Sn-based solder is a widely used interconnection material in the field of electronic packaging; however, the performance requirements for these solders are becoming increasingly demanding owing to the rapid development in this area. In recent years, the addition of micro/nanoreinforcement phases to Sn-based solders has provided a solution to improve the intrinsic properties of the solders. This paper reviews the progress in Sn-based micro/nanoreinforced composite solders over the past decade. The types of reinforcement particles, preparation methods of the composite solders, and strengthening effects on the microstructure, wettability, melting point, mechanical properties, and corrosion resistance under different particle-addition levels are discussed and summarized. The mechanisms of performance enhancement are summarized based on material-strengthening effects such as grain refinement and second-phase dispersion strengthening. In addition, we discuss the current shortcomings of such composite solders and possible future improvements, thereby establishing a theoretical foundation for the future development of Sn-based solders.

This study investigated the mechanical responses and debonding mechanisms of a bolt–resin–rock composite anchoring system subjected to cyclic shear loading. A systematic analysis was conducted on the effects of the initial normal load (F_sd), cyclic shear displacement amplitude (u_d), frequency (f), and rock type on the shear load, normal displacement, shear wear characteristics, and strain field evolution. The experimental results showed that as F_sd increased from 7.5 to 120 kN, both the peak and residual shear loads exhibited increasing trends, with increments ranging from 1.98% to 35.25% and from 32.09% to 86.74%, respectively. The maximum shear load of each cycle declined over the cyclic shear cycles, with the rate of decrease slowing and stabilizing, indicating that shear wear primarily occurred at the initial cyclic shear stage. During cyclic shearing, the normal displacement decreased spirally with the shear displacement, implying continuous shear contraction. The spiral curves display sparse upwards and dense downward trends, with later cycles dominated by dynamic sliding along the pre-existing shear rupture surface, which is particularly evident in coal. The bearing capacity of the anchoring system varies with the rock type and is governed by the coal strength in coal, resin-rock bonding in sandstone#1 and sandstone#2, combined resin strength and resin–rock bonding in sandstone#3 (sandstone#1, sandstone#2 and sandstone#3, increasing strength order), and resin strength and bolt–resin bonding in limestone. Cyclic shear loading induces anisotropic interfacial degradation, characterized by escalating strain concentrations and predominant resin-rock interface debonding, with the damage severity modulated by the rock type.

The problems of tailings storage and high-stress conditions in deep mining have emerged as critical factors that limit the security, efficiency, and sustainability of such mines. This study explores the potential to utilize tungsten tailings to create cementitious backfill (CTB) materials and investigates the macroscopic strength features and microscopic damage evolution mechanisms of different-sized CTBs with varying dosages of hydroxypropyl methyl cellulose (HPMC). Specimens with bottom diameters of 50, 75, and 100 mm are combined with HPMC dosages of 0, 0.15wt%, 0.25wt%, and 0.35wt%. A diameter/height ratio of 1:2 is maintained for all CTB specimens. The experimental results show that as the HPMC dosage is increased from 0 to 0.35wt%, the uniaxial compressive strength (UCS) of the CTBs decreases significantly in a linear manner. The 75 mm × 150 mm CTB specimen exhibits relatively high plasticity and toughness, with good plastic deformation and energy absorption capabilities, indicating significant size effects. HPMC introduces connected bubbles during the CTB pouring process, but it exhibits anti-segregation and anti-bleeding characteristics, thus reducing tailing settling. The hydration reaction of the CTB doped with HPMC is more uniform, and the Ca/Si atomic ratio dispersion at different sites is smaller. The three CTB sizes all exhibit combined tensile and shear failure, with the 75 mm × 150 mm specimen exhibiting macroscopic tensile cracks and relatively few shear cracks. At the micro-scale, excessive ettringite and hydrated calcium silicate are interwoven and fuse, and the tungsten tailings are tightly wrapped. These results provide valuable data and notional insights for optimizing the fluidity of the backfill, and elucidate the strength and damage evolution of solidified materials during filling and extraction. This study contributes to the advancement of green, economical, safe, and sustainable mining practices.

