Monoxide Poisoning Research Articles

The strategy of using heme proteins and synthetic porphyrins as injectable antidotes for fire gas poisoning

Abstract During fire accidents, 2 highly toxic components of fire smoke, carbon monoxide (CO) and hydrogen cyanide (HCN), are produced simultaneously, and more than 50% of fire-related deaths can be attributed to the inhalation of these toxic gases. Despite the different CO and HCN detoxification mechanisms, oxygen (O2) ventilation is currently the primary clinical treatment, and no alternative methods are available at present. In this review, the toxicological mechanisms of CO and HCN are investigated with an emphasis on the toxic effects of their combination. On the basis of these toxic mechanisms, the advantages and disadvantages of the current clinical detoxification methods are analyzed and discussed. We also summarize the latest advancements in the development of CO- and HCN-scavenging antidotes, highlighting the strategy of using synthetic iron porphyrins that have been synthesized mainly in our laboratory as water-soluble synthetic hemoglobin biomimetics.

Biofilm mass transfer and thermodynamic constraints shape biofilm in trickle bed reactor syngas biomethanation

Syngas (H2, CO2, CO) produced thermochemically from lignocellulosic biomass is an underexploited source for resource recovery and valorisation through its biological conversion for the production of a wide range of chemicals and fuels. Syngas biomethanation is one such promising bioconversion pathway, displaying interesting features such as high conversion efficiency and product selectivity, as methane is the sole product of the process. The biological conversion of syngas to high purity biomethane is still typically associated with a number of challenges related to the syngas composition, CO toxicity, and gas–liquid mass transfer limitations. In this work, the syngas biomethanation process carried out in trickle bed reactors was investigated at its boundary conditions to explore the limits of the process, focusing on syngas composition and mass-transfer conditions potentially limiting process performance. The process was found to be robust when exposed to CO excess, but highly sensitive to H2 excess, which caused severe inhibition even under small amounts of excess H2. This implies that biomethane purity comparable to natural gas can be achieved by addition of renewable H2, but this requires precise control to avoid process failure. Modulating the liquid recirculation rate and gas residence time allowed for a maximum methane productivity of 9.8 ± 0.5 mmol CH4 h−1 Lreactor−1 with full conversion of H2 and CO at a gas residence time of 1 h. Nevertheless, increasing the gas–liquid mass transfer with increasing liquid recirculation rate did not lead to increased methane productivity, which suggested additional rate-limiting bottlenecks in the process. Careful investigation of other factors potentially limiting the process led to the conclusion that diffusive transport of syngas components in the biofilm was the main bottleneck of the process. This diffusive limitation leads to a scenario of severe substrate scarcity in the biofilm phase that conditions the thermodynamic feasibility of the different biochemical reactions involved in syngas biomethanation. In turn, these thermodynamic constraints were found to drive the stratification of microbial groups and sequential consumption of syngas components along the height of the reactor

Investigating base-catalyzed aldol condensation reactions on alkali-free hydrotalcites and the role of thermal decomposition

Aldolization is a crucial carbon–carbon coupling reaction used in the conversion of biomass-derived platform molecules into valuable chemicals and fuels. In this work, we combine experiment and theory to explore the role thermal decomposition has in controlling the structure of alkali-free Mg-Al layered double hydroxides (LDHs) and their subsequent performance in the base-catalyzed aldol condensation of acetone, focusing on the constituent aldolization and dehydration steps. LDHs were synthesized via co-precipitation and subjected to calcination at temperatures up to 600 °C to produce mixed metal oxides of the form Mg3AlOz which were further examined by SEM, N2 physisorption, XRD, and CO2-TPD. Aldolization and dehydration behaviors were examined in a batch reactor and fit with kinetic models to capture the sensitivities of both reactions to calcination temperature. Additional experiments involving the selective blocking of base sites by CO2 poisoning and reversal at varying temperatures showed that both aldolization and dehydration are likely driven by the strongest base sites, yielding a site density (0.19 μmol m−2) in agreement with separate propionic acid titration studies. Density functional theory (DFT) simulations of Mg5Al2O8 surfaces were employed to gain microscopic insights into these materials, revealing the importance of Al substitution in creating cation vacancies which can drive aldol condensation through enolate intermediates stabilized in the oxyanion resonance form. High-coverage simulations of the surface show participation of the vacancy in both aldolization and dehydration, rationalizing the coupling of rate trends observed experimentally. Ultimately, this study provides new insights and approaches useful in the design of heterogeneous aldolization catalysts.

