Surface acoustic wave (SAW) sensors are widely employed for detecting dimethyl methylphosphonate (DMMP, a simulant of the chemical warfare agent sarin) due to their wireless and passive monitoring capability, digital output, and cost-effectiveness. Zirconium dioxide (ZrO2) nanoparticles are considered one of the most promising sensing materials for DMMP detection owing to their unique and strong surface interactions with phosphorus-containing compounds, as well as their excellent chemical and thermal stability. However, the practical deployment of ZrO2 SAW sensors faces significant challenges, as atmospheric humidity severely degrades their performance, causing substantial sensitivity drift and even polarity reversal. This work reports a strategy involving the modification of ZrO2 nanoparticle surfaces with hydrophobic functional groups (-Si(CH3)3). This approach successfully transformed the inherently superhydrophilic ZrO2 material (water contact angle, WCA = 19°) into a hydrophobic state (WCA = 136°). For SAW sensors based on this hydrophobized ZrO2, the initial frequency drift induced by humidity was suppressed by 92.6 at 85% relative humidity (RH). More importantly, across the dynamic humidity range of 20-85% RH, the DMMP response remained stable at approximately -325 Hz/ppm (fluctuation <6%). This performance is significantly superior to that of unmodified ZrO2 SAW sensors, whose responses fluctuated drastically between -1030 Hz/ppm and +1141 Hz/ppm under identical conditions. The mechanisms underlying the humidity-induced sensitivity drift in ZrO2 SAW sensors were elucidated using in situ infrared absorption spectroscopy and X-ray photoelectron spectroscopy techniques. This study not only provides a straightforward strategy for imparting hydrophobicity to ZrO2 but also offers novel insights for addressing the issue of frequency drift in SAW sensors caused by atmospheric moisture.

Traditional tunable diode laser absorption spectroscopy (TDLAS) techniques primarily rely on single-point or sparse-point measurements, making it difficult to fully capture the two-dimensional spatial structure of combustion fields. Additionally, existing combustion diagnostic methods suffer from dynamic response delays. This paper proposes a spatio-temporal predictive diagnostic method integrating two-dimensional array TDLAS direct imaging with deep learning. Leveraging the absorption characteristics of O2 molecules, a 64-pixel array detector replaces conventional single-point sensors to achieve parallel direct imaging of the two-dimensional temperature field within the flame, effectively capturing the spatial distribution information of the combustion zone. A prediction model centered on the SwinLSTM deep network is constructed. Its sliding window attention mechanism effectively learns the spatial global dependencies of the temperature field, while the Long Short-Term Memory (LSTM) unit captures its temporal dynamic characteristics, enabling forward prediction from historical sequences to future time points. The experiment employed a "point-surface integration" strategy combining standard Type B thermocouples with an infrared thermal imager for multidimensional validation. Results demonstrated that the maximum relative error in single-point quantitative inversion was on was merely 3.75%, whilst accurately reflecting the flame's macroscopic topological structure. In prediction tasks, the SwinLSTM-D model achieves an SSIM value of 0.961 and a PSNR value of 38.625 dB, significantly outperforming traditional methods such as ConvLSTM and PredRNN. Research indicates that the method proposed in this paper can accurately reconstruct the two-dimensional temperature field of flames. Furthermore, in short-term prediction tasks, the model can precisely capture the spatiotemporal evolution patterns of flame temperature fields and perform accurate predictions. This provides new research approaches and methodologies for current combustion measurement and diagnostic technologies.

High-spectral-resolution retrievals of nitrogen dioxide (NO2) provide detailed atmospheric absorption information, but they usually involve large data volume, low computational efficiency, and complex instrument requirements. To address these limitations, we employ a low-spectral-information retrieval strategy for fast atmospheric monitoring. In this study, the Discrete-Wavelength Differential Optical Absorption Spectroscopy (DWDOAS) technique is applied by selecting 14 representative wavelength samples in the 420–450 nm window. Multiple wavelength–resolution configurations are constructed and quantitatively assessed using an entropy-weighting scheme to identify the optimal setup. Using TROPOspheric Monitoring Instrument (TROPOMI) and Environmental Trace Gases Monitoring Instrument (EMI-II) measurements as case studies, we show that at a spectral resolution of ~2 nm, DWDOAS-derived NO2 vertical column density (VCD) are highly consistent with those from conventional DOAS retrievals (correlation coefficient R &gt; 0.7) and exhibit relative differences of approximately ±30%. Monte Carlo simulations further demonstrate method robustness, yielding mean uncertainties below 2 × 1014 molecules·cm−2. The results indicate that DWDOAS effectively suppresses high-frequency spectral noise while preserving key differential absorption structures, thereby achieving a favorable trade-off between information retention and noise robustness. Nevertheless, increased retrieval uncertainty is observed under low-NO2 background conditions or strong aerosol loading, which reduces sensitivity to weak absorption features. Overall, this study confirms that reliable NO2 retrieval performance can be maintained while substantially reducing spectral information requirements, offering practical implications for low-resolution spectrometer design, onboard data compression, and rapid, wide-area atmospheric trace-gas monitoring.