Hemihydrate phosphogypsum (HPG)-based filling materials have become a new low-cost green alternative for early strength filling materials. They also provide a promising solution for the large-scale utilization of phosphogypsum. However, pipe plugging, which is caused by the poor workability of HPG-based filling materials, has become a major safety hazard in the filling process. Determining an economical and practicable method is urgently needed to improve the workability of HPG slurry work. First, this work found that grinding treatment was much more effective than increasing concentration (59wt%–65wt%) and adding tailings (20wt%–100wt%) in enhancing the workability of HPG slurry based on a comprehensive analysis of water retention, fluidity, and flow stability. Then, the combined effects of particle size, particle morphology, water film, and interparticle interactions on the workability of HPG slurry were quantitatively described through a microanalysis. Moreover, the first direct evidence for the transformation from robust embedded structures to soft stacking structures was presented. In practice, the filling materials should be prepared by grinding HPG for 20 min and mixing with 0–200wt% phosphorus tailings to achieve satisfactory workability and mechanical performance. The results of this study provide practical and feasible methods for addressing the stable transportation problem of HPG slurry.

Understanding the differences in CO₂ adsorption in cementitious material is critical in mitigating the carbon footprint of the construction industry. This study chose the most common β-C₂S phase in the industry as the cementitious material, selecting the β-C₂S(111) and β-C₂S(100) surfaces for CO₂ adsorption. First-principles calculations were employed to systematically compare the CO₂ adsorption behaviors on both surfaces focusing on adsorption energy, adsorption configurations, and surface reconstruction. The comparison of CO₂ and H₂O adsorption behaviors on the β-C₂S(111) surface was also conducted to shed light on the influence of CO₂ on cement hydration. The adsorption energies of CO₂ on the β-C₂S(111) and β-C₂S(100) surfaces were determined as −0.647 and −0.423 eV, respectively, suggesting that CO₂ adsorption is more energetically favorable on the β-C₂S(111) surface than on the β-C₂S(100) surface. The adsorption energy of H₂O on the β-C₂S(111) surface was −1.588 eV, which is 0.941 eV more negative than that of CO₂, implying that β-C₂S tends to become hydrated before reacting with CO₂. Bader charges, charge density differences, and the partial density of states were applied to characterize the electronic properties of CO₂ and H₂O molecules and those of the surface atoms. The initial Ca/O sites on the β-C₂S(111) surface exhibited higher chemical reactivity due to the greater change in the average number of valence electrons in the CO₂ adsorption. Specifically, after CO₂ adsorption, the average number of valence electrons for both the Ca and O atoms increased by 0.002 on the β-C₂S(111) surface, while both decreased by 0.001 on the β-C₂S(100) surface. In addition, due to the lower valence electron number of O atoms, the chemical reactivity of O atoms on the β-C₂S(111) surface after H₂O adsorption was higher than the case of CO₂ adsorption, which favors the occurrence of further reactions. Overall, this work assessed the adsorption capacity of the β-C₂S surface for CO₂ molecules, offering a strong theoretical foundation for the design of novel cementitious materials for CO₂ capture and storage.

Copper–nickel tailings (CNTs), consisting of more than 80wt% magnesium-bearing silicate minerals, show great potential for CO₂ mineral sequestration. The dissolution kinetics of CNTs in HCl solution was investigated through a leaching experiment and kinetic modeling, and the effects of reaction time, HCl concentration, solid-to-liquid ratio, and reaction temperature on the leaching rate of magnesium were comprehensively studied. Results show that the suitable leaching conditions for magnesium in CNTs are 2 M HCl, a solid-to-liquid ratio of 50 g·L⁻¹, and 90°C, at which the maximum leaching rate of magnesium is as high as 83.88%. A modified shrinking core model can well describe the leaching kinetics of magnesium. The dissolution of magnesium was dominated by a combination of chemical reaction and product layer diffusion, with a calculated apparent activation energy of 77.51 kJ·mol⁻¹. This study demonstrates the feasibility of using CNTs as a media for CO₂ mineral sequestration.

