Conversion Efficiency Research Articles

Design and optimization of two stage annular thermoelectric generator coupling with high temperature heat pipe application

Traditional energy sources have limited applications in deep space and deep-sea exploration as they cannot provide a long-term, reliable energy supply. Small nuclear reactors are ideal because of their high adaptability and long life, especially for powering deep space missions. This study focuses on integrating thermoelectric generators (TEG) with small nuclear reactors. Due to the limitation of conventional planar thermoelectric devices in conversion efficiency, a novel annular thermoelectric device (ATEG) is proposed and discussed. Compared with the traditional flat thermoelectric devices, annular thermoelectric devices have the advantages of larger contact area with heat source, smaller volume and stable heat flux. According to the application requirements of heat pipe reactor, the geometric parameters of thermoelectric conversion system are optimized in order to find the best geometric parameters and external load resistance. Through detailed investigation, we found that under certain conditions (such as 900 K hot end temperature and 10 mm device height), the single-stage SKD thermoelectric device can achieve the highest conversion efficiency of 8.99 %. Optimizing contact characteristics (e.g., surface roughness less than 2 µm, contact resistivity less than 10 microohms square centimeters) is critical to maintaining this high level of efficiency. Based on the thermoelectric characteristics of single-stage thermoelectric devices, two-stage thermoelectric devices are studied. The two-stage SKD-BT device exhibits better performance. When the height ratio of thermoelectric material is 0.7, the efficiency of the two-stage SKD-BT device is as high as 11.49 %, which is 27.8 % higher than that of the single-stage thermoelectric device. In this study, two innovative ways of integrating cascaded annular thermoelectric devices are proposed, which are simple in structure and easy to be modularized. Under the same temperature boundary condition, the thermoelectric conversion efficiency of the PN leg alternating connection structure can reach 10.95 % under the optimal load resistance, which is better than 6.45 % of the parallel connection structure.

Metabolic engineering of Escherichia coli for improved cofactor regeneration in lactate to acetoin via whole-cell conversion

Background: Acetoin is a crucial intermediate in asymmetric syntheses of high-value chemicals and pharmaceuticals. However, its production still relies on traditional fossil-based processes. Developing efficient microbial cell factories for green and low-cost acetoin production is urgently needed. Methods: Acetoin was produced from inexpensive and shortcut lactate substrate using whole-cell Escherichia coli through overexpression of highly active α-acetolactate synthetase and decarboxylase from Bacillus subtilis (annotated as SD). Precise stepwise optimization of pathway and enzymatic reaction was executed by (1) harboring the most efficient cofactor-regenerating system, (2) tuning expression design, (3) disrupting byproduct pathway, and (4) optimizing a series of biotransformation parameters. Significant Findings: The recombinant E. coli successfully produced acetoin. The titer was gradually increased by expressing a pyruvate-producing gene from NAD+ dependent or independent system and its cofactor regeneration systems. Co-expressing lactate oxidase (lox) and catalase (cat) achieved a conversion efficiency of 50% and eliminated NAD+ usage. The conversion efficiency was further pulled by knocking out acetate-generating genes (pta and poxB), thus boosting acetoin conversion to 92.4%. Under optimized whole-cell biotransformation parameters, the highest acetoin titer reached 20.6 g/L within 30 h. This work provides an economical biomanufacturing process for acetoin from lactate via whole-cell bioconversion with remarkable yield.

Molybdenum disulfide nanosheets hybridized with lysine molecules for highly efficient near-infrared photothermal energy conversion

The paper reports a facile way for noncovalent functionalization of 1T-MoS2 with L-lysine (Lys) monolayers. The structure of the resultant hybrid compound was revealed by the powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, absorption spectroscopy and density functional theory (DFT) calculations study. A significant strength of the in-layer organic and organic-inorganic hydrogen bonding amounting to 24.6 and 29.9 kcal per mole of Lys, respectively, was found to hold the hydrated Lys molecules arranged in 2D chains and keep these chains tightly bound to the MoS2 sheets. The MoS2 hybridization with Lys significantly rises the upper temperature stability limit of 1T-MoS2 polymorph, which possesses the remarkable photothermal properties in near infra-red (NIR) region. The hybrid structure demonstrates excellent photothermal light-to-heat conversion efficiency reaching 49.5% upon 808 nm laser irradiation and higher thermal durability than unmodified 1T-MoS2.

