Conversion Performance Research Articles

Enhanced Na-Ion Electrochemical Performance through Cu Doping-Mediated Sb2Se3 Phase Transformation into CuSbSe2 with Improved Kinetics.

This work investigates the influence of structural and electronic modification on the electrochemical performance of conversion and alloying materials. The CuSbSe2, a promising 2D layered conversion, and alloying material is being investigated with references to parent pristine Sb2Se3 and a doped version of later Sn0.2Sb1.8Se3 for their sodium-ion battery performance. The CuSbSe2 with layered structure is well known to accommodate lattice distortions via inter-layer movement, potentially mitigating distortions brought about by the Alkali ion (Na in this case) insertion. In contrast, the parent conversion-cum-alloying material Sb2Se3 with its one-dimensional crystal structure leads to structural disintegration during battery operation. The Sn-doped analog, Sn0.2Sb1.8Se3, comparatively exhibits enhanced kinetics owing to the reduced long-range order. The 2D layered, CuSbSe2 despite exhibiting 2D long-range order exhibits superior electrochemical performance owing to the favorable electronic and structural features. The CuSbSe2 exhibits a reversible capacity of 881 mAh g-1 compared to 516 mAh g-1 for Sn0.2Sb1.8Se3 and 429 mAh g-1 for Sb2Se3, with an improved Coulombic efficiency as well. The transient electrochemical investigations of Electrochemical Impedance Spectroscopy (EIS) and Galvanostatic intermittent titration techniques (GITT) reveal that better performance exhibited by CuSbSe2 may well be attributed to kinetics owing to enhanced diffusion coefficients in the intercalation and conversion regime.

Janus Photothermal Films with Orientated Plasmonic Particle-in-Cavity Surfaces Enabling Heat Control in Solar-Thermal-Electric Generators.

Solar thermoelectric generators (STEGs) consisting of solar absorbers and thermoelectric generators (TEGs) can utilize solar energy to generate electrical power. However, performances of STEGs are limited by the heat losses of solar absorbers in air, which become more and more significant with an increase in the solar absorbing area. Herein, we describe the preparation of Au@AgPd nanostructure monolayer/poly(vinyl alcohol) (PVA) Janus photothermal films with broadband plasmonic absorption in the visible and near-infrared regions. By uniaxially stretching the Janus film, Au@AgPd can align along the stretching direction, which creates particle-in-cavity structures on the PVA surface. Benefiting from the oriented plasmonic particle-in-cavity configuration, the Janus films effectively convert sunlight into heat, trap the heat within their micrometer-depth structure, and facilitate its transfer along the direction of the nanostructure orientation. Integration of the Janus films with commercial TEGs allows thermal concentration onto a small thermoelectric surface, yielding an open-circuit voltage of 308 mV under 102 mW/cm2 natural sunlight illumination. Heat losses in commercial TEGs integrated with Janus films are reduced by approximately 50% while maintaining the same voltage output. Furthermore, incorporating the Janus films into a conventional STEG with carbon-based solar absorbers significantly enhances solar-thermal-electric conversion performance, achieving an output power density of 1.3 W m-2. Our design of Janus photothermal films with oriented particle-in-cavity surfaces can be extended to various solar-thermal systems for high-efficiency solar energy conversion and heat management.

Zeolitic Imidazolate Frameworks Derived Magnetic Nanocage/MXene/Nanocellulose Bilayer Aerogels for Low Reflection Electromagnetic Interference Shielding and Light‐to‐Heat Conversion

