Carbon monoxide (CO) is a colorless, odorless, and highly toxic gas, primarily produced by vehicle emissions and incomplete fossil fuel combustion. It poses significant environmental risks and binds to hemoglobin in the bloodstream, leading to hypoxia. Catalytic oxidation is an efficient and energy-saving method for CO removal. Noble metal catalysts, such as Pd-based and Pt-based systems, demonstrate excellent activity for CO oxidation, though their high cost hinders large-scale industrial application. Thus, developing non-noble metal catalysts that enable complete CO oxidation at low temperatures is crucial. The sol-gel method, a versatile wet-chemical synthesis technique, allows precise control over catalyst composition and microstructure, ensuring highly uniform dispersion of active components on the support. In this work, a series of trimetallic 5%CuFe_x/CeO₂ (x=0~0.1) catalysts with controlled Fe doping were prepared via sol-gel method to elucidate the promotional effect of Fe on Cu/CeO₂ for low-temperature CO oxidation. Comprehensive characterization including X-ray diffraction (XRD), Raman, Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) was conducted to probe the catalysts' structural, textural, and electronic properties. H₂-temperature-programmed reduction (H₂-TPR), O₂-temperature-programmed desorption (O₂-TPD), and CO-temperature-programmed desorption (CO-TPD) were used to elucidate the redox capacity of the catalyst and the activation of reactant molecules CO and O₂.The catalytic evaluation demonstrated that 5%CuFe_0.025/CeO₂ catalyst showed optimal performance, achieving 100% CO conversion at 70 ℃, which represented a significant 40% improvement in low-temperature activity compared to the Fe-free Cu/CeO₂ reference catalyst. Furthermore, the catalyst exhibited excellent stability, maintaining complete CO conversion throughout a 60 h stability test. XRD patterns confirmed the preservation of CeO₂ fluorite structure in all catalysts, with no detectable CuO_x or FeO_x crystalline phases, suggesting the high dispersion of both Cu and Fe species on the catalyst surface. SEM and N₂ physisorption analysis revealed that the sol-gel synthesized 5%CuFe_x/CeO₂ catalysts possessed a hierarchical porous architecture. Fe incorporation promoted the formation of an interconnected network-like morphology with uniform pore distribution, increasing the specific surface area, which optimized texture and facilitates mass transport while maximizing active site accessibility, significantly enhancing reaction kinetics. Raman spectroscopy analysis demonstrated that Fe doping modifies metal-oxygen bond lengths, creating additional oxygen vacancies. These defect sites facilitated oxygen activation from ambient air, generating reactive oxygen species for CO oxidation. Supporting evidence from O₂-TPD revealed a distinct low-temperature shift in oxygen desorption peaks after Fe incorporation, while XPS analysis of O 1s spectra confirmed the increased abundance of reactive oxygen species-both findings corroborating the enhanced oxygen activation capacity induced by Fe doping. H₂-TPR analysis revealed enhanced α-peak hydrogen consumption with increasing Fe loading, indicating improved oxygen mobility. Combined CO-TPD and XPS characterizations demonstrated that optimal Fe doping promotes CuO_x dispersion and increases the concentration of active Cu⁺ sites for CO chemisorption. However, excessive Fe loading (x=0.1) led to attenuated CO desorption intensity in TPD profiles, suggesting iron oxide over-deposition may block active sites and reduce CO adsorption capacity. In-situDRIFTS analysis revealed a carbonate-mediated Mars-van Krevelen (M_V-K) mechanism for CO oxidation over the catalyst. As the reaction temperature rose, the abundance of Cu⁺-CO species increased, accompanied by enhanced peaks corresponding to carbonate intermediates. This suggested that adsorbed CO reacted with surface-active oxygen species to form carbonate species, which subsequently decomposed into CO₂ and desorbed from the catalyst surface. The vacant oxygen sites were then replenished by adsorbed O₂ from the gas phase, generating new active oxygen species. These reactive oxygen species reacted with adjacent adsorbed CO to produce additional CO₂, completing the catalytic cycle. These results indicated that the catalytic performance of copper-cerium catalysts for complete CO oxidation could be significantly improved by strategically doping trace metal additives, thereby enabling completed CO conversion at lower operating temperatures.

