoparticle degradation processes in various operating conditions. This review is primarily intended to disseminate knowledge about this technique to scientists using electron microscopy in the study of energy materials and to draw attention to issues related to the characterization of the structure of carbon supports. [ABSTRACT FROM AUTHOR]

Using pumps operating as turbines (PATs) offers the possibility of increasing the sustainability of water and energy systems by recovering the excess energy that would be otherwise lost in pressure-reducing valves or head loss chambers. Regarding on-grid applications, there have been many research works, and PATs have been implemented in several ways. However, more research still needs to be done on optimizing the efficiency and stability of PATs operating in off-grid systems. This work contributes to the development of stable direct current (DC) off-grid electric systems based on PATs using a self-excited induction generator (SEIG). In this context, a methodology is proposed, based on the hydraulic, mechanical, and electric subsystems, to define the PAT-SEIG operational area to maximize energy conversion and system efficiency. These limits depend highly on the capacitor value, rotational speed, and electric load. In addition, an analytical model is proposed to estimate the PAT-SEIG operation under specific conditions. With this, water managers can design and optimize an off-grid PAT-SEIG system and define the best hydraulic machines, electronic equipment, and control elements to maximize energy conversion within the target of operational limits. Two micro PAT-SEIG setups were implemented in the hydraulic laboratory of IST/CERIS under typical operating conditions to validate the proposed methodology. The system's maximum efficiency and operational limits can be adapted using different capacitor values for the excitation of the SEIG. Considering the nominal efficiencies of the system's components, the maximum p.u. efficiency obtained for each PAT-SEIG system was between 0.7 and 0.8 p.u. [ABSTRACT FROM AUTHOR]

Layered halide perovskites are solution‐processed natural heterostructures where quantum and dielectric confinement down to the nanoscale strongly influence the optical properties, leading to stabilization of bound excitons. Detailed understanding of the exciton properties is crucial to boost the exploitation of these materials in energy conversion and light emission applications, with on‐going debate related to the energy order of the four components of the most stable exciton. To provide theoretical feedback and solve among contrasting literature reports, this work performs ab initio solution of the Bethe–Salpeter equation (BSE) for symmetrized reference Cs2PbX4 (X = I and Br) models, with detailed interpretation of the spectroscopic observables based on group‐theory analysis. Simulations predict the following Edark < Ein‐plane < Eout‐of‐plane fine‐structure assignment, consistent with recent magneto‐absorption experiments and obtain similar increase in dark/bright splitting when going from lead‐iodide to a lead‐bromide composition as found experimentally. The authors further suggest that polar distortions may lead to stabilization of the in‐plane component and end‐up in a bright lowest exciton component, discuss exciton landscape over a broad energy range and clarify the exciton spin‐character, when large spin‐orbit coupling is in play, to rationalize the potential of halide perovskites as triplet sensitizers in combination with organic dyes. [ABSTRACT FROM AUTHOR]

During the construction of smart grids, due to technological limitations, traditional sequential control systems have been unable to meet the needs of grid operation, exposing problems such as single control methods and functions, low operational efficiency, inability to independently complete complex tasks, and poor anti-interference ability, which in turn affect the power supply quality and operational stability of the grid, and fail to truly achieve the reliability, safety, and reliability of smart grids Economic and efficient goals. For this purpose, the author describes an adaptive intelligent control method for an integrated biomass energy heat conversion system consisting of more than one suction biomass gasifier, biomass gas burner, and steam boiler. The system uses PLC as a tool and takes the boiler outlet steam pressure as the control parameter. Based on the changes in the boiler outlet steam pressure, it automatically adjusts the feed and gas production of the gasifier, and subsequently adjusts the air supply of the burner. Ultimately, it achieves the goal of automatically adjusting the boiler heating volume with changes in steam pressure. The integrated heating and adaptive intelligent control system based on biomass gasification has been reliably verified in industrial applications. [ABSTRACT FROM AUTHOR]