The solvatochromism, solvation, and excited-state dipole moment of the nonsteroidal anti-inflammatory drugs (NSAIDs) ibuprofen (IBP) and ketoprofen (KEP) have been investigated using UV–Visible absorption and fluorescence spectroscopic techniques. A bathochromic shift is observed in the emission wavelength of IBP and hypsochromic shift in KEP. The solvatochromic behavior of both molecules has been analyzed in detail by correlating their spectral properties with the Lippert–Mataga function and solvent polarity parameters ([Formula: see text]), Kamlet–Taft and Catalan multiple linear regression methods. Preferential solvation (PS) studies of both molecules were carried out in a tetrahydrofuran (THF)–water (H2O) solvent mixture. The results, based on the PS method, are discussed in terms of the variation of transition energy ([Formula: see text]) with the mole fraction of water, the solvation index ([Formula: see text]), and the proportionality coefficient ratio ([Formula: see text]). The excited-state dipole moments of the molecules were estimated using both DFT and experimental methods. The influence of solute polarizability on the estimated excited-state dipole moment and the change in dipole moment was analyzed using the Bilot–Kawski approach. This study reveals the distinctive photophysical properties of these molecules, underscoring their relevance beyond biomedical and pharmaceutical applications.

Environmental pollution is considered as one of the important and serious problem faces the humanity nowadays. Pollution can take the form of chemical substances or energy, such as noise, heat, or light. Pollutants are chemicals or materials that pollute the air, the water, or the soil in some form and are caused by human activities. Tree bark has been proven to be a valuable source of information on air pollution. bark has a large absorbent surface. Tree bark enables the identification and mapping of organic and inorganic air pollutants, Heavy metals are one of the important types of contaminants that can be found in the tree barks, which bark polluted with heavy metals have become common across the globe due to increase in geologic and anthropogenic activities. The Eucalyptus tree is an effective bio-indicator for heavy metals accumulation from road traffic. The aim of this study was to investigate and assess heavy metal pollution in the atmosphere such as zinc (Zn), cupper (Cu), cobalt (Co), cadmium (Cd), lead (Pb), nickel (Ni), and chromium (Cr) concentrated in the atmosphere of Tripoli city using Eucalyptus tree barks as a good indicator adsorbents of airborne pollutants. the samples were collected from 5 different localities in Tripoli city – Libya districts, which are having different traffic activities and all sites that have civil war, were takin in April 2024 and analyzed accomplished by flame atomic absorption spectroscopy technique (f - AAS). In this study, the result from heavy metal determination showed the presence of all the seven targeted elements in the barks samples. Highest mean concentrations of lead (40.770±1.43mg/kg), while Cd gave the lowest concentration at (0.065±0.003 mg/kg).

