High Carbon Monoxide Research Articles

Highly Chemoselective One‐Step Synthesis of Novel N‐Substituted‐Pyrrolo[3,4‐b]quinoline‐1,3‐diones via Palladium‐Catalyzed Aminocarbonylation/Carbonylative Cyclisation Sequence

AbstractNovel N‐substituted pyrrolo[3,4‐b]quinoline‐1,3‐diones have been prepared via a highly chemoselective palladium‐catalyzed carbonylative imidazation‐cyclization reaction in a one‐pot synthetic approach. This methodology, which has been applied for the first time to access such original scaffolds through two different protocols involving 3‐bromo‐2‐iodoquinoline, as a typical partner, primary amines, and atmospheric or high carbon monoxide pressure (20 bar), has shown an excellent tolerance for many functional groups. The use of bidentate ligands such as XantPhos and dppp, either under atmospheric or high‐pressure conditions, provides a wide range of carbonylated compounds in good to excellent yields (up to 82 %). Furthermore, some new quinoline‐2,3‐dicarboxamides have been isolated as side products in very low yields and have been fully characterized. The solid state structures of three of the synthesized acridinimides have been unequivocally established by single‐crystal XRD analysis.

Tailoring Copper Chemical Status and Hydrophobicity of Biomimetic Photocatalytic Films for Carbon Dioxide Conversion.

Naturally hierarchical nanostructures of leaves were successfully replicated on thermally stable polyimide (PI) films to obtain biomimetic substrates for the grafting of p-type semiconductor, cuprous oxide (Cu2O). The chemical states of Cu2O and the hydrophobicity on the photocatalytic films were tunable by altering the process time of ion-exchange or chemical reduction. The obtained photocatalytic films showed activity to photocatalytically convert carbon dioxide (CO2) into carbon monoxide (CO) under visible light illumination. The yield of CO was initially improved with the increasing hydrophobicity on the film but then leveled off. The photocatalytic activity could be further improved by tailoring the amount or composition of copper oxides. An optimum ratio of Cu2O and moderate basicity on the surface, as well as more metallic Cu from the bulk, will achieve more efficient interfacial charge transfer, resulting in a higher CO production rate.

Cost effective decarbonisation of blast furnace – basic oxygen furnace steel production through thermochemical sector coupling

We present here a first-principles study of the sector coupling between a thermochemical carbon dioxide (CO2) splitting cycle and existing blast furnace – basic oxygen furnace (BF-BOF) steel making for cost-effective decarbonisation. A double perovskite, Ba2Ca0.66Nb0.34FeO6, is proposed for the thermochemical splitting of CO2, a viable candidate due to its low reaction temperatures, high carbon monoxide (CO) yields, and 100% selectivity towards CO. The CO produced by the TC cycle replaces expensive metallurgical coke for the reduction of iron ore to metallic iron in the blast furnace (BF). The CO2 produced from the BF is used in the TC cycle to produce more CO, therefore creating a closed carbon loop, allowing for the decoupling of steel production from greenhouse gas emissions. Techno-economic analysis of the implementation of this system in UK BF-BOFs could reduce steel sector emissions by 88% while increasing the cost-competitiveness of UK steel on the global market through cost reduction. After five years, this system would save the UK steel industry £1.28 billion while reducing UK-wide emissions by 2.9%. Implementation of this system in the world's BF-BOFs could allow the steel sector to decarbonise in line with the Paris Climate Agreement to limit warming to 1.5 °C.

New horizons of MBenes: highly active catalysts for the CO oxidation reaction.

