High Temperature Operation Research Articles

Controllable synthesis of heterostructured CuO–ZnO microspheres for NO2 gas sensors

Nitrogen dioxide (NO2) sensors experience the drawback of requiring high operating temperatures because of the low charge transfer ability of gas-sensing materials. Herein, an advanced NO2 sensor resistant to interference is designed using the interfacial energy barriers of a hierarchical CuO/ZnO composite. With the benefits of abundant desirable defect features, and the amplification effect of heterojunctions, the sensor based on CuO/ZnO composite with 10% Cu(CH3COO)2·H2O (S2) shows outstanding performance in terms of faster response and recovery time (1.8-fold/1.1-fold), higher response (3.1-fold), and lower power consumption (140℃ decrease) compared to the pristine ZnO sensor. Furthermore, the composite sensor exhibits long-term stability and reproducibility, indicating the potential promise of CuO/ZnO heterojunctions in interference-resistant detection of low-concentration NO2 in real applications. This study not only provides a rational solution to designing advanced gas sensors by tuning the interfacial energy barriers of heterojunctions, but also provides a fundamental understanding of CuO structures in the gas-sensing field.

Mn-doped 0.67BiFeO3-0.33BaTiO3 ceramic sensor for high-temperature structural health monitoring

Real-time monitoring of structural health status is very important for supersonic aircraft, since the long-term operation in harsh service environments, such as high temperatures, can cause potential damage. Structural health monitoring (SHM) based on lamb wave has been approved to be a critical technique for the reliable operation of supersonic aircraft, but is limited by the operating temperature of conventional piezoelectric sensors, which makes it difficult to meet the high-temperature monitoring requirements. The BiFeO3–BaTiO3 ceramics exhibit excellent piezoelectric properties and high Curie temperature (Tc), making them promising for high-temperature SHM of supersonic aircraft. Here, we fabricated a piezoelectric sensor using 0.67BiFeO3-0.33BaTiO3-0.25%molMnO2 (BF33BTMN-025) ceramic, which exhibits a piezoelectric charge constant (d33) of 135 pC/N at room temperature and a Tc of 448 °C. The BF33BTMN-025 ceramic sensor operates effectively at temperatures up to 200 °C and maintains stable damage monitoring sensitivity as well. Compared with Pb(Zr, Ti)O3 (PZT), BaTiO3 (BTO) and other piezoelectric sensors commonly used in SHM field, the BF33BTMN-025 ceramic sensor has a higher operating temperature and a comparable sensitivity. Our work demonstrates that the BF33BTMN-025 ceramic sensor can be employed as piezoelectric sensor for high-temperature SHM, which has a wide application potential in the field of real-time monitoring of supersonic aircraft.

Effect of Ce0.6Zr0.4O2 nanocrystals on boosting hydrogen storage performance of MgH2

Magnesium hydride (MgH2) has been widely recognized as a highly promising solid-state media for hydrogen storage. However, the high operating temperature and the intrinsic sluggish kinetics hinder the practical application as a portable solid storage carrier. To address this issue, we have successfully fabricated a novel rare earth-containing bimetallic oxide additive, namely Ce0.6Zr0.4O2 nanocrystals, which exhibits a significant catalytic effect in enhancing the hydrogen storage properties of MgH2. By incorporating 7 wt% Ce0.6Zr0.4O2 into MgH2, the modified composite releases hydrogen as low as 201 °C. Furthermore, in an isothermal dehydrogenation test conducted at 270 °C for 8 min, approximately 6.15 wt% of H2 was desorbed. The composites can rapidly recharge hydrogen at a low temperature of 50 °C and 6.02 wt% H2 being absorbed within 3 min at 150 °C under 50.0 bar. Comparatively, the dehydrogenation activation energy of the Ce0.6Zr0.4O2-modified MgH2 significantly decreased compared to MgH2 by ball milling. In addition to its improved hydrogen storage properties, the composite also exhibits excellent cycling stability. Through cyclic de-/rehydrogenation experiments conducted at 270 °C, a capacity retention of 98.9 % was achieved over 20 cycles. This exceptional performance can be attributed to the in-situ formation of the CeH2.73/CeO2-x and ZrO2, which originated from the Ce0.6Zr0.4O2 additive following the first de-/rehydrogenation cycle. The uniform dispersion of the multiphase component nano-sized active species within the MgH2 matrix facilitates charge transfer and accelerates hydrogen diffusion. Density functional theory calculations revealed the dissociation energy barrier and dissociation energy of H2 were alleviated by integrating Zr into CeO2. This work provides valuable insights for further rational designs of novel catalysts by transition metals and rare earths in promoting the commercialization of MgH2.