Unlocking Superior Hydrogen Oxidation and CO Poisoning Resistance on Pt Enabled by Tungsten Nitride-Mediated Electronic Modulation.

Enhancing the activity and CO poisoning resistance of Pt-based catalysts for the anodic hydrogen oxidation reaction (HOR) poses a significant challenge in the development of proton exchange membrane fuel cells. Herein, we leverage theoretical calculations to demonstrate that tungsten nitride (WN) can intricately modulate the electronic structure of Pt. This modulation optimizes the hydrogen adsorption, significantly boosting HOR activity, and simultaneously weakens the CO adsorption, markedly improving resistance to CO poisoning. Through prescreening with rational design, we synthesized an efficient catalyst comprising a minimal Pt content (only 1.4 wt %) supported on the small-sized WN/reduced graphite oxide (Pt@WN/rGO). As anticipated, this catalyst showcases a remarkable acidic HOR mass activity of 3060 A gPt-1, which is approximately 11.8 times greater than that of the commercial 20 wt % Pt/C catalyst. Impressively, it maintains high activity with 98.2% retention even in the presence of 1000 ppm of CO, indicating exceptional poison resistance. Operando synchrotron radiation analyses reveal that WN harmonizes the electron state of Pt during electrochemical reactions, optimizing hydrogen adsorption/desorption dynamics. This leads to a lower peak potential of CO stripping on Pt@WN/rGO compared to that on Pt/rGO, suggesting that WN mitigates competitive CO adsorption and enhances the availability of hydrogen adsorption sites on Pt. The synergistic effect significantly accelerates HOR activity and increases antipoisoning efficacy. The assembled PEMFC demonstrates substantial tolerance to CO concentration from 10 to 1000 ppm in the H2/CO mixture.

Ordered PdBi Alloys for High‐Performance CO2 Electroreduction and Enhanced Formic Acid Selectivity

AbstractElectrocatalytic conversion of CO2 to formic acid (HCOOH) represents a promising approach for storing renewable energy and addressing the challenges of hydrogen storage and transportation. Palladium (Pd) is the only known metal capable of achieving this process at nearly zero overpotential. However, its practical applications are severely limited by hydrogen evolution reaction (HER) competition and CO poisoning. Bimetallic alloys, especially intermetallics with ordered structures, offer an effective way to optimize performance due to their unique catalytic properties. Here, PdBi alloys are synthesized with ordered structures and adjustable ratios of active sites for efficient CO2 electroreduction to HCOOH. The o‐PdBi2 alloy effectively suppresses both HER competition and CO production during the CO2 reduction process, achieving ≈95% HCOOH selectivity across a wide range of current densities and excellent stability at industrial‐level current densities. Additionally, the ordered structure facilitates high selectivity maintenance while mitigating overpotential, resulting in a cell voltage of only 2.65 V at 200 mA cm−2. These findings provide a pathway for the practical application of Pd‐based catalysts in CO2 electroreduction.

OH Regulator of Amorphous CrOx on Defect-Rich Ultrafine Pd Nanowires Boosts Electrocatalytic Ethanol Oxidation.

