Carbon Monoxide Generation Research Articles

Atomically Dispersed Ni-N-C Catalysts for Electrochemical CO2 Reduction.

The atomic dispersion of nickel in Ni-N-C catalysts is key for the selective generation of carbon monoxide through the electrochemical carbon dioxide reduction reaction (CO2RR). Herein, the study reports a highly selective, atomically dispersed Ni1.0%-N-C catalyst with reduced Ni loading compared to previous reports. Extensive materials characterization fails to detect Ni crystalline phases, reveals the highest concentration of atomically dispersed Ni metal, and confirms the presence of the proposed Ni-Nx active site at this reduced loading. The catalyst shows excellent activity and selectivity toward CO generation, with a faradaic efficiency for CO generation (FECO) of 97% and partial current density for CO (jco) of -9.0 mA cm-2 at -0.9 V in an electrochemical H-type cell. CO2RR activity and selectivity are also studied by rotating disk electrode (RDE) measurements where transport limitations can be suppressed. It is expected that the utility of these Ni-N-C catalysts will lie with tandem CO2RR reaction schemes to multi-carbon (C2+) products.

CORMs Mediated Pd‐Catalyzed Carbonylative Coupling Reaction: Ketone Synthesis and CO‐releasing Mechanism

Palladium‐catalyzed carbonylative C‐C coupling reactions provide an efficient route to synthesize natural products and pharmaceuticals through three‐component condensation processes. However, the use of gaseous carbon monoxide (CO) ‐ a colorless, odorless, and toxic gas ‐ has hindered its broad adoption as a C1 source. Addressing this, the development of versatile CO‐releasing molecules (CORMs) and user‐friendly, nongaseous palladium‐catalyzed carbonylation techniques has emerged as a crucial research area. This review outlines recent advancements in the application of CORMs to palladium‐catalyzed carbonylative C‐C coupling reactions, with a focus on CO generation mechanisms and carbonyl utilization efficiency. CORMs are classified into three categories: single carbon monoxide releasing molecules (s‐CORMs), multiple carbon monoxide releasing molecules (m‐CORMs), and binary metal carbonyl compounds (BMCCs). By offering a comprehensive overview of the current research landscape and providing practical guidelines for CORM selection, this review aims to assist researchers in developing effective carbonylation strategies.

A Multifunctional Ru-Re Complex for Photodynamic Therapy and CO-Mediated Therapeutics in Alzheimer's Disease.

The development of multifunctional therapeutic agents is crucial for addressing complex diseases such as Alzheimer's disease. Herein, we report a ruthenium-rhenium (Ru-Re) complex that combines photodynamic therapy (PDT) and carbon monoxide (CO) generation capabilities. The Ru-Re complex shows promising photophysical property and significant therapeutic potential. Our studies reveal the complex's ability to generate singlet oxygen (1O2), CO, inhibit tau aggregation, and enhance mitochondrial respiration. These multifunctional properties position the Ru-Re complex as a versatile tool for therapeutic applications in Alzheimer's disease.

Shape-Selective Zeolites for Tandem CO2 Hydrogenation-Carbonylation Reactions.

The valorization of carbon dioxide as a C1 building block in C-C bond forming reactions is a critical link on the road to carbon-circular chemistry. Activation of this inert molecule through reduction with H2 to carbon monoxide in the reverse water-gas shift (RWGS) reaction can be followed by a wide spectrum of consecutive carbonylation reactions, but the RWGS is severely equilibrium limited at the moderate temperatures of carbonylations. Here we successfully reconcile both reactions in one pot, while avoiding incompatibilities through a zeolite-based compartmentalized approach. More specifically, Pt encapsulated in a small-pore LTA zeolite selectively generates carbon monoxide in mild reaction conditions; an ensuing one-pot carbonylation reaction allows to shift the equilibrium through continuous consumption of CO. Moreover, the zeolite encapsulation avoids undesired reactions like hydrogenation of the olefin reactant through a molecular sieving effect. This strategy was first studied in-depth for Rh-catalyzed olefin hydroformylation with CO2/H2, affording aldehydes in good yields with high regioselectivities. The methodology was then extended to a variety of carbonylations using CO2 for the synthesis of bulk and fine chemicals.