Effect of long-term thermal aging on lead-bismuth eutectic corrosion behavior of 9Cr ferritic/martensitic steel

In lead-cooled fast reactor (LFR) systems, the liquid lead-bismuth eutectic (LBE) coolant provides a corrosive environment that damages the steel components during high-temperature operation. This study investigated the microstructural deterioration of 9Cr ferritic/martensitic (F/M) steel under thermal aging at 550 °C for 2,000, 10,000, or 20,000 h and its effect on oxidation corrosion in an LBE environment using multiscale characterization techniques. The results indicated that the thickness of the internal oxidation zone (IOZ) increased significantly with extended thermal aging, whereas that of the spinel layer remained relatively constant. The abundant subgrain boundaries that emerged during extensive thermal aging facilitated Fe diffusion, and the enlarged Cr-rich M23C6 carbides contributed to the formation of preferential oxidation regions, accelerating IOZ layer growth. The spinel layer formed from the IOZ was influenced by microstructural defects within the IOZ. A theoretical model describing the accelerated oxide layer growth due to thermal aging was developed. These findings support the advancement of LFR technology.

Enhanced PtRu by CeO2 hollow nanofibers: Hydrogen gas sensing with CO-resistant in fuel cell

The broad flammability range of hydrogen (4–75 %) underscores the critical need for precise and efficient detection methods. Traditional catalytic combustion sensors can detect combustible gases rapidly; however, they have disadvantages such as high operating temperatures, increased power consumption, and dependence on platinum, with vulnerability to CO poisoning. This study introduced a groundbreaking approach that utilizes CeO₂ hollow nanofibers supported by PtRu nanoparticles to sense hydrogen under extreme conditions, including environments with CO concentrations up to 500 ppm. The unique structure of CeO₂, derived from the Pt/Ce3+ redox pair, provides a high density of oxygen vacancies, which enhances hydrogen detection and enables reactions at room temperature. Our sensor can detect hydrogen concentrations ranging from as low as 100 ppm to as high as 50 %, showcasing its wide detection range and superior selectivity. Our findings confirmed the superior performance of the sensor in realizing consistent and rapid detection in a CO-rich atmosphere. This study presented a significant step toward robust wide-range hydrogen detection, paving the way for safer and more sustainable environmental monitoring.

Mechanical failure analysis of drill string aggravated by stuck pipe after high-temperature melting-cutting operations

High-temperature melt cutting is an important technology for fast cutting and unjamming of downhole jammed tubular rods, but due to the well depth and mud environment, it cannot completely cut through the large wall thickness tubular rods such as weighted drill pipe, and it needs to be damaged by external load applied by drilling rig. The shape of the drill pipe kerf after the melt cutting operation is not the same, so the size of the applied external load needs to be further investigated. To address this problem, firstly, this paper establishes the Johnson-Cook ontology and failure model of S135 steel grade drilling tools based on the high temperature tensile test; secondly, according to the characteristics of the weighted drill pipe melt-cutting notch, a finite element model for mechanical damage failure analysis of weighted drill pipe with melt-cutting notch is established, and the reliability of the model is verified; lastly, the influence of high temperature and different notch characteristics (melt-cutting depth, circumferential cutting angle, Finally, the effects of high temperature and different notch characteristics (depth of cut, circumferential cutting angle, number of perforations) on the mechanical failure capacity of weighted drill pipe with fusion notch are analysed. The results show that the errors of the maximum stresses and strains of the samples obtained from the tensile fracture simulations at 20 °C and 400 °C and the maximum stresses and fracture strains obtained from the experiments are within 9 %, which verifies the accuracy of the model. Tensile loading was more effective than compressive loading in destroying the drill pipe; the change in loading speed had a small effect of 4.1 % on the tensile force required to destroy the drill pipe. The damage load of the drill pipe and the pressure acting on the cross-section of the fusion cut decreases with the increase of the fusion cutting depth; the damage load required decreases with the increase of the circumferential cutting angle and the number of openings, but the pressure acting on the cross-section of the fusion cut does not decrease. The softening effect of high temperature on the drill pipe is very obvious, and the tensile capacity of the drill pipe is attenuated by 80.6 % at a temperature of 800 °C. The research work can improve the operation process of cutting and unjamming thick-walled drilling tools in deep wells and guide the field operation to achieve the purpose of rapid unjamming.