Lignosulfonate-based sulfonated polymers for highly efficient one-pot conversion of fructose into 5-ethoxymethylfurfural in ethanol

Lignosulfonate-based sulfonated polymers for highly efficient one-pot conversion of fructose into 5-ethoxymethylfurfural in ethanol

Off-axis dispersion-managed metasurface for routing orbital angular momentum mode and wavelength multiplexing channels

Offering the strengths of mode orthogonality and physical independence from wavelength dimension, optical orbital angular momentum (OAM) modes hold immense potential for enhancing communication capacity through multi-dimensional channel multiplexing. Although methods using angle-separated gratings have seen advances in multi-dimensional (de)multiplexing, routing these multiplexed channels is impeded by the resultant mode-wavelength dispersion resulting from Bragg diffraction of grating. This induces not only multi-level mode conversion but also confined wavelength separation scope, posing obstacles in spatial reallocation of both OAM modes and wavelengths for routing channels. To tackle these issues, we propose a wavelength-dependent multi-foci transformation solution for OAM mode-wavelength routing that utilizes an off-axis dispersion-managed metasurface. Incorporated with composite lens phases and helical modulations, the metasurface enables the precise manipulation of OAM mode-wavelength dispersion upon multi-foci Fourier transform without multi-level diffraction, facilitating both efficient mode conversion and versatile wavelength separation. Harnessing the multi-dimensional independence, this approach establishes a high-dimensional linear mapping relationship among OAM modes, wavelengths, and spatial positions, thereby achieving the routing of mode-wavelength hybrid channels. In a proof-of-concept simulation, we demonstrated the successful routing of 20 channels with five OAM modes and four wavelengths across four depth planes, with the average channel crosstalk below -15.2 dB. Additionally, 16-ary quadrature amplitude modulation signals carried by these 20 multiplexed channels were successfully routed, and the bit-error-rates approach 1 × 10-5. Our method shows flexibility in spatial reallocation of both OAM modes and wavelengths, as further explored by altering the number of routing channels and their spatial positions, which may provide new insights for advanced OAM-based optical communications.

A simple ultra-broadband metamaterial solar perfect absorber with highly efficient photothermal conversion performance

A simple ultra-broadband metamaterial solar perfect absorber with highly efficient photothermal conversion performance

Enhancing glycerol hydrogenolysis to n-propanol: Key role of Lewis acid in HZSM-5 supported Cu catalyst.

Glycerol hydrogenolysis to n-propanol (1-PO) represents an approach to realize synthesizing sustainable fuels from biodiesel byproduct. However, it suffers from harsh reaction conditions and noble catalysts. Herein, a simple Cu20/HZSM-5(Si/Al=120) was fabricated, demonstrating high efficiency under mild conditions for non-noble metal catalysts, achieving a 71.08% yield of 1-PO and 80.73% mono-alcohols. The catalyst, characterized by a high density of Lewis acid sites from both CuO and HZSM-5 and a favorable Cu2+/Cu0/1+ ratio, significantly enhances the hydrogenolysis process. Furthermore, it demonstrated superior selectivity for the removal of the secondary -OH group from 1,2-propanediol (1,2-PDO), which is crucial for high yields of 1-PO. This Cu20/HZ-5(120) catalyst showed significant potential for the efficient and selective conversion of glycerol to 1-PO, presenting a promising approach for the sustainable production of value-added chemicals from glycerol.

Determination of biomass energy potential based on regional characteristics using adaptive clustering method

Determining the energy potential of biomass is the first step in selecting the most suitable and efficient energy conversion technology based on regional characteristics. The approach to estimating and determining biomass potential generally uses geospatial technology related to collecting and processing data about mapping an area. Unfortunately, this method is inadequate for simulating the interaction between variables, nor can it provide accurate predictions for the biomass supply chain. As a result, the results obtained from this method tend to be biased and macro, particularly in regions experiencing rapid land-use development. In this paper, the author has developed a clustering methodology with a fuzzy c-means (FCM) algorithm to determine biomass energy potential based on regional characteristics to produce data clusters with high accuracy. Grouping the characteristics of clustering-based areas involves grouping physical or abstract objects into classes or similar objects.