The impedance matching control, also known as approximate complex conjugate control (ACC), is one of the main strategies for improving the capture of energy by point absorber wave energy converters. Such a strategy shapes the mechanical impedance related to the floater dynamics via the control law. Since the traditional ACC is given by a linear control law, this work proposes a generalization denoted as nonlinear complex conjugate control (NCC) that considers the presence of nonlinear viscous damping in addition to the usual linear damping and stiffness. The energy maximization conditions for the proposed NCC are derived in the frequency domain through the describing function method. These conditions show that the ACC is a special case of the NCC when the total damping on the floater is approximated as a linear function of its velocity. From numerical simulations of a point absorber wave energy converters with nonlinear damping, which is based on the Archimedes wave swing prototype, it is shown that the NCC provides greater energy conversion than the ACC, as well as a robust performance in the presence of variations of the damping coefficient and the excitation force peak frequency. [ABSTRACT FROM AUTHOR]

Li‐N2 batteries have received widespread attention for their potential to integrate N2 fixation, energy storage, and conversion. However, because of the low activity and poor stability of cathode catalysts, the electrochemical performance of Li‐N2 batteries is suboptimal, and their electrochemical reversibility has rarely been proven. In this study, a novel bifunctional photo‐assisted Li‐N2 battery system was established by employing a plasmonic Au nanoparticles (NPs)‐modified defective carbon nitride (Au‐Nv‐C3N4) photocathode. The Au‐Nv‐C3N4 exhibits strong light‐harvesting, N2 adsorption, and N2 activation abilities, and the photogenerated electrons and hot electrons are remarkably beneficial for accelerating the discharge and charge reaction kinetics. These advantages enable the photo‐assisted Li‐N2 battery to achieve a low overpotential of 1.32 V, which is the lowest overpotential reported to date, as well as superior rate capability and prolonged cycle stability (≈500 h). Remarkably, a combination of theoretical and experimental results demonstrates the high reversibility of the photo‐assisted Li‐N2 battery. The proposed novel strategy for developing efficient cathode catalysts and fabricating photo‐assisted battery systems breaks through the overpotential bottleneck of Li‐N2 batteries, providing important insights into the mechanism underlying N2 fixation and storage. [ABSTRACT FROM AUTHOR]

Harnessing and effectively utilizing abundant and sustainable solar energy is regarded as a promising solution to the global energy crisis. Forests, being nature's largest light energy capturing units, bestow oxygen and shelter upon all living beings, making them an invaluable gift to humanity. Apart from serving as natural air ionizers, load-bearing structures, and traditional building materials, wood and its derivatives can also be employed in cutting-edge sustainable applications. Their manifold advantages encompass a naturally porous and hierarchical structure for efficient water and nutrient transport, low thermal conductivity, mechanical stability, as well as versatile chemistry achieved through structural engineering and chemical or thermal modifications. This review provides an overview of the synergistic optical and thermal applications of wood for seawater desalination, wastewater treatment, and light management in energy-efficient buildings. The emphasis lies on elucidating the structure and application properties of wood with respect to establishing a symbiotic relationship between solar energy and wood towards sustainability. [ABSTRACT FROM AUTHOR]

Li‐N2 batteries have received widespread attention for their potential to integrate N2 fixation, energy storage, and conversion. However, because of the low activity and poor stability of cathode catalysts, the electrochemical performance of Li‐N2 batteries is suboptimal, and their electrochemical reversibility has rarely been proven. In this study, a novel bifunctional photo‐assisted Li‐N2 battery system was established by employing a plasmonic Au nanoparticles (NPs)‐modified defective carbon nitride (Au‐Nv‐C3N4) photocathode. The Au‐Nv‐C3N4 exhibits strong light‐harvesting, N2 adsorption, and N2 activation abilities, and the photogenerated electrons and hot electrons are remarkably beneficial for accelerating the discharge and charge reaction kinetics. These advantages enable the photo‐assisted Li‐N2 battery to achieve a low overpotential of 1.32 V, which is the lowest overpotential reported to date, as well as superior rate capability and prolonged cycle stability (≈500 h). Remarkably, a combination of theoretical and experimental results demonstrates the high reversibility of the photo‐assisted Li‐N2 battery. The proposed novel strategy for developing efficient cathode catalysts and fabricating photo‐assisted battery systems breaks through the overpotential bottleneck of Li‐N2 batteries, providing important insights into the mechanism underlying N2 fixation and storage. [ABSTRACT FROM AUTHOR]