Water pollution due to discharge of industrial wastes into aquatic environment remains a major challenge associated with adverse health effects and environmental destruction worldwide. The activated carbon was produced from the plant biosorbent using potassium hydroxide activator method. The activated carbon produced was characterized by surface characteristics and Fourier Transform Infrared (FTIR) spectroscopic technique. The levels of heavy metals in the treated and untreated industrial wastewater sample were determined by atomic absorption spectroscopic (AAS) technique. Batch adsorption study was conducted using the American Public Health Association (APHA) method. The mechanism of heavy metals adsorption capacity of the plant-derived activated carbon was evaluated using Freundlich isotherm and Langmuir isotherm models. The result showed that the plant-derived activated carbon derived exhibited significant (p &lt; 0.05) value of surface area (570.33 m2/g), pore volume (2.56 g/cm3), pH (6.46), conductivity (64.03 µS/cm), moisture content (20.86 %), and ash content (7.53 %) coupled with low value of porosity (0.82 %), bulk density (0.53 g/cm3), apparent density (0.32 g/cm3), and real density (1.91 g/cm3).. The FT-IR spectrum of the activated carbon displayed various band peaks at wavenumber ranged 3350 – 801 cm−1 indicating stretching of C–H, C=O, C–C C−O, and O−H. The untreated wastewater sample demonstrated high significant (p &lt; 0.05) amount of cadmium (0.23 mg/L), cobalt (0.83 mg/L), lead (3.02 mg/L), manganese (1.47 mg/L), nickel (0.62 mg/L), and chromium (0.60 mg/L). The plant-derived activated carbon exhibited high significant (p &lt; 0.05) percentage efficiency for removal of cadmium (95.55 %), cobalt (96.48 %), lead (97.16 %), manganese (99.25 %), nickel (96.09 %), and chromium (96.88 %) from the industrial wastewater sample. The results of this study showed that the regression coefficient (R²) values of cadmium, cobalt, lead, manganese, nickel, and chromium for the Langmuir isotherm are higher than that demonstrated by the metals for the Freundlich isotherm model. The experimental equilibrium data for cadmium, cobalt, lead, manganese, nickel, and chromium were best fitted to the Langmuir isotherm model than the Freundlich isotherm model. The activated carbon derived from the roots of Typha domingensis demonstrated high adsorption capacity for removal of cadmium, cobalt, lead, manganese, nickel, and chromium from the industrial wastewater.

Abstract Understanding potassium (K) speciation in soils is essential for evaluating its availability to plants and guiding sustainable nutrient management. In this study, five distinct soils from Taiwan, representing varying management practices and physicochemical properties—including soils with and without long‐term K fertilization, alkaline soil, red soil, and forest soil—were analyzed to determine K speciation. A combination of indirect (sequential chemical extraction) and direct (synchrotron‐based X‐ray absorption spectroscopy) techniques was employed to comprehensively characterize soil K forms. Wet chemical extraction revealed that &gt;95% of total K resides in the residual fraction, while exchangeable, carbonate‐bound, Fe/Mn oxide‐bound, and organic‐bound forms collectively accounted for &lt;5%. X‐ray absorption near‐edge structure and extended X‐ray absorption fine structure analyses provided insights into the local coordination environment of K, revealing a consistent white line feature at ∼3615.2 eV across samples, with intensity trends indicating K availability in the order: alkaline soil &gt; long‐term fertilized soil &gt; forest soil &gt; red soil &gt; unfertilized soil. Linear combination fitting indicated that illite‐smectite is the dominant K‐bearing phase, while soluble and organic‐associated K forms vary with soil type and management. This study demonstrates the advantages of combining wet chemical and synchrotron‐based spectroscopic approaches for an accurate, multiscale understanding of soil K speciation.

The study assesses the concentration level of six heavy metals (Lead, Nickel, Mercury, Cobalt, Arsenic, and Copper) in three selected meat samples from the market using the Atomic Absorption Spectroscopy (AAS) techniques. The results showed varying levels of contamination across different meat types (Chicken, Goat, and Cow). While most heavy metal concentrations were below WHO/FAO acceptable limits, some differences were observed, particularly in copper levels, which were significantly higher in Goat meat compared to Chicken meat. The study emphasizes the importance of continuous monitoring of meat products to ensure consumer safety

Heavy Metals (HMs) pollution is currently of major environmental concern. An investigative study was carried out along Nnamdi Azikiwe Expressway to determine the spatial distribution of heavy metal in roadside soils and vegetables samples with nine selected areas. The samples were digested and analyzed for toxic metals: Pb, Cd, Zn, Cu, and Ni using Atomic Absorption Spectroscopy (AAS) technique. The assessment of the heavy metals was derived using the geo-accumulation index and enrichment factor. This study revealed that the soil and vegetable contain metals hi which is predominantly Ni &lt; Cu &lt; Zn&lt; Pb &lt; Cd. The data were subjected to analysis of variance (ANOVA) to explain the factors interaction between the soil and vegetable obtained from the sample sites, geo accumulation and enrichment factor revealed that the enrichment factor was greater than 1. With the exception of one location that exhibits heavy pollution with PLI &gt;1, the area was not significantly polluted. Nonetheless, the assessment's findings show that there was an increased concentration of Zn and Pb across the nine locations, which was consistent with findings from other researchers. As a result, the toxicants were below the NESREA-established permissible limit .It shows that the area is not heavily impacted due to human activity and is safe.

