Low-temperature Activity Research Articles

Boosting Pt utilization via strategic Co Integration: Structural and mechanistic investigation of High-Performance Pt-Co alloy nanocatalysts for catalytic benzene combustion

Platinum (Pt)-based catalysts exhibit notable efficacy in reducing emissions of hazardous volatile organic compounds (VOCs), such as benzene. Nevertheless, the high cost and limited availability of Pt necessitate exploring reasonable strategies to optimize Pt utilization and enhance catalytic efficiency. Thus, pressing needs emerge to develop efficient Pt-based catalysts. This study investigates the catalytic combustion of benzene utilizing an antimony-doped tin oxide (ATO) supported platinum-cobalt (Pt-Co) alloy catalyst. The incorporation of cobalt into Pt nanoparticles leads to Co atoms occupying bulk sites in the Pt-Co alloy, elevating the surface exposure of Pt atoms and enriching Pt on the surface, thereby providing additional active sites for catalysis. Advanced characterization techniques provide critical insights into the morphology, size distribution, crystallinity and valence states of Pt upon strategic Co alloying. Pt-Co/ATO exhibits exceptional low-temperature activity, achieving 95 % benzene conversion at 170 °C, which is 30 °C lower than the 200 °C required for Pt/ATO. Pressure-dependent kinetic analysis reveals a Langmuir-Hinshelwood mechanism involving the co-adsorption of benzene and oxygen reactants on active Pt-Co alloy sites. This study contributes insights into tuning bimetallic alloy nanostructures to optimize noble metal utilization and catalytic performance for VOC abatement, establishing a foundation for advancing sustainable emissions control technology.

Enhancing the Carbon Monoxide Oxidation Performance through Surface Defect Enrichment of Ceria-Based Supports for Platinum Catalyst.

Effective synthesis and application of single-atom catalysts on supports lacking enough defects remain a significant challenge in environmental catalysis. Herein, we present a universal defect-enrichment strategy to increase the surface defects of CeO2-based supports through H2 reduction pretreatment. The Pt catalysts supported by defective CeO2-based supports, including CeO2, CeZrOx, and CeO2/Al2O3 (CA), exhibit much higher Pt dispersion and CO oxidation activity upon reduction activation compared to their counterpart catalysts without defect enrichment. Specifically, Pt is present as embedded single atoms on the CA support with enriched surface defects (CA-HD) based on which the highly active catalyst showing embedded Pt clusters (PtC) with the bottom layer of Pt atoms substituting the Ce cations in the CeO2 surface lattice can be obtained through reduction activation. Embedded PtC can better facilitate CO adsorption and promote O2 activation at PtC-CeO2 interfaces, thereby contributing to the superior low-temperature CO oxidation activity of the Pt/CA-HD catalyst after activation.

Enhanced low-temperature CO oxidation activity through crystal facet engineering of Pd/CeO2 catalysts

Cerium dioxide (CeO2) supported palladium (Pd) catalysts have found widespread application in CO oxidation reaction owing to their exceptional catalytic performance. The morphology of the CeO2 support dictates the exposed crystal plane, exerting a profound influence on surface structure and redox properties. This is crucial as the atomic arrangement at the surface directly impacts catalytic activity. In this study, a range of CeO2 supports with diverse morphologies (e.g. nano-octahedra, nano-cubes, nano-particles, nano-spheres, and nano-rods) were successfully synthesized through hydrothermal methods and subsequently supported with Pd for CO oxidation. The spherical 1Pd/CeO2–S catalyst, revealing exposed (111) + (100) crystal planes, exhibited significantly higher CO catalytic oxidation activity compared to the catalysts with other morphological CeO2 supports. The results indicated a positive correlation between the content of PdxCe1-xO2-y species and catalytic activity. Notably, this species was most abundantly formed in the spherical 1Pd/CeO2–S catalyst with exposed (111) + (100) crystal planes. The presence of this active species facilitated the formation of surface defects, increased oxygen vacancy concentration, and enhanced metal-support interaction, consequently greatly improving the CO low-temperature catalytic oxidation activity. Consequently, the oxidation state of Pd in the Pd/CeO2 catalyst could be effectively regulated by controlling the exposure of (111) + (100) crystalline surfaces of the CeO2 support, further optimizing the catalytic performance of the Pd/CeO2 catalytic system.