The search for materials with high intrinsic carbon monoxide oxidation reaction (COOR) catalytic activity is critical for enhancing the efficiency of reducing CO contamination. COOR catalysts, however, have long relied heavily on noble metals and CeO2. Herein, in order to search for non-noble COOR catalysts that are more active than CeO2, 18 oxygen-functionalized MBenes with orthorhombic and hexagonal crystal structures, denoted as orth-M2B2O2 and hex-M2B2O2 (M = Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W), were investigated in terms of their COOR catalytic activity by high-throughput first-principles calculations. Hex-Mo2B2O2, orth-Mo2B2O2, hex-V2B2O2 and hex-Cr2B2O2 were found to be more active than CeO2 and possess structural stability below 1000 K, showing the potential to replace CeO2 as the substrates of COOR catalysts. Moreover, orth-Mo2B2O2, hex-V2B2O2 and hex-Cr2B2O2 exhibit even higher COOR catalytic activity than Pt-CeO2 and Au-CeO2, and are expected to be applied as COOR catalysts directly. Further investigations showed that the formation energy of oxygen vacancies could be used as the descriptor of COOR catalytic activity, which would help to reduce the amount of calculations significantly during the catalyst screening process. This work not only reports a series of 2D materials with high COOR catalytic activity and opens up a new application area for MBenes, but also provides a reliable strategy for highly efficient screening for COOR catalysts.

Atomic-Scale Mechanism of Platinum Catalyst Restructuring under a Pressure of Reactant Gas.

Heterogeneous catalysis is key for chemical transformations. Understanding how catalysts' active sites dynamically evolve at the atomic scale under reaction conditions is a prerequisite for accurately determining catalytic mechanisms and predictably developing catalysts. We combine in situ time-dependent scanning tunneling microscopy observations and machine-learning-accelerated first-principles atomistic simulations to uncover the mechanism of restructuring of Pt catalysts under a pressure of carbon monoxide (CO). We show that a high CO coverage at a Pt step edge triggers the formation of atomic protrusions of low-coordination Pt atoms, which then detach from the step edge to create sub-nano-islands on the terraces, where under-coordinated sites are stabilized by the CO adsorbates. The fast and accurate machine-learning potential is key to enabling the exploration of tens of thousands of configurations for the CO-covered restructuring catalyst. These studies open an avenue to achieve an atomic-scale understanding of the structural dynamics of more complex metal nanoparticle catalysts under reaction conditions.

Correlation Air CO Level with HbCo Level, Hemoglobin, and Blood Pressure to Street Vendors in The Gading Fajar Sidoarjo Street Vendor Area

Motor vehicles emit exhaust gas emissions that produce pollutants, one of the compounds contained is carbon monoxide (CO). CO may cause intoxication in humans if exposed for a long time especially street vendors because the work area is filled with vehicle fumes containing CO gas. High CO levels in the air indicate HbCO levels to increase. The increased of HbCO levels will cause abnormal hemoglobin levels and induce vasoconstriction which makes blood pressure increase. The purpose of this study was to prove the correlation between CO levels in the air with HbCO, hemoglobin, and blood pressure levels to street vendors in the Gading Fajar Sidoarjo Street Vendor Area. This research uses the Conway diffusion cell method and is an analytic observational study with a cross sectional design implemented at the Surabaya Health Laboratory Center and the Hematology Laboratory of Medical Laboratory Technology Department Poltekkes Kemenkes Surabaya in March 2022. Blood tests was carried out on 25 street vendors using random sampling technique. The results showed that average air CO level was 11.0 ppm and 13.3 ppm; mean HbCO levels 0.87%; mean hemoglobin levels 14.4 g/dL; mean systolic blood pressure levels 128 mmHg; and the mean of diastolic blood pressure levels 80 mmHg. The data were analyzed using SPSS. The outcome of normality test showed that the data was not normally distributed. Statistical tests was performed using Spearman correlation. The conclusion showed there was correlation between air CO level with HbCO level, hemoglobin level, and blood pressure level on street vendors in the Gading Fajar Sidoarjo Street Vendor Area. If CO levels in the air increase, then HbCO levels and blood pressure also increase. Street vendors are expected to always use Personal Protective Equipment (PPE) such as mouth masks when working to reduce the risk of exposure to CO gas and doing a healthy lifestyle as a preventive effort to avoid health problems.