Reasonable construction of high activity and selectivity electrocatalysts is crucial to achieve efficient ethanol oxidation reaction (EOR). However, the oxidation of ethanol tends to produce CO species that poison the active centers of the EOR electrocatalysts. Herein, a unique amorphous CrOx-protected defect-rich ultrafine Pd nanowires (CrOx-Pd NWs) is developed. On the one hand, the CrOx layer can act as a protective layer to maintain the structure of the nanowire. On the other hand, it can play the role of OH regulator to optimize the adsorption energy barrier of intermediate species in Pd nanowire, thereby enhancing the ability of the catalyst to resist CO poisoning. The CrOx-Pd NWs exhibit excellent EOR performance with 3.64 times higher mass activity and 50mV lower CO electro-oxidation potential than commercial Pd black. The results show that the CrOx layer promotes the dissociation of H2O into OHads, while the CrOx transfers electrons to neighboring Pd atoms optimizing the electronic configuration of Pd, thus selectively oxidizing ethanol to acetate and preventing the formation of toxic *CO. This work provides an effective strategy for the synthesis of nanowire materials with oxide/metal interfaces and offers new ideas for the design of catalysts that can efficiently drive EOR.

N-doped titanium oxide/carbon composite as supports for platinum catalysts in highly efficient methanol oxidation

The commercialization of direct methanol fuel cells (DMFCs) faces significant challenges due to the susceptibility of conventional platinum-based catalysts to poisoning by intermediates such as CO and HCOO− generated during the methanol oxidation reaction (MOR). This study details the synthesis of a highly porous titanium dioxide/carbon composite (TCC) using NH2-MIL-125(Ti) (MIL = Matérial Institut Lavoisier) as a precursor. To enhance the conductivity and catalytic properties of TCC, a nitriding reaction is conducted in an NH3 atmosphere, producing a nitrogen-doped titanium oxide/carbon composite (N-TCC). The resulting N-TCC is employed as a support for a platinum catalyst to improve MOR performance in DMFCs. The Pt/N-TCC catalyst demonstrates high catalytic performance, achieving a mass activity of 537 mA mg−1 for the MOR, marking a 39 % increase over the commercial Pt/C catalyst. Furthermore, the Pt/N-TCC catalyst exhibits a low onset potential for CO oxidation, a higher If/Ib ratio, and greater stability in chronoamperometry test, indicating high resistance to CO poisoning and enhanced chemical stability. Therefore, N-TCC can be used as a promising support for Pt-based catalysts in DMFC applications.

SISTEMA PARA DETECÇÃO DE VAZAMENTO DE GÁS

Gas poisoning, such as Liquefied Petroleum Gas (LPG), is responsible for around 19,000 deaths annually, due to its high flammability and toxic effects when inhaled in large quantities(Science Advances, 2024). In response to this, a prototype low-cost LPGgas detection system was developed, based on Arduino. The system uses sensors to identify leaks and trigger alerts via LEDs, buzzer, fan and relay, an LCD board and an android app that receives the data sent viaBluetooth to the owner. Tests have confirmed the system’s efficiency in detecting dangerous levels of gas, with positive results for residential and commercial safety.

Enhanced carbon monoxide poisoning resistance of Pd/BEA by integrating with CeO2 for low temperature NO adsorption: The role of CeO2 on oxidizing carbon monoxide to CO32−

Passive NOx adsorption (PNA) represents a promising technology for controlling NOx emissions during cold starts. However, Pd/zeolite catalysts, the latest generation of PNA materials, suffer from serious deactivation under CO concentrations, owing to the CO induced aggregation of highly dispersed Pd sites to PdO particles. In this work, we found that the resistance to CO poisoning of Pd/BEA can be enhanced by integrating with CeO2 through physical mixing. The resulting CeO2 + Pd/BEA composite catalyst demonstrated a notably higher NOx storage capacity (with a NOx/Pd ratio of 1.3) compared to Pd/BEA (0.8). This improvement can be attributed to the interaction between CeO2 and the BEA support, which promoted the formation of nitrates on CeO2 during NO adsorption at 80 °C. More importantly, CeO2 effectively shielded Pd2+ ions from reduction by CO, with 88 % of Pd2+ ions remaining after CO exposure, significantly outperforming Pd/BEA, which retained only 66 %. Spectra characterization and DFT results indicate that the defects in CeO2 strongly trapped CO (−0.973 eV), and the oxidation of trapped CO to CO32− by adsorbed oxygen (Oads) was exothermic (−1.35 eV), which reduced the exposure of Pd2+ ions to CO and inhibited the reduction and agglomeration of Pd2+ ions. While the composite sample still exhibited a slight reduction in NOx storage capacity after CO poisoning, with the NOx/Pd ratio decreasing from 1.3 to 0.9. The DFT simulation results indicate that the Ce-Oads bonds in CeO2 are weakened during the decomposition of the CO32− intermediate. This weakening could potentially facilitate the release of Oads, thereby reducing the Oads content as evidenced by spectral evidence. The decrease of Oads diminished nitrate formation on the CeO2 component in composite sample, resulting in the decline of NOx storage capacity after CO poisoning.