Promoting effects of cerium oxide on catalysts performance for selectivity catalytic oxidation of NH3 over RuOx/TiO2

Cerium oxide (CeO2) was added to modified Ru/TiO2 catalyst by a two-step impregnation method for selective catalytic oxidation of ammonia (NH3-SCO). The low-temperature NH3 oxidation activity and N2 selectivity of the 1Ru/xCe-TiO2 catalyst were investigated with the result that both SCO activity and N2 selectivity were influenced by the amount of Ce. Specifically, the presence of 5 wt% CeO2 demonstrated a great promoting effect on both parameters, reaching an NH3 conversion and N2 selectivity of 97 % and 93 % at 180 ℃, respectively. Various characterization methods indicated that the presence of CeO2 regulates the dispersion of the 1Ru/xCe-TiO2 catalysts, changes the amount, strength and ratio of strong and weak acid sites on the catalyst surface, and promotes the formation of Ru-O-Ce bonds through the interaction between Ce and Ru species, which facilitates electron transfer and oxygen vacancy formation, thereby enhancing the oxidation ability of the catalysts. Furthermore, the results of in situ diffuse reflectance infrared Fourier transform spectroscopy indicated that the NH3-SCO reaction over the 1Ru/xCe-TiO2 catalysts follows the “internal” selective catalytic reduction (i-SCR) mechanism, involving the oxidation of NH3 into nitric oxide (NO) species and the reaction of -NH2 with in situ-formed NO to form N2.

A New Nanoplatform Under NIR Released ROS Enhanced Photodynamic Therapy and Low Temperature Photothermal Therapy for Antibacterial and Wound Repair.

Skin injury, often caused by physical or medical mishaps, presents a significant challenge as wound healing is critical to restore skin integrity and tissue function. However, external factors such as infection and inflammation can hinder wound healing, highlighting the importance of developing biomaterials with antibiotic and wound healing properties to treat infections and inflammation. In this study, a novel photothermal nanomaterial (MMPI) was synthesized for infected wound healing by loading indocyanine green (ICG) on magnesium-incorporated mesoporous bioactive glass (Mg-MBG) and coating its surface with polydopamine (PDA). In this study, Mg-MBG and MMPI was synthesized via the sol-gel method and characterized it using various techniques such as scanning electron microscopy (SEM), the energy dispersive X-ray spectrometry (EDS) system and X-ray diffraction (XRD). The cytocompatibility of MMPI was evaluated by confocal laser scanning microscopy (CLSM), CCK8 assay, live/dead staining and F-actin staining of the cytoskeleton. The antibacterial efficiency was assessed using bacterial dead-acting staining, spread plate method (SPM) and TEM. The impact of MMPI on macrophage polarization was initially evaluated through flow cytometry, qPCR and ELISA. Additionally, an in vivo experiment was performed on a mouse model with skin excision infected. Histological analysis and RNA-seq analysis were utilized to analyze the in vivo wound healing and immunomodulation effect. Collectively, the new photothermal and photodynamic nanomaterial (MMPI) can achieve low-temperature antibacterial activity while accelerating wound healing, holds broad application prospects.