The rapid growth of semiconductor, photovoltaic, and other emerging industries has led to a sharp increase in the demand for high-purity quartz in China, particularly 4N5-grade (99.995% pure SiO₂). However, heavy reliance on imported high-purity quartz poses a significant risk to the security of key national strategic industries. To address this challenge, China is focusing on identifying domestic sources of high-purity quartz and developing efficient evaluation methods. This study investigates the inclusion content in three types of quartz: pegmatite, vein quartz, and white granite. A grading system based on the transmittance of quartz grains was established by analyzing the number of inclusions. Five quartz ore samples from different regions were purified, and the resulting concentrates were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The relationships among the inclusion content of raw quartz, impurity composition of purified quartz, and quality of sintered fused quartz products were examined. The findings demonstrate that quartz with fewer inclusions results in lower impurity levels after purification, higher SiO₂ purity, and more translucent glass, as confirmed by firing tests. Herein, this study establishes a clear connection between quartz inclusions and the overall quality of high-purity quartz. The proposed approach enables the rapid assessment of quartz deposit quality by identifying inclusions, offering a practical and efficient method for locating high-quality quartz resources.

The mixing injection of natural gas and pulverized coal into the blast furnaces shows a promising technological approach in the context of global carbon reduction initiatives. Carrier gas and coal pass through the air inlet of coal lance, and the characteristics of carrier gas affect the flow in the air inlet and the combustion efficiency of coal, so it is very important to study the change of carrier gas characteristics in the lower part of blast furnace. By means of numerical simulation, the influence of carrier gas characteristics (injection rate, composition, and temperature) on the mixed combustion of natural gas (NG) and pulverized coal in the tuyere raceway of Russian blast furnace was analyzed. When N₂ is used as carrier gas, the injection rate of carrier gas is reduced from 4000 to 2000 m³/h, the average tuyere temperature is increased (1947.42 to 1963.30 K), the mole fractions of CO and H₂ are increased, and the burnout rate of pulverized coal is decreased. Increasing the carrier gas temperature is helpful to improve the burnout of pulverized coal. For every 20 K increase of carrier gas temperature, the average temperature in the raceway increases by 20.6 K, which promotes the release and combustion of volatiles, but the increase of carrier gas temperature from 373 to 393 K only leads to 1.16% burnout change. Considering the transportation characteristics of pulverized coal, it is suggested that the carrier gas temperature should be kept at about 373 K to obtain the best performance. It is worth noting that when air is used as carrier gas, the burnout rate of pulverized coal is increased by 2.69% compared with N₂.

The converter steelmaking process represents a pivotal aspect of steel metallurgical production, with the characteristics of the flame at the furnace mouth serving as an indirect indicator of the internal smelting stage. Effectively identifying and predicting the smelting stage poses a significant challenge within industrial production. Traditional image-based methodologies, which rely on a single static flame image as input, demonstrate low recognition accuracy and inadequately extract the dynamic changes in smelting stage. To address this issue, the present study introduces an innovative recognition model that preprocesses flame video sequences from the furnace mouth and then employs a convolutional recurrent neural network (CRNN) to extract spatiotemporal features and derive recognition outputs. Additionally, we adopt feature layer visualization techniques to verify the model’s effectiveness and further enhance model performance by integrating the Bayesian optimization algorithm. The results indicate that the ResNet18 with convolutional block attention module (CBAM) in the convolutional layer demonstrates superior image feature extraction capabilities, achieving an accuracy of 90.70% and an area under the curve of 98.05%. The constructed Bayesian optimization-CRNN (BO-CRNN) model exhibits a significant improvement in comprehensive performance, with an accuracy of 97.01% and an area under the curve of 99.85%. Furthermore, statistics on the model’s average recognition time, computational complexity, and parameter quantity (Average recognition time: 5.49 ms, floating-point operations per second: 18260.21 M (1 M = 1 × 10⁶), parameters: 11.58 M) demonstrate superior performance. Through extensive repeated experiments on real-world datasets, the proposed CRNN model is capable of rapidly and accurately identifying smelting stages, offering a novel approach for converter smelting endpoint control.

