Abstract Introduction Lower respiratory tract infections(LRTIs) in adults are complicated by diverse pathogens that challenge traditional detection methods, which are often slow and insensitive. ...Metagenomic next-generation sequencing (mNGS) offers a comprehensive, high-throughput, and unbiased approach to pathogen identification. This retrospective study evaluates the diagnostic efficacy of mNGS compared to conventional microbiological testing (CMT) in LRTIs, aiming to enhance detection accuracy and enable early clinical prediction. Methods In our retrospective single-center analysis, 451 patients with suspected LRTIs underwent mNGS testing from July 2020 to July 2023. We assessed the pathogen spectrum and compared the diagnostic efficacy of mNGS to CMT, with clinical comprehensive diagnosis serving as the reference standard. The study analyzed mNGS performance in lung tissue biopsies and bronchoalveolar lavage fluid (BALF) from cases suspected of lung infection. Patients were stratified into two groups based on clinical outcomes (improvement or mortality), and we compared clinical data and conventional laboratory indices between groups. A predictive model and nomogram for the prognosis of LRTIs were constructed using univariate followed by multivariate logistic regression, with model predictive accuracy evaluated by the area under the ROC curve (AUC). Results (1) Comparative Analysis of mNGS versus CMT : In a comprehensive analysis of 510 specimens, where 59 cases were concurrently collected from lung tissue biopsies and BALF, the study highlights the diagnostic superiority of mNGS over CMT. Specifically, mNGS demonstrated significantly higher sensitivity and specificity in BALF samples (82.86% vs. 44.42% and 52.00% vs. 21.05%, respectively, p < 0.001) alongside greater positive and negative predictive values (96.71% vs. 79.55% and 15.12% vs. 5.19%, respectively, p < 0.01). Additionally, when comparing simultaneous testing of lung tissue biopsies and BALF, mNGS showed enhanced sensitivity in BALF (84.21% vs. 57.41%), whereas lung tissues offered higher specificity (80.00% vs. 50.00%). (2) Analysis of Infectious Species in Patients from This Study : The study also notes a concerning incidence of lung abscesses and identifies Epstein-Barr virus (EBV), Fusobacterium nucleatum , Mycoplasma pneumoniae , Chlamydia psittaci , and Haemophilus influenzae as the most common pathogens, with Klebsiella pneumoniae emerging as the predominant bacterial culprit. Among herpes viruses, EBV and herpes virus 7 (HHV-7) were most frequently detected, with HHV-7 more prevalent in immunocompromised individuals. (3) Risk Factors for Adverse Prognosis and a Mortality Risk Prediction Model in Patients with LRTIs : We identified key risk factors for poor prognosis in lower respiratory tract infection patients, with significant findings including delayed time to mNGS testing, low lymphocyte percentage, presence of chronic lung disease, multiple comorbidities, false-negative CMT results, and positive herpesvirus affecting patient outcomes. We also developed a nomogram model with good consistency and high accuracy (AUC of 0.825) for predicting mortality risk in these patients, offering a valuable clinical tool for assessing prognosis. Conclusion The study underscores mNGS as a superior tool for lower respiratory tract infection diagnosis, exhibiting higher sensitivity and specificity than traditional methods.
Due to the high energy density, mature production technology, ease of storage and transportation, and the no carbon/sulfur nature of ammonia fuel, direct-ammonia solid oxide fuel cells (DA-SOFCs) ...have received rapidly increasing attention, showing distinct advantages over H2-fueled SOFCs and low-temperature fuel cells. However, DA-SOFCs with conventional Ni-based cermet anodes still suffer from several drawbacks, including serious sintering and inferior activity for ammonia decomposition, strongly limiting the large-scale applications. To tackle the above-mentioned issues, exsolved NiCo nanoparticles decorated double perovskite oxides are fabricated and employed as high-performance anodes for DA-SOFCs in this work. By optimizing the Ni doping amount in Sr2CoMo1−xNixO6−δ (x = 0.1, 0.2 and 0.3), the reduced Sr2CoMo0.8Ni0.2O6−δ (r-SCMN2) anode exhibits superb catalytic activity for ammonia cracking reaction and high anti-sintering capability. More specifically, the electrolyte-supported single cell with r-SCMN2 nanocomposite anode delivers superior power outputs and operational durability in ammonia fuel as compared with other r-SCMN anodes owing to the significantly promoted nanoparticle exsolution and stronger interaction between alloy nanoparticles and the support. In summary, this study presents an effective strategy for the design of efficient and stable nanocomposite anodes for DA-SOFCs.