Hydrogen activation by rhodium under the cover of a copper oxide thin film

The activation of reactants by catalytically active metal sites at metal-oxide interfaces is important for understanding the effect of metal-support interactions on nanoparticle catalysts and for tuning activity and selectivity. Using a combined experimental and theoretical approach, we studied the activation of H2 and the effect of CO poisoning on isolated Rh atoms completely or partially covered by a copper oxide (Cu2O) thin film. Temperature-programmed desorption (TPD) experiments conducted in ultra-high vacuum (UHV) show that neither a partially nor a fully oxidized Cu2O layer grown on a Rh/Cu(111) single-atom alloy can activate hydrogen in UHV. However, in situ ambient pressure X-ray photoelectron spectroscopy (AP-XPS) experiments performed at elevated H2 pressures reveal that Rh significantly accelerates the reduction of these Cu2O thin films by hydrogen. Remarkably, the fastest reduction rate is observed for the fully oxidized sample with all Rh sites covered by Cu2O. Both TPD and AP-XPS data demonstrate that these covered Rh sites are inaccessible to CO, indicating that Rh under Cu2O is active for H2 dissociation but cannot be poisoned by CO. In contrast, an incomplete oxide film leaves some of the Rh sites exposed and accessible to CO, and hence prone to CO poisoning. Density functional theory calculations demonstrate that unlike many reactions in which hydrogen activation is rate limiting, the rate-determining step in the dissociation of H2 on thin-film Cu2O with Rh underneath is the adsorption of H2 on the buried Rh site, and once adsorbed, the dissociation of H2 is barrierless. These calculations also explain why H2 can only be activated at higher pressures. Together, these results highlight how different the reactivity of atomically dispersed Rh in Cu can be depending on its accessibility through the oxide layer, providing a way to engineer Rh sites that are active for hydrogen activation but resilient to CO poisoning.

Boosting synergistic effects between PtGe nanoalloys and 2D materials for PEMFC applications

In the present work we have investigated the stability, CO poisoning tendency and HOR and ORR activities of small-sized monometallic Pt and bimetallic PtGe nanoclusters deposited on a series of 2D materials. By means of global minima search and mechanistic studies at the density functional theory (DFT) level with continuum implicit solvent, a screening of size, composition and support material has been carried out to obtain the optimal catalyst compositions that may boost the catalytic performance. Alloying and support effects work in two directions. On the one hand, the support increases the stability and modifies the electronic structure of the cluster via metal-support interaction. On the other hand, the cluster can change the electronic properties and catalytic activity of the support, which can be modulated with its size and composition. In addition, the 2D support assists pure Pt clusters in reducing the propensity to undergo CO poisoning, which can be further reduced by Ge alloying. This effect can be exploited to the point that the interaction with CO is not even favorable, as in Pt5Ge5/germanene, thus completely inhibiting the CO poisoning on the catalyst. Regarding the catalytic activities, all the catalysts studied in this work yield too high overpotentials for the ORR in acidic conditions, due to the presence of too oxophilic active sites which results in the overbinding of oxygenated species. However, the combination of Ge alloying and 2D support yield remarkable results in the HOR performance. The simultaneous tailoring of catalyst composition and support is demonstrated to be an effective strategy to successfully adjust the catalytic properties.