Improvement of fame retardancy and thermal stability of epoxy composites by modifying salen-based polyphosphazene microspheres with Co-based metal organic frameworks

A functionalized cross-linked polyphosphazenes microsphere (Salen-PZN-Ni@Co-MOF) was fabricated by enveloping Salen-Ni-based polyphosphazenes (Salen-PZN-Ni) with a type of hybrid flame retardant (Co-MOF) to enhance the flame retardant, smoke suppression properties and mechanical properties of epoxy (EP) composites. Thermogravimetric analysis indicated that the incorporation of Salen-PZN-Ni@Co-MOF significantly enhanced the thermal stability of the EP composites. The existence of Salen-PZN-Ni@Co-MOF enhanced both the vertical burning rating and resulted in a higher limiting oxygen index. The addition of 5 wt% Salen-PZN-Ni@Co-MOF conspicuously improved the fire safety of EP, as evidenced by the results of the cone calorimeter. For instance, the peak heat release rate and total heat release rate of the EP composites were decreased by 25.3% and 44.97%, respectively. In addition, the incorporation of Salen-PZN-Ni@Co-MOF significantly inhibited the generation of toxic carbon monoxide and other volatile compounds. Furthermore, a synergistic effect between Salen-PZN-Ni and Co-MOF was observed. The proposed flame retardant mechanism of Salen-PZN-Ni@Co-MOF is attributed to the synergistic catalytic carbonization effect and the formation of thermally stable components. Consequently, enhanced fire safety in EP composites is achieved through the synergistic interaction among various components (nickel and Co-MOF) with polyphosphazene microspheres. Meanwhile, the excellent compatibility between Salen-PZN-Ni@Co-MOF and EP enhances the mechanical properties of EP composites.

Gold Deposited Gas Diffusion Electrodes by RF Sputtering and Their CO2 Reduction Activity to CO

The electrochemical CO2 reduction reaction (CO2RR) is attracting attention as a promising method to convert CO2 into value-added products such as CO, which is used as a feedstock in the Fischer-Tropsch process. Previous research demonstrated that precious metal catalysts, such as Ag or Au, proceed CO2 reduction to CO generation with high efficiency[1]. Despite their high Faradaic efficiency (current efficiency) and current density in using porous gas diffusion electrode (GDE) systems, a higher utilization efficiency of those catalysts is needed due to their high cost of those catalysts. Based on the above background, in the present study, we employed the sputtering process as a direct formation method of catalysts’ nanoparticles on the catalyst layer on GDEs. We used gold as a model catalyst, fabricated Au-supported GDEs (Au-GDEs), and evaluated their CO2RR activity. Au-GDEs were fabricated using an RF sputtering process, and Au nanoparticles were directly deposited onto commercially available GDEs. The thicknesses of the catalysts’ layer were controlled by adjusting the sputtering time. The Au-modified GDEs with the conventional spray-coating method were also prepared using Au nanoparticles synthesized by a conventional solution process using citric acid as the reduction agent(Au_Spray) [2] for comparison. The CO2RR activity was evaluated by galvanostatic measurements using 1 M KHCO3 as electrolytes. Fig. 1(a) shows a cross-section scanning electron microscopy (SEM) image of an Au-GDE with a typical catalyst layer thickness of 100 nm (Au_100). The catalyst layer composed of Au (the white part of the figure) was uniformly formed on the surface of GDE. The X-ray absorption structure (XAS) analyses revealed that the valence state of Au was Au(0), and that the catalyst layer on the GDEs was composed of Au nanoparticles. Next, the CO2RR activity of the Au-GDE was evaluated. Carbon monoxide (CO) was detected as the main CO2RR product, and formate (HCOO−) and hydrogen (H2) as a side reaction product were also detected. The effect of film thickness of Au-GDE on CO2RR selectivity was evaluated at a current density of 50 mA cm-2. Au-GDE with a film thickness of 10 nm (Au_10) and Au_100 produced CO with the Faradaic efficiencies (FEs) of 72.7 % and 79.8 %, respectively. The FEs of hydrogen evolution reaction (HER) of Au_10 and Au_100 were 26.1% and 10.3%, respectively. The CO efficiencies for Au_10 and Au_100 were significantly higher than those of Au_Spray, which had a similar Au loading to that of Au_100. The higher CO selectivity of the Au-GDEs prepared by sputtering might be attributed to the higher coverage of Au on GDEs, which was confirmed by SEM-EDX mapping.The potential dependence of partial current density for CO (j CO) normalized by Au mass loading was evaluated as an indicator of Au utilization efficiency for CO2RR (Fig. 1(b)). The electrode with a catalyst layer thickness of 10 nm showed the 1882 A g-1 (potential of -0.85 V vs. RHE). As far as we know, this is the highest value among the Au-based electrodes using GDEs [3]. The value is about one order of magnitude higher than that of Au_Spray. This high CO production activity can be attributed to the formation of a thin Au catalyst layer composed of Au nanoparticles on the electrode surface by sputtering. [4] The results of the electrode structure analysis and details of the CO2RR activity will be discussed in the presentation.[1]A. Fen wick et. al., ACS Energy Lett., 2022, 7, 871−879 [2] X. Ji et. al., J. Am. Chem. Soc., 2007, 129, 13939–13948 [3] M. Sassenburg et. al., ACS Appl. Energy Mater., 2022, 5, 5983–5994. [4] T. Yamada et. al., in preparation. Figure 1