AbstractTo cope with the increasingly serious electromagnetic pollution, the demand for electromagnetic interference (EMI) shielding materials with low electromagnetic wave reflection ability has become urgent. Controlling electrical components, magnetic components, and designing the EMI material structure can effectively improve electromagnetic shielding performance, but this remains a significant challenge. Besides, extreme cold weather conditions also do considerable potential damage to the normal work of outdoor electronic equipment. Integrated light‐to‐heat conversion capability on electromagnetic shielding materials can further improve the stability and reliability of the equipment. Herein, the novel bilayer aerogels composed of zeolitic imidazolate frameworks derived hollow CoNi carbon nanocage/MXene Ti3C2Tx/nanocellulose (BZMN) are prepared by a two‐step freezing method. BZMN aerogels exhibit good EMI shielding effectiveness (SE) with low reflection coefficient (R coefficients): 35.1 dB (R coefficient = 0.28) and 21.2 dB (R coefficient = 0.25). The unique structures of bilayer aerogels demonstrate the ability to absorb more electromagnetic waves through interfacial polarization and multiple scattering. The green shielding index (gs) of BZMN aerogels can reach 2.88. Moreover, BZMN aerogels show remarkable and unique light‐to‐heat conversion performance on different surfaces. Under 2.0 sun intensity, temperatures can reach 109.3 °C in the upper layer and 102.3 °C in the lower layer. Under 0.8 W cm−2 near‐infrared (NIR) laser intensity, the temperatures can rise to 234.1 °C in the upper layer and 167.4 °C in the lower layer. In addition, the size and shape of BZMN aerogels can be customized according to the mold. These features present BZMN aerogels as advanced potential low reflection EMI shielding device candidates, useful for future telecommunication and electronic equipment protection.

Measurement and correction on optical-thermal conversion of tubular solar cavity receiver with errors of installation and incident energy

The optical-thermal conversion performance of lab-scale solar receivers with a power greater than 10 kW is challenging to accurately evaluate due to errors of installation and incident energy. In this study, we utilized a solar simulator as the incident energy source for testing the outlet temperature of the solar receiver and proposed a method for correcting incident light power to precisely assess its optical-thermal conversion performance and potential. The impact of incident spot shift on the thermal conversion performance of the solar receiver is analyzed using Monte Carlo and CFD methods. Finally, based on experimental and simulation results, the operational characteristics of the solar receiver is predicted at a mass flow rate of 0.04 kg/s. The results indicate that when there is no deviation in spot position, the outlet temperature stabilizes at 1224K, whereas it stabilizes at 1215K with deviation present. However, there is a significant discrepancy of 159.7K between experimental and simulation results, which exceeds the variation caused by installation errors during verification (13K). Furthermore, compared to incident light incidence, deviations of 5 mm, 10 mm, 15 mm, 20 mm and 25 mm resulted in output power decreases by 0.08 %, 0.3 %, 1.35 %, 1.86 % and 2.8 % respectively. Considering fluctuations in optical-thermal conversion efficiency due to instantaneous changes in solar flow rate, averaging out oscillations reveals that after light power correction, the optical-thermal conversion efficiency can reach a peak value of 82.61 %, an increase of 8.33 % compared to before correction.

Efficient solar-driven interfacial water evaporation: Construction of facilely PVA/TA/GO gel copper foam evaporator

Solar-driven interfacial water evaporation (SDIWE) technology is crucial to alleviating the freshwater and energy crisis problems. However, most of the current evaporators have complex synthesis processes and some of the materials used are not biologically and environmentally friendly. Therefore, it is crucial to develop green, simple and efficient solar evaporators. Hence, photothermal interfacial gel copper foam (PTG@CF) solar evaporator was prepared by using a simple chemical cross-linking and "dip-coating" technique. The bio-friendly polyvinyl alcohol (PVA) and tannic acid (TA) were selected as the gel materials, and the in situ re-crosslinking of the copper foam (CF) surface to form a gel was realized by adjusting the hydrogen bonding cross-linking through water-ethanol solution. In addition, graphene oxide (GO) was introduced to improve the photothermal conversion performance, which was combined with CF to further enhance the thermal conductivity. Furthermore, the effects of the number of pores per inch (ppi) and thickness of CF on its performance in SDIWE were deeply explored. When comparing different ppi values and thicknesses, it was found that the PTG@CF evaporator with a thickness of 2 mm and a ppi of 80 exhibited excellent performance. The evaporation rate and solar-to-vapor conversion efficiency reached 1.88 kg m−2 h−1 and 88.47 %, respectively, under one solar irradiation. The PTG@CF evaporator demonstrated excellent photothermal conversion and evaporation performances, which is expected to provide a new idea for the SDIWE technology.