Effects of functional nanomaterials for reduction of carbon monoxide levels in the workplace and homes

Carbon monoxide (CO) at high concentrations is extremely poisonous to humans and other invertebrates. It is one of the leading causes of unintentional deaths in the United States. Furthermore, people with heart diseases are more vulnerable to high CO levels since they already have a reduced ability to get oxygenated blood to their hearts. Functional nanomaterials (metallic nanoparticles [NPs], carbon nanotubes [CNTs], and nanofibers [NFs]) offer a high surface area, low weight-to-volume ratio, flexibility, and high porosity, which are perfect properties for gas absorption. Many nanomaterials are currently playing an essential role in CO-capturing technologies. This paper focuses on the usage of those functional nanomaterials for CO absorption and their absorption mechanisms. Due to high surface area and porosity, these materials have been widely used to absorb pollutants, including toxic gas like CO. Fabrications, CO-absorbing mechanisms, and absorbing properties of some nanomaterials will be discussed here.

Low-temperature CO oxidation by silver nanoparticles in silica aerogel mesoreactors

Low-temperature carbon monoxide (CO) oxidation on silver/silica aerogel (Ag/SiO2 AG) catalyst prepared by one-pot sol–gel synthesis followed by supercritical ethanol drying method is reported. Highly stable and sinter-proof catalyst led to easy reactant diffusion to the active sites. The Ag/SiO2 AG catalyst showed enhanced catalytic activity toward low-temperature CO oxidation by preventing agglomeration of silver nanoparticles inside pores and facilitating well-dispersed active sites to enhance the mass heat transfer in the mesopores. Catalyst pre-treatment conditions were found to play a crucial role in achieving high CO conversion efficiency at low light-off temperatures. Inverse counter-clockwise CO oxidation hysteresis was found to occur after the first run. The active sites contributing to this enhanced catalytic behavior were confirmed to be Ag0 from XPS, XRD, and TEM analysis. The catalyst exhibited good thermal stability up to 450 °C over repeated number of cycles.

High sensitivity trace carbon monoxide gas sensor based on endlessly single-mode photonic crystal fiber Sagnac interferometer

Abstract In this paper, a novel carbon monoxide (CO) gas sensor based on α-Fe2O3/MgO is presented and constructed. The endlessly single-mode photonic-crystal fibers (ESPCF) was sandwiched between the four-core fibers (FCF) to form the ESPCF-FCF-ESPCF structure, which was embedded it in the Sagnac loop to construct the Sagnac interferometer. The crystal structure, composition and morphology of α-Fe2O3/MgO sensing film were characterized by the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM), respectively. The results indicated that the α-Fe2O3/MgO sensing film was uniformly coated on the outside surface of two ESPCFs, with a thickness of about 1 μm. When these sensing films adsorbed CO, the monitoring wavelength showed blueshift and the maximum sensitivity was 99.42 pm/ppm. The response time and recovery time were respectively 90 s and 100 s respectively. The Sagnac fiber-optic sensor exhibt high sensitivity, good selectivity and strong stability, and it can effectively realize the monitoring of carbon monoxide.

Characterizing and assessing the fuel economy, particle number and gaseous emissions performance of hybrid electric and conventional vehicles under different driving modes

Hybrid electric vehicle (HEV) is considered to be more energy efficient and less emissions than conventional gasoline vehicle (CV). A growing number of studies suggested that real-road emissions may be much higher than laboratory measurements. To compare the fuel economy and emissions performance of HEV and CV on real roads, this study conducted real driving emission (RDE) tests on HEV and CV of the same configuration under real driving conditions with aggressive and normal driving styles. The results indicated that the HEV had lower fuel consumption (L/100 km), nitrogen oxides (NOX) and carbon dioxide (CO2) emissions compared to the CV. Fuel saving of HEV compared to CV was up to 41.14% under urban conditions. Compared to emissions of other trip conditions, The CO2 and NOX reductions of HEV under urban conditions were the largest, which were more than 33.65% and 61.98% respectively. However, the particle number (PN) and carbon monoxide (CO) emissions of HEV were larger than those of CV. This was due to the frequent stopping and restarting of the internal combustion engine of the HEV. In order to comprehensively compare the fuel economy and emissions performance of HEV and CV, the evaluation index of real conformity factor was proposed. The analysis showed that to reduce the high PN and CO emissions of HEV, a combination of fuel economy-focused and emission control-focused strategies should be used.