One case of comprehensive treatment of acute severe ammonia-induced intoxication with extracorporeal membrane oxygenation

Acute ammonia-induced intoxication is a kind of acute irritant gas poisoning, which mainly causes systemic inflammatory reaction and immune dysfunction through direct and indirect lung injury, leading to chemogenic pulmonary edema and acute respiratory distress syndrome (ARDS). The mechanism of its toxic injury is complex, and the fatality rate of patients increases significantly once ARDS occurs. In this paper, the patient with acute and severe ammonia-induced intoxication was successfully treated by extracorporeal membrane oxygenation (ECMO) combined with fiberoptic bronchoscopy and other critical technologies, and achieved good results. By analyzing the diagnosis and treatment process of severe ammonia-induced intoxication complicated with ARDS patients, this paper summarizes the clinical characteristics of ammonia-induced intoxication injury, and the application opportunities of ECMO and various critical medical technologies, so as to facilitate the efficient intervention and treatment of ammonia-induced intoxication according to the clinical opportunity and improve the survival rate of patients.

Carbon Monoxide: A Pleiotropic Redox Regulator of Life and Death.

Despite recent technological progress, carbon monoxide poisoning is still one of the leading causes of domestic and industrial morbidity and mortality. The brain is particularly vulnerable to CO toxicity, and thus the majority of survivors develop delayed movement and cognitive complications. CO binds to haemoglobin in erythrocytes, preventing oxygen delivery to tissues, and additionally inhibits mitochondrial respiration. This renders the effect of CO to be closely related to hypoxia reperfusion injury. Oxygen deprivation, as well as CO poisoning and re-oxygenation, are shown to be able to activate the production of reactive oxygen species and to induce oxidative stress. Here, we review the role of reactive oxygen species production and oxidative stress in the mechanism of neuronal cell death induced by carbon monoxide and re-oxygenation. We discuss possible protective mechanisms used by brain cells with a specific focus on the inhibition of CO-induced ROS production and oxidative stress.

Ultrathin ternary PtNiRu nanowires for enhanced oxygen reduction and methanol oxidation catalysis via d-band center regulation

Direct methanol fuel cells rely on the efficiency of their anode/cathode electrocatalysts to facilitate the methanol oxidation reaction and oxygen reduction reaction, respectively. Platinum-based nanocatalysts are at the forefront due to their superior catalytic properties. However, the high-cost, scarcity, and low CO tolerance of platinum pose challenges for the scalable application of DMFCs. Herein, we report novel ultrathin ternary PtNiRu alloy nanowires to improve Pt utilization and CO tolerance. These novel electrocatalysts incorporate the oxophilic metal Ru into ultrathin PtNi nanowires, aiming to enhance the intrinsic activity of platinum while leveraging the long-term durability and high utilization efficiency provided by the bimetallic synergistic effect. The PtNiRu NWs significantly enhance both mass activity and specific activity for ORR, performing about 6.9 times and 3.9 times better than commercial Pt/C, respectively. After a rigorous durability test of 10,000 cycles, the PtNiRu NWs only exhibited a 25.2 % loss in mass activity. Additionally, for MOR, the MA and SA of PtNiRu NWs exceed that of Pt/C catalyst by 4.30 and 2.72 times, respectively, and exhibit exceptional resistance to CO poisoning. Theoretical insights from density functional theory calculations suggest that the introduction of Ru modulates the d-band center of the surface Pt atoms, which contributes to decreased binding strength of oxygenated species and an elevated dissolution potential, substantiating the enhanced performance metrics, and the durability enhancement stems from the stronger PtM bonds than those in PtNiRu NWs resulted from PtRu covalent interactions. These findings not only provide a new perspective on platinum-based nanocatalysts but also significantly advance the quest for more efficient and durable electrocatalysts for DMFCs, representing a substantial stride in fuel cell technology.