Nanoparticels Exsolution on Perovskite Oxides: From Growth Mechanism to Energy Conversion Applications

Exsolution method is a bottom-up process for growing uniformly distributed nanoparticles embedded on the oxide surface, exhibiting excellent activity and stability in energy conversions. Despite suggestions of diverse techniques for controlling and optimizing nanoparticle exsolution, research for quantitative control remains insufficient. Herein, we investigate the distribution of endogenous nanoparticles in the bulk of the fully reduced oxide, providing evidence of ion diffusion limitation rather than surface reduction limitation. Thus, we suggest a diffusion limitation model to understand the growth behavior of exsolved nanoparticles on the oxide support. Based on the experimental results, a theoretical model is developed using Fick’s laws and confirmed in designed perovskite oxides in which their Ni doping levels are controlled within the range of solubility. Their exsolution tendencies in the gas reduction, depending on doping level, reduction temperature, and time, are matched with the theoretical model. According to experimental and theoretical results, highly Ni-doped perovskite oxides are employed to improve exsolution and achieve high performance in energy conversions, including solid oxide cells and reforming. This framework between experimental and theoretical approaches provides insight for understanding and controlling nanoparticle exsolution on perovskite oxides.

Enhancing Solar Chemical Conversion Performance through Underlayer Modification on Copper-Based Mixed Oxide Films

This study focuses on synthesizing copper-based delafossite films through electrodeposition on transparent conducting substrates (FTO) and investigates their photoelectrochemical (PEC) behavior and unassisted photocatalytic (PC) activities for solar chemical conversion in aqueous solutions. We observe that the surface property, crystalline structure, PEC, and PC performance for Solar chemical conversion are significantly influenced by the synthetic conditions. Optimized Cu-based delafossite catalysts exhibit suitable energetics for solar chemical conversion. However, we have identified a challenge with rapid electron-hole recombination in this copper-based delafossite material due to its narrow bandgap, posing a disadvantage in solar chemical conversion. To address this issue, we introduce a hole extraction underlayer deposited on FTO substrate for the catalyst. The primary roles of the underlayer are to establish a robust contact between the delafossite catalyst and substrates, facilitate hole transfer, and improve the deposition kinetics of the delafossite precursors. Additionally, the underlayer plays a secondary role in establishing firm contact between the substrate and catalyst. Through this underlayer, we were able to improve the Faradaic efficiency (F.E.), Solar-to-chemical conversion (STC) efficiency and selectivity of solar chemical conversion. Furthermore, we provide clear insights into the interests through Density Functional Theory (DFT) calculations. This research was supported by the National Research Foundation of Korea (RS-2023-00246948), Korea Polar Research Institute (PE24124) and Korea Water Cluster (KWC) as Korea Water Cluster ProjectLab.

Tailored Iron Fluoride Lattices and Nanocomposites for High Energy, Rate, and Long Cycle Life