Electrocatalysis is an important energy conversion and storage technology that has made significant progress in areas such as fuel cells, hydrogen production from electrolyzed water and electrochemical synthesis. In practical applications, the efficiency and stability of electrocatalytic processes remain challenging. Spatially confined (or called domain‐limited) water refers to the immobilization of water molecules in a limited region near the catalyst surface to form a specific aqueous phase environment. This domain‐limited aqueous phase environment can greatly influence the electrocatalytic efficacy by enhancing adsorption and lowering the proton transport and solvent diffusion energy barriers in the reaction. In recent years, the goal of improving electrocatalytic performance has been successfully achieved through interfacial domain‐limited, microporous domain‐limited and nanoreactor domain‐limited. Spatially domain‐limited water as a novel strategy can significantly enhance the activity and selectivity of electrocatalytic reactions, but understanding its mechanism of action remains a challenge. With a deeper understanding of domain‐limited water and further development of the technology, it is believed that it will bring greater breakthroughs and application prospects in the field of electrocatalysis. [ABSTRACT FROM AUTHOR]

Clean energy devices have a great ability to change the world because they strengthen the economy and preserve society. The continuous improvement and progress in nanomaterials and nanotechnology have a great role in human life. The increasing prevalence of PEM fuel cells makes them one of the most viable sustainable energy sources. Nanostructured materials synthesis methodologies have introduced a breakthrough and found to overcome the obstacles for PEMFC commercialization. Amongst them, wet chemical approaches are rapidly expanding and beneficial for the fabrication of nanoparticles since they contribute toward the attainment of a range of essential nanoparticle characteristics like sizes, morphologies, structures, and phases. Wet chemical manufacturing enables fine-tuning of reaction parameters to generate the desired nanomaterials. This review article focuses on the latest improvements in wet chemical methods to better regulate the quality of nanomaterials. This paper examines how wet chemical approaches (hydrothermal synthesis, spray pyrolysis, sol-gel processing, and co-precipitate synthesis, among others) can contribute to the scalable manufacturing of nanoparticles to uphold rising industrial requirements. And how wet chemical methods have a significant influence on power generation systems (Fuel cells) along with their pros and cons. This review carefully analyzes and summarizes synthetic methods and optimized factors in order to prepare nanoparticles and carefully analyzes the reported data. In this paper, the electrochemical analysis, morphological evaluation, compositional analysis, and performance testing of materials produced using wet chemical techniques have been investigated. Recent signs of progress and innovative techniques used to overcome the complexities of synthetic nanoparticle processing. This article is a holistic approach including social, economic, and ecological aspects in the wet chemical process and will certainly help in the fabrication, and application of nanoparticles for PEM Fuel cells. [Display omitted] • Introduction to the status of materials synthesis in energy generating devices. • Overview of wet chemistry Approaches for PEMFC. • Impact of synthesis parameters on properties of materials. • Pros and Cons of wet chemistry techniques for material synthesis. [ABSTRACT FROM AUTHOR]

Rare earth-based perovskite nanostructures are potential materials for electrocatalytic water splitting and energy storage applications due to their great chemical stability. DyMnO 3 nanoaggregates and DyFeO 3 nanoflakes were synthesized using the polymeric citrate precursor and ethylene glycol-assisted hydrothermal routes, respectively. A comprehensive set of characterization techniques, including X-ray diffraction, scanning and transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and Brunauer–Emmett–Teller (BET) surface area analysis were carried out. Surface area studies showed that DyMnO 3 has higher specific surface area (33 m2/g) than DyFeO 3 nanoflakes (8 m2/g). Electrochemical water splitting and supercapacitor performance revealed DyMnO 3 nanoaggregates displayed remarkable activity for oxygen evolution reaction with an overpotential of 0.22 V vs. RHE and a faster reaction kinetics. DyFeO 3 nanoflakes demonstrated superior pseudo-capacitance behavior, exhibiting a specific capacitance of 97.82 F/g and 100 % coulombic efficiency. These findings contribute to the advancement of materials design for electrochemical energy conversion and storage applications, emphasizing the potential of rare earth-based perovskite nanostructures in sustainable energy technologies. [Display omitted] • Citrate and hydrothermal techniques employed for diverse synthesis approaches. • Studied multiferroic nature; DyMnO 3 NAs exhibits enhanced characteristics-unit e g filling, high specific surface area. • DyMnO 3 NAs showed superior OER performance (0.22 V vs. RHE) in overall electrocatalytic water splitting. • DyFeO 3 NWs showed superior supercapacitor performance of specific capacitance of 97.82 F/g. [ABSTRACT FROM AUTHOR]