Enhancing output performance and thermoelectric conversion efficiency in thermal regeneration ammonia-based flow battery through a novel W-like flow channel

Enhancing output performance and thermoelectric conversion efficiency in thermal regeneration ammonia-based flow battery through a novel W-like flow channel

Cytokinin B-Mo-based Product Influences the Source-to-sink Dynamics and Nonstructural Carbohydrate Contents in Hydroponic Lettuce Plants

An understanding of how amendments influence the sink-to-source relationship in leafy crops can be used to optimize plant resource allocation for enhanced growth and quality. Variations in growth rates and carbon pools across individual leaves or groups of leaves at similar developmental stages allow us to comprehend plant strategies of carbon allocation and partitioning. We hypothesized that products enhancing the carbon source-to-sink relationship during leaf development can increase growth and dry matter accumulation. This project aimed to determine whether exogenous applications of a cytokinin-B-Mo-based product during the leaf development of lettuce plants impact the carbon source-to-sink relationship, thus influencing plant growth and quality. The experiment was a complete randomized design with two treatments: a negative control and the application of the product twice during the growing cycle. Each experimental unit consisted of a deep-water culture reservoir with three lettuce plants. Destructive sampling was conducted five times throughout the cycle. At each sampling time (n = 4 per experimental run), the phenological stage was determined, and measurements of root and shoot length, root and shoot dry matter, leaf length, leaf width, leaf area, chlorophyll contents, and nonstructural carbon contents were performed. These data were used to estimate growth indices. The results indicated that the cytokinin-B-Mo-based product increased the number of true unfolded leaves by 1 ± 0.4 and the overall size of the lettuce head by 9%. The treated lettuce reached marketable size 4 days earlier than that of the control treatment. Statistically significant differences were observed in shoot and root dry matter accumulation and foliar length and width at some sampling points. Some growth indices indicate an increase in leaf surface area investment and enhanced conversion efficiency of assimilates into biomass in plants treated with the product. Plants exhibiting these alterations had higher sucrose and total soluble sugar contents. There was a noticeable pattern of higher concentrations of nonstructural carbohydrates, proteins, and amino acids in the leaves compared with those in the roots across all plants and treatments. Overall, the cytokinin-B-Mo-based product appears to strengthen the source-to-sink relationship during lettuce development, resulting in a high-quality plant within a shorter timeframe.

Modulating the local electron density at built-in interface iron single sites in Fe-CN/MoO3 heterostructure for enhanced CO2 reduction to CH4 and Photo-Fenton reaction

The catalytic efficiency of heterogeneous photocatalytic CO2 reduction and photo-Fenton H2O2 activationisclosely related to the local electron density of reaction center atoms. However, electron-hole recombination from random charge transfer significantly restricts the targeted electron delivery to the active center. Herein, Fe-C3N4/MoO3 heterojunction with interfacial coordination of atomically dispersed Fe-N4 sites with the O interface of MoO3 was synthesized by simple hydrothermal method. Based on the experimental results and density functional theory calculation (DFT), the heterojunction structure fosters accelerated interfacial electron transfer due to directional interfacial electric field (IEF) between Fe-CN and MoO heterogeneous interfaces, and the interfacial bond between Fe-N4 sites and O at the built-in interface regulates the local electron density of Fe-N4 active center. DFT further reveals that the interfacial electron flow and concentrated electron density at Fe-N4 sites result from the coordination between Fe-N4 and MoO3 interfaces. This directs electron flow towards the Fe center, significantly enhancing CO2 adsorption and H2O2 conversion efficiency. PDOS analysis shows that the dyz and dz2 orbitals of the isolated Fe atom in Fe-CN overlap with the pz orbital of the O atom in MoO3, playing a pivotal role in CO2 adsorption. Consequently, the Fe-CN/MoO3 heterojunction demonstrated highly efficient photocatalytic CO2 reduction to CH4, coupled with benzyl alcohol oxidation and photo-Fenton tetracycline degradation. These findings offer a promising multifunctional catalyst strategy for the development of energy conversion and environmental remediation.