Due to the rapidly growing energy demands of portable electronics, electric vehicles and grid storage, the need for efficient, energy dense secondary batteries is more important than ever before. Current commercial lithium batteries generally use a layered transition metal oxide, such as LiCoO2 (LCO), which is an intercalation positive electrode that has a theoretical capacity of 274mAh/g, but a practical capacity of only 140-160 mAh/g (3). Current graphite negative electrode capacities are approximately 300mAh/g (4), lithium metal has a capacity of 3860mAh/g (5), and newly incorporated Si alloys enable a range of capacities between the two end points. Considering this, it is clear the limiting factor for lithium battery capacities is the positive electrode. Further, LCO as with many of the Ni based layered compounds is toxic, expensive, and requires mining which is both detrimental to the environment and generally done in unethical working conditions (2). Conversion materials offer a solution to this problem having significantly higher capacity than their intercalation counterparts and many of which are sourced from abundant elements. Of particular interest is iron(III) fluoride (FeF3) because of its high theoretical capacity (712mAh/g), low toxicity, and low cost and environmental impact due to the abundance of iron (1). Although much improvement has been accomplished in the community, a number of challenges remain to be addressed before conversion materials can become a competitive alternative. These limitations include poor rate capabilities, cycling stability and electrochemical performance at room temperature. FeF3 is an electrical insulator, which makes it a poor electrode material at room temperature. Our group has also shown that the majority of the impedance is related to ion transport (6). To work around the transport challenged nature of FeF3 and enable it electrochemically, molybdenum disulfide (MoS2) was used to create conductive pathways in the form of a dense FeF3:xMoS2 nanocomposites. The resulting nanocomposites created a matrix of 10-23nm iron fluoride crystallites encapsulated by quasi 2D MoS2 nanosheets. This nanocomposite also led to modification of the core FeF3 crystal lattice and voltage profile paralleling a systematic improvement of the conversion kinetics, performance, and rate capabilities. At room temperature, the new dense composites exhibited very stable cycling with capacities of up to 693mAh/g (1303 Wh/kg) and good performance at 1C rate; both a significant improvement when compared to benchmark FeF3: C nanocomposites (Fig. 1). Details regarding mechanism, enabling electrolytes, comprehensive physical characterization, data in Li-ion cells and pathways for future enhancement will be discussed. F. Badway et al 2003 J. Electrochem. Soc. 150 A1209Célestin Lubaba Nkulu Banza et al 2009 Environmental Research, Volume 109, Issue 6Qian, J., Liu, L., Yang, J. et al. Nat Commun 9, 4918 (2018)Kaifeng Yu, Jian Li, Hui Qi, Ce Liang, Diamond and Related Materials, Volume 86 (2018)Xu, W et al 2014 Energy Environ. Sci.,7, 513-537Jonathan K. Ko et al 2015 J. Electrochem. Soc. 162 A149 Figure 1

Model construction and photothermal conversion performance of a miniature non-imaging concentrator for capturing solar radiation in full sunlight

Non-imaging concentrators have been widely applied in the field of solar concentration. However, there are also unfavorable factors such as short effective working time, high production cost of curved reflector, which restrict its wider application in industry and agriculture. Therefore, this paper proposes a miniature non-imaging concentrator (FC-CPC) that can capture solar radiation in full sunlight based on the principle of edge ray. The geometric structure of the FC-CPC was optimized using the VC++ program, resulting in the development of an all-equal multi-section non-imaging concentrator (FM-CPC). On this basis, the optical performance and photothermal conversion performance of FM -CPC during operation were investigated. The results indicate that the average optical efficiency of FM-CPC direct radiation is 50.9 %, and the energy density distribution on the absorber surface is relatively uniform with a low energy density peak. The photothermal conversion system integrated with the FM-CPC shows an increase in collection efficiency as air flow rate increases, reaching a highest average efficiency of 54.1 %.

Cellulose Nanocrystal Composite Membrane Enhanced with In Situ Grown Metal-Organic Frameworks for Osmotic Energy Conversion.

Access to clean and renewable energy, osmotic energy from salinity gradient difference, for example, is central to the sustainability of human civilization. Despite numerous examples of nanofluidic membranes for osmotic energy conversion, one produced from abundant and renewable biomass resources remains largely unexplored. In this work, cotton-derived cellulose nanocrystals (CNCs) are employed to fabricate a membrane by self-assembly with polyvinyl alcohol (PVA) and subsequent in situ growth of metal-organic framework (MOF), UiO-66-(COOH)2, to provide an example. The composite membrane exhibits excellent mechanical strength and toughness due to the long chains and hydrogen bonding interactions of PVA. The incorporation of UiO-66-(COOH)2 endows the composite membrane with abundant nano- and subnano-sized ion transport channels, resulting in a 150% increase in ion conductance, while also providing superior cation selectivity through collaboration with the sulfated CNCs. The composite membrane with 27.4% MOF content can achieve an osmotic energy conversion performance of 5.10Wm-2 under a 50-fold KCl gradient condition and a monovalent cation selectivity of ≈16 for K+/Mg2+. This work presents a solution for harvesting renewable osmotic energy by constructing nanofluidic membranes using plentiful renewable biomass materials and a simple, low-emission fabrication procedure.