Printed circuit boards (PCBs), serving as critical carriers for electrical interconnections among numerous electronic components, are widely employed in computers, communications, aerospace, and medical applications. Electroless copper deposition is a key step in PCB manufacturing, involving the chemical deposition of a thin copper layer (2~3 μm) on the insulating via walls to establish conductive interconnections between different circuit layers or copper foils. The quality of this deposited copper layer directly determines the electrical connectivity performance of PCB. However, due to limitations in production equipment capabilities or outdated electroless copper plating technology, defects such as copper voids on via walls, rough copper surfaces, uneven copper thickness, microcracks, and poor copper adhesion may occur. During soldering or normal operational life cycles, PCBs are subjected to high-temperature reflow soldering or repeated thermal cycling, imposing stringent requirements on the uniformity, surface roughness, adhesion strength, and thermal shock resistance of the deposited copper layer. These challenges drive manufacturers to continuously explore methods for achieving stable and reliable electroless copper deposition. Extensive research has been conducted by scholars worldwide to investigate the influence of magnetic fields on the physicochemical properties of materials. It has been well-documented that external magnetic fields can exert directional control over the deposition rate, surface morphology, and crystal growth orientation in chemical deposition processes. In this study, electroless copper plating was conducted on Flame Retardant 4(FR-4) substrates under different magnetic fields with central intensities of 30 and 60 mT. The copper deposition rate was measured gravimetrically, while scanning electron microscopy (SEM) was employed to analyze the microstructure of deposited copper layers. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were utilized to investigate the effects of magnetic fields on deposition processes at different copper ion concentrations and the resulting corrosion resistance. The results indicated that the copper deposition rate peaked at approximately 2.5 min before stabilizing. During the stable phase, the applied magnetic field increased the deposition rate from 8 to 10 mg·dm⁻²·min⁻¹, representing a 25% enhancement. The plating tank size significantly influenced the deposition rate during the pre-peak phase, with smaller tanks yielding higher peak rates. Visual and SEM observation revealed that magnetic field-assisted deposition produced brighter, smoother, and more uniform copper layers with improved density. While negligible effects were observed at low copper ion concentrations (<1 g·L⁻¹), significant changes occurred at 2~5 g·L⁻¹ concentrations under magnetic fields：increased cathodic polarization accompanied by negative shifts in deposition potential peaks, with the shift magnitude being concentration-dependent. Specifically, at 60 mT, the reduction peak potential for 5 g·L⁻¹ copper solution shifted from –0.85 to –0.89 V, with current density increasing from 2.11 to 2.34 A·dm⁻². EIS analysis confirmed that magnetic field-deposited copper layers exhibited higher charge transfer resistance during electrochemical corrosion, indicating superior corrosion resistance.

Hydroquinone (HQ), as an important chemical raw material and antioxidant, has been widely used in industrial production such as rubber, dyes cosmetics, antioxidant, and medical procedures. With the development of modern industry, more and more HQ pollutions are released into nature. Due to its high toxicity and persistence in ecosystems, HQ is particularly harmful to human health and environment. There is an urgent need for developing simple and sensitive methods for real-time monitoring of HQ. At present, a lot of efforts have been made to detect HQ, and many sensitive and selective methods have been used, such as mass spectrometry, electrochemical sensing, high-performance liquid chromatography, fluorescence sensing, and so on. However, most of those methods need complicated processes or expensive measurement equipment which limits its applications. Colorimetric sensing with simple preparation, low-cost and good selectivity has been focused. High-performance of transition metal oxides including Co₃O₄, Fe₃O₄, CuO, etc had been proved in the detection of heavy ions and pesticides in environment. To our best knowledge, Ag₂Cu₂O₃ as a mimic enzyme is not reported yet for now. Herein, Ag₂Cu₂O₃ nanoparticles were fabricated by a simple method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS). The measurement results showed that the morphology of Ag₂Cu₂O₃ was nanorods with the length 0.63~1.54 μm of and the diameter of 0.15~0.47 μm. XPS spectrum determined valence states and surface atomic compositions of Ag₂Cu₂O₃. The peaks of O 1s, Cu 2p, and Ag 3d appeared in the spectrum of Ag₂Cu₂O₃. The high-resolution XPS analysis of Cu 2p and Ag 3d showed the binding energy peaks at 374.2 and 368.3 eV were correspond to Ag⁺ oxidation state, the binding energy peaks at 953.6 and 933.75 eV were correspond to Cu²⁺ oxidation state. The high-resolution XPS analysis of O 1s showed the binding energy peaks at 529.5, 531.2 and 532.2 eV were respectively correspond to lattice oxygen (O_L), surface-adsorbed oxygen (O_A), and adsorbed H₂O (O_H2O). The oxidase-like activity of Ag₂Cu₂O₃ was measured in presence of 3, 3′, 5, 5′-tetra-methylbenzidine (TMB). Different pH values (2~8) and temperatures (5~45 ℃) were used to estimate the influences of pH and temperature on the properties of Ag₂Cu₂O₃ The highest catalytic performance of the nanorods appeared at temperature of 25 ℃ and pH of 5. The catalytic reaction of Ag₂Cu₂O₃ on TMB was explored by adding three trapping agents EDTA (ethylene diamine tetraacetic acid), IPA (isopropanol) and PBQ (1, 4-benzoquinone) to trap h⁺ (hole), ·OH (hydroxyl radical) and O₂·^- (superoxide radical) respectively. After adding EDTA and PBQ, the solution absorbance was obviously reduced, proving that lots of h⁺ and O₂·⁻ were generated during the catalytic process. Furthermore, HQ as a kind of reductive molecule could react with blue ox-TMB to form colorless TMB. According to the above abovementioned results, a colorimetric sensing platform with Ag₂Cu₂O₃ for detection of HQ was built. The absorbance and concentration of HQ had a linear relationship between 3~30 μmol·L^-1 with the limit of detection 1.67 μmol·L⁻¹ (limit of detection=3s/k, s-standard deviation of instrument response, k-slope of calibration curve). Various ion interferents (Na⁺, K⁺, Ca²⁺, Zn²⁺, NH₄⁺, Mn²⁺, Cd²⁺ and Mg²⁺) were added into detecting system to explore selective and anti-interference properties of this detecting system. The result showed that the absorption intensity of HQ was the strongest of all, even if the concentration of interferents was 10 times. Detection of HQ in river samples was evaluated by standard addition method. Considerable recovery rate demonstrated enormous potential for this method in detecting HQ in real samples.