Nanoscale structural transformations in LaFeO3 oxygen carriers for enhanced reactivity in chemical looping combustion

The push for decarbonization necessitates the development of clean and efficient energy conversion technologies. Among these, the chemical looping platform has emerged as a promising approach, albeit with challenges such as high operating temperatures. This necessitates the design of high-performance chemical looping carriers. In this study, we explore the potential of nanosized oxygen carriers, noted for their high reactivity, for the chemical looping combustion of methane (CH4). LaFeO3, a widely investigated perovskite-type mixed metal oxide known for its effectiveness as an oxygen carrier, is examined. Nanosized LaFeO3 is synthesized by embedding LaFeO3 onto mesoporous silica matrix (LFO-SBA15), and its reactivity is benchmarked against bulk-scale LaFeO3 supported on SiO2 (LFO-SiO2). The nanosized carrier demonstrates a ∼ 1000% improvement in reactivity compared to the bulk carrier. This enhancement is attributed to the formation of a highly reactive cubic phase of LaFeO3 at the nanoscale, in contrast to the orthorhombic phase present in bulk-scale LaFeO3. This finding is supported by density functional theory calculations, which reveal that the cubic phase of LaFeO3 facilitates the formation of oxygen vacancies and lowers the energy barrier for CH4 dissociation. This work highlights the potential of nanosized LaFeO3 for the chemical looping combustion of CH4, providing valuable guidance for the rational design and development of high-performance chemical looping carriers.

Research on thermodynamic modeling and temperature prediction of double flapper-nozzle servo valves

The thermal characteristic design of the aerospace servo valve is of significant importance due to the high temperature operating conditions. This paper aims to study the law of temperature variation of the internal chambers and shell of the servo valve while it is driven dynamically, in order to ensure that the components inside the servo valve work within an acceptable temperature range and avoid failure. This paper establishes thermodynamic models of the nozzle flapper assembly and the spool valve, as well as the whole servo valve, using the control volume method. The models consider the throttling heating generation of each throttling component in the servo valve and heat exchange between the shell and air. Based on these models, the temperature curves of the shell and oil in each chamber in the servo valve are simulated and analyzed, given a specified input signal. Finally, a test is conducted, and the results demonstrate that the temperature curve trend obtained through simulation and test is reasonable and more accurately reflects the internal temperature characteristics of servo valves. This research provides a reference for further studies on the internal heating mechanism of servo valves and the fault diagnosis of servo valves at high temperatures.

Blade tip clearance measurement technology in gas turbines

Many technologies are used for engine development and testing but no technology has been successfully adopted for long term monitoring over the life of the engine. The challenge is to find a technology that is suitable for long term, high temperature operation but that can also provide accurate and reliable measurement. Blade turbine monitoring is an important area of work for improvements in gas turbine operation. Blade tip clearance measurements offer improvement in engine efficiency by enabling active clearance control. However, this is a difficult measurement because of the harsh turbine environment. The high temperature microwave sensor presented in this paper is one of the most promising candidates for clearance measurement. It has been tested on the high pressure stage of a 25MW gas turbine engine during different operating modes

A room-temperature ppb-level detection limit of NO2 sensor based on Cellulose/SnO2 heterojunction under UV illumination

In light of growing concerns over air pollution, particularly NO2 emissions from vehicular and industrial sources, there is a critical demand for advanced gas sensors. Traditional metal oxide semiconductors, while widely used, face challenges such as poor selectivity and high operating temperatures. In this work, we have achieved a high selectivity and room temperature NO2 gas sensor by composite of sponge-like porous cellulose with SnO2 nanoparticle. As a result, the gas sensor exhibits excellent performance in terms of high response (260.4 at 20 ppm), excellent selectivity and low detection limit (100 ppb) for NO2 gas, due to the unique sponge-like porous structure of cellulose with its high specific surface area facilitating the uniform distribution of SnO2 particles. This study not only highlights the superior sensing capabilities of cellulose-based sensors but also lays the foundation for further advancements in environmentally-friendly gas sensing applications.

P‐60: Automotive Dual Cell microZone™ LCD Gamma Control Algorithm

Consumer experience with high performing mobile device displays sets high expectations for the automotive market in contrast, color performance and brightness. OLED based displays continue to experience difficulties in penetrating the automotive display market primarily due to image burn at high luminance operation and high costs. The microZone™ LCD is an alternative display configuration that can meet the desirable properties of OLED displays while providing high luminance at high temperature operation without image burn in.