The design of low-cost and high-performance bifunctional catalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is of great significance for overall water splitting. Herein, RuNi single atom alloy (SAA) decorated on reduced graphene oxide (RuNi@rGO) was synthesized by a facile strategy for use as a bifunctional HER/OER catalyst. The as-obtained RuNi@rGO catalyst exhibits outstanding electrocatalytic activities with an ultralow overpotential for the HER (15 mV) and the OER (240 mV) at a current density of 10 mA cm−2. Density functional theory (DFT) calculations demonstrate that the introduction of Ru single atoms can evidently change the electron distribution and coordination environment around Ni, and reduce the intermediate's adsorption free energy of RuNi@rGO, thus facilitating the HER/OER catalytic rate. Moreover, when used as the cathode and anode of a two-electrode system, the RuNi@rGO-based water splitting device exhibits a low potential of 1.52 V at a current density of 10 mA cm−2, as well as a high faradaic efficiency almost up to 100%, making RuNi@rGO bifunctional electrocatalysts attractive for energy storage and conversion. [ABSTRACT FROM AUTHOR]

Single-atom catalysts (SACs) with maximized metal atom utilization and intriguing properties are of utmost importance for energy conversion and catalysis science. However, the lack of a straightforward and scalable synthesis strategy of SACs on diverse support materials remains the bottleneck for their large-scale industrial applications. Herein, we report a general approach to directly transform bulk metals into single atoms through the precise control of the electrodissolution--electrodeposition kinetics in ionic liquids and demonstrate the successful applicability of up to twenty different monometallic SACs and one multimetallic SAC with five distinct elements. As a case study, the atomically dispersed Pt was electrodeposited onto Ni3N/Ni-Co-graphene oxide heterostructures in varied scales (up to 5 cm x 5 cm) as bifunctional catalysts with the electronic metal--support interaction, which exhibits low overpotentials at 10 mA cm-2 for hydrogen evolution reaction (HER, 30 mV) and oxygen evolution reaction (OER, 263 mV) with a relatively low Pt loading (0.98 wt%). This work provides a simple and practical route for large-scale synthesis of various SACs with favorable catalytic properties on diversified supports using alternative ionic liquids and inspires the methodology on precise synthesis of multimetallic single-atom materials with tunable compositions. [ABSTRACT FROM AUTHOR]

Promoting advanced functional films that integrate protective behaviors for synergetic radar, infrared (IR), and visible light is confronted with extreme challenges. The effective integration of shielding capacity and IR camouflage into single‐component carbon films remains an enormous challenge because of limited conductivity and high IR absorption. In this work, carbon nanotube (CNT) films with excellent electromagnetic interference (EMI) shielding, switchable IR camouflage, and energy conversion are obtained via a (FCCVD) method and subsequent defect engineering strategies induced by temperature (Strategy I) and N/S co‐doping (Strategy II). Wherein the effect on the electronic configuration as well as multi‐spectra performance is deeply explored. Ascribing to the synergistic effects of strategies, defective CNT films present superior EMI shielding effectiveness (SE) with a high absorption effectiveness ratio of 86.9%, and a large span of emissivity (0.479), which provides the necessary condition for various application scenarios. Under the applied electric field excitation, the IR radiation of CNT films can adapt to rapidly changing surroundings, such as low‐high/high‐low temperatures. Besides, the desirable energy conversion performance and de‐icing can be achieved. This work supplies a feasible strategy for designing EM absorption, adaptive IR camouflage, and energy conversion to confront multiband surveillance. [ABSTRACT FROM AUTHOR]

Electromagnetically induced rotation is a key process of many technological systems that are used in daily life, especially for energy conversion. In this context, the Lorentz force‐induced deviation of charges is a crucial physical phenomenon to generate rotation. Herein, they combine the latter with the concept of bipolar electrochemistry to design a wireless magnetoelectrochemical rotor. Such a device can be considered as a wet analog of a conventional electric motor. The main driving force that propels this actuator is the result of the synergy between the charge‐compensating ion flux along a bipolar electrode and an external magnetic field applied orthogonally to the surface of the object. The trajectory of the wirelessly polarized rotor can be controlled by the orientation of the magnetic field relative to the direction of the global electric field, producing a predictable clockwise or anticlockwise motion. Fine‐tuning of the applied electric field allows for addressing conducting objects having variable characteristic lengths. [ABSTRACT FROM AUTHOR]