Wire arc additive manufacturing (WAAM) presents a promising approach for fabricating medium-to-large austenitic stainless steel components, which are essential in industries like aerospace, pressure vessels, and heat exchangers. This research examines the microstructural characteristics and tensile behaviour of SS308L manufactured via the gas metal arc welding-based WAAM (WAAM 308L) process. Tensile tests were conducted at room temperature (RT, 25°C), 300°C, and 600°C in as-built conditions. The microstructure consists primarily of austenite grains with retained δ-ferrite phases distributed within the austenitic matrix. The ferrite fraction, in terms of ferrite number (FN), ranged between 2.30 and 4.80 along the build direction from top to bottom. The ferrite fraction in the middle region is 3.60 FN. Tensile strength was higher in the horizontal oriented samples (WAAM 308L-H), while ductility was higher in the vertical ones. Tensile results show a gradual reduction in strength with increasing test temperature, in which significant dynamic strain aging (DSA) is observed at 600°C. The variation in serration behavior between the vertical and horizontal specimens may be attributed to microstructural differences arising from the build orientation. The yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) of WAAM 308L at 600°C were (240 ± 10) MPa, (442 ± 16) MPa, and (54 ± 2.00)%, respectively, in the horizontal orientation (WAAM 308L-H), and (248 ± 9) MPa, (412 ±19) MPa, and (75 ± 2.80)%, respectively, in the vertical orientation (WAAM 308L-V). Fracture surfaces revealed a transition from ductile dimple fracture at RT and 300°C to a mixed ductile–brittle failure with intergranular facets at 600°C. The research explores the applicability and constraints of WAAM-produced 308L stainless steel in high-temperature conditions, offering crucial insights for its use in thermally resistant structural and industrial components.

Latent heat thermal energy storage (LHTES) is an attractive method for enhancing the functionality and availability of renewable energy sources, and it is extensively used to support concentrated solar power technologies. The main feature of every LHTES system is a phase change material (PCM), i.e., a substance used to absorb/release energy upon cyclic melting/solidification. This study investigates the potential of ferro-alloys as high-performance PCM candidates, targeting energy storage capacities exceeding 1 MWh·m⁻³, and operational temperatures above 1000°C. A thermodynamic assessment of binary and ternary Fe-based systems, alloyed with Si, B, Cr, V, and Ti, was conducted to identify compositions with optimal phase transition characteristics and heat storage potential. The results highlight the significant potential of the Fe–Si–B system, where boron’s exceptionally high latent heat enhances energy storage capacity despite challenges posed by its high melting point and cost. The Fe–Si–Cr system revealed promising alloys, such as Fe–34Si–38Cr and Fe–34Si–43Cr, offering excellent energy storage density and favorable phase transition temperatures. In the Fe–Si–V system, vanadium additions produced alloys like Fe–36Si–14V and Fe–34Si–10V, which meet energy storage criteria, although the high melting points of some Si–V phases may restrict their practical applicability. The Fe–Si–Ti system showed standout compositions, including Fe–38Si–20Ti and Si–48Ti, achieving energy storage capacities of approximately 1.5 MWh·m⁻³. This study compares ferro-alloy PCMs against state-of-the-art metallic PCMs, highlighting the performance of certain ferro-alloys.

Digital modeling and autonomous control of the die forging process are significant challenges in realizing high-quality intelligent forging of components. Using the die forging of AA2014 aluminum alloy as a case study, a machine-learning-assisted method for digital modeling of the forging force and autonomous control in response to forging parameter disturbances was proposed. First, finite element simulations of the forging processes were conducted under varying friction factors, die temperatures, billet temperatures, and forging velocities, and the sample data, including process parameters and forging force under different forging strokes, were gathered. Prediction models for the forging force were established using the support vector regression algorithm. The prediction error of F_f, that is, the forging force required to fill the die cavity fully, was as low as 4.1%. To further improve the prediction accuracy of the model for the actual F_f, two rounds of iterative forging experiments were conducted using the Bayesian optimization algorithm, and the prediction error of F_f in the forging experiments was reduced from 6.0% to 1.5%. Finally, the prediction model of F_f combined with a genetic algorithm was used to establish an autonomous optimization strategy for the forging velocity at each stage of the forging stroke, when the billet and die temperatures were disturbed, which realized the autonomous control in response to disturbances. In cases of −20 or −40°C reductions in the die and billet temperatures, forging experiments conducted with the autonomous optimization strategy maintained the measured F_f around the target value of 180 t, with the relative error ranging from −1.3% to +3.1%. This work provides a reference for the study of digital modeling and autonomous optimization control of quality factors in the forging process.