Pt-Ru atomic alloys confined in mesoporous carbon hollow spheres for accelerating methanol oxidation

Active and durable electrocatalysts are essential for commercializing direct methanol fuel cells. However, Pt-based catalysts, extensively utilized in the methanol oxidation reaction (MOR), are suffered from resource scarcity and CO poisoning, which degrade MOR activity severely. Herein, Pt1Rux bimetallic catalysts were synthesized by confining Pt1Rux alloys within the shells of mesoporous carbon hollow spheres (MCHS) via a vacuum-assisted impregnation method (Pt1Rux@MCHS). The confinement effect induced by mesoporous carbon hollow spheres resulted in a robust structure of Pt1Ru3@MCHS with an ultrafine dispersion of alloy nanoparticles. The experimental and theoretical results confirmed that the boosting electrocatalytic activity and stability of the MOR over Pt1Ru3@MCHS were contributed to the regulated electronic structure as well as the superior CO tolerance of atomic Pt site caused by the electronic interaction between single Pt atoms and Ru nanoparticles. This strategy is versatile for the rational design of Pt-based bimetallic catalysts and has a positive impact on MOR performance.

Epidemiological, clinical, therapeutic and toxicological profile of acute intoxications: A monocentric retrospective study

Objectives. Acute poisonings remain a significant cause of morbidity and mortality globally, posing a major public health challenge. In Algeria, data on the profile of acute poisonings are limited. The objective of this study, conducted at the University Hospital of Setif, was to provide an epidemiological, clinical, therapeutic, and toxicological overview of acute poisonings in this country. Results. This retrospective study, covering the period from the last quarter of 2016 to April 30, 2018, included 406 cases. The results showed a sex ratio of 1.41 with a female predominance. The intoxicated patients had a mean age of 24.74 years, with the most affected age group being between 19 and 29 years (28%). Poisonings were mainly accidental (57%), with 18% of cases involving intentional poisonings, more common among men. Medication poisonings were the most common (54%), followed by carbon monoxide poisonings (37%). Carbon monoxide poisonings were exclusively accidental, while medication poisonings were intentional in 27% of cases. Cosmetics, household products, and carbon monoxide were more often implicated in cases involving females. An incidence peak was observed in winter. The average time between poisoning and hospitalization was 15 hours and 24 minutes. Symptomatic treatment alone or combined with evacuation or detoxification treatment was used in 8.9%, 2%, and 0.2% of cases, respectively. About one-third of patients received specific management, with antidote administration only for carbon monoxide poisonings. Conclusion. The results underscore the importance of public awareness regarding the dangers of poisonings, reducing access to toxic products, and providing healthcare professionals with training to improve therapeutic management and reduce the incidence of acute poisonings.

Influences of reformate on the performance of high temperature proton exchange membrane fuel cell and its optimization strategy

Due to the challenges of hydrogen production, storage and transport, hydrocarbon reformate-based high temperature proton exchange membrane fuel cell (HT-PEMFC) has wide application opportunities. However, the inevitable water vapor and CO in reformate significantly determines the fuel cell performance and durability. In this work, a three-dimensional, non-isothermal and multiphase model based on agglomerate sub-model is developed to investigate the effects of reformate components and operating conditions, in which multiphase transport, dissolution, diffusion, adsorption, desorption and reaction of H2 and CO are considered. The results show that the fuel cell performance increases with the rising of water vapor content as CO content higher than 2 % (dry basis, the same below) and water vapor content lower 20 % (wet basis). The alleviation effect of water vapor on CO poisoning is discovered due to reduced CO coverage rather than enhanced CO electrochemical oxidation. An elevated temperature leads to improved performance and the effect of CO poisoning (CO<3%) is weak at 180°C.