Several international studies have reported qualitative alterations in the concentrations of specific trace elements among individuals diagnosed with leukemia. However, further investigations are required to validate these associations and better understand the observed elemental variations. In Karbala province, there is a lack of research addressing the distribution of trace elements in pediatric leukemia cases. The aim of this study was to evaluate the concentrations of selected trace elements (Cd, Pb, Co, Al, Cu) in the blood of children with leukemia in Karbala, and to determine whether these levels differ from the normal reference ranges reported by WHO and NIH guidelines, as well as between urban and rural populations. This study measured the concentrations of cadmium (Cd), lead (Pb), cobalt (Co), aluminum (Al), and copper (Cu) in blood samples collected from 20 children with leukemia at Al-Hussein Medical City Hospital. Atomic absorption spectroscopy (AAS), using both Flame and Graphite Furnace techniques, was used to quantify the levels. The observed concentrations were copper (46.192 to 274.866 ppb), lead (0.767 to 8.675 ppb), cobalt (0.331 to 3.170 ppb), cadmium (0.466 to 1.752 ppb), and aluminum (15.011 to 24.787 ppb). The results indicated that the concentrations of these trace elements were generally lower than the internationally recognized normal ranges. In addition, a geographic variation was observed: children residing in the urban center exhibited lower trace element concentrations compared with those living in rural areas.

In this study, we reported the design, synthesis, and comprehensive evaluation of a series of nitro carbazole‐based oxime photoinitiators (OPIs, OP1: oxime oxalate, OP2: oxime glyoxylate), as a series of efficient Type I photoinitiators (PIs) for the free radical photopolymerization (FRP) of trimethylolpropane triacrylate (TMPTA) and ethoxylated trimethylolpropane triacrylate (ETPTA) under blue light‐emitting diodes and sunlight irradiation. Computational molecular modeling was employed to predict the effect of OPIs structures on the photoinitiation properties. The predictions suggest that OP1 had a higher propensity for decarboxylation and therefore a better photoinitiation behavior. Compared to OP2, OP3, and commercial benchmark photoinitiator TPO, OP1 exhibits exceptional photoinitiation performance when exposed to LED@405 nm, LED@450 nm, and sunlight. OP1 undergoes decarboxylation to efficiently produce CO2 and free radicals, thereby initiating the photopolymerization reaction. Remarkably, OP1 is successfully applied in 3D printing, producing complete morphology with high‐resolution structure, showcasing its potential for advanced manufacturing applications. The photochemical mechanism of OPIs is comprehensively elucidated using the monitoring of the CO2, steady state photolysis, UV–vis absorption spectroscopy, fluorescence spectroscopy, and electron spin resonance techniques. These experimental investigations are supported by data OP1 from the molecular modelling carried out. Additionally, thermal polymerization shows that OP1 had a high thermal initiation capability, and the composites are successfully prepared together with carbon fibers. The cytotoxicity of the synthesized oxime oxalate and TPO on human umbilical vein endothelial cells (HUVECs) results in a lower cytotoxicity for the oxalate than for TPO. Therefore, OP1, which has never been reported before, can be used as a highly efficient and low cytotoxic dual photo/thermal initiator. This research not only provides theoretical and practical insights into the design and development of new efficient Type I PIs, but also opens up new perspectives for curing applications that require scalability, cost‐effectiveness, environmental sustainability, and green chemistry.