The as-deposited coating–substrate microstructure has been identified to substantially influence the high-cycle fatigue (HCF) behavior of Ni-based single-crystal (SX) superalloys at 900°C, but the impact of degraded microstructure on the HCF behavior remains unclear. In this work, a PtAl-coated third-generation SX superalloy with sheet specimen was thermal-exposed at 1100°C with different durations and then subjected to HCF tests at 900°C. The influence of microstructural degradation on the HCF life and crack initiation were clarified by analyzing the development of microcracks and coating–substrate microstructure. Notably, the HCF life of the thermal-exposed coated alloy increased abnormally, which was attributed to the transformation of the fatigue crack initiation site from surface microcracks to internal micropores compared to the as-deposited coated alloy. Although the nucleation and growth of surface microcracks occurred along the grain boundaries in the coating and the interdiffusion zone (IDZ) for both the as-deposited and the thermal-exposed coated alloys, remarkable differences of the microcrack growth into the substrate adjacent to the IDZ were observed, changing the crack initiation site. Specifically, the surface microcracks grew into the substrate through the cracking of the non-protective oxide layers in the as-deposited coated alloy. In comparison, the hinderance of the surface microcracks growth was found in the thermal-exposed coated alloy, due to the formation of a protective Al₂O₃ layer within the microcrack and the γ′ rafting in the substrate close to the IDZ. This study will aid in improving the HCF life prediction model for the coated SX superalloys.

The GH141 superalloy ring-rolled parts often face microstructural inhomogeneity during production. This work investigated the effect of post-dynamic recrystallization on the microstructural evolution of GH141 superalloy after gradient thermal deformation to solve the problem of microstructural inhomogeneity. Compression tests involving double cone (DC) samples were conducted at various temperatures to assess the effect of gradient strain on internal grain microstructure variation, which ranged from the rim to the center of the samples. The results demonstrate considerable microstructural inhomogeneity induced by gradient strain in the DC samples. The delay in heat preservation facilitated post-dynamic recrystallization (PDRX) and promoted extensive recrystallization in the DC samples experiencing large gradient strain, which resulted in a homogeneous grain microstructure throughout the samples. During compression at a relatively low temperature, dynamic recrystallization (DRX) was predominantly driven by continuous dynamic recrystallization (CDRX). As the deformation temperature increased, the DRX mechanism changed from CDRX-dominated to being dominated by discontinuous dynamic recrystallization (DDRX). During the delay of the heat preservation process, PDRX was dominated by a static recrystallization mechanism, along with the occurrence of meta-dynamic recrystallization (MDRX) mechanisms. In addition, the PDRX mechanism of twin-induced recrystallization nucleation was observed.

This study examines how ball milling parameters, specifically rotational speeds (20, 40, and 60 r/min) in dry and wet conditions, affect the development of mullite/5wt% nano-fly ash coatings on AISI 410 steel, focusing on their impact on feedstock powders and plasma-sprayed coatings. Optimized milling parameters at 60 r/min under wet conditions yielded high-quality feedstock powders with a particle size of 14 µm and limited size distribution. Coatings produced from wet-milled powders demonstrated a higher deposition efficiency (35%) due to their smaller, uniformly distributed particles, which enhanced melting during the spraying process. These coatings also exhibited significantly lower porosity (7.9%), resulting in denser structures with superior mechanical properties, including a hardness of HV₁ 647, fracture toughness of 1.41 MPa·m^0.5, and a smoother surface finish with a roughness (R_a) of 6.1 µm. Residual stress analysis showed that wet-milled coatings had higher residual stresses, reaching up to 165.95 MPa, compared to dry-milled coatings. This increase is attributed to finer particle sizes and rapid thermal cycling during deposition, which intensified tensile stresses within the coating. These results highlight the importance of optimizing milling parameters to enhance coating performance and process efficiency.