Solid oxide fuel cells (SOFCs) offer a significant advantage over other fuel cells in terms of flexibility in the choice of fuel. Ammonia stands out as an excellent fuel choice for SOFCs due to its ...easy transportation and storage, carbon-free nature and mature synthesis technology. For direct-ammonia SOFCs (DA-SOFCs), the development of anode catalysts that have efficient catalytic activity for both NH3 decomposition and H2 oxidation reactions is of great significance. Herein, we develop a Mo-doped La0.6Sr0.4Fe0.8Ni0.2O3−δ (La0.6Sr0.4Fe0.7Ni0.2Mo0.1O3−δ, LSFNM) material, and explore its potential as a symmetrical electrode for DA-SOFCs. After reduction, the main cubic perovskite phase of LSFNM remained unchanged, but some FeNi3 alloy nanoparticles and a small amount of SrLaFeO4 oxide phase were generated. Such reduced LSFNM exhibits excellent catalytic activity for ammonia decomposition due to the presence of FeNi3 alloy nanoparticles, ensuring that it can be used as an anode for DA-SOFCs. In addition, LSFNM shows high oxygen reduction reactivity, indicating that it can also be a cathode for DA-SOFCs. Consequently, a direct-ammonia symmetrical SOFC (DA-SSOFC) with the LSFNM-infiltrated doped ceria (LSFNM-SDCi) electrode delivers a superior peak power density (PPD) of 487 mW cm−2 at 800 °C when NH3 fuel is utilised. More importantly, because Mo doping greatly enhances the reduction stability of the material, the DA-SSOFC with the LSFN-MSDCi electrode exhibits strong operational stability without significant degradation for over 400 h at 700 °C.
Compared with conventional oxygen-ion-conducting solid oxide fuel cells (O–SOFCs), proton ceramic fuel cells (PCFCs) are more attractive for low-temperature operation due to their smaller activation ...energy and higher ionic conductivity at reduced temperatures. However, most of the PCFCs still exhibit lower power outputs than O–SOFCs until now due to the lack of suitable and high-performance cathode materials. Cobalt (Co)-based perovskite oxides have been widely employed as cathodes for PCFCs, and suffer from poor thermo-mechanical compatibility with the electrolyte and inferior structural stability. Herein, Co-free triple-conducting perovskite-based nanocomposites are reported as highly active and stable cathodes for PCFCs. By tailoring the Ce/Y co-doping amounts in BaFeO3−δ, Ba(Ce0.8Y0.2)xFe1−xO3−δ (x = 0.1, 0.2 and 0.3) perovskites experience a phase transformation from a single-phase (x = 0.1, O2−/e− conducting) into a composite (x = 0.2 and 0.3, O2−/e− and H+/e− conducting) to achieve triple-conducting capability. The optimized BaCe0.16Y0.04Fe0.8O3−δ nanocomposite cathode displays superior activity for the oxygen reduction reaction (ORR) with low area-specific resistances of 0.27 and 1.49 Ω cm2 at 600 and 500 °C, respectively, surpassing most of the reported Co-free PCFC cathodes. The BaCe0.16Y0.04Fe0.8O3−δ cathode also exhibits superior thermo-mechanical compatibility with BaZr0.1Ce0.7Y0.1Yb0.1O3−δ electrolyte and improved CO2 tolerance due to the strong interaction between O2−/e− and H+/e− conducting phases and the optimized dual-phase composition. Consequently, an anode-supported single cell with the BaCe0.16Y0.04Fe0.8O3−δ cathode delivers a high peak power density of 829 mW cm−2 at 650 °C and a durable operation for ∼450 h at 550 °C. This work provides a highly promising Co-free cathode for PCFCs, which may accelerate the commercialization of this technology.
Nowadays, the excessive thermal expansion behavior of Co-based electrode always leads to the cell degradation or delamination. Especially for BaCoO3-δ-type perovskite oxides, as the result of the ...large ionic radius of Ba2+ (1.61 Å), the phase structures of these materials are not stable. Herein, we developed a novel single-phase electrode Ba2Sc0.1Nb0.1Co1.5Fe0.3O6-δ (BSNCF) with a stable cubic perovskite structure and suitable thermal expansion coefficient (TEC, 11.9 × 10−6 K−1), which showed a great stability in symmetrical cell area specific resistances (ASRs) subjecting to the harsh thermal cycling procedure with 30 cycles between 300 °C and 600 °C (increased from 0.197 Ω cm2 to 0.222 Ω cm2,13% increase). The high-temperature hard X-ray absorption spectroscopy measurement directly monitored a small change of Co valence in BSNCF as the temperatures rising. Also, BSNCF exhibits well proton uptake for its appropriate oxygen-site basicity and excellent surface reaction activity. The single cell based on BSNCF achieved an outstanding peak power density of 977 mW cm−2 at 600 °C.