Fabrication of the multifunctional Pd modified NiCuFe Prussian blue analogue nanoplatform and its sensitive colorimetric detection of L-cysteine

It is essential to establish a simple, effective and sensitive platform for L-Cysteine (L-Cys) detection because the level of L-Cys is related to many diseases in the human body. Herein, we successfully fabricated polyaniline bridging NiCuFe Prussian blue analogue@palladium (NiCuFe@Pd) nanocomposite with integration of photothermal conversion performance and catalytic performance. And, various spectroscopic and microscopic techniques were adopted to prove the formation of the nanocomposite. 4-nitrothiophenol and 3,3′,5,5′-tetramethylbenzidine (TMB) were employed to prove the catalytic activity of the nanocomposite. Due to the catalytic activity, the nanocomposite was used as a nanoplatform for colorimetric detection of L-Cys, which showed high sensitivity with a detection limit as low as 0.027 μM. In addition, the excellent photothermal conversion performance makes it a potential candidate for photothermal therapy for various diseases. This study may be beneficial to promote the construction of novel nanostructures and their medical application.

An emerging route for efficient conversion of monopotassium phosphate via a pilot-scale electrodialysis metathesis

This study explores energy-efficient KH₂PO₄ (KDP) preparation, examining its implications for sustainability, and offers insights on enhancement and benefits. For the first time, electrodialysis metathesis (EDM) process was considered as a potential technique for efficient conversion and cleaner production of KDP in this study. The effects of key operational parameters including applied voltage, initial feed concentration, concentration ratio, and volume ratio on the conversion performance of EDM were systematically investigated. The promising conditions were established with an applied voltage of 2.3 V per repeating unit, a concentration ratio of 0.5 M NH4Cl to 0.6 M KCl, and a critical 1.43-fold volume ratio, yielding a high-purity KDP solution of 96.65 % at 78.52 g/L with an energy consumption rate of 0.52 KWh/kg. An economic evaluation indicates a 15.4 % cost reduction compared to the market price, presenting the EDM process as a viable and leading technology for the production of high-purity KDP.

A multifunctional carbon fiber composite film inspired by pumpkin growth toward tunable electromagnetic interference shielding

Carbon fiber composite film is an excellent electromagnetic interference (EMI) shielding material. However, its further application is limited by its single-loss characteristics of electromagnetic waves and unadjustable EMI shielding performance. Inspired by pumpkin growth, a carbon fiber/Co and Ni nanoparticles composite (PCF/CN) with porous, multi-interface, and cross-linked structure was designed through in-situ growth strategy in this work. In this process, Co2+ and Ni2+ were used as ovules while the composite nanofibers were used as the ovaries to provide active sites for seed growth. Polyether (P123) inside the composite nanofibers decompose under a high-temperature treatment and form a porous structure. The polyacrylonitrile (PAN) will form the "peel" during the high-temperature treatment. The PCF/CN provides abundant pores, plentiful non-homogeneous interfaces, and rich conduction paths for the attenuation of electromagnetic waves. After encapsulation with waterborne polyurethane (WPU), the obtained flexible PCF/CN/W composite film displays tunable EMI shielding efficiency using the "Origami" strategy. And the EMI shielding efficiency for PCF/CN-2/W reaches 24.73 dB after two folds due to the absorption loss, reflection loss, conduction loss, and interfacial polarization of the porous multi-interface cross-linked structure. Interestingly, the fabricated composite film also exhibits excellent photothermal conversion performance with fast thermal response time and stability. In addition, the resultant composite film processed sensitive sensing function to detect human joint motion.