Low-cost scalable high-power-density solar thermochemical energy storage via accelerating ion diffusion in Calcium-based solid wastes

Calcium-based solar thermochemical energy storage (TCES) has a great potential for next-generation concentrated solar power (CSP) systems due to its unique advantages of high operation temperature from 750 ℃ to 900 ℃ and high energy storage density, while current Calcium-based pellets suffer from poor cyclic stability and slow reaction kinetics. The mainstream solution relies on expensive inert stabilizers and complicated fabrication processes, which severely limited their affordability and scalability. Herein, we propose a strategy for recycling different Ca-based solid wastes, achieving low-cost and scalable high-power-density solar TCES simultaneously via the synergistic effect of multiple solid wastes and MgCl2. The power density of proposed pellets is 2 times than that of the conventional CaCO3, as the promoted solid-state diffusion of Ca2+ accelerates the decomposition of CaCO3. The energy storage density is as high as 1191 kJ/kg after 50 cycles, along with energy storage economy higher than 70 MJ/$ and friction loss less than 0.3 %, far exceeding that of the state-of-the-art Calcium-based TCES pellets. The feasibility of high-performance solar-driven TCES is further demonstrated on a pilot-scale system, providing a promising high-temperature thermal energy storage solution for next-generation CSP techniques.

High-temperature heat pumps: Fundamentals, modelling approaches and applications

In March 2023, the European Parliament and Council reached a consensus to increase the binding renewable energy target (RES) to a minimum of 42.5 % by 2030, effectively doubling the proportion of RES from the 2020 baseline. This significant development aligns the EU more closely with the objectives of the European Green Deal and the REPowerEU initiative. High-temperature heat pumps (HTHP), due to their appropriateness for industrial-scale applications, integrate perfectly within this progressive trajectory. They enable waste heat generated by various production processes to be recovered (temperatures typically ranges from around 50 °C–100 °C) and subsequent use at temperatures above 100 °C, thus reducing the consumption of fossil fuels and greenhouse gas emissions. The high operating temperatures and pressures of HTHPs are challenging. They require an in-depth analysis of the system processes involved, taking into account refrigerants, efficient heat pump cycles and key components. One possibility for a preliminary analysis of vapour compression HTHP system performance without incurring the costs associated with manufacturing and testing the device is modelling. However, there is no comprehensive review of research work on possible software. Commonly, the researchers report on one chosen methodology and the tools used. This paper provides a comprehensive review of modelling approaches. It also discusses aspects related to the principles of operation, refrigerants and system components. Additionally, the paper presents an overview of vapour compression heat pump applications in various sectors. The literature review conducted indicates the need for further research and development of HTHP covering not only technological aspects but also software development.

Surface reconstruction of β-Ga2O3 nanorod electrolyte for LT-SOFCs

Solid oxide fuel cell (SOFC) is a promising energy conversion technology, but the high operating temperature caused by electrolytes impedes its widespread application. The development of alternative electrolytes with fast ionic transport plays a vital role in tackling this challenge. In this study, a new electrolyte is proposed based on the wide bandgap semiconductor Ga2O3, by using a facile surface treatment on the nanorods of β-Ga2O3 in hydrogen. The treatment reconstructs the surface of the β-Ga2O3 nanorod to form a core–shell structure with an oxygen vacancy-rich shell. The nanorod sample is applied as the electrolyte in SOFC, delivering a high ionic conductivity of 0.15 S cm−1 and promising power densities of 485 mW cm−2 at 550 °C. Further studies confirm dominated proton conduction in the electrolyte and propose different mechanisms to elucidate the fast proton transport in terms of surface reconstruction. Particular attention is paid to the homo-junction at the core–shell interface by discussing the modulating effect of the junction s built-in field on proton diffusion. This work develops a new electrolyte based on β-Ga2O3 for LT-SOFC and presents an effective method of surface reductive reconstruction to enable fast proton conduction in semiconductor electrolytes.