Ammonia decomposition over La-doped Al2O3 supported Co catalyst

As the hydrogen source of carbon-free fuel cells, the key to realize the green and low-energy decomposition hydrogen production process is to select materials with excellent catalytic performance for ammonia dehydrogenation. In this study, the rare earth element lanthanum (La) was doped onto the surface of Al2O3 by the impregnation method. The aforementioned material was subsequently used as a new material for the synthesis of single metal Co catalysts that catalyzed ammonia decomposition. Various characterization techniques (XRD, HRTEM, N2 physical adsorption-desorption, ICP, XPS, SEM, H2-TPR) were employed to investigate the relationship between the structure and performance of Co/La–Al2O3 catalysts. The findings indicated that the 10Co/La(5)-Al2O3 catalyst was the most active. Under the conditions of 550 °C and 9000 mL h−1·gcat−1, the conversion of ammonia reached 90 %, and the yield of hydrogen reached 8.9 mmol·gcat−1·min−1. A perovskite-type metal oxide layer of LaAlO3 was generated on the surface of Al2O3 support after doping the appropriate amount of lanthanum (5 %), which directly affects the catalytic performance of the catalyst. The small amount of LaAlO3 optimized the strong interaction between the metal Co and the supports, thereby enhancing catalytic performance. While stabilizing the active component Co, XPS and H2-TPR also implied that the presence of La could enhance the electron transfer between the support and Co, as well as facilitate the desorption of nitrogen and hydrogen products, therefore, the low temperature activity of Co/La–Al2O3 catalyst can be improved. The ammonia decomposition efficiency of the catalyst doped with 5 % wt La was much higher than that of the catalyst without La incorporation. The simple modified support developed by us, which loads a monoatomic Co catalyst, provides a new approach for the development of high-activity transition metal catalysts.

Enhanced low-temperature activity of CO2 methanation over Ni/CeO2 catalyst: Influence of preparation methods

Enhanced low-temperature activity of CO2 methanation over Ni/CeO2 catalyst: Influence of preparation methods

Determining the Effectiveness of Solar Collectors Used In Low-Radiation Areas

Background: In this paper considers the issues of using solar collectors as an alternative source of energy for territories remote from the power grids. One of the main criteria when choosing the solar collectors is the choice of the working fluid for heat transfer. Solar collectors according to the type of coolant are divided into a liquid and air. Materials and Methods: The solar collector works on the principle of energy transfer to a liquid from a source of radiant energy that is located a certain distance away, unlike conventional heat exchangers. In actual use, there are two types of solar collectors: one concentrates solar energy, the other doesn’t. Results: It is possible to give air clusters in places with low air temperature and low solar activity, and we use energy equations and their balances. Moreover, we have determined the thermal properties of solar clusters and useful energies. Conclusion: Climate characteristics and structures are crucial to the results of a solar array's efficiency in covering ocean temperatures and the types of solar arrays to choose from with good results, heat fluxes and densities. In addition, we show that the solar collector is not considered a basic criterion in choosing the types of collectors. Key words: Solar energy, sustainable energy, low-radiation, solar collector, heat transfer

Study on Novel SCR Catalysts for Denitration of High Concentrated Nitrogen Oxides and Their Reaction Mechanisms

With the rapid development of industrialization, the emission of nitrogen oxides (NOx) has become a global environmental issue. Uranium is the primary fuel used in nuclear power generation. However, the production of uranium, typically based on the uranyl nitrate method, usually generates large amounts of nitrogen oxides, particularly NO2, with concentrations in the exhaust gas exceeding 10,000 ppm. High concentrations of nitrogen dioxide are also produced during silver electrolysis processing and the treatment of waste electrolyte solutions. Traditional V-W/TiO2 NH3-SCR catalysts typically exhibit high catalytic activity at temperatures ranging from 300 to 400 °C, under conditions of low NOx concentrations and high gas hourly space velocity. However, their performance is not satisfying when reducing high concentrations of NO2. This study aims to optimize the traditional V-W/TiO2 catalysts to enhance their catalytic activity under conditions of high NO2 concentrations (10,000 ppm) and a wide temperature range (200–400 °C). On the basis of 3 wt% Mo/TiO2, various loadings of V2O5 were selected, and their catalytic activities were tested. Subsequently, the optimal ratios of active component vanadium and additive molybdenum were explored. Simultaneously, doping with WO3 for modification was selected in the V-Mo/TiO2 catalyst, followed by activity testing under the same conditions. The results show that: the NOx conversion rates of all five catalysts increase with temperature at range of 200–400 °C. Excessive loading of MoO3 decreased the catalytic performance, with 5 wt% being the optimal loading. The addition of WO3 significantly enhanced the low-temperature activity of the catalysts. When the loadings of WO3 and MoO3 were both 3 wt%, the catalyst exhibited the best denitrification performance, achieving a NOx conversion rate of 98.8% at 250 °C. This catalyst demonstrates excellent catalytic activity in reducing very high concentration (10,000 ppm) NO2, at a wider temperature range, expanding the temperature range by 50% compared to conventional SCR catalysts. Characterization techniques including BET, XRD, XPS, H2-TPR, and NH3-TPD were employed to further study the evolution of the catalyst, and the promotional mechanisms are explored. The results revealed that the proportion of chemisorbed oxygen (Oα) increased in the WO3-modified catalyst, exhibiting lower V reduction temperatures, which are favorable for low-temperature denitrification activity. NH3-TPD experiments showed that compared to MoOx species, surface WOx species could provide more acidic sites, resulting in stronger surface acidity of the catalyst.