The increasing concentration of atmospheric CO₂ and the escalating severity of global warming have made CO₂ capture, utilization, and storage (CCUS) technologies crucial solutions for reducing carbon emissions and mitigating climate change. CO₂ hydrogenation to methanol represents a crucial pathway for CO₂ recycling. Industrially, Cu-based catalysts are widely employed due to their abundant raw materials, low cost, and excellent stability, with CuZnAl catalysts already being utilized in industrial-scale CO/CO₂ hydrogenation to methanol processes. However, the introduction of ZrO₂ as a promoter, due to its weak alkalinity and weak hydrophilicity, can inhibit the toxic effect of water on the active site during methanol synthesis, playing an important role in CO₂ adsorption and methanol selectivity. In this study, ZnO hexagonal nanorods were used as support to load Cu-ZnO-ZrO₂. Different catalysts were prepared by regulating the content of the loaded substances in the catalyst, changing the morphology of the ZnO support, and with or without the support, and their CO₂ hydrogenation catalytic performance was investigated. The catalysts were characterized by methods such as scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDX), X-ray powder diffraction (XRD), hydrogen-programmed temperature reduction (H₂-TPR) and X-ray photoelectron spectroscopy (XPS). The morphology, elemental distribution, reducing property and valence state of surface metal elements of the catalysts were analyzed. STEM characterization results showed that 0.33CuZnZr/ZnO-HN and 0.5CuZnZr/ZnO-HN catalysts retained the rod-like structure of the support ZnO hexagonal nanorods in terms of morphology and structure. Due to different loading amounts, there were obvious differences in morphology. 0.5CuZnZr/ZnO-t catalyst retained the granular form of the traditional ZnO support, but the distribution was uneven. The support-free CuZnZr catalyst was composed of randomly piled particles, with smaller particle size and more uniform distribution. XPS spectra showed that Zn species and Zr species existed in the form of ZnO and ZrO₂ phases respectively in all catalysts, and Zn atoms migrated to the surface during the reduction process. Compared with other catalysts, the catalyst supported by ZnO hexagonal nanorods could not completely reduce Cu²⁺ to Cu⁰ in H₂ reduction treatment. H₂-TPR test results showed that the reduction peak of the catalyst supported by ZnO hexagonal nanorods was around 270 ℃, which was much higher than that of other catalysts. This might be due to the stronger interaction between Cu and ZnO, making it more difficult for CuO to be reduced to Cu⁰. It could also be that the loading layer was thicker, significantly reducing the reducing property of the catalyst. The CO₂ hydrogenation performance of all catalysts was tested, and the results showed that the supported materials on 0.5CuZnZr/ZnO-HN catalyst were uniformly dispersed, the interaction between Cu and ZnO was stronger, and the selectivity of methanol at high temperatures was higher. Using ZnO hexagonal nanorods as the support might change the reaction path of CO₂ hydrogenation to methanol. At 290 ℃, the methanol selectivity of 0.5CuZnZr/ZnO-HN catalyst was 34.9%, significantly higher than that of 0.5CuZnZr/ZnO-t (24.1%) and CuZnZr (25.7%), and its methanol space-time yield was 65.9 mg·g_Cu⁻¹·h⁻¹.