Shape‐Selective Zeolites for Tandem CO2 Hydrogenation‐Carbonylation Reactions

The valorization of carbon dioxide as a C1 building block in C‐C bond forming reactions is a critical link on the road to carbon‐circular chemistry. Activation of this inert molecule through reduction with H2 to carbon monoxide in the reverse water‐gas shift (RWGS) reaction can be followed by a wide spectrum of consecutive carbonylation reactions, but the RWGS is severely equilibrium limited at the moderate temperatures of carbonylations. Here we successfully reconcile both reactions in one pot, while avoiding incompatibilities through a zeolite‐based compartmentalized approach. More specifically, Pt encapsulated in a small‐pore LTA zeolite selectively generates carbon monoxide in mild reaction conditions; an ensuing one‐pot carbonylation reaction allows to shift the equilibrium through continuous consumption of CO. Moreover, the zeolite encapsulation avoids undesired reactions like hydrogenation of the olefin reactant through a molecular sieving effect. This strategy was first studied in‐depth for Rh‐catalyzed olefin hydroformylation with CO2/H2, affording aldehydes in good yields with high regioselectivities. The methodology was then extended to a variety of carbonylations using CO2 for the synthesis of bulk and fine chemicals.

Conditional over-expression of heme-oxygenase 1 in myelomonocytic cells reduces AngII-induced hypertension and vascular inflammation in mice

Abstract Background Systemic arterial Hypertension is one of the most important risk factor responsible for morbidity and mortality world-wide. Angiotensin II (Ang II), a potent vasoconstrictor and key player in the renin-angiotensin-aldosterone system (RAAS) is responsible for vascular dysfunction, inflammation, and tissue damage. Heme oxygenase-1 (HO-1) overexpression may confer antioxidant and anti-inflammatory properties in Ang II-induced hypertension through its action on heme catabolism, generating carbon monoxide (CO), ferritin and biliverdin/bilirubin by the action of biliverdin reductase A (BLVRA). Methods and results Male 9–12-weeks-old HO-1indxLySMCre/wt and LySMCre/wt mice were infused with AngII (1mgAngII/Day/Kg) for 7 days to induce hypertension and compared to sham treatment. Blood pressure monitoring by tail-cuff method, and endothelium-dependent vasodilator studies via organ chamber system using acetylcholine (ACh) in isolated aortic segments (~4 mm), revealed that overexpression of HO-1 in myeloid cells resulted in decreased systolic blood pressure and improved endothelial function in AngII-infused HO-1indxLySMCre/wt mice compared to controls. Concurrently, increased BLVRA expression in liver tissue and elevated plasma bilirubin levels were detected by transcriptome analysis and high-performance liquid chromatography, respectively. These results were supported by a reduction in the expression of inducible cytokines and cell adhesion molecules (CAMs) in the aorta, assessed using qPCR. Bone marrow transplant experiments demonstrated that bone marrow from LysMcre mice in HO-1indxLySMCre/wt mice abrogated the protective effect of HO-1, resulting in endothelial damage and increased blood pressure, potentially due to decreased liver BLVRA expression and the accumulation of bone marrow-derived cells in the vessel wall in response to AngII. Additionally, adeno-associated viral vector (AAV) transfection targeting specifically BLVRA activity in liver lead to an increase in blood pressure values and worse endothelium relaxation, in parallel with higher oxidative stress and the blood neutrophils concentration, as assessed in whole blood by using oxidative burst method and blood count system respectively. Conclusion The overexpression of HO-1 in myeloid cells confers anti-inflammatory protection in AngII-induced arterial hypertension in mice. Myeloid cells bone marrow-derived overexpressing HO-1 regulate the differentiation and infiltration of pro-inflammatory immune cells in the vasculature. BLVRA expression and bilirubin levels downstream of HO-1 play a critical role in protecting against vascular damage by reducing leukocyte infiltration.