Multifunctional Bamboo-Derived Porous Carbon for Efficient Electrical-Thermal Energy Management and Electromagnetic Interference Shielding

Joule heating is an effective heating method but is often limited by the extra heat dissipation. To address this, we developed bamboo-derived porous carbon (CB) for use as Joule heaters, which exhibits remarkable electrothermal conversion efficiency, driven by its high electrical conductivity and porous structure. The natural porous structure of bamboo reduces electrothermal conversion losses, allowing for a steady-state saturation temperature of 164 °C at 2 V. The microcrystalline graphite structure, 3D microporous channels, and low thermal conductivity (0.03 W m-1 k-1) contribute to an electrothermal conversion efficiency of 99.14%. Moreover, CB heaters demonstrate remarkable surface heating and cooling rates of 114.36 °C/min and 113.78 °C/min, respectively. CB Joule heaters are suitable for de-icing and body-assisted heat treatment at various applied voltages. Its unique gradient porous structure also provides asymmetrical electromagnetic interference (EMI) shielding performance, with high absorption losses concentrated in the sparse inner layer. This sustainable CB material has significant potential for advanced Joule heating and EMI shielding applications.

Analysis and Design of CUK-SEPIC-based Converter for Hybrid Power Generation Systems

Background: The increasing demand for electricity, coupled with an imbalanced supply and demand, population growth, and climate change, has prompted the shift from conventional to non-conventional energy systems. However, the unreliability and intermittency of the latter pose a challenge to their feasibility. To address this challenge, a proposal has been made to explore the combination of two renewable energy sources (RES) using a unique DC-DC converter topology, with the aim of meeting the load demand in a sustainable and efficient manner. Objective: The focus of this research was to explore solutions for the challenges associated with operating RES independently, including issues with intermittency, weather dependence, and meeting load demands. The proposed hybrid system features exclusively RES, offering a promising approach to reducing carbon footprint. Ultimately, we aimed to develop a CUK-SEPIC-based converter that can effectively integrate two independent RES to satisfy the load demand of a standalone application. Method: Effective hybrid power generation through RES is a complex challenge, but it has been found that combining solar and biomass energy sources is one of the best options for achieving this goal. To tap into these sources, it is essential to have a suitable power electronic converter, and the CUK-SEPIC converter has been chosen for its many benefits. The features of this converter have been described in detail. The integration of solar and biomass energy sources is achieved using this converter, which has been designed and mathematically modeled in the MATLAB/Simulink environment to ensure optimal performance. To validate the effectiveness of the proposed converter, a comparison with existing power electronic converters has been done using the MATLAB/Simulink platform. Results: The hybrid power generation system model has been comprehensively developed in this work using the sophisticated MATLAB/Simulink environment. The input and output parameters have been diligently estimated through an extensive simulation process. The research has yielded valuable insights, indicating that the CUK-SEPIC converter exhibits an impressive power conversion efficiency of 96.57%, along with an overall step-up ratio of 5.25 and significantly reduced ripple content. Conclusion: Upon conducting a comprehensive analysis of the CUK-SEPIC DC-DC converter, it has been observed that the proposed system exhibits significant promise in rectifying the reliability issues commonly associated with renewable energy power generation. Therefore, it is recommended that this system be considered for implementation in rural electrification initiatives. Furthermore, it is worth noting that this system represents one of the most recent developments in the field of renewable energy power generation technology.

Construction of a self-floating fabric based on CVD-assisted coating and its application in interfacial evaporation

The discharge of industrial wastewater and the shortage of fresh water resources are increasingly endangering human daily life. In this experiment, bismuth oxychloride with oxygen vacancies was attached to a fabric surface using the solution deposition method, and then perfluoro-trichlorosilane was grafted on the surface to prepare a multifunctional superhydrophobic fabric. After mechanical stability testing, the fabric retained a water contact angle that consistently exceeded 150°, which could realize the selective adsorption of insoluble oil such as cyclohexane. Through a capture experiment of active species, the conclusion drawn was that holes (h+) and superoxide free radicals (·O2−) were primary active species for the photocatalytic degradation process. After 4 cycles of photodegradation, the degradation efficiency could still reach 92.8 %, showing excellent cyclic degradation stability. An interfacial solar steam generator (ISSG) was assembled using the superhydrophobic fabric as the support layer and a polypyrrole sponge as the photothermal layer, whose evaporation efficiency under one sun reached 2.8376 kg·m−2·h−1, with a photothermal conversion efficiency of 92.255 %. This ISSG demonstrates excellent wastewater purification capabilities. Interfacial evaporation devices show promising prospects in solar-powered wastewater purification, which further expand the use of interfacial evaporation to solve the problem of water scarcity.