With the gradual scarcity of non-renewable conventional energy sources, clean and sustainable fusion energy has emerged as a promising solution to future energy crisis. As one of the main fuels in fusion reactors, tritium can easily penetrate from structural materials to other systems, and even into the environment, causing fuel loss and radioactive contamination. Therefore, controlling tritium penetration has become an urgent technical challenge for fusion energy development. Tritium permeation barriers (TPBs) can effectively suppress permeation. Among these, Al₂O₃ composite coatings play an important role in the research of tritium permeation barriers due to their excellent comprehensive performance, such as higher permeation reduction factor (PRF), stronger substrate adhesion, higher resistivity, more effective mitigation of thermal mismatch, fewer tritium diffusion paths, more tritium traps, and resistance to liquid Pb-Li corrosion. This paper mainly reviewed the research progress of mainstream Al₂O₃ composite tritium permeation barriers such as FeAl/Al₂O₃, Al₂O₃/Ti and Al₂O₃/Cr₂O₃, and introduced the commonly used preparation techniques, including magnetron sputtering (MS), electrochemical deposition (ECD), pack cementation (PC), metal-organic decomposition (MOD), pulsed laser deposition (PLD), sol-gel and hot-dip aluminizing (HDA). The effects of material composition, preparation technology, irradiation, thermal shock, corrosion and other factors on the tritium blocking properties of Al₂O₃ composite tritium permeation barriers in the actual operating conditions of fusion reactors were emphasized. The tritium blocking mechanisms such as substrate effect, permeation mechanism and irradiation effect were discussed. Additionally, it highlighted potential pathways to directly or indirectly enhance the performance of Al₂O₃ coatings, such as developing simple and innovative deposition techniques, constructing composite coatings with diverse materials, modifying coatings through beneficial element doping, adjusting microstructural properties, and conducting performance evaluation tests under simulated fusion reactor environments. The ways to improve the tritium blocking of Al₂O₃ composite tritium barriers were pointed out, and the future research focus was envisioned. Preliminary breakthroughs had been achieved in both the design and preparation of Al₂O₃ composite TPBs, with PRF generally maintained at 3~5 orders of magnitude. However, further investigation was needed into the effects of neutron and heavy ion irradiation, as well as Pb-Li environments, on the structural and functional stability and lifespan of Al₂O₃ composite TPBs. For complex and specialized components like blankets and elbow inner walls, key technical challenges in the large-scale production of high-quality TPBs at an engineering level remained unresolved. These could be addressed by advancing large-area, complex-structure, high-efficiency, and low-cost coating preparation techniques, such as liquid-phase methods. Meanwhile, more research efforts should be directed toward other composite TPB materials, such as GO-Al₂O₃, Y₂O₃/Al₂O₃ and Er₂O₃/Al₂O₃, including their preparation processes, performance testing and exploration of multilayer gradient-structure composite coating systems, to provide more reliable options for the engineering application of TPBs in fusion reactors.

Hydrogen, as a key clean energy source, is essential for global energy transition and carbon neutrality. Nevertheless, challenges associated with its safe and efficient storage and transportation hinder large-scale implementation. Among various hydrogen carriers, ammonia borane (NH₃BH₃, AB) stands out as a promising candidate due to its exceptional hydrogen storage capacity (19.6%), ambient stability, and mild hydrolysis conditions. While catalytic hydrolysis of AB offers a sustainable route to hydrogen generation under mild conditions, the reliance on costly noble metal catalysts has driven research into cost-effective alternatives. Copper-based catalysts have attracted significant interest as attractive alternatives to noble metal catalysts due to their intrinsic catalytic activity, cost-effectiveness, and earth abundance. This review systematically examined recent advances in copper-based catalysts, focusing on three key aspects：AB hydrolysis mechanism, catalyst synthesis strategies and structure-activity relationships, and AB byproduct recycling and regeneration. AB hydrolysis, fundamentally involving the synergistic activation of B–H and O–H bonds, proceeded via a complex mechanism where water dissociation (O–H bond cleavage) was identified as the rate-determining step. This review comprehensively analyzed various catalyst systems, ranging from copper monometallic catalysts to bimetallic, trimetallic, polymetallic, and copper-based oxides, as well as other types such as borides and phosphides. Early studies demonstrated that support-free Cu nanoparticles (NPs) showed low activity while supported-Cu nanoparticles exhibited an enhanced activity. Among them, reduced graphene oxide-supported Cu NPs (Cu/RGO) showed a highly efficient activity toward AB hydrolysis due to the strong interaction between metal NPs and support. The core-shell structured (e.g., Cu@SiO₂) showed a good catalytic activity and superior reusability due to the active site protected by the porous shell. Compared to monometallic systems, Cu-based heterometallic catalysts exhibited significant advantages in catalytic activity and stability, which was due to the synergistic effects between copper and other metals. A series of Cu-based noble and non-noble heterometallic catalysts had been synthesized and applied in AB hydrolysis for hydrogen generation. Noble metal catalysts possessed unique electronic structures and surface properties that enable effective adsorption and activation of AB and water molecules, thereby reducing activation energy and accelerating hydrolysis kinetics. Combining Cu with noble metals could take the advantage of the high activity of noble metals and the cost advantages of Cu. For example, RuCu, PdCu, and PtCu alloys a better catalytic activity than their corresponding monometallic catalysts. Noble metal-containing Cu-based catalysts indicated efficient catalytic performance toward AB hydrolysis reaction, but it was important to search the cheap and efficient noble-metal free catalysts from the perspective of industrial applications. The optimal CuFe, Cu@Co-MOF, and CuNi/g-C₃N₄ catalyst displayed excellent catalytic performance. Compared to their bimetallic and monometallic counterparts, CuNiCo and CuCoMo trimetallic catalysts displayed superior catalytic activity. Polymetallic catalysts derived from high-entropy alloys offered broad compositional tunability and exceptional stability, making them promising candidates for future research. MnFeCoNiCu high-entropy alloys showed a good structural stability but require further activity optimization. Due to the high oxidation rate of non-precious metal NPs, the direct use of non-precious metal