Experimental and Theoretical Study on Surface Reactivity and CO Generation Mechanism of Bituminous Coal during Room-Temperature Oxidation.

To investigate the evolution of the microscopic chemical structure during the oxidation of bituminous coal at room temperature (25 °C) and infer the formation mechanism of carbon monoxide (CO), a self-designed closed-system coal oxidation experimental setup was employed to measure the CO generation from three bituminous coal samples [Duanwang (DW), Linsheng (LS), and Kunning (KN)]. 13C nuclear magnetic resonance and X-ray photoelectron spectroscopy were used to determine the structures and contents of different carbon atoms and surface elemental compositions and chemical states of the coal samples. Molecular models were constructed on the basis of the experimental data, and reactive force field pyrolysis simulation was used to trace the carbon atoms in the generated CO molecules. In combination with the results of interactive Mantel correlation analysis on the Fourier transform infrared experimental data of coal samples oxidized at room temperature for 0, 12, 24, 36, 48, and 60 h, the main functional groups, structures, and evolution of coal involved in CO formation during normal temperature oxidation were determined. The constructed molecular formulas for the coal samples were C154H122O28N2S for DW, C145H114O16N2S2 for LS, and C155H92O16N2S for KN. The formation of CO was related to the transformation of carbonyl (C═O), phenolic hydroxyl (-OH), ether (C-O-C), aromatic, and aliphatic structures in the coal.

Mechanism of Carbon Monoxide (CO) Generation and Potential Human Health Hazard during Mechanized Tunnel Driving in Organic-Rich Rocks: Field and Laboratory Study

The monitoring of carbon emissions is increasingly becoming a sustainability issue worldwide. Despite being largely unnoticed, the toxic gas carbon monoxide (CO) is ubiquitous in mechanized tunnel driving, but the individual sources, release and enrichment mechanisms are often unknown. In this study, the generation of CO from organic matter containing sedimentary rocks was investigated during mechanized tunnel driving and by reacting claystone and sandstone with 10 mM NaCl solutions for 2 months at 70 °C and 140 °C. The mineralogical and geochemical evolution of the solids and fluids was assessed by CO measurements and the XRD, DTA, TOC, IC and ICP-OES methods. The CO concentration in the atmosphere reached up to 1920 ppm (100 ppm on average) during tunnel driving, which is more than three times higher than the legal daily average dose for tunnellers, thus requiring occupational safety operations. Mineral-specific dissolution processes and the rapid decomposition of labile organic matter upon thermal alteration contributed to the liberation of CO and also carbon dioxide (CO2) from the host rocks. In mechanized tunnel driving, frictional heat and ‘cold’ combustion with temperatures reaching 50–70 °C at the drill head is an important mechanism for increased CO and CO2 generation, especially during drilling in sedimentary rocks containing significant amounts of OM and when the ventilation of the tunnel atmosphere and air mixing are limited. Under such conditions, human health damage due to CO exposure (HHDCO) can be 30 times higher compared to tunnel outlets, where CO is emitted from traffic.

Regulated Photocatalytic CO2-to-CH3OH Pathway by Synergetic Dual Active Sites of Interlayer.