Perovskite solar cells (PSCs) based on α-phase FAPbI₃ (α-FAPbI₃) microcrystals precursor outperform those with δ-phase microcrystals due to their superior crystallinity and fewer defects, making α-phase microcrystals precursor more advantageous for high-performance PSCs. However, most reported synthesis methods of perovskite microcrystals, especially for aqueous synthesis, fail to reach the energy threshold required for α-phase transformation and therefore exhibit the δ phase. In this study, we introduce a novel aqueous synthesis method to fabricate α-FAPbI₃ microcrystals. Our approach overcomes the energy barrier by properly heating the reaction system, enabling the direct formation of α-FAPbI₃ in water. This direct one-step aqueous synthesis route yields α-FAPbI₃ microcrystals with superior phase purity, crystallinity, and minimal defect density. Combined with green anti-solvent, the high-quality α-FAPbI₃ microcrystals serving as exceptional precursors endow perovskite films with reduced nonradiative recombination. The PSC achieves a remarkable power conversion efficiency (PCE) of 24.43%, which is one of the highest PCE reports for using the green anti-solvent in ambient air condition. This aqueous synthesis approach shows a significant potential for scalable production of high-performance PSCs.

NaTi₂(PO₄)₃ (NTP) is a material with a NASICON structure, a three-dimensional open type skeleton, and suitable negative voltage window, which is widely regarded as a magnetic anode material for aqueous sodium ion batteries (ASIBs). However, NTP’s intrinsically poor conductivity hampers their use in ASIBs. Herein, bimetallic doped carbon material was designed and combined with the sol–gel method to prepare NaTi₂(PO₄)₃–C–FeNi (NTP–C–FeNi) composite materials. This bimetallic doped carbon composite NTP material not only has a large specific surface area, but also effectively improves conductivity and promotes rapid migration of Na⁺. Following the rate performance test, NTP–C–FeNi retained a reversible capacity of 116.75 mAh·g⁻¹ at 0.1 A·g⁻¹, representing 95.9% of the first cycle capacity. After 500 cycles at 1.5 A·g⁻¹, the cycle fixity was 85.3%. The enhancement of electrochemical performance may owe to the widening of pathways and acceleration of Na⁺ insertion/extraction facilitated by FeNi–C doping, while the carbon coating effectively promotes electrode charge transfer. The results indicate that the bimetallic doped carbon composite NaTi₂(PO₄)₃ holds potential for practical applications in novel aqueous sodium ion battery systems.

Nitrogen-doped single-walled carbon nanohorns (N-SWCNHs) can serve as an effective carrier for platinum (Pt) catalysts, which has the potential to improve the electrocatalytic activity of oxygen reduction reaction (ORR) and the operation life of the catalyst. In this work, dahlia-like SWCNHs with N contents ranging from 2.1at% to 4.3at% are controllably synthesized via arc discharge and applied as a carrier of Pt nanoparticles (NPs), denoted as Pt/N-SWCNHs. Pt/N-SWCNHs-2:1 (graphite and melamine with the mass ratio of 2:1) exhibits excellent electrocatalytic activity (onset potential = 0.95 V). The half-wave potential of Pt/N-SWCNHs-2:1 is only reduced by 2 mV after 3000 cyclic voltammetry cycles. This can be attributed to the enhanced dispersion of Pt NPs and the strong electronic interaction between the N-SWCNHs and Pt, facilitated by the optimal nitrogen doping level. The results of this work offer important perspectives on the design and enhancement of Pt-based electrocatalysts for ORR applications, highlighting the critical role of the nitrogen doping level in balancing the electrocatalytic activity and long-term stability.