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•Ba2Sc0.1Nb0.1Co1.5Fe0.3O6-δ (BSNCF) achieves lower thermal expansion coefficient.•Ba substitution can improve the proton uptake ability.•BSNCF exhibits a prominent thermo-mechanical stability in test.•BSNCF shows a peak power density of 977 mW cm−2 at 600 °C.
Hydrogen (H2) is regarded as an important energy carrier to achieve a clean and sustainable future. In particular, protonic ceramic cells (PCCs) as promising energy conversion technologies have ...received rapidly increasing attention for the production and use of H2, showing higher energy efficiencies at reduced temperatures than oxygen-ion-conducting counterparts. Nevertheless, the sluggish kinetics of air electrodes for oxygen reduction/evolution reactions has become one of the main obstacles to achieving high-efficiency PCCs. Therefore, the key point to realizing the commercialization of PCCs is the development of high-performance air electrodes. Particularly, perovskite-based nanocomposites received increasing interests as high-efficiency air electrodes for PCCs recently due to the synergistic effect and strong interaction between various phases with different functionalities at nanoscale. Herein, the advances of this area in 2020–2022 are mainly reviewed by highlighting the superiorities, design strategies, and remaining challenges of perovskite-based nanocomposites as air electrodes for PCCs at reduced temperatures.
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•The superiorities of nanocomposites over micro-sized counterparts for PCCs are analyzed.•Promising strategies to construct high-performance nanocomposite air electrodes are proposed.•The remaining challenges of this research area are also provided.
Compared with conventional oxygen-ion-conducting solid oxide fuel cells (O–SOFCs), proton ceramic fuel cells (PCFCs) are more attractive for low-temperature operation due to their smaller activation ...energy and higher ionic conductivity at reduced temperatures. However, most of the PCFCs still exhibit lower power outputs than O–SOFCs until now due to the lack of suitable and high-performance cathode materials. Cobalt (Co)-based perovskite oxides have been widely employed as cathodes for PCFCs, and suffer from poor thermo-mechanical compatibility with the electrolyte and inferior structural stability. Herein, Co-free triple-conducting perovskite-based nanocomposites are reported as highly active and stable cathodes for PCFCs. By tailoring the Ce/Y co-doping amounts in BaFeO 3− δ , Ba(Ce 0.8 Y 0.2 ) x Fe 1− x O 3− δ ( x = 0.1, 0.2 and 0.3) perovskites experience a phase transformation from a single-phase ( x = 0.1, O 2− /e − conducting) into a composite ( x = 0.2 and 0.3, O 2− /e − and H + /e − conducting) to achieve triple-conducting capability. The optimized BaCe 0.16 Y 0.04 Fe 0.8 O 3− δ nanocomposite cathode displays superior activity for the oxygen reduction reaction (ORR) with low area-specific resistances of 0.27 and 1.49 Ω cm 2 at 600 and 500 °C, respectively, surpassing most of the reported Co-free PCFC cathodes. The BaCe 0.16 Y 0.04 Fe 0.8 O 3− δ cathode also exhibits superior thermo-mechanical compatibility with BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3− δ electrolyte and improved CO 2 tolerance due to the strong interaction between O 2− /e − and H + /e − conducting phases and the optimized dual-phase composition. Consequently, an anode-supported single cell with the BaCe 0.16 Y 0.04 Fe 0.8 O 3− δ cathode delivers a high peak power density of 829 mW cm −2 at 650 °C and a durable operation for ∼450 h at 550 °C. This work provides a highly promising Co-free cathode for PCFCs, which may accelerate the commercialization of this technology.
Compared with conventional oxygen-ion-conducting solid oxide fuel cells (O-SOFCs), proton ceramic fuel cells (PCFCs) are more attractive for low-temperature operation due to their smaller activation ...energy and higher ionic conductivity at reduced temperatures. However, most of the PCFCs still exhibit lower power outputs than O-SOFCs until now due to the lack of suitable and high-performance cathode materials. Cobalt (Co)-based perovskite oxides have been widely employed as cathodes for PCFCs, and suffer from poor thermo-mechanical compatibility with the electrolyte and inferior structural stability. Herein, Co-free triple-conducting perovskite-based nanocomposites are reported as highly active and stable cathodes for PCFCs. By tailoring the Ce/Y co-doping amounts in BaFeO
3−
δ
, Ba(Ce
0.8
Y
0.2
)
x
Fe
1−
x
O
3−
δ
(
x
= 0.1, 0.2 and 0.3) perovskites experience a phase transformation from a single-phase (
x
= 0.1, O
2−
/e
−
conducting) into a composite (
x
= 0.2 and 0.3, O
2−
/e
−
and H
+
/e
−
conducting) to achieve triple-conducting capability. The optimized BaCe
0.16
Y
0.04
Fe
0.8
O
3−
δ
nanocomposite cathode displays superior activity for the oxygen reduction reaction (ORR) with low area-specific resistances of 0.27 and 1.49 Ω cm
2
at 600 and 500 °C, respectively, surpassing most of the reported Co-free PCFC cathodes. The BaCe
0.16
Y
0.04
Fe
0.8
O
3−
δ
cathode also exhibits superior thermo-mechanical compatibility with BaZr
0.1
Ce
0.7
Y
0.1
Yb
0.1
O
3−
δ
electrolyte and improved CO
2
tolerance due to the strong interaction between O
2−
/e
−
and H
+
/e
−
conducting phases and the optimized dual-phase composition. Consequently, an anode-supported single cell with the BaCe
0.16
Y
0.04
Fe
0.8
O
3−
δ
cathode delivers a high peak power density of 829 mW cm
−2
at 650 °C and a durable operation for ∼450 h at 550 °C. This work provides a highly promising Co-free cathode for PCFCs, which may accelerate the commercialization of this technology.