Lichen Biodiversity Index (LBI) for the Assessment of Air Quality in an Industrial City in Pahang, Malaysia

Lichen is a well-documented useful biological indicator for monitoring air pollution using various methods such as the biodiversity of lichens. However, the use of lichen biodiversity to estimate air pollution levels in industrial areas, particularly in Malaysia, is still weak, and the determinants of its diversity are unknown. As a result, the purpose of this research is to analyse air pollution in Malaysia’s industrial urban area using the lichen biodiversity index and its determining factor. This research was carried out at Gebeng, Pahang, Malaysia. A total of 14 sample locations were chosen, each with three replication stations. The Lichen Biodiversity Index (LBI) approach was employed in this study to estimate the degree of air pollution in Gebeng. This study also investigated three potential determinants of lichen biodiversity: carbon monoxide (CO) concentration, relative humidity (%), and vehicle motor frequency (per hour). The LBI was plotted and analysed using the Geographical Information System (GIS) programme ArcGIS 10.8.1, and the determining variables were identified using Pearson’s Correlation Coefficient software PAST 4.03. This study discovered a total of 11 lichen species known as metropolitan lichen. The average LBI across Gebeng is 19.5 (moderate alteration). In the industrial region, CO has an inversely significant relation with lichen biodiversity (r = −0.7433), relative humidity has a significant relation with lichen biodiversity (r = 0.8249), and vehicle motors are not significant as a determining factor for lichen biodiversity (r = 0.2068). This study demonstrates that lichen, with its diversity of species in one place, can be utilised to measure and quantify the degree of air pollution in industrial areas. In addition to that, in the context of an industrial city, vehicle motors do not have a significant impact on lichen biodiversity due to the existence of other pollutants sources from industrial activities. Relative humidity is a sign of clean air and humid surroundings, which is good for lichen growth; meanwhile, higher CO concentration will restrict the growth of sensitive-type lichen and will only allow the resistant type of lichen to grow.

Thermophilic Water Gas Shift Reaction at High Carbon Monoxide and Hydrogen Partial Pressures in Parageobacillus thermoglucosidasius KP1013

The facultatively anaerobic Parageobacillus thermoglucosidasius oxidizes carbon monoxide to produce hydrogen via the water gas shift (WGS) reaction. In the current work, we examined the influence of carbon monoxide (CO) and hydrogen (H2) on the WGS reaction in the thermophilic P. thermoglucosidasius by cultivating two hydrogenogenic strains under varying CO and H2 compositions. Microbial growth and dynamics of the WGS reaction were monitored by evaluating parameters such as pressure, headspace composition, metabolic intermediates, pH, and optical density. Our analyses revealed that compared to the previously studied P. thermoglucosidasius strains, the strain KP1013 demonstrated higher CO tolerance and improved WGS reaction kinetics. Under anaerobic conditions, the lag phase before the WGS reaction shortened to 8 h, with KP1013 showing no hydrogen-induced product inhibition at hydrogen partial pressures up to 1.25 bar. The observed lack of product inhibition and the reduced lag phase of the WGS reaction support the possibility of establishing an industrial process for biohydrogen production with P. thermoglucosidasius.