Biobased Activated Carbon from Palm Biomass Enhancing with Acid Treatment as Supercapacitor Electrode Material

Current research on energy storage systems, batteries, and supercapacitor devices is aimed to enhance efficiency and improve environmental sustainability. Supercapacitors offer remarkable attributes such as high transient response and power density. Typically, supercapacitor electrode is made from highly porous carbon material, activated carbon. Commercial activated carbon could be produced from coal, peat, or coconut shell. This study focused on utilization of palm biomass, palm empty fruit bunch (EFB), as raw material to produce activated carbon electrode. The highly porous activated carbon from EFB was synthesized via a low-temperature hydrothermal process and chemical activation. The resulting EFB activated carbon demonstrates favorable characteristics in terms of elevated surface area and porosity. This research investigates the enhancement of activated carbon with acid treatment during hydrothermal process. Two types of acid, citric acid, and phosphoric acid, at different concentrations, were added to biomass. The acid-treated activated carbon from palm biomass was characterized for the specific surface area (BET), pore size distribution and pore volume using the N2 adsorption/desorption technique. The acid-treated activated carbon was fabricated into carbon electrodes and assembled in a symmetrical supercapacitor with 1M H2SO4 as an electrolyte. The supercapacitor performance of acid-treated activated carbon was tested in a symmetrical Swagelok cell to assess specific capacitance using cyclic voltammetry and galvanostatic charge-discharge methods. The acid-treated activated carbon has higher specific capacitance than the activated carbon without acid treatment. This superior performance is attributed to the reduced internal resistance as revealed by the Electrochemical Impedance Spectroscopy (EIS) result. This is possibly due to the formation of micropores in the range of 0.6−0.7 nm which is a suitable pore size for ion transportation in H2SO4 electrolytes. This research has shown that biobased activated carbon from palm oil biomass with acid treatment has a high potential to be used as supercapacitor electrode material. Keywords: Activated carbon, Palm biomass, Hydrothermal, Energy storage, Supercapacitor

Three-dimensionally ordered macroporous CeZrVOx catalyst with remarkable NH3-SCR performance and SO2 tolerance: Key roles of the morphology and highly dispersed V species

Developing effective low-temperature deNOx catalysts with high activity, SO2 tolerance, and stability is crucial yet challenging. Thus, in this work, CeZrVOx catalyst with a three-dimensional ordered macroporous structure was successfully prepared using the PMMA hard template method, and the catalyst has a macropore diameter of up to 110−140 nm. The modification with highly dispersed V significantly enhances the low-temperature activity and broadens the activity temperature window of the catalyst. This is mainly attributed to the increased number of surface acid sites, as well as the higher proportion of Ce3+ and active surface oxygen species induced by V modification. The V species prepared by this method are highly dispersed on the CeZrOx solid solution and combine with Ce to form CeVO4, which is also an important factor in enhancing catalytic activity. The catalyst does not react with SO2 to produce inactive sulfate species; even the formed cerium sulfate species are beneficial for high-temperature performance. More importantly, due to its unique interconnected three-dimensional ordered structure, the catalyst can significantly inhibit the blockage and coverage of NH4HSO4 on the catalyst, thereby exhibiting remarkable resistance to physical poisoning caused by SO2. Even in high concentrations of sulfur-containing atmospheres, the catalyst still shows high catalytic activity. This work offers meaningful guidance into developing denitration catalysts that show superior performance and robust resistance to both physical and chemical poisoning induced by SO2.