In recent decades, significant progress has been achieved in rational developments of electrocatalysts through constructing novel atomistic structures and modulating catalytic surface topography, realizing substantial enhancement in electrocatalytic activities. Numerous advanced catalysts were developed for electrochemical energy conversion, exhibiting low overpotential, high intrinsic activity, and selectivity. Yet, maintaining the high catalytic performance under working conditions with high polarization and vigorous microkinetics that induce intensive degradation of surface nanostructures presents a significant challenge for commercial applications. Recently, advanced operando and computational techniques have provided comprehensive mechanistic insights into the degradation of surficial functional structures. Additionally, various innovative strategies have been devised and proven effective in sustaining electrocatalytic activity under harsh operating conditions. This review aims to discuss the most recent understanding of the degradation microkinetics of catalysts across an entire range of anodic to cathodic polarizations, encompassing processes such as oxygen evolution and reduction, hydrogen reduction, and carbon dioxide reduction. Subsequently, innovative strategies adopted to stabilize the materials' structure and activity are highlighted with an in-depth discussion of the underlying rationale. Finally, we present conclusions and perspectives regarding future research and development. By identifying the research gaps, this review aims to inspire further exploration of surface degradation mechanisms and rational design of durable electrocatalysts, ultimately contributing to the large-scale utilization of electroconversion technologies. [ABSTRACT FROM AUTHOR]

Bioinspired two-dimensional (2D) nanofluidic membranes have been explored for the creation of high-performance ion transport systems that can mimic the delicate transport functions of living organisms. Advanced energy devices made from these membranes show excellent energy storage and conversion capabilities. Further research and development in this area are essential to unlock the full potential of energy devices and facilitate the development of high-performance equipment toward real-world applications and a sustainable future. However, there has been minimal review and summarization of 2D nanofluidic membranes in recent years. Thus, it is necessary to carry out an extensive review to provide a survey library for researchers in related fields. In this review, the classification and the raw materials that are used to construct 2D nanofluidic membranes are first presented. Second, the top–down and bottom–up methods for constructing 2D membranes are introduced. Next, the applications of bioinspired 2D membranes in osmotic energy, hydraulic energy, mechanical energy, photoelectric conversion, lithium batteries, and flow batteries are discussed in detail. Finally, the opportunities and challenges that 2D nanofluidic membranes are likely to face in the future are envisioned. This review aims to provide a broad knowledge base for constructing high-performance bioinspired 2D nanofluidic membranes for advanced energy applications. [ABSTRACT FROM AUTHOR]

A molecular robot, which is a system comprised of one or more molecular machines and computers, can execute sophisticated tasks in many fields that span from nanomedicine to green nanotechnology. The core parts of molecular robots are fairly consistent from system to system and always include (i) a body to encapsulate molecular machines, (ii) sensors to capture signals, (iii) computers to make decisions, and (iv) actuators to perform tasks. This review aims to provide an overview of approaches and considerations to develop molecular robots. We first introduce the basic technologies required for constructing the core parts of molecular robots, describe the recent progress towards achieving higher functionality, and subsequently discuss the current challenges and outlook. We also highlight the applications of molecular robots in sensing biomarkers, signal communications with living cells, and conversion of energy. Although molecular robots are still in their infancy, they will unquestionably initiate massive change in biomedical and environmental technology in the not too distant future. [ABSTRACT FROM AUTHOR]

Plasmonic catalysis has emerged as a promising approach to solar‐chemical energy conversion. Notably, hot carriers play a decisive role in plasmonic catalysis since only when their energy matches with the LUMO or HOMO energy of the reactant molecule, can the reaction be activated. However, the hot carrier energy depends on the intrinsic physicochemical properties of the plasmonic metal substrate and the interaction with incident light. Tuning the hot carrier energy is of great significance for plasmonic catalysis but remains challenging. Here, we demonstrate that the energy of hot electrons can be significantly elevated to an unprecedented level through the coordination of amines on Ag surface. The bonding of amines and Ag reduces the work function of nanoparticles, leading to the increase of hot electron energy by 0.4 eV. This enhancement of energy promotes the cleavage of C−X (X=Cl, F) bonds upon excitation by visible light. This study provides new insights for promoting plasmonic charge transfer and enhancing the photocatalytic performance of plasmon‐mediated systems. [ABSTRACT FROM AUTHOR]