Modulating Metal Activation Energy via Cerium-Mediated Heterointerface Defect Evolution for Photovoltaic-Driven Efficient Water Electrolysis

Exploring electrocatalysts with high-valence metal sites is crucial to accelerate oxygen evolution reaction (OER), yet it encounters challenges arising from thermodynamic formation barriers. We have in-situ constructed a multi-defective Ce³⁺-Ov-M active interface through a dynamic interface defect integration strategy, regulating the ionic conductivity and the formation barrier of high-valence Ni and achieving an ultralow overpotential of 155mV at 10mAcm-2 current density for OER. The recordings from in-situ Raman and UV-Vis spectroscopy illustrate that the modulated catalyst facilitates a cathodic shift in the transition potential for forming γ-NiOOH. Theoretical calculations have confirmed the mechanism, indicating that defect-engineering at the heterointerface leads to electron localization, lower d-band centers enhance the electron distribution at metal active centers, and activate lattice oxygen for efficient water oxidation. This property extended to hydrogen evolution catalysts also exhibits high versatility. Perovskite/crystalline silicon tandem solar cells are used to drive the electrolytic assembly system to achieve 21.01% solar hydrogen conversion efficiency.

A multifunctional biosensor for selective identification, sensitive detection and efficient photothermal sterilization of Salmonella typhimurium and Staphylococcus aureus.

The foodborne pathogens, e.g., Salmonella typhimurium (S. typ) and Staphylococcus aureus (S. aureus), pose a serious threat to human health. Accurate identification, rapid detection and efficient inactivation are crucial in the early diagnosis and treatment of S. typ and S. aureus. To date, however, the majority of studies have only concentrated on the construction of single-function biological platform for detection or inactivation of S. typ and S. aureus. Therefore, it is imperative to develop a multifunctional surface-enhanced Raman scattering (SERS) biosensor that can effectively sterilize S. typ and S. aureus while simultaneously achieving sensitive detection and selective identification. Herein, we designed and constructed a multifunctional SERS biosensor based on sandwich structure of "capture probe/bacteria/signal probe" in order to simultaneously identify, detect and kill S. typ and S. aureus. Aptamer-modified ZnO/Ag was used as a capture probe to accurately identify and capture the target bacteria in complex environments. Au@Ag-4-MPBA-Aptamer was employed as signal probe to provide the corresponding bacterial SERS "fingerprint" information. The SERS enhancement mechanism of the sandwich-structure ZnO/Ag-Au@Ag SERS substrate was discussed. The sandwich-type SERS biosensor exhibited the strong localized surface plasmon resonance (LSPR) effect and the detection limit for S. typ and S. aureus was as low as 10cfu/mL. Furthermore, the sandwich-type SERS biosensor offered excellent photothermal conversion efficiency (54.32%), enabling photothermal killing of target bacteria when exposed to laser irradiation. A dual enhancement strategy based on a sandwich structure was proposed to maximize the sensitivity of SERS signals using synergistic action of electromagnetic enhancement and chemical enhancement. SERS enhancement factor (EF) was as high as 4.67×105. In addition, the sandwich-type SERS biosensor not only exhibited negligible cytotoxicity, but also was proved to be a promising tool for photothermally inactivate of S. typ and S. aureus in food samples.

Stable and Eco-Friendly Ag–In–S/Zn–S Quantum Dots for an Efficient and Optically Transparent Luminescent Solar Concentrator-Organic Photovoltaic System

Quantum dot (QD) based luminescent solar concentrator-organic photovoltaic (LSC-OPV) systems demonstrate significant potential in applications including building-integrated photovoltaics (BIPV). In this study, eco-friendly Ag–In–S/Zn–S QDs with a high photoluminescence quantum yield (PLQY = 73%) are synthesized using a simple hydrothermal method. The influence of Zn-S precursor reactivity on QD properties is studied. The synthesized QDs exhibit excellent stability over a wide temperature range (90–360 K). The Ag–In–S/Zn–S LSCs maintain over 90% of their initial PLQY after a two-month exposure to natural sunlight. Additionally, the power conversion efficiency (PCE) of the fabricated LSC-OPV system reaches 1.00% under near-actual condition (9 mW cm-2). Moreover, when the irradiation intensity is further decreased to 0.4 mW cm-2, the LSC-OPV system shows a PCE as high as 5.27%, demonstrating that the LSC-OPV system can operate efficiently at low illumination intensities. Notably, the fabricated LSCs have minimal impact on the incident sunlight spectrum, making them suitable for BIPV applications. Thus, this study is a first that is known to report the integration of eco-friendly QD-based LSCs with organic photovoltaic cells, which positively contributes to the advancement of BIPV.