Designing Dual-Site Catalysts for Selectively Converting CO2 into Methanol.

The variability of CO2 hydrogenation reaction demands new potential strategies to regulate the fine structure of the catalysts for optimizing the reaction pathways. Herein, we report a dual-site strategy to boost the catalytic efficiency of CO2-to-methanol conversion. A new descriptor, τ, was initially established for screening the promising candidates with low-temperature activation capability of CO2, and sequentially a high-performance catalyst was fabricated centred with oxophilic Mo single atoms, who was further decorated with Pt nanoparticles. In CO2 hydrogenation, the obtained dual-site catalysts possess a remarkably-improved methanol generation rate (0.27 mmol gcat. -1 h-1). For comparison, the singe-site Mo and Pt-based catalysts can only produce ethanol and formate acid at a relatively low reaction rate (0.11 mmol gcat. -1 h-1 for ethanol and 0.034 mmol gcat. -1 h-1 for formate acid), respectively. Mechanism studies indicate that the introduction of Pt species could create an active hydrogen-rich environment, leading to the alterations of the adsorption configuration and conversion pathways of the *OCH2 intermediates on Mo sites. As a result, the catalytic selectivity was successfully switched.

Low-Temperature Methane Activation Reaction Pathways over Mechanochemically-Generated Ce4+/Cu+ Interfacial Sites.

Methane is a valuable resource and its valorization is an important challenge in heterogeneous catalysis. Here it is shown that CeO2/CuO composite prepared by ball milling activates methane at a temperature as low as 250°C. In contrast to conventionally prepared catalysts, the formation of partial oxidation products such as methanol and formaldehyde is also observed. Through an in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and operando Near Edge X-Ray Absorption Fine Structure Spectroscopy (NEXAFS) approach, it can be established that this unusual reactivity can be attributed to the presence of Ce4+/Cu+ interfaces generated through a redox exchange between Ce3+ and Cu2+ atoms facilitated by the mechanical energy supplied during milling. DFT modeling of the electronic properties confirms the existence of a charge transfer mechanism. These results demonstrate the effectiveness and distinctiveness of the mechanical approach in creating unique and resilient interfaces thereby enabling the optimization and refining of CeO2/CuO catalysts in methane activation reactions.

Promotional effect of WO3 in V2O5–WO3/TiO2 on low-temperature activity in the catalytic oxidation of 1,2-dichloroethane

Transition metal oxides are promising catalysts for the degradation of chlorinated volatile organic compounds (CVOCs). However, their practical applications are limited due to their poor low-temperature (<300 °C) activity. In this study, we introduced WOx into VOx/TiO2 to modulate its redox and acidic properties. We found that the V2O5(2 wt%)–WO3(10 wt%)/TiO2 (2V10W/TiO2) catalyst exhibited a 1,2-dichloroethane (DCE) conversion of 90 % at 256 °C, which is comparable to that of Ru-based catalysts (DCE conversion of 90 % at 257–340 °C) for the oxidation of DCE. The addition of WOx into VOx/TiO2 gave rise to the formation of labile surface oxygen species and promoted interactions between V and W, which improved the reducibility, oxygen mobility, and Brønsted acidity of the 2V10W/TiO2 catalyst. These properties of 2V10W/TiO2 lowered its activation barrier for DCE oxidation and mitigated coke formation and Cl deposition on the catalyst, enhancing the low-temperature activity and long-term stability. The 2V10W/TiO2 catalyst also exhibited superior resistance to water. This study provides insights into catalytic design for balancing the redox and acidic properties in the catalytic oxidation of CVOCs.