The shift to green energy highlights Liquid Organic Hydrogen Carrier (LOHC) systems for hydrogen storage, leveraging existing fuel infrastructure. Conventional storage methods, like compression or cryogenics, demand high pressure and low temperatures, making them energy-intensive. LOHC systems chemically bind hydrogen to liquid organic carriers, enabling storage and release under ambient conditions. Electrocatalytic pathways facilitate hydrogenation and dehydrogenation under milder conditions than traditional catalysts. Metal-organic frameworks (MOFs) are ideal electrocatalysts due to their high surface area, tunable metal sites, and controlled environments, enhancing reaction selectivity and efficiency. The Ni HHTP MOF catalyst ( Ni hexahydroxytriphenylene Metal-Organic Framework) shows significant promise for improving the efficiency, stability, and selectivity in Liquid Organic Hydrogen Carrier applications. This catalyst can facilitate hydrogen release with higher efficiency, and to demonstrate its functionality, we use isopropanol (IPA) oxidation to acetone as model reactions, as IPA is a particularly attractive LOHC for specific mobile device applications. A deeper understanding of catalytically active species at low overpotential is essential to optimize processes further. The X-ray Absorption Spectroscopy (XAS) investigation is a beneficial technique for this task, where metal K edges and L edges help determine the electronic structure during heterogeneous catalysis and catalyst stability. Further, the Operando X-ray absorption spectroscopy technique can provide information on real-time changes in the electronic structure and the local environment during catalysis, which helps to interpret the mechanism accurately. Analyzing the Ni K edge of the pristine catalyst provides insightful ideas about the catalyst structure, such as the oxidation state of transition metal, coordination geometry, and the local environment around the Ni atom. Implementing metal L edge measurements after catalysis is beneficial because there are small changes that might not be sensitive to the K edges, as L edges are much more sensitive to the changes in d states, which is a good qualitative assessment of catalyst stability. Implementing operando XAS indicates shifts in Ni K edge spectra, indicating redox transitions during catalysis. Hence, operando XAS is crucial for identifying the active state during IPA oxidation and providing insights into catalytic pathways that stabilize the MOF.

Disordered rocksalt oxyfluoride (DRSOF) cathode materials display promising electrochemical characteristics, further enhanced when high F is present. It is known that the formation of DRSOF with significant levels of oxygen and fluorine requires the application of specific conditions and methods such as mechanochemical methods, as this indicates their metastable nature. In our study, we investigated the thermal stability of different electrochemical states of two model DRSOF compounds, Li2TMO2F (where TM represents Mn or Co), in an inert atmosphere. We employed differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, and X-ray absorption spectroscopy techniques to conduct our analysis. Our comprehensive observations highlighted subtle yet significant changes in the disordered rocksalt structure of the pristine material as the temperature gradually increased even before it decomposed completely (> 400°C) into various other phases. Then, delithiation and re-lithiation processes were performed in a coin cell battery to establish various electrochemical states of Li2TMO2F. Upon subjecting both delithiated and re-lithiated materials of Li2TMO2F (i.e., Li2-xTMO2F) to thermal annealing within a carefully controlled temperature range of 100°C to 400°C, we discovered that Li2-xTMO2F containing a higher transition metal oxidation state demonstrated notably low decomposition onset temperatures. Furthermore, analysis through X-ray absorption spectroscopy revealed that both Mn and Co underwent changes in their oxidation states, accompanied by evident local structural distortions. Our findings suggest that the presence of metal–fluorine bonds, identified as redox-active, introduces additional destabilization mechanisms into the system. We assume that these bonding states tend to become increasingly unstable when higher formal oxidation states of the metal are present, potentially contributing to the complex behavior observed during thermal treatment.

GeO2–PbO–PbF2 glasses doped with rare-earth ions have been widely studied; however, the codoping of Tb3+ and Yb3+ in this glass system has not yet been explored. This work presents a novel approach involving the tailored combination of Tb3+/Yb3+ ions, optimized to enhance up-conversion efficiency under low-power near-infrared (NIR) excitation. To the best of our knowledge, this codoping strategy, together with a comprehensive investigation of the associated energy transfer mechanisms and multicolor emission behavior, has not been previously reported. In this study, the prepared glasses were systematically investigated using X-ray diffraction, absorption, excitation, and emission spectroscopic techniques to examine their structural characteristics and optical performance. Up conversion emission was studied under 976 nm excitation, supported by decay time analysis, while power dependence was probed using a 940 nm laser diode (300–600 mW). Furthermore, multicolor emission characteristics were analyzed through chromaticity coordinate determination and CIE diagram mapping under 375 and 976 nm excitation. These results demonstrate the significant potential of these materials for use in advanced photonic applications, such as bioimaging, photovoltaics, optical data storage, and light-emitting devices.