Exploring the role of π-Spacers in six novel Push-Pull photovoltaic systems based on N-Methylarylamine: A theoretical DFT Investigation

This study examines the impact of spacers on the performance of six push–pull type molecules (D-π-A) in solar cells. MPTA-1 (without a spacer) is compared to MPTA-2 to MPTA-6, which incorporate thiophene, benzothiazole (BTZ), furane, selenophene, and pyridine spacers. N-phenyl-N-(thiazol-2-yl)aniline (MPTA) is the donor, and dicyanovinyl (DCV) is the acceptor in all molecules. Quantum chemical calculations using Density Functional Theory (DFT) confirm these compounds as suitable electron donors with acceptors like PCBM in bulk-heterojunction solar cells. Key findings: i) molecules absorb in the visible range (446.54 nm to 671.23 nm); ii) energy gaps range from 1.34 eV to 2.21 eV, making them suitable for photovoltaics; iii) MPTA-4 shows the highest power conversion efficiency (PCE) at 14.363 % due to its higher open circuit voltage (Voc) of 1.848 V. The furane spacer significantly enhances photovoltaic properties, making MPTA-4 the most efficient.

Green synthesis of CuO nanoparticles from <i>Cucurbita maxima</i> leaf extract; a platinum free counter electrode for dye sensitized solar cells

Green synthesis of metal oxides has attracted attention as the latest technology in synthesizing metal oxide nanoparticles due to its simplicity, cheapness, non-toxicity and its ability for large scale production. Metal oxides find applications in dye sensitized solar cells (DSSCs) as counter electrodes (CEs) and photo-anodes. However, applications of green synthesized metal oxides as counter electrodes have not been fully explored. In this study, CuO nanoparticles (NPs) were synthesized from Cucurbita maxima leaf extract and applied as a CE in DSSC. Uniformly synthesized CuO NPs were subjected to various characterization tools to obtain the crystal structure, surface morphology, particle size, optical properties, chemical bonds and photovoltaic properties. Using a natural dye from of Cucurbita maxima as a photon absorber, a short circuit current density ( Jsc) of 4.2 µA/cm2, open circuit voltage (Voc) of 0.17 V, a maximum power (Pmax) of 0.18 mW/cm2, and a power conversion efficiency (PCE) of 1.8 × 10?4 % under one-sun illumination were obtained.

Ultrasmall gold-encapsulated mesoporous platinum to promote photodynamic/catalytic therapy through cascade enzyme-like reactions

Mesoporous platinum (mPt) nanozyme possessed enzyme-like property of catalase (CAT) and peroxidase (POD), but the insufficient hydrogen peroxide (H2O2) concentration severely restricted its application in photodynamic therapy (PDT) and catalytic therapy. Herein, by depositing ultrasmall gold nanoparticles (AuNPs) and modifying photosensitizer IR808, a multifunctional nanozyme (mPt@Au-IR808) was designed to promote PDT/catalytic therapy through cascade enzyme-like reactions of glucose oxidase (GOx) and CAT/POD. In tumor microenvironment, the CAT-like oxygen (O2) generation improved the PDT efficacy, and the POD-like hydroxyl radical (·OH) generation achieved endogenous catalytic therapy. Using the GOx/CAT-like activities and endogenous H2O2, the yields of singlet oxygen and ·OH were significantly promoted. Furthermore, mPt@Au-IR808 showed higher photothermal conversion efficiency (41.2%) than mPt (36.1%). By combining the photothermal therapy and enhanced PDT/catalytic therapy, the developed mPt@Au-IR808 nanozyme showed excellent anti-tumor efficacy, which will be promising as cascade nanozyme to promote photo/catalytic therapy.