Low-temperature NOx reduction over Cu-LTA and SmMnOx composite catalysts

Low-temperature selective catalytic reduction of NOx with ammonia (NH3-SCR) over zeolite catalysts remains a great challenge in diesel exhaust purification. Herein, Cu-LTA zeolite with excellent hydrothermal stability was composited with a small proportion of SmMnOx oxides, the composite catalytic system efficiently resolves the low-temperature activity challenge encountered by Cu-LTA. The promoting pathways revealed the presence of active nitrite intermediates formed on SmMnOx by activating NO, that were able to migrate to the Cu-LTA and can be further decomposed on the Brønsted acid sites. Compared to the continuous deposition of nitrates in Cu-LTA, the presence of SmMnOx in composite catalysts efficiently reduced the accumulation of inert nitrate and improved the nitrate deposition phenomena. This innovative research would provide a rational strategy to break the barrier of limited low-temperature performance faced by zeolite catalysts, effectively promoting the NOx removal in vehicles sources.

Constructing highly active vanadyl species for efficient selective catalytic reduction of NOx

Vanadia-based catalysts have been commercially applied for selective catalytic reduction with NH3 of NOx (NH3-SCR). Considering the biotoxicity of V2O5, V-based catalysts are demanded to exhibit high catalytic activity with low V2O5 loadings. However, at low vanadium contents, surface VOx primarily present in the form of monomers, which show poor low-temperature activity. Here, efficient low-vanadium-loading catalysts were designed via constructing highly reactive polymeric vanadyl species by introducing disparate forms of niobia species. Niobia species were found to promote the polymerization of surface VOx, and the disparate forms of niobia species had a key influence on the formation of polymeric vanadyl species. Crystalline Nb2O5 promoted the formation of polymeric vanadyl species, induced by a structural effect. By contrast, uniformly dispersed niobium species on the surface of a Nb-Ti-O solid solution support served as new anchoring sites for VOx and promoted a greater extent of polymerization of VOx species via electronic interactions among V, Nb and Ti. Ultimately, Nb-Ti-O solid solution-supported V2O5 exhibited much higher low-temperature reaction rates than TiO2-supported Nb2O5 and V2O5 due to more polymeric vanadyl species. This study provides new methods to design low-vanadium-loading catalysts, offering new perspectives for the modification of transition metal oxides to design efficient catalysts.

Utilization of low-stability variants in protein evolutionary engineering

Evolutionary engineering involves repeated mutations and screening and is widely used to modify protein functions. However, it is important to diversify evolutionary pathways to eliminate the bias and limitations of the variants by using traditionally unselected variants. In this study, we focused on low-stability variants that are commonly excluded from evolutionary processes and tested a method that included an additional restabilization step. The esterase from the thermophilic bacterium Alicyclobacillus acidocaldarius was used as a model protein, and its activity at its optimum temperature of 65 °C was improved by evolutionary experiments using random mutations by error-prone PCR. After restabilization using low-stability variants with low-temperature (37 °C) activity, several re-stabilizing variants were obtained from a large number of variant libraries. Some of the restabilized variants achieved by removing the destabilizing mutations showed higher activity than that of the wild-type protein. This implies that low-stability variants with low-temperature activity can be re-evolved for future use. This method will enable further diversification of evolutionary pathways.

BaZr0.1Ce0.7Y0.1Yb0.1O3-δ particles embedded PrBa0.5Sr0.5Co1.5Fe0.5O5+δ hollow nanofibers with 3D fast transmission path as oxygen electrode for proton-conducting solid oxide electrolysis cell

To address the challenge of low-temperature catalytic activity of oxygen electrodes, a high-activity triplex ionic conductor material, PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF), is prepared using electrospinning. The preparation PBSCF and BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb) nanofibers composite electrodes are used with different composite methods to improve the catalytic activity and the proton transport pathway within the electrode. The results show that PBSCF@BZCYYb prepared by PBSCF and BZCYYb pre-mixed one-step electrospinning has high porosity and 3D interwoven continuous transmission path, exhibiting minimal polarization impedance on symmetric cells. The electrolysis cell with PBSCF@BZCYYb|BZCYYb|NiO-BZCYYb (active layer) |NiO-BZCYYb (support layer) structure shows electrolysis current densities of 775.4 mA cm−2 under 1.3 V at 650 °C with 20%H2O+80%Air atmosphere. Additionally, during the constant voltage electrolysis, the cell shows acceptable stability in 60 h at 650 °C, considered to be a promising oxygen electrode material in this work.