BaCe
0.16
Y
0.04
Fe
0.8
O
3−
δ
nanocomposite cathode exhibits excellent activity and stability for ORR in PCFCs due to the strong interaction between phase components, optimized dual-phase composition and well-balanced proton and oxygen ion conductivity.
Solid oxide fuel cells (SOFCs) offer a significant advantage over other fuel cells in terms of flexibility in the choice of fuel. Ammonia stands out as an excellent fuel choice for SOFCs due to its ...easy transportation and storage, carbon-free nature and mature synthesis technology. For direct-ammonia SOFCs (DA-SOFCs), the development of anode catalysts that have efficient catalytic activity for both NH
decomposition and H
oxidation reactions is of great significance. Herein, we develop a Mo-doped La
Sr
Fe
Ni
O
(La
Sr
Fe
Ni
Mo
O
, LSFNM) material, and explore its potential as a symmetrical electrode for DA-SOFCs. After reduction, the main cubic perovskite phase of LSFNM remained unchanged, but some FeNi
alloy nanoparticles and a small amount of SrLaFeO
oxide phase were generated. Such reduced LSFNM exhibits excellent catalytic activity for ammonia decomposition due to the presence of FeNi
alloy nanoparticles, ensuring that it can be used as an anode for DA-SOFCs. In addition, LSFNM shows high oxygen reduction reactivity, indicating that it can also be a cathode for DA-SOFCs. Consequently, a direct-ammonia symmetrical SOFC (DA-SSOFC) with the LSFNM-infiltrated doped ceria (LSFNM-SDCi) electrode delivers a superior peak power density (PPD) of 487 mW cm
at 800 °C when NH
fuel is utilised. More importantly, because Mo doping greatly enhances the reduction stability of the material, the DA-SSOFC with the LSFN-MSDCi electrode exhibits strong operational stability without significant degradation for over 400 h at 700 °C.
Solid oxide fuel cells (SOFCs) offer a significant advantage over other fuel cells in terms of flexibility in the choice of fuel. Ammonia stands out as an excellent fuel choice for SOFCs due to its ...easy transportation and storage, carbon-free nature and mature synthesis technology. For direct-ammonia SOFCs (DA-SOFCs), the development of anode catalysts that have efficient catalytic activity for both NHsub.3 decomposition and Hsub.2 oxidation reactions is of great significance. Herein, we develop a Mo-doped Lasub.0.6 Srsub.0.4 Fesub.0.8 Nisub.0.2 Osub.3−δ (Lasub.0.6 Srsub.0.4 Fesub.0.7 Nisub.0.2 Mosub.0.1 Osub.3−δ , LSFNM) material, and explore its potential as a symmetrical electrode for DA-SOFCs. After reduction, the main cubic perovskite phase of LSFNM remained unchanged, but some FeNisub.3 alloy nanoparticles and a small amount of SrLaFeOsub.4 oxide phase were generated. Such reduced LSFNM exhibits excellent catalytic activity for ammonia decomposition due to the presence of FeNisub.3 alloy nanoparticles, ensuring that it can be used as an anode for DA-SOFCs. In addition, LSFNM shows high oxygen reduction reactivity, indicating that it can also be a cathode for DA-SOFCs. Consequently, a direct-ammonia symmetrical SOFC (DA-SSOFC) with the LSFNM-infiltrated doped ceria (LSFNM-SDCi) electrode delivers a superior peak power density (PPD) of 487 mW cmsup.−2 at 800 °C when NHsub.3 fuel is utilised. More importantly, because Mo doping greatly enhances the reduction stability of the material, the DA-SSOFC with the LSFN-MSDCi electrode exhibits strong operational stability without significant degradation for over 400 h at 700 °C.