Dynamic performance and control analysis of supercritical CO2 brayton cycle for solid oxide fuel cell waste heat recovery

Due to the high-temperature operation of solid oxide fuel cell, recovering its exhaust waste heat is worthwhile. The supercritical CO2 cycle features low compression power consumption and high thermal efficiency, making it a promising power cycle. Therefore, this paper adopts the supercritical CO2 recompression cycle as the bottom cycle, combined with solid oxide fuel cell to form a joint system, further improving energy utilization. Given the long temperature response time of the solid oxide fuel cell and the variability of its exhaust waste heat with load changes, this paper innovatively proposes establishing an integrated dynamic model of the joint system, instead of directly providing heat source flow and temperature changes as in traditional research, to more accurately study the dynamic response of the cycle during solid oxide fuel cell startup and load variations. Based on this, a control strategy utilizing inventory control is proposed, and the feasibility of the control effect is verified. The research results indicate that the uncontrolled cycle may lead to safety issues with a significant increase in turbine inlet temperature when solid oxide fuel cell load increases. Under the control strategy, the turbine inlet temperature and main compressor inlet temperature are rapidly stabilized at the target values. The controlled cycle achieves higher efficiency compared to the uncontrolled cycle, particularly prominent during solid oxide fuel cell load reduction, with an efficiency increase of approximately 5.23%.

Enhancing toluene gas sensing performance using Co3O4/ZnO hollow porous flower-like material

ZnO is widely used in semiconductor oxide gas sensors due to its remarkable physical and chemical properties. However, ZnO-based gas sensors face several challenges in practical applications, including limited selectivity, reduced sensitivity, and the requirement for high operating temperatures. In this study, a three-dimensional hollow porous flower-like Co3O4/ZnO material was synthesized by single-step hydrothermal method, exhibiting an average diameter ranging from 4 to 5 μm. The presence of Co3O4 within ZnO was confirmed through X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Through the detection of different gases, the results indicate that the ZnO-based gas sensor, doped with 0.5 at% Co3O4, exhibits exceptional sensitivity towards toluene gas, with the limit of detection (LOD) (1 ppb). The sensor's response values Ra/Rg to 0.1–200 ppm toluene at 260 °C range from 2 to 225, respectively. In the presence of toluene gas at a concentration of 100 ppm, the sensor demonstrated a high response value of 130, with response and recovery times of 30 s and 50 s, respectively. Furthermore, the response value of this sensor type was tested over a period of 15 days, confirming the device's excellent long-term stability.

Effect of striae on the high temperature dielectric and electrical properties of lithium aluminosilicate glass-ceramics

Lithium Aluminosilicate glass-ceramics with striae (LAS-WS) and without striae (LAS-WoS) were processed using melt casting technique. LAS-WS and LAS-WoS samples were characterized and found stress birefringence >10 nm/cm and <10 nm/cm, respectively. LAS-WS and LAS-WoS samples were subjected to structural, microstructural, high temperature dielectric and electrical characterization. The presence of striation did not significantly affected the formation of β-spondumene structure during crystallization heat treatment. TEM image confirms the formation of nanocrystals in the glass matrix of lithium aluminosilicate glass-ceramics. The homogeneous distribution of LAS nanocrystals of average size of 3–6 nm is evident from TEM results. Stress birefringence distribution in lithium aluminosilicate glass-ceramic clearly shows the striae formation. Shadowgraphy images confirmed the striae free and striae containing regions in the glass-ceramic. The effect of striae on dielectric properties and AC conductivity was analysed using impedance spectroscopy and it was found that the value of the relative permittivity decreased from 415 (1.2 Hz) to 9.76 (1.2 MHz) for LAS-WoS and from 401 (1.2 Hz) to 10.3 (1.2 MHz) for LAS-WS, respectively. It was found that striae in LAS glass-ceramics influence the electrical impedance and AC conductivity relaxation process rather than relative permittivity. The effect of striae on crystallization and morphology are presented. Both the samples have shown crystallinity of more than 75 %. The electrical conductivity of σ = 2.0 × 10−3 S/cm for LAS-WoS and 2.7 × 10−3 S/cm for LAS-WS at 300 °C as well as σ = 4.6 × 10−3 S/cm for LAS-WoS and 6.9 × 10−3 S/cm for LAS-WS at 700 °C are found to be in good agreement due to increase in the electrical conductivity with temperature. The ionic conductivity of the material due to Li-ion mobility with respect to temperature and electric field and possible mechanism of AC conductivity are discussed. The results presented indicates the potential application of this material that demands high temperature operation of lithium aluminosilicate glass-ceramics.