A sulfur nanoparticles-incorporated iron-doped titanium oxide (Fe/TiO2) with different ratio was successfully synthesized by photolysis method and utilized as effective photoanode in dye sensitized solar cell (DSSC) application with N719 dye. The photolysis method was contained the irradiation of the Fe, S and Ti mixture solution with 15 W source irradiation, and then calcined the formed precipitate. The DSSCs fabricated with Fe/S–TiO2 photoanode appeared an improved solar-to-electrical energy conversion efficiency of 6.46, which more than pure TiO2 (3.43) below full sunlight illumination (1.5 G). The impact of Fe content on the total efficiency was also inspected and the Fe content with 6% S–TiO2 was found 5 wt%. Due to the improved the efficiency of solar cell conversion of Fe/S–TiO2 nanocomposite, it should be deemed as a potential photoanode for DSSCs with high performance. [ABSTRACT FROM AUTHOR]

Li–O2 batteries deliver ultrahigh theoretical specific energy while suffering from low energy efficiency and poor cyclability due to sluggish kinetics of oxygen electrode reactions. Herein, a strategy of engineering interfacial electron structure of MXene‐based composites is presented to boost oxygen electrode reactions for advancing Li–O2 batteries with the cation vacancy‐rich CoSe@MXene (VCo‐CoSe2@MXene) as the case study. The formation of interfacial Co─C bond between VCo‐CoSe2 and Ti3C2 MXene and its enhanced covalency after introducing Co vacancy leads to promoted electron transfer from Ti3C2 MXene to CoSe2 and optimized electronic structure of interfacial Co sites, especially the second Co sites neighboring Co vacancy, which serve as the active centers for oxygen redox reactions. On this basis, VCo‐CoSe2@MXene‐based Li─O2 batteries exhibit low overpotential (0.35 V) and excellent cycling stability (250 cycles at 500 mA g−1). This work proposes an effective strategy to develop MXene‐based electrocatalysts for Li–O2 batteries by tailoring interfacial electron structure. [ABSTRACT FROM AUTHOR]

In this study, we conducted a detailed exploration of stimulated Raman scattering (SRS) in heavy water (D2O), focusing specifically on its behavior at the air–D2O interface. The analysis revealed discernible SRS characteristic peaks corresponding to different vibrational modes, showing a 3.31-fold reduction in the SRS threshold at the air–D2O interface. Notably, we achieved a remarkable 6.83% energy conversion efficiency, approximately 3.36 times higher than the 2.03% efficiency observed in bulk D2O. Through cascaded Raman scattering and Raman-enhanced four-wave mixing (FWM) processes, up to third-order Stokes and corresponding anti-Stokes SRS were obtained in an unprecedented manner at a low pump energy of 8.26 mJ. Additionally, distinctive conical spatial structures of Stokes and anti-Stokes generated at air–D2O interface were attributed to Raman-enhanced FWM processes. Our investigation into the temporal behavior of SRS pulses revealed a unique mechanism: the initial decline of pump pulse was due to SRS-induced pump energy loss and heat dissipation, while the behavior of latter half resulted from non-uniform refractive index, causing self-defocusing and inhibiting the sustained generation of SRS. Our study sheds light on the development of multi-wavelength and significant frequency shift Raman lasers, offering valuable perspectives for future research endeavors. [ABSTRACT FROM AUTHOR]

Plasmonic catalysis has emerged as a promising approach to solar‐chemical energy conversion. Notably, hot carriers play a decisive role in plasmonic catalysis since only when their energy matches with the LUMO or HOMO energy of the reactant molecule, can the reaction be activated. However, the hot carrier energy depends on the intrinsic physicochemical properties of the plasmonic metal substrate and the interaction with incident light. Tuning the hot carrier energy is of great significance for plasmonic catalysis but remains challenging. Here, we demonstrate that the energy of hot electrons can be significantly elevated to an unprecedented level through the coordination of amines on Ag surface. The bonding of amines and Ag reduces the work function of nanoparticles, leading to the increase of hot electron energy by 0.4 eV. This enhancement of energy promotes the cleavage of C−X (X=Cl, F) bonds upon excitation by visible light. This study provides new insights for promoting plasmonic charge transfer and enhancing the photocatalytic performance of plasmon‐mediated systems. [ABSTRACT FROM AUTHOR]