A Hybrid Optimization Strategy for Minimizing Conversion Losses in Semi-Series-Resonant Dual-Active-Bridge Converter

To enhance the performance of resonant DC–DC converters, particularly under low-load conditions, a semi-series-resonant dual-active-bridge (Semi-SRDAB) converter with a hybrid optimization strategy is proposed. This strategy aims to reduce conduction-related losses and is designed for applications requiring a wide voltage range. The proposed Semi-SRDAB converter comprises a full-bridge inverter on the primary side and a hybrid-output bridge rectifier on the secondary side. It adopts phase-shift modulation combined with frequency modulation for power control. The hybrid optimization strategy for the Semi-SRDAB converter is investigated, beginning with the deduction of resonant current minimization using phasor analysis. Based on these analysis results, zero reactive power operation and soft-switching operation are achieved for both buck and boost modes. Successful validation has been demonstrated through experimental testing on a 300 W laboratory prototype. Enhanced conversion performance is confirmed by comparing the results with those from previous works.

Steam-treated SAPO-18 with well-regulated acidity and excellent dimethyl ether to olefin conversion performance

Steam-treated SAPO-18 with well-regulated acidity and excellent dimethyl ether to olefin conversion performance

Unveiling Suppressed Concentration Quenching Enhanced Broadband Near-Infrared Emitters.

Transition metal ions are exceptional emitters of broadband near-infrared (near-IR) luminescence, enabling various applications in photonics and optics; however, their weak absorption and excitation bands often limit conversion performance. Among potential sensitizers, Cr3+ stands out, allowing the excitation of Ni2+ with broadband visible-near-IR light while preserving luminescence properties. Nevertheless, concentration-induced quenching in doped luminescent solids fundamentally undermines brightness due to a trade-off between internal quantum efficiency and excitation energy dynamics. In this study, we demonstrate unprecedented brightness in the broadband near-IR photoluminescence (PL) of the Cr3+-Ni2+ system, where single, heavily doped Cr3+ exhibits minimal PL, and tuning Ni2+ concentration offsets the competitive relationship between the light emitter and quencher. By coupling InGaN light-emitting diodes (LEDs) with an ultrabroadband near-IR PL phosphor, we achieve phosphor-converted LEDs with a record output power of 41.5 mW at 100 mA and a photoelectric efficiency of 19.53% at 20 mA, nearly doubling previous reports. Our findings unveil intrinsic suppression of concentration quenching and eliminate competing energy sinks by emphasizing the dominant role of emitters in downshifting excitation energies, thus opening new avenues for the design of bright, sensitized luminescent materials.

Flexible electrospun porous carbon nanofiber@PEG phase change nanofibrous membrane for advanced solar-/electro-thermal energy conversion and storage

Flexible phase change materials (PCMs) showed great application prospects in the field of thermal management of flexible electronic devices and wearable devices, nevertheless, their development was seriously hindered by the intrinsic solid rigidity, liquid leakage and lack of functionality of PCMs. Herein, a multifunctional flexible leakage-proof composite PCM (named PCNF@PEG) was fabricated, in which poly(ethylene glycol) (PEG) was encapsulated in robust flexible porous carbon nanofibers (PCNFs) derived from electrospun polyacrylonitrile/polystyrene (PAN/PS) composite nanofibers. The as-prepared PCNF@PEG showed excellent flexibility, shape stability, satisfactory phase change performance with melting/freezing latent heat of 71.9/70.9 J g−1 and prominent thermal reliability after 100 thermal cycles. Moreover, the thermal conductivity of PCNF@PEG was noticeably enhanced by 45 % compared to pure PEG. Significantly, the interconnect carbon nanofiber matrix endowed PCNF@PEG unprecedented solar-/electro-thermal energy conversion performance and cycle stability. Therefore, the fabricated PCNF@PEG with pronounced comprehensive performance is a promising candidate for advanced thermal management applications in flexible devices.