Environmental analysis of methanol production from steel-making offgas

Linz-Donawitz gas is currently used as a heat source for the steel-making process by combustion, which is a conventional pathway. In a resource-efficient and environment-friendly point of view, methanol can be produced from Linz-Donawitz gas with balancing hydrogen due to its high carbon monoxide contents. This study designs a large-scale process for the catalytic conversion of Linz-Donawitz gas to methanol based on the validated kinetic studies and performs a lifecycle assessment of the proposed process. A lifecycle assessment of the methanol production from Linz-Donawitz gas, a new pathway, is conducted by defining the “cradle-to-gate” system boundary and are compared with those of the conventional pathway based on the ReCiPe 2016 Midpoint level methodology. Consequently, the lifecycle assessment results show that three ones among eighteen environmental impact results, global warming, fossil resource scarcity, and water consumption, of the new Linz-Donawitz gas pathway are lower than those of the conventional pathway by 86.9%, 88.8%, and 75.5%, respectively. They are dominated by the displacement effect of the heat generation of Linz-Donawitz gas by the primary sources. Using wood chips as a primary source could reduce especially global warming, fossil resource scarcity, and water consumption than using hard coal or natural gas by 29.8–58.9%, 32.5–49.1%, and 50.0–91.7%, leading to an environmental-friendly Linz-Donawitz gas process. • The environmental impact of Linz-Donawitz gas-to-methanol is examined using LCA. • Global warming, fossil resource scarcity, and water consumption had better impacts. • Primary source for heat is the critical factor on total environmental impact.

Robust O-Pd-Cl catalyst-electrolyte interfaces enhance CO tolerance of Pd/C catalyst for stable CO2 electroreduction

Carbon-supported Pd catalysts are highly active yet can be easily poisoned by the in-situ formed carbon monoxide (CO) during CO2 electrochemical reduction reaction (CO2RR). Herein, we introduce a novel approach to enhance the CO tolerance and activity of Pd/C catalyst by manipulating catalyst-electrolyte interfaces in saturated KCl electrolyte. During the CO2RR, the Cl- ions in electrolyte trigger the surface dynamic reconstruction of Pd/C catalyst with the formation of O-Pd-Cl species at catalyst-electrolyte interfaces. The reconstructed Pd/C catalysts can achieve nearly 100% of CO Faradaic efficiency and feature high stability and CO tolerance, which can maintain a better activity in the presence of over 2000 ppm and 23200 ppm of CO in H-type cell and flow cell, respectively. Meanwhile, using such highly concentrated electrolyte, the hydrogen evolution reaction is strongly suppressed. The experimental and theoretical results have confirmed that the O-Pd-Cl species mediated by Cl- ions enable the high activity, good CO resistance and long lifetime of the Pd/C catalyst. These findings may provide some inspirations into the design and fabrication of active yet stable Pd-based catalysts for CO2 electroreduction, and offer some insights into manipulation of the activity and stability for the Pd catalysts at catalyst-electrolyte interfaces.

Evolution and distribution of the anode overpotential and its oscillations in a polymer electrolyte membrane fuel cell exposed to carbon monoxide

Carbon monoxide (CO) poisoning of polymer electrolyte membrane fuel cells (PEMFCs) remains a challenge for their deployment, and a deeper understanding of the spatiotemporal dynamics involved is needed to develop effective mitigation strategies. In this work, localised reference electrodes were used to measure the anode overpotential at three locations across the active area of a galvanostatically operated cell (0.3 A cm−2) exposed to 100 ppm CO/H2. The anode region closest to the inlet was poisoned more rapidly than the rest of the cell, following a sigmoidal variation, and presented a higher CO coverage. The varying CO concentration, combined with local operating conditions, had a direct impact on the distribution of CO coverage. Additionally, complex self-sustained oscillations of the cell voltage and the anode overpotential were observed and correlated with the rate of CO oxidation in the overall cell. The coexistence of a dominant mean-field coupling area closer to the anode inlet, and a dominant migration coupling region closer to the outlet was identified, consistent with reported modelling predictions for a single straight channel cell. Finally, the cell recovery with pure H2 was shown to be a faster process than the CO adsorption, which follows first-order kinetics and is affected by local conditions.