oxides as catalyst of AB hydrolysis had received much attention. For example, CuCo₂O₄ with oxygen vacancies demonstrated enhanced catalytic activity due to the increased density of active sites and improved electron mobility. The dynamic state of oxides (potential reduction during reaction) and the precise role of vacancies required deeper investigation. Cu-based boride and phosphide catalysts displayed enhanced catalytic performance, however, the intrinsic active sites of these catalysts and their stability under practical conditions needed further clarification. To facilitate the widespread adoption of AB as a liquid-phase hydrogen storage material, there was an urgent need to develop cost-effective recycling technologies to achieve efficient and sustainable AB regeneration from its hydrolysis borate byproducts. Several efficient routes for the regeneration of AB had been established. Copper-based catalysts demonstrated significant potential for efficient and cost-effective hydrogen generation from AB hydrolysis. However, significant challenges remained in advancing hydrogen production via AB hydrolysis, warranting further investigation：1) exploring single-atom or fully-exposed cluster Cu catalysts to maximize metal atom utilization；2) designing high-entropy alloys to enhance both catalytic activity and stability；3) employing in-situ/operando characterization techniques and density functional theory (DFT) calculations to deepen understanding, particularly concerning active site dynamics and the roles of vacancies and oxidized states；4) developing cost-effective and scalable pathways for the regeneration of AB hydrolysis byproducts；5) coupling AB hydrolysis directly with downstream hydrogen applications (e.g., fuel cells, hydrogenation processes)；6) applying artificial intelligence (AI) for accelerated catalyst design and system optimization. Overcoming limitations in intrinsic catalyst activity, long-term stability under operational conditions, and system integration complexity was essential for realizing AB as a practical hydrogen carrier to enable portable and distributed clean energy systems.

The continuous growth of copper slag waste occupies a large amount of land and erodes soil, resulting in a serious waste of resources and environmental pollution. However, the abundance of valuable metals, silicates and other active components in copper slag makes it a valuable secondary resource. Recycling of copper slag can reduce the contradiction between the supply and demand of copper resources in China and reduce the dependence on primary ores, while at the same time alleviating the environmental hazards of waste and realizing the sustainable use of resources, which is of great economic and environmental significance. Therefore, in-depth study of copper smelting slag recovery and high-value utilization technology has urgency and necessity, how to achieve reasonable recovery and efficient use of copper slag has become a key issue in the field of non-ferrous metal smelting urgently needs to be resolved. This paper discussed the source, yield and nature of copper slag, and analyzes in depth the research progress of metal resource recovery technology (including fire depletion, wet leaching, beneficiation and enrichment technology) and non-metal resource utilization technology (covering building materials, functional catalysis, soil improvement and waste heat recovery). Through the discussion of these technologies, the advantages and disadvantages of various technologies were compared, and the corresponding optimization and improvement directions were proposed. Firstly, for the recovery of metal resources in copper slag, the secondary pollution caused by the reaction and the difficulty of metal separation and purification were the common problems faced by thermal depletion and wet leaching technologies. For the soot and harmful gases, efficient capture and treatment technology could be developed, and for the leaching waste liquid, electrochemical methods for resource utilization could be adopted, and a green closed-loop system could be built for the whole process of pyrolysis and wet process. For metal separation and purification, the selective dissolution of copper could be improved by adding complexing agents to inhibit the leaching of impurity metals, and at the same time, surface modifiers could be used to regulate the interfacial reaction between the copper slag and the acid solution to improve the metal selectivity of the leaching process. Secondly, for the utilization of non-metallic resources in copper slag, the application of building materials could reduce the extraction of natural sand and gravel resources, while reducing the potential threat to the environment of waste slag stockpiling, in line with the concept of sustainable development. However, most of the building materials application scenarios have heavy metal leaching risk, which on the one hand, it should be clarified that the copper smelting slag in the harmful elements of the storage pattern and migration law, through chemical stabilization and physical coating and other technical means of harmful elements for curing treatment；on the other hand, improving the relevant environmental risk assessment system, strict monitoring of the release of hazardous elements in the building materials to ensure that it met the environmental protection and use of safety standards. Again, copper slag had good stability when used for functional catalysis, thus suitable for high-temperature catalytic reaction system. As an industrial waste, it had significant economic benefits compared with precious metal catalysts. However, there was still the problem of uneven distribution of active sites and insufficient surface activity. The surface activity could be improved by nanomorphic modification and surface engineering techniques, such as acid-base treatment and mechanical force chemical treatment. In addition, the surface of copper slag could be precisely modified by atomic layer deposition or plasma treatment to enhance the uniformity and reactivity of active sites. Subsequently, there were limited problems and scenarios that could be addressed by a single type of resourcing technology, and the integration between various recovery and utilization technologies was still in the exploratory stage. Efficient all-in-one combined treatment processes should be developed, such as the recovery of valuable metals, such as metallic copper, through pyrolysis technology, combined with wet leaching for the recovery of rare precious metals, while the treated inorganic residues could be further processed into building materials；or the combination of waste heat recovery with the preparation of microcrystalline glass, which was a high-energy consuming process. Multi-technology linked process design, in the realization of the efficient recovery of metals and heat in the copper slag at the same time could also significantly reduce solid waste emissions and environmental pollution, thus enhancing the overall economic and environmental benefits.