A novel additive promoting lignocellulose alkali pretreatment for its “two birds with one stone” role

Alkali pretreatment is one of the most commonly used pretreatment methods in lignocellulose bioprocessing. However, there are still some “pseudo-lignin” that hinder enzymatic hydrolysis and seriously affect the industrialization process of biorefining. Excellent pretreatment additives can effectively cover these shortages. However, most additives have disadvantages like high operating temperature, low effective utilization efficiency, or poor performance. To address this issue, we proposed a novel additive, dicyandiamide (DICY), by means of quantum chemical prediction, and verified its ability on assisting alkali to remove lignin by experiments. The results indicate that the lignin removal by KOH-DICY pretreatment is about 15% higher than KOH pretreatment, thereby increasing the enzymatic efficiency to 97%, while the reaction temperature was lower 20 ℃ than common alkali pretreatment. These are due to the “two birds with one stone” role of DICY on lignocellulose alkali-DICY pretreatment. DICY not only dissolves small amounts of lignin, but also assists alkali to remove lignin by reducing the diffusion resistance of KOH in lignin and blocking the generation of “pseudo-lignin”. Thus, DICY effectively improved the lignin removal and enzymatic hydrolysis efficiency of alkali pretreated lignocellulose, and performed better than urea. Moreover, the waste liquid pretreated by DICY combined with KOH has the potential on preparation of agricultural fertilizers. In summary, DICY is a new, environmentally friendly, and energy conservation additive for lign ocellulose alkali pretreatment

Stabilizing high temperature operation and calendar life of LiNi0.5Mn1.5O4

Severe capacity degradation at high operating voltages and poor interphase stability at elevated temperature have thus far precluded the practical application of LiNi0.5Mn1.5O4 (LNMO) as a cathode material for lithium-ion batteries. Addressing these challenges through a combination of experimental and theoretical methods in this work, we demonstrate how a fluorinated carbonate electrolyte enables both high-voltage and high temperature operation by mitigating the traditional interfacial reactions observed in electrolytes with conventional carbonate solvents. Computational studies confirm the exceptional oxidation stability of fluorinated carbonate electrolyte which reduces deprotonation at high voltage. The mitigated deprotonation will then minimize the formation of HF acid which corrodes the LNMO surface and leads to phase transformation and poor interphases. With fluorinated carbonate electrolyte at elevated temperature, it was found on LNMO’s subsurface a reduced amount of Mn3O4 phase which can block Li+ transfer and result in drastic cell failure. Leveraging this approach, LNMO/graphite full cells with a high loading of 3.0 mAh/cm2 achieve excellent cycling stability, retaining ∼84 % of their initial capacity at room temperature (25 °C) after 200 cycles and ∼68 % after 100 cycles at 55 °C. This advanced electrolyte also shows promise for improving calendar life, retaining >30 % more capacity than the carbonate baseline after high temperature storage. These results indicate that electrolytes based on fluorinated carbonates are a promising strategy for overcoming the remaining challenges toward practical commercial application of LNMO.

InGaN/GaN multi-quantum well nanowires: Enhanced trace-level NO2 detection for environmental and breath analysis

The World Health Organization highlights nitrogen dioxide (NO2) as a key atmospheric pollutant impacting air quality and human health. To date, several sensors have been proposed for NO2 detection and disease monitoring, but their effectiveness is limited because of low sensitivity and high operational temperatures. Herein, we propose a selective and sensitive NO2 sensor based on indium gallium nitride/gallium nitride multiple quantum wells (InGaN/GaN-MQWs). We explored different InGaN/GaN-MQWs configurations (InGaN/GaN-MQW1, InGaN/GaN-MQW2, InGaN/GaN-MQW3), developed through metal–organic chemical vapor deposition (MOCVD), to analyze their impact on gas sensing performance. Our findings reveal that the InGaN/GaN-MQW2 sensor at 150 °C exhibits a response 4.0, 3.1, and 1.65 times greater than GaN-NWs, InGaN/GaN-MQW1, and InGaN/GaN-MQW3 sensors, respectively. The limit of detection (LOD) for the InGaN/GaN-MQW2 sensor is 3 parts per billion (ppb), significantly lower than the NO2 threshold value of 53 ppb. Under ultraviolet (UV) light, the response of InGaN/GaN-MQW2 is 5.51-fold, 4.18-fold, and 1.82-fold higher than that of the GaN-NWs, InGaN/GaN-MQW1, and InGaN/GaN-MQW2 sensors, respectively. Importantly, our hybrid nanocomposite-based electronic nose (e-nose) sensor arrays could distinguish between healthy and simulated unhealthy breaths with high accuracy, promising a new era of efficient, non-invasive disease detection through breath analysis.