Electrochemical CO₂ reduction is a sustainable method for producing fuels and chemicals using renewable energy sources. Sn is a widely employed catalyst for formate production, with its performance closely influenced by the catalyst ink formulations and reaction conditions. The present study explores the influence of catalyst loading, current density, and binder choice on Sn-based CO₂ reduction systems. Decreasing catalyst loading from 10 to 1.685 mg·cm⁻² and increasing current density in highly concentrated bicarbonate solutions significantly enhances formate selectivity, achieving 88% faradaic efficiency (FE) at a current density of −30 mA·cm⁻² with a cathodic potential of −1.22 V vs. reversible hydrogen electrode (RHE) and a catalyst loading of 1.685 mg·cm⁻². This low-loading strategy not only reduces catalyst costs but also enhances surface utilization and suppresses the hydrogen evolution reaction. Nafion enhances formate production when applied as a surface coating rather than pre-mixed in the ink, as evidenced by improved faradaic efficiency and lower cathodic potentials. However, this performance still does not match that of binder-free systems because Sn-based catalysts intrinsically exhibit high catalytic activity, making the binder contribution less significant. Although modifying the electrode surface with binders leads to blocked active sites and increased resistance, polyvinylidene fluoride (PVDF) remains promising because of its stability, strength, and conductivity, achieving up to 72% FE to formate at −30 mA·cm⁻² and −1.66 V vs. RHE. The findings of this research reveal methodologies for optimizing the catalyst ink formulations and binder utilization to enhance the conversion of CO₂ to formate, thereby offering crucial insights for the development of a cost-efficient catalyst for high-current-density operations.

To prevent bacterial growth and ensure food safety, common practice involves the use of nitrite and phosphate salts. Nevertheless, elevated nitrite levels in the body can contribute to the development of stomach and esophageal cancers, while excessive phosphate levels may increase the risk of kidney dysfunction and the onset of osteoporosis. Electrochemical sensing has emerged as a reliable technique for detecting nitrites and phosphates. This study specifically focuses on the use of TiO₂-based sensing materials for such detection. The synthesis of nanoparticulate TiO₂ and Ag-doped TiO₂ was successfully achieved through a solution combustion technique. The composition of the materials was examined using X-ray diffraction (XRD) and X-ray absorption near-edge structure (XANES) methods, revealing a predominant anatase composition. Doping resulted in particle refinement, contributing to an increased specific surface area and enhanced electron transfer efficiency, as indicated in the examination by electrochemical impedance spectroscopy (EIS). Cyclic voltammetry (CV) assessed the electrochemical behavior, demonstrating that in nitrite detection, a significant oxidation reaction occurred at an applied voltage of approximately 1.372 V, while in phosphate detection, the main reduction peak occurred at a voltage close to −0.48 V. High sensitivity (2 µA·µM⁻¹·mm⁻² for sodium nitrite and 2.1 µA·µM⁻¹·mm⁻² for potassium phosphate) and low limits of detection (0.0052 mM for sodium nitrite and 0.0045 mM for potassium phosphate) were observed. Experimental results support the potential use of Ag-doped TiO₂ as a sensing device for nitrites and phosphates.

In the field of broadband metamaterial absorbers, most research efforts have focused on optimizing the resonant layers and designing multi-layer structures, but relatively little attention has been paid to the dielectric layers themselves. This paper proposed a method using carbonyl iron powder to modify the dielectric layer. This method significantly enhances the electromagnetic wave attenuation capability of the dielectric layer with the X-band range for metamaterial absorbers. A broadband absorber with a reflection loss (RL) of less than −10 dB within the frequency range of 4.98–18 GHz and covering the C, X, and Ku band was designed. This work analyzed the surface current distribution and the power loss distribution to elucidate the absorption mechanism of the absorber. It was found that the modified dielectric layer accounted for more than 30% of the total loss in the 2–18 GHz frequency band, and the effective absorption bandwidth (RL ≤ −10 dB) was almost twice that of the unmodified dielectric layer. This enhancement in absorption bandwidth is attributed to the introduction of a new electromagnetic wave loss mechanism by carbonyl iron powder. Meanwhile, the absorber exhibited good angular stability, maintaining at least 80% absorption (RL ≤ −7 dB) in the 7.0–18.0 GHz range even when the incident angle was increased to 60°. The experimental results showed that the measured results matched the simulation results well. Furthermore, compared with other methods for broadening the absorption bandwidth, the metamaterial absorber obtained by this method offers several advantages, including wideband absorption, thin profile, and a simple manufacturing process. This approach provides a new and promising direction for the design of broadband absorbers.