Cu-SSZ-39 zeolite catalyst has become a research hotspot due to its unique AEI topology and excellent high-temperature hydrothermal stability. This article systematically explored their synthesis, modification, and catalytic applications, with a focus on summarizing the pathways for constructing Cu-SSZ-39 catalysts using different silicon-aluminum sources. The catalytic performance was enhanced through bimetallic synergistic modification and oxide composite modification, and their effectiveness in selective catalytic reduction (SCR) of nitrogen oxides (NO_x) and other catalytic reactions was evaluated. Specifically, in terms of synthesis, SSZ-39 zeolite was initially synthesized using FAU-type zeolite as the primary silicon-aluminum source, resulting in highly crystalline products. Additionally, a solvent-free method was developed, utilizing ultra-stable Y zeolite (USY) zeolite and colloidal silica as silicon-aluminum sources to prepare lamellar SSZ-39 zeolite, significantly improving the acidity and hydrothermal stability of the product. Compared to traditional hydrothermal synthesis, this method offered higher SiO₂ utilization and scalability. To reduce preparation costs, synthesis routes using ZSM-5 and Beta zeolites as precursors were explored. The transformation mechanism involved the aggregation of single four-membered and six-membered rings from ZSM-5/Beta zeolites into AEI framework and the resulting SSZ-39 zeolite exhibited comparable crystallinity and catalytic activity to FAU-derived products. Furthermore, silica sol was directly used as the silicon source in alkaline media with N, N-diethyl-2, 6-dimethylpiperidinium (DEDMP) as the template, although this method suffered from low yield and limited Si/Al ratio control. Cu-SSZ-39 catalysts could be prepared through ion exchange and one-pot methods. In the ion exchange process, copper ions (Cu²⁺) were introduced into SSZ-39 framework by replacing Na⁺ or H⁺. The one-pot method combined FAU zeolite with copper-tetraethylenepentamine (Cu-TEPA) complexes, enabling simultaneous zeolite crystallization and copper incorporation. This approach simplified the synthesis process and produces catalysts with higher copper dispersion and SCR activity. In terms of modification strategies for Cu-SSZ-39 catalysts, approaches included bimetallic synergistic modification and metal oxide composite modification. Ce, Mn, and Y were introduced via ion exchange to enhance catalytic performance. Ce-Cu-SSZ-39 catalyst exhibited excellent low-temperature SCR activity (90% NO_x conversion at 180℃), attributed to the addition of Ce, which inhibited the aggregation of copper oxides and induced more Cu²⁺ into ion exchange sites. Yttrium modification (Y-Cu-SSZ-39)suppressed dealumination and stabilized Cu²⁺ active sites, maintaining 75% NO_x conversion even after hydrothermal aging at 900℃. Metal oxide composites, such as Ce-MnO_x and CeZrO_x, were combined with Cu-SSZ-39 to broaden the active temperature window. Ce-MnO_x/Cu-SSZ-39 achieved 90% NO_x conversion within the range of 180~600℃, remaining stable even after aging at 850℃, owing to the Ce-Mn synergistic effect and structural stability. CeZrO_x/Cu-SSZ-39 extended the operating window to 190~550℃ and retained 80% NH₃-SCR activity after hydrothermal aging at 750℃. In terms of the application of Cu-SSZ-39 catalysts, the focus was on their progress in ammonia selective catalytic reduction (NH₃-SCR) for NO_x removal. Cu-SSZ-39 catalysts achieved ≥90% NO_x conversion within the temperature range of 250~500℃. After hydrothermal aging (750~900℃), the catalysts maintained ≥90% activity in the range of 250~450℃. Copper loading and its location significantly influenced the catalytic activity, with Cu²⁺ located in double six-membered rings (D6R) identified as the active sites. Excessive copper loading (>4%) led to the aggregation of CuO_x and a decline in activity. After high-temperature hydrothermal aging, Cu²⁺ near the double six-membered rings could transform into Cu_xO_y, promoting the formation of key nitrate intermediates during NH₃-SCR reaction, thereby maintaining high low-temperature catalytic activity. Despite the progress made, challenges remained in reducing template costs, controlling silicon-to-aluminum ratios, and ensuring long-term stability. Future research should focus on multi-metal co-modification, catalytic mechanism studies, and expansion into photocatalysis and biomass conversion. Cu-SSZ-39 catalysts held significant potential in environmental catalysis and green chemistry, with their tunable properties and robust performance under demanding conditions laying the foundation for broad applications. Additionally, this study provided valuable insights for further exploration and development of small-pore zeolites in the field of catalysis.