Multiphysics modeling and optimization of an innovative shape memory alloy-polymer active composite

Shape memory alloys (SMAs) are a unique class of smart materials capable of recovering significant deformations through temperature variations, making them attractive for adaptive structures and morphing applications. However, integrating SMAs into polymer composites poses significant challenges, such as interfacial delamination and matrix overheating during thermal activation, in addition predicting the stress acting on the SMA during the actuation is pivotal. Addressing these issues is crucial for realizing the full potential of SMA-based active composites in aerospace, automotive, and renewable energy sectors. This study presents a novel multi-material design strategy for SMA-polymer active composites, featuring a rigid PC/ABS layer for mechanical integrity, a soft high-temperature silicone coating for encapsulating SMA wires, and aluminum terminals for wire crimping. A comprehensive multiphysics FEM model was developed to accurately capture the coupled thermo-mechanical response. Extensive experimental characterization and validation were conducted, followed by systematic parametric studies to investigate the effects of critical design parameters on key performance metrics. The developed prototype exhibited remarkable shape morphing capabilities, with a maximum tip deflection of 68 mm (deflection-to-length ratio of 0.4). Excellent agreement between experiments and simulations was achieved, with a maximum error of 1.7 % in tip deflection, validating the accuracy of the multiphysics model. Parametric analyses quantified the trade-offs between geometric parameters, revealing their influence on activation temperature, deflection, SMA wire stress, and fatigue life. Optimal configurations enabling low activation temperatures (<150 °C), low stress levels (<400 MPa), and high predicted fatigue life (>50,000 cycles) were identified. The multi-material design approach effectively addressed common issues in SMA-polymer composites, enabling reliable actuation cycles without damage accumulation. The validated multiphysics model and parametric insights provide a comprehensive framework for optimizing the design and performance of SMA-polymer active composites, paving the way for their widespread adoption in shape morphing applications. Potential implications include the development of adaptive aerodynamic surfaces, deployable structures, and energy-efficient systems across various industries.

Formation of Fe2(SO4)3-Fe2O3 interface induced by OCFGs electrostatic anchoring on AC surface: High efficiency NH3-SCR performance at low temperatures

Low-temperature activity and SO2 poisoning were the key factors limiting the application of NH3-SCR catalysts. In this study, Fe2(SO4)3/AC and Fe2(SO4)3/OAC catalysts were prepared by oxidation function modification and incipient wetness impregnation. In the temperature range of 100–250 ℃, the catalytic performance and SO2 resistance of Fe2(SO4)3/AC and Fe2(SO4)3/OAC catalysts were investigated, the denitrification efficiency increased from 28 % (Fe2(SO4)3/AC) to 80 % at 100 °C and reached 100 % at 170 °C, and 100 ppm SO2 was introduced at 250 ℃ for 24 h, the denitrification efficiency remains 100 % unchanged. The mechanism of activity enhancement was further explored by BET, XRD, ICP, TG, XPS, FT-IR, H2-TPR and NH3-TPD. The results showed that (NH4)2S2O8 modification enhanced the surface acidity, and the increase of surface oxygen-containing functional groups improved the redox performance. At the same time, due to electrostatic anchoring effects of oxygen-containing functional groups, Fe3+ and SO42- were adsorbed at different sites and promoted the binding of S to the carbon skeleton to form −C-S-C-. Thus, the interaction between OAC and Fe2(SO4)3 caused part of Fe2(SO4)3 to decompose into Fe2O3, and the formation of Fe2(SO4)3-Fe2O3 interface further enhanced the acidity and redox properties. More importantly, the decomposition temperature of NH4HSO4 was lower and the decomposition was more thorough on the Fe2(SO4)3/OAC than that of Fe2(SO4)3/AC. Finally, the possible mechanism of (NH4)2S2O8-modified Fe2(SO4)3/OAC catalyst to improve NH3-SCR performance was proposed, which is of great significance for the development of NH3-SCR catalyst with sulfur resistance at low temperatures.