The impact of organic carbon mineralization on pollution and toxicity of toxic metal in sediments: Yellow Sea and East China Sea study

Organic carbon mineralization is the main driving force of metal migration and transformation in sediments, greatly influencing the distribution, pollution degree, and toxicity of toxic metals. However, relevant research on this subject is still limited. In this study, the concentration of toxic metals (Cr, Cd, Cu, Pb, Zn, Co, Fe, Mn, Ni, As) in the solid and liquid phase (porewater) of sediments were measured, toxic metal pollution degree and toxicity of the Yellow Sea (YS) and the East China Sea (ECS) were assessed. Combined with the rate of organic carbon mineralization, the impact of organic carbon mineralization was analyzed. The results showed that Ni was slightly enriched and posed a certain ecological risk, and As was moderately enriched in the studied area, Pb was at a moderate pollution level in the studied area. Zn, Co, Mn, and Fe were at a moderate pollution level in the mud area of SYS and the west coastal area of ECS. Additionally, the total organic carbon mineralization rate (TCMR) in the ECS (5.12–18.04 mmol C m−2 d−1) was slightly higher than that in the YS (3.29–14.46 mmol C m−2 d−1) during spring. Moreover, organic carbon mineralization promotes metal enrichment, and the TCMR was significantly correlated with the pollution load index. Thus, TCMR can be used as an indicator to predict the degree of metal pollution. Furthermore, organic carbon mineralization promotes the mobilization of Cu from the solid phase to the liquid phase, while facilitating the transfer of Cr, Pb, Co, Ni, and Fe from the liquid phase to the solid phase. This process increases the potential risks of Cu and reduces the toxicity of Cr, Pb, Co, Ni, and Fe. Therefore, the impact of organic carbon mineralization should be considered in future assessments and predictions of toxic metal pollution and toxicity.

Bioinspired design of rhodium single-atom nanozymes enable a non-poisoning pathway for direct formic acid oxidation in enzymatic biofuel cells

Solving the dilemma of CO poisoning in electrocatalysts is the crucial step in the commercialization of direct formic acid fuel cells, however, it remains a challenge to design catalysts with high reaction tendency for the direct formic acid oxidation reaction (FAOR) as elaborately as natural enzymes. Herein, inspired by formate oxidase (FOD) with a delicate catalytic pocket, we report that rhodium single-atom nanozymes (Rh SAzymes) can catalyze direct FAOR without worrying about CO poisoning. Impressively, Rh SAzymes exhibit non-CO pathway for direct FAOR in both enzyme-like biocatalytic and electrocatalytic conditions. By combining docking studies and density functional theory calculations, we reveal that this striking reaction tendency mainly stems from thermodynamically unfavorable pathway in the generation and adsorption of CO, much more like that of natural FOD. Moreover, we successfully construct the membrane-less FA/O2 enzymatic biofuel with an open-circuit potential (OCP) of 0.68±0.01 V and a maximum power density (Pmax) of 0.41±0.01 mW cm−2. With 100 % selectivity toward direct anti-poisoning pathway and flexible configuration, the device realizes long-term stable operation and miniaturized goals. Our work not only provides a methodological template for exploring the CO-resilient reaction mechanism of enzyme-like biocatalysts as well as their homologous electrocatalysts in canonical reactions of fuel cells but also paves avenues for the integration of nanozymes in energy equipment.

Untargeted and targeted metabolomics analysis of CO poisoning and mechanical asphyxia postmortem interval biomarkers in rat and human plasma by GC[sbnd]MS

Accurate and objective estimation of the postmortem interval (PMI) is crucial in forensic practice. This study aimed to infer PMI through equations based on the relationship between PMI and metabolomics biomarkers.Rats were subjected to models representing various temperatures and causes of death, with blood collected at different intervals. Untargeted gas chromatographymass spectrometry metabolomics detection methods were developed, and candidate biomarkers were chosen as co-differentially expressed metabolites in four models. A targeted method was then developed for quantitatively determining candidate biomarkers. Animal tests and human cadaver samples with clearly documented causes of death and time were used to verify the reliability of the regression equation.Results: Unique differential metabolites for CO poisoning deaths included 2,3-butanediol, hypoxanthine, and dehydrated hexanol, while those for mechanical asphyxia deaths comprised propylamine, 1,3-propylene glycol, phosphoric acid, and sorbitol. Pyruvate, glycerol and isoleucine were identified as candidate biomarkers. Human case results demonstrated the method's potential (error rate < 20 %). The findings of this study may offer reference points for estimating PMI and causes of death in forensic practice.