NO_x contained in the exhaust gas emitted by motor vehicles not only causes serious harm to the environment but also poses a threat to human health. Given that the current National Ⅵ B emission standards impose increasingly strict limits on NO_x, there is an urgent need to develop more efficient selective catalytic reduction of nitrogen oxides with ammonia (NH₃-SCR) catalysts. The small crystal grain size of nano-molecular sieves not only endows them with a high specific surface area and rich pore structure, providing more adsorption sites for gases, but also effectively reduces the influence of internal diffusion resistance on the mass transfer rate, thereby enhancing catalytic performance. Among the myriads of molecular sieve catalysts, Cu-SAPO-34 stands out due to its versatility in employing various templating agents and its exceptional high-temperature hydrothermal stability, coupled with superior NH₃-SCR catalytic performance. Consequently, it holds promising potential for commercial applications. Meanwhile, compared to other chemical products, the natural mineral attapulgite boasts abundant reserves, low cost, and convenient transportation, making it a viable silicon source for synthesizing molecular sieves. Currently, there is limited research on synthesizing SAPO-34 molecular sieves using attapulgite as the silicon source, which presents a novel direction for exploration. In this work, nano SAPO-34 molecular sieves were successfully synthesized via a dynamic hydrothermal method, employing natural attapulgite as the silicon source, pseudoboehmite as the aluminum source, and phosphoric acid as the phosphorus source. Additionally, triethylamine and tetraethylammonium hydroxide were selected as co-templating agents. Subsequently, a series of Cu-SAPO-34 molecular sieve catalysts was prepared using the impregnation method. In order to delve deeply into the impact of the silicon-to-aluminum ratio (Si/Al) on catalytic performance, we conducted a systematic series of experimental studies. Comprehensive characterization of the catalyst's structure and physicochemical properties was carried out using various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis for specific surface area and pore size distribution, ammonia temperature-programmed desorption (NH₃-TPD), hydrogen temperature-programmed reduction (H₂-TPR), ultraviolet-visible spectroscopy (UV-Vis), and electron paramagnetic resonance (EPR). The experimental results showed that when Si/Al ratio was between 0.13 and 1, the crystal size of all samples was smaller than 1 μm, and with the increase of Si/Al ratio, the crystallinity of SAPO-34 gradually decreased, accompanied by a reduction in crystal size. Nevertheless, all samples maintained a high specific surface area, with a surface area of more than 600 m²·g^-1 and a pore size of about 0.49 nm. The results of NH₃-TPD showed that Si/Al ratio had a significant effect on the acid amount of Cu-SAPO-34 zeolite catalyst. Specifically, when Si/Al ratio was either too low or too high, the amount of medium and strong acids decreased；when Si/Al ratio increased from 0.4 to 0.6, the amount of medium and strong acids increased with the increase of Si/Al ratio. When Si/Al ratio exceeded 0.6, the acidic sites decreased due to the increase in the number of silicon islands, and the acid content of medium and strong acids also decreased. Therefore, when Si/Al ratio was 0.6, the medium and strong acid content of Cu-SAPO-34 catalyst reached the maximum value. Further UV-Vis and H₂-TPR analyses showed that copper species in Cu-SAPO-34 molecular sieve catalysts were mainly in the form of CuO, Cu⁺ and isolated Cu²⁺. Variations in Si/Al ratio did not exert an influence on the types of copper species. EPR test results showed that at normal temperature, the isolated Cu²⁺ existed in the six-membered ring of CHA structure only in a set-off way. At the same time, Si/Al ratio also affected the amount of isolated Cu²⁺ as the active site in Cu-SAPO-34 catalyst. H₂-TPR and EPR quantitative analyses showed that the content of isolated Cu²⁺ was lower in both Si/Al ratios greater than or less than 0.6 than in Si/Al ratios of 0.6, with a trend consistent with the quantity of medium strong acids, which was because isolated Cu²⁺ was generated by an ion exchange between Cu²⁺ and the H⁺ occurrence of the acidic site of Cu-SAPO-34 catalyst, and a higher amount of acid means that more isolated Cu²⁺ active sites could be formed. In summary, the sample with Si/Al ratio of0.6 exhibited the highest acid content and the most isolated Cu²⁺, and the catalyst exhibited the best activity in the NH₃-SCR reaction with 99.29% NO_x conversion and the widest temperature window of 250~550 ℃. This research result provided a new idea for the development of an efficient NH₃-SCR catalyst.