Herein, composites of nanosheets with van der Waals contacts are employed to disclose how the interlayer-microenvironment affects the product selectivity of carbon dioxide (CO2) photoreduction. The concept of composites of nanosheets with dual active sites is introduced to manipulate the bonding configuration and promote the thermodynamic formation of methanol (CH3OH). As a prototype, the CoNi2S4-In2O3 composites of nanosheets are prepared, in which high-resolution transmission electron microscopy imaging, X-ray photoelectron spectroscopy spectra, and zeta potential tests confirm the presence of van der Waals contacts rather than chemical bonding between the In2O3 nanosheets and the CoNi2S4 nanosheets within the composite. The fabricated CoNi2S4-In2O3 composites of nanosheets exhibit the detection of the key intermediate *CH3O during CO2 photoreduction through in situ Fourier transform infrared spectra, while the In2O3 nanosheets and CoNi2S4 nanosheets alone do not show this capability, further verified by the density functional theory calculations. Accordingly, the CoNi2S4-In2O3 composites of nanosheets show the ability to produce CH3OH, whereas the CoNi2S4 and In2O3 nanosheets solely generate carbon monoxide products from CO2 photoreduction.

“Three birds, one stone” strategy of NIR-responsive CO/H2S dual-gas Nanogenerator for efficient treatment of osteoporosis

Osteoporosis (OP), the most prevalent bone degenerative disease, has become a significant public health challenge globally. Current therapies primarily target inhibiting osteoclast activity or stimulating osteoblast activation, but their effectiveness remains suboptimal. This paper introduced a “three birds, one stone” therapeutic approach for osteoporosis, employing upconversion nanoparticles (UCNPs) to create a dual-gas storage nanoplatform (UZPA-CP) targeting bone tissues, capable of concurrently generating carbon monoxide (CO) and hydrogen sulfide (H2S). Through the precise modulation of 808 nm near-infrared (NIR) light, the platform could effectively control the release of CO and H2S in the OP microenvironment, and realize the effective combination of promoting osteogenesis, inhibiting osteoclast activity, and improving the immune microenvironment to achieve the therapeutic effect of OP. High-throughput sequencing results further confirmed the remarkable effectiveness of the nanoplatform in inhibiting apoptosis, modulating inflammatory response, inhibiting osteoclast differentiation and regulating multiple immune signaling pathways. The gas storage nanoplatform not only optimized the OP microenvironment with the assistance of NIR, but also restored the balance between osteoblasts and osteoclasts. This comprehensive therapeutic strategy focused on improving the bone microenvironment, promoting osteogenesis and inhibiting osteoclast activity provides an ideal new solution for the treatment of metabolic bone diseases.

Numerical Investigation of the Effect of Intake Closing Timing on Flow Field and Combustion Process in an Elliptical Rotary Engine

Abstract The aim of this research is to investigate the effect of intake closing timing (ICT) on the flow field and combustion process in elliptical rotary engines. The model that can accurately describe the working process of the elliptical rotary engine was established, five kinds of ICTs were designed, and the influence of ICT on the flow field and combustion process was studied. The results show that the advance of the ICT can increase the intake mass flowrate and reduce the back flowrate, the volumetric efficiency is 86.1% at a 145-deg crank angle (°CA) before top dead center (BTDC), which is 7.6% higher than 125 °CA BTDC. The advance of the ICT improves the consumption speed, makes the combustion reaction more intense, and shortens the combustion time. When the ICT is 145 °CA BTDC, the crank angle when the burned mass fraction is 90% (CA90) is 19.4 °CA earlier than 125 °CA BTDC, the peak mass of hydroxy in a cylinder is 41.6% higher, and the peak pressure in a cylinder is 25.9% higher. With the advance of the ICT, the pressure and heat release in the cylinder are significantly increased, the peak temperature in the cylinder is increased, the rate of carbon monoxide generation is accelerated, and the mass of nitrogen oxide emission is significantly increased. However, advancing the ICT cannot improve the indicated thermal efficiency of the elliptical rotary engine. This analysis provides a comprehensive understanding of the ICT of elliptical rotary engines.

Carbon monoxide-related fatalities: A fifteen-year single institution experience.