Proper N[sbnd]Coordination improves catalytic activity of graphene edge anchored Pt single atom for conversion of methane and carbon dioxide to acetic acid

The reaction of directly converting CH4 and CO2 into acetic acid has a wide and important application in the chemical industry. In this work, we carried out systematically computational chemistry study on the catalytic performance of the single Pt atom catalyst anchored at the edge of N-doped graphene for the direct co-conversion of CH4 and CO2 to acetic acid based on density functional theory (DFT) calculations. The DFT calculation results show the catalytic activity of single Pt atom is significantly tuned by the local N-atom coordination. The Pt-N1C exhibits the best catalytic performance of CH4 and CO2 conversion with a low rate-determining free energy barrier of 0.69 eV The microkinetic modeling shows that the TOF of CH3COOH on Pt-N1C catalyst reaches 7.63×102s−1 at 600 K and 2 bar Further analysis shows that the adsorption strength of reactant CH4 and CO2 is linearly correlated with the energy level of dxy orbital center of Pt atom. A moderate adsorption strength of CH4 and CO2 over the Pt-N1C leads to easier activation of methane and migration of H and CH3 during the conversion reaction.

Regulation of coordinated nitrogen species for atomically dispersed Fe-N5 catalyst to boost electrocatalytic CO2-to-CO conversion

Single atom Fe catalysts coordinated with five N atoms (Fe-N5) have been adopted for excellent CO2-to-CO conversion. However, Fe-N5 catalysts typically face trade-offs among Faradaic efficiency (FE), current density, and stability, posing challenges for further commercialization. Additionally, the role of coordinated N species in their catalytic activities remains unclear. Herein, Fe-N5 catalysts coordinated with a high abundance of pyridinic-N (Fe-N5-pyri) or pyrrolic-N (Fe-N5-pyrro) are synthesized. Both operando experiment results and theoretical calculation manifest that pyrrolic-N increases CO2 adsorption capacity, reduces the reaction free energies required for CO2 activation, and facilitates *CO desorption by weakening the bonding strength with reaction centers. As a result, Fe-N5-pyrro exhibits superior CO2-to-CO conversion performance, achieving a maximum FECO of 96.6% and a partial current density exceeding –130mAcm-2 in 0.5M KHCO3, maintaining stable operation for over 100h. This work highlights the role of nitrogen species in Fe-N5 catalysts and provides a promising strategy for synthesizing robust catalyst for CO2 electrochemical reduction.

Impact of the continuity of spinning rate function on circular SOP conversion performance in spun quarter wave plate

Spun quarter wave plate (SQWP) exhibits superior state of polarization (SOP) conversion performance compared to the conventional quarter wave plate (QWP), with low loss and high accuracy, making it a promising choice for fiber optic systems. The spinning rate function, as a crucial component of SQWP, characterizes the process of spinning rate (ξ) from 0 to maximum (ξmax), playing a vital role in the performance of SQWP. To enhance circular SOP conversion, the traditional way is that we raise the spinning rate, but this increases ellipticity fluctuation (ΔE), impacting SQWP stability. Urgent exploration of alternative solutions is needed. In order to address this issue, in this study, the impact of the continuity of spinning rate function on circular SOP conversion performance in SQWP is thoroughly investigated through theoretical research and numerical simulation. The results show that spinning rate functions with higher order continuity decrease ellipticity fluctuation and enhance the circular SOP conversion performance in SQWP more effectively. We introduce and compare two novel higher order continuous spinning rate functions with the conventional linear and cosine functions regarding their robustness (σ) on circular SOP conversion performance. The average values of σ for the two proposed spinning rate functions are 4.01×10−5 and 2.17×10−6, respectively. They are one and two orders of magnitude smaller than the linear and cosine functions. The results demonstrate that the proposed spinning rate functions outperform conventional linear and cosine functions in both circular SOP conversion performance and robustness. The research findings of this study are expected to offer valuable insights and guidance for the future development and design of SQWP.