Glutathione (GSH) exists in all cells and plays a vital role in controlling the redox state of cells. Abnormal GSH concentrations are closely related to many diseases, including AIDS, cancer, liver damage, and diseases caused by aging. Therefore, the development of effective and sensitive GSH detection methods is extremely important. Because of the importance of GSH, its detection methods have emerged endlessly. So far, different methods, such as electroluminescence, surface-enhanced Raman scattering (SERS), mass spectrometry (MS), capillary electrophoresis, high-performance liquid chromatography (HPLC), enzyme-linked immunosorbent assay (ELISA), electrochemical, and colorimetric methods have been employed to detect GSH. However, the high price and cumbersome operation limit its practical application. Colorimetric approaches have attracted significant attention due to their rapidity, low cost, and visibility. Mimetic enzyme +3, 3, 5, 5-tetramethylbenzidine (TMB)+H₂O₂ system is one of the most commonly used methods to detect GSH. In the presence of simulated enzyme, including carbon-based nanomateraials, inorganic nanoparticles, and metal-organic frameworks-based nanomaterials, TMB is oxidized by H₂O₂, and the color of the solution changed from colorless to blue. Inspired by the above facts, in this work, well-dispersed Au@MnO₂ nanoparticles were prepared using a simple method. Scanning electron microscope (SEM) image showed that the as-prepared Au@MnO₂ products had structures of the core/shell UFO-like nanoparticles. Line scanning plot suggested Au nanoparticles with an average size of about 50 nm in the center surrounded by the tightly coated layer of MnO₂ with a thickness of 20~30 nm, producing a uniform core-shell structure. Elemental analysis indicated the nanoparticle was composed of elements (Au, Mn, and O). Au@MnO₂ had oxidase-like catalytic activity and could catalyze the oxidation-reduction reaction between TMB and oxygen in the air, resulted in a change in absorbance at 650 nm and a color changed from colorless to blue. In the presence of GSH, GSH reacted with oxidation products (oxTMB) of TMB successfully to inhibit the reaction between MnO₂ and TMB, resulted in the decrease of the absorbance and the lightening of solution color (blue). Under the optimized conditions (pH of 3.6, the reaction time between MnO₂ and TMB：10 min, and incubation time of GSH：5 min), the absorbance of oxTMB at 650 nm wavelength gradually decreased as GSH concentration varies from 0 to 5 μmol·L^-1, accompanied by color changes from dark blue to light blue. Absorbance change (ΔA_{650 nm}), where ΔA was the difference of the absorbance of the solution without and with GSH, was proportional to logarithm of GSH concentration from 1 nmol·L^-1 to 50 μmol·L^-1 (R=0.991). The limit of detection (LOD) reached 0.79 nmol·L^-1 based on signal-to-noise ratio (S/N)=3. Compared with other methods for GSH detection, it was worth noting that the method in this paper was more sensitive for GSH detection, and LOD was lower. The selectivity of Au@MnO₂-TMB reaction system toward other potential interfering antioxidans, including ascorbic acid (AA), cysteine (Cys), tea polyphenols (TP), dopamine (DA), uric acid (UA), citric acid (CA), glucose (Glu), melatonin (Mel), was also investigated. These interfering substances, with 100-time of GSH concentration (5 μmol·L^-1), exhibited very small effect toward the oxTMB absorbance. Compared with the blank absorbance, the absorbance difference values caused by these interferences were in the range of 0.012~0.05. However, GSH, 100 times lower than the concentration of the interfering substances, induced a tremendous change in absorbance compared to the blank, with 0.362 of the absorbance difference value. These results manifested almost no effect of AA, Cys, TP, DA, UA, CA, Glu, and Mel on the GSH detection, and the GSH selectivity for the assay was acceptable. In order to evaluate the feasibility of the assay in complex real samples, GSH in serum was determined. First, serum was diluted 100 times. Then, GSH with a certain content was spiked into the diluted serum samples, so that the final concentration of GSH in serum ranged from 5 nmol·L^-1 to 50 μmol·L^-1. Compared with the GSH detection result in buffer, there was almost no change in absorbance caused by low concentration of GSH (0~1 μmol·L^-1) in serum, and beyond 1 μmol·L^-1, a higher absorbance difference (˂0.223) occurred, meaning the GSH detection of high concentrations influenced by milk media was more serious. However, in view of the good linear relationship between absorbance change and GSH concentration in the range of 5 nmol·L^-1~1 μmol·L^-1 and 1~50 μmol·L^-1, the sensor was suitable for quantitative analysis of GSH in actual samples. In addition, GSH tablets were used to perform the recovery test. The average recovery for GSH tablet (0.1 g) sample was 99.76%~102.1%, which indicated that the method is reliable for GSH detection in real samples.