The winter climate in Delhi is severe, with temperatures dropping below 10°C. As a result, individuals often resort to utilizing diverse heat sources such as electrical heating appliances, coal and gas geysers. Unfortunately, these sources are commonly associated with the emission of carbon monoxide (CO) which can accumulate in inadequately ventilated spaces. Exposure to this noxious gas can lead to acute lethargy and debilitation, leaving individuals in a state of helpless distress. The present study utilized a retrospective descriptive analysis to examine cases of fatal carbon monoxide exposure retrieved from the Department of Forensic Medicine archives at the esteemed All India Institute of Medical Sciences, New Delhi. Autopsy records were thoroughly examined with respect to various parameters including age, gender, seasonality of the incident, circumstances surrounding the death, source of carbon monoxide generation, post mortem observations, as well as toxicological analysis reports. This study entailed an analysis of 56 individuals who fell victim to carbon monoxide poisoning, with a staggering 95% of fatalities occurring during the winter season. The majority of the individuals affected belonged to the age bracket of 21-30 years. The most common sources of carbon monoxide exposure were linked to the use of coal-burning earthen or iron vessels for room heating, as well as structural fires. With the exception of one case, all incidents were accidental in nature. Additionally, nearly all of the victims were discovered in enclosed spaces with heating equipment in close proximity, and evidence of a struggle was noted on the crime scene or with the deceased. The findings of this study indicate that the principal contributor to the inadvertent build-up of lethal concentrations of carbon monoxide gas is the utilization of heating appliances within inadequately ventilated, enclosed spaces. Due to the scentless and non-irritating properties of this gas, individuals who are asleep may be unable to detect its presence in their surroundings, thereby leading to a silent death. To mitigate such risks, the installation of carbon monoxide detectors is crucial. Additionally, it is of utmost importance to raise public awareness regarding the perils associated with using fire pots, coal burning and electrical heating appliances in areas with insufficient ventilation.

Interfacial delivery of carbon monoxide via smart titanium implant coating for enhanced soft tissue integration with switchable antibacterial and immunomodulatory properties

Soft tissue integration around titanium (Ti) implants is weaker than that around natural teeth, compromising long-term success of Ti implants. Carbon monoxide (CO) possesses distinctive therapeutic properties, rendering it as a highly promising candidate for enhancing STI. However, achieving controlled CO generation at the STI interface remains challenging. Herein, a controlled CO-releasing dual-function coating was constructed on Ti surfaces. Under near-infrared (NIR) irradiation, the designed surface could actively accelerate CO generation for antibiosis against both aerobic and anaerobic bacteria. More importantly, in the absence of NIR, the slow release of CO induces macrophage polarization from pro-inflammatory phenotype towards pro-regenerative phenotype. In a rat implantation model with induced infection, the designed surface effectively controlled the bacterial infection, alleviates accompanying inflammation and modulated immune microenvironment, leading to enhanced STI. Single-cell sequencing revealed that the coating alters the cytokine profile within the soft tissue, thereby influencing cellular functions. Differentially expressed genes in macrophages are highly enriched in the PIK3-Akt pathway. Furthermore, the cellular communication between fibroblasts and macrophages was significantly enhanced through the CXCL12/CXCL14/CXCR4 and CSF1-CSF1R ligand-receptor pair. These findings indicate that our coating showed an appealing prospect for enhancing STI around Ti implants, which would ultimately contribute to the improved long-term success of Ti implants.

Impact of Intermediate Species in Simulating Oblique Detonation with Pre-Vaporized N-Decane/air Mixtures Substituting for Kerosene/Air Mixtures

ABSTRACT A renewed two-step n-decane mechanism is presented to improve reliable and robust simulation results, substituting for kerosene. This mechanism demonstrates that effective control of ignition delay time and heat release, based on the Chapman – Jouguet condition, enables successful simulation of oblique detonation waves. Chain reactions influence the overall reaction heat and explosion temperature, especially in simplified mechanisms with few steps. Therefore, carbon monoxide (CO) generation is crucial for balancing the overall reaction heat and reducing species sensitivity to pressure, a factor previously not discussed in simplified models. The computational time for solving detailed chemical kinetics increases exponentially with species count, driving the pursuit for further reduction in kinetic mechanism size. The sensitive interaction between density and temperature during the fuel/air mixture explosion process affects initiation zone formation and cellular structure. Analyzing the distribution of CO can provide insights into structural details. The study considers applying the Rankine – Hugoniot curve to confirm detonation speeds, temperatures, and kinetic energy changes induced by chemical reactions.