The importance of Cu(II) in environmental, biological, and industrial systems makes it crucial to develop a highly selective and sensitive analytical methodology for its determination. Herein, a graphitic based sensor modified with a Schiff base, namely 2-(((3-aminophenyl) imino) methyl) phenol was developed and applied. A broad concentration range (1 × 10-7- 1 × 10-1) mol L-1 was covered by the electrode's linear response to Cu(II), which had a 29.571 ± 0.8 mV decade-1 Nernstian slope. It was highly reproducible (inter and intraday RSDs%=0.94-2.12), with a response time of approximately 15s and pH working rang was from 3.5 to 6.5. and had a two-month lifespan. With this modified sensor, 5.0 × 10-8 mol L-1 was the detection limit and1.65 × 10-7 mol L-1 was the limit of quantification. Over a wide range of metal ions, the suggested electrode exhibited very good selectivity for Cu(II) applying separate solution method(SSM), fixed interference method (FIM) and matched potential method (MPM). Cu(II) levels in Several samples like spiked water samples, Hairvogine multivitamin and Nutrifol vegetable foliar were accurately determined potentiometrically by either direct, or standard addition methods using this chemically altered carbon paste electrode giving a comparable results with atomic absorption spectroscopy (AAS) technique. Scanning electron microscope (SEM) combined with energy dispersive X-ray (EDX) were utilized for morphological analysis of sensors' reactive surface combined with elemental analysis as well.

Source apportionment, ecological and human health risk assessment of potentially toxic elements in Tumet River, Ethiopia

Simultaneous multiparameter measurement of NaCl solution liquid film based on absorption spectroscopy technique

Trakošćan Lake is an artificial lake created in the mid-19th century for aesthetic and economic purposes. The area around the lake has been protected as park forest. Recently, the lake has become the most famous example of eutrophication in Croatia, as by 2022, a significant amount of sediment had accumulated in it. Therefore, the lake was drained that same year, followed by mechanical removal of the sediment. The total amount of sediment removed was 204,000 m3. After the removal work, a particularly important question arose of what to do with such a large amount of sediment. The objective of this research was to gain specific insight into the chemical composition of the sediment with the aim of its possible use in agricultural production for increasing the quality of arable land. A comprehensive qualitative geochemical and agrochemical analysis of the sediment composition was carried out for the first time, including indicators of the pH value, amount of organic matter and carbon, total nitrogen, available phosphorus and potassium, amount of carbonates, and the presence of metals, metalloids, and non-metals, of which As, Cd, Hg, and Pb are toxic. Electrochemical, spectrophotometric, and titration methods were used, along with three atomic absorption spectrometry techniques. The results of the analyses were interpreted in comparison with the natural substrate, as well as with the current regulations for agricultural land in the Republic of Croatia. According to this, sediment is not harmful for the environment.

This study presents an innovative calibration-free artificial peak-laser absorption spectroscopy (AP-LAS) technique that fundamentally overcomes the inherent dynamic range-sensitivity trade-off and eliminates reliance on specific absorption line pairs for multiparameter measurements in laser absorption spectroscopy. By implementing a unique signal-driven and wavelength-tuning mechanism, the proposed approach generates tailored artificial absorption peaks within a single natural spectral line, enabling simultaneous temperature and concentration quantification. This method is validated through CO absorption experiments in a high-temperature, high-pressure shock tube environment. Experimental results demonstrate that the AP-LAS technique significantly extends the detectable concentration range by 4 times compared to conventional methods while maintaining excellent linearity. The technique achieves enhanced dynamic range and multiparameter quantification performance without requiring matched absorption line pairs under extreme conditions. These advancements highlight AP-LAS technique as a promising solution for real-time gas monitoring in demanding applications such as combustion diagnostics.

An operando X-ray absorption spectroscopic technique,which enablesus to measure X-ray absorption spectra with a position resolutionof submicrometers at increased temperatures while controlling atmospheresand passing an electrical current through the specimen, was developed.By applying this technique, the electrochemically active area in aporous La0.6Sr0.4CoO3−δ electrode for a solid oxide fuel cell (SOFC) was experimentallyand directly evaluated for the first time. The characteristic lengthof the active area was approximately 1 μm from the electrode–electrolyteinterface under a cathodic overpotential of 140 mV at 873 K under10–2 bar of P(O2), althoughthe investigated electrode was thicker than 50 μm. This demonstratedthat a reaction in an SOFC electrode inhomogeneously proceeds in avery limited area near the electrode–electrolyte interface,even when a mixed ionic and electronic conducting oxide is used asthe electrode, and that direct evaluation of the active area can provideguidelines for high-performance electrode design.