Experimental study on flame morphology, ceiling temperature and carbon monoxide generation characteristic of prismatic lithium iron phosphate battery fires with different states of charge in a tunnel

Lithium-ion battery (LIB) fire in a tunnel can generate a high-temperature environment, massive toxic and harmful smoke in a short period. This work carried out a series of thermal runaway (TR) experiments on large prismatic lithium cells in a model tunnel. Results showed that the flame height of LIBs with above 50 % SOC was above 40 cm for much time of the stage (Ⅰ) and (Ⅱ). The average flame height is further proposed to quantify the flame profile at different phases. The greater the SOC was, the higher the ceiling temperature and peak CO concentration were also relatively. For example, while decreasing the distance to the fire source from 0 m to -0.7 m, the peak ceiling temperature of 25 Ah batteries with 100 % SOC decreases from 309 °C to 118 °C, with a decay rate of 62 %. The CO concentration showed a comparable variation pattern to the tunnel ceiling temperature. Finally, a dimensionless relationship was employed to describe the ceiling temperature decay. Meanwhile, the ceiling maximum temperature rise for different capacity battery fires in a tunnel was integrated into a relational correlation. The study results are expected to further understand the battery fire hazards in tunnel.

Characteristics of Carbon Monoxide and Ethylene Generation in Mine’s Closed Fire Zone and Their Influence on Methane Explosion Limits

Methane explosions often occur during the closure process of mine fire zones, during which the concentration of combustible gases such as monoxide and ethylene produced by coal combustion dynamically changes, which changes the risk of methane explosion. Therefore, studying the gas concentration distribution and methane explosion limits during the process of mine closure is of great significance for disaster prevention and control. In this paper, a three-dimensional physical model of gob was built, and the distribution of monoxide and ethylene in the process of fire zone closure was investigated. Further, the explosion limits of methane enriched with CO and C2H4 in the closed fire zone of gob were analyzed. The results indicate that CO and C2H4 would form a small-scale accumulation phenomenon near the fire zone after the closure of the fire zone, and when the fire zone is closed for more than 15 min, the mixed combustible gases in the environment lose their explosiveness.

Polyprodrug nanomedicine for chemiexcitation-triggered self-augmented cancer chemotherapy and gas therapy

Carbon monoxide (CO) has emerged as a potential antitumor agent by inducing the dysfunction of mitochondria and the apoptosis of cancer cells. However, it remains challenging to deliver appropriate amount of CO into tumor to ensure efficient tumor growth suppression with minimum side effects. Herein we developed a CO prodrug-loaded nanomedicine based on the self-assembly of camptothecin (CPT) polyprodrug amphiphiles. The polyprodrug nanoparticles readily dissociate upon exposure to endogenous H2O2 in the tumor, resulting in rapid release of CPT and generation of high-energy intermediate dioxetanedione. The latter can transfer the energy to neighboring CO prodrugs to activate CO production by chemiexcitation, while CPT promotes the generation of H2O2 in tumors, which in turn facilitates cascade CPT and CO release. As a result, the polyprodrug nanoparticles display remarkable tumor suppression in both subcutaneous and orthotopic breast tumor-bearing mice owing to the self-augmented CPT release and CO generation. In addition, no obvious systemic toxicity was observed in mice treated with the metal-free CO prodrug-loaded nanomedicine, suggesting the good biocompatibility of the polyprodrug nanoparticles. Our work provides new insights into the design and construction of polyprodrug nanomedicines for synergistic chemo/gas therapy.

Photocatalytic CO2 Reduction Using an Osmium Complex as a Panchromatic Self‐Photosensitized Catalyst: Utilization of Blue, Green, and Red Light

AbstractThe photocatalytic reduction of carbon dioxide (CO2) represents an attractive approach for solar‐energy storage and leads to the production of renewable fuels and valuable chemicals. Although some osmium (Os) photosensitizers absorb long wavelengths in the visible‐light region, a self‐photosensitized, mononuclear Os catalyst for red‐light‐driven CO2 reduction has not yet been exploited. Here, we discovered that the introduction of an Os metal to a PNNP‐type tetradentate ligand resulted in the absorption of light with longer‐wavelength (350–700 nm) and that can be applied to a panchromatic self‐photosensitized catalyst for CO2 reduction to give mainly carbon monoxide (CO) with a total turnover number (TON) of 625 under photoirradiation (λ≥400 nm). CO2 photoreduction also proceeded under irradiation with blue (λ0=405 nm), green (λ0=525 nm), or red (λ0=630 nm) light to give CO with >90 % selectivity. The quantum efficiency using red light was determined to be 12 % for the generation of CO. A catalytic mechanism is proposed based on the detection of intermediates using various spectroscopic techniques, including transient absorption, electron paramagnetic resonance, and UV/Vis spectroscopy.