Secret Carbon Monoxide Intoxication Assessments of the Patients Who Presented to Emergency

Aim: The primary aim of this study is to evaluate patients who present to the emergency department with atypical symptoms in terms of occult Carbon monoxide (CO) poisoning, and the secondary aim is to compare the invasive and non-invasive values of Carboxyhemglobin (COHb) levels in patients with high CO levels.
 Material and Method: This prospective and descriptive study was conducted on 2775 adult patients who visited the Emergency Department (ED) between January 1 and March 31, 2015. The COHb levels of the individuals who applied to the emergency department with non-specific complaints were measured with a non-invasive multiwave pulse oximeter device and the date of application, age, gender, complaint, smoking history, pregnancy status, pulse COHb, blood COHb and blood metHb parameters were recorded in the preformed form. Values under 10% in smokers and under 6.6% in non-smokers were recorded as secret COHb intoxication.
 Results: 52.8% of the patients were male and 34.4% were smokers. The rate of pregnant women among female patients was 13.4%. The first three complaints were shortness of breath, chest pain and stomach ache. It was determined that the mean COHb of the patients was 1.44±1.65 in arterial blood gas and 1.75±1.63 in finger measurement. A highly significant positive correlation was found between the two averages. The COHb value measured by both techniques was higher in male patients and in smokers and non-pregnant patients. The rate of latent COHb intoxication was determined as 1% in smokers and 0.1% in non-smokers.
 Conclusion: We came to the conclusion that non-invasive COHb measurement can make positive contributions to the diagnosis of secret carbonmonoxyde intoxications.

3D-CFD RANS Methodology to Predict Engine-Out Emissions with Gasoline-Like Fuel and Methanol for a DISI Engine

<div class="section abstract"><div class="htmlview paragraph">Renewable fuels, such as bio- and e-fuels, are of great interest for the defossilization of the transport sector. Among these fuels, methanol represents a promising candidate for emission reduction and efficiency increase due to its very high knock resistance and its production pathway as e-fuel. In general, reliable simulation tools are mandatory for evaluating a specific fuel potential and optimizing combustion systems. In this work, a previously presented methodology (Esposito et al., Energies, 2020) has been refined and applied to a different engine and different fuels. Experimental data measured with a single cylinder engine (SCE) are used to validate RANS 3D-CFD simulations of gaseous engine-out emissions. The RANS 3D-CFD model has been used for operation with a toluene reference fuel (TRF) gasoline surrogate and methanol. Varying operating conditions with exhaust gas recirculation (EGR) and air dilution are considered for the two fuels. The laminar flame speed for the fuels has been tabulated by means of detailed chemistry 1D-flame calculations. The G-equation model is used to simulate flame propagation in combination with chemical kinetics to estimate the emission species correctly. The resulting G-equation calibration is compared between the two fuels. Emission results are analyzed, validated with experiments, and compared between the two fuels. The methodology shows a good overall predictivity regarding trends and absolute values. Simulated carbon dioxide (CO<sub>2</sub>) shows to be mainly within a 4 % deviation from the measurements. Oxygen (O<sub>2</sub>) deviations are within 3 % at lean operation and higher at stoichiometric conditions due to the low overall oxygen content. The maximum nitrogen oxides (NO<sub>x</sub>) deviation for the TRF is 22 %, while higher deviations are observed for methanol up to 42.3 %. Total hydrocarbon (THC) emissions are mainly below 20 % deviation. Higher carbon monoxide (CO) deviations are observed due to high CO sensitivity to mixture formation prediction, even if the trends with EGR and air dilution are correctly reproduced. Overall, the methodology shows good potential for virtual pollutant evaluation, assessment of emission reduction strategies, and development of engines with methanol fuel.</div></div>

Use of biomass fuels predicts indoor particulate matter and carbon monoxide concentrations; evidence from an informal urban settlement in Fort Portal city, Uganda

BackgroundPoor indoor air quality (IAQ) is a leading cause of respiratory and cardiopulmonary illnesses. Particulate matter (PM2.5) and carbon monoxide (CO) are critical indicators of IAQ, yet there is limited evidence of their concentrations in informal urban settlements in low-income countries.ObjectiveThis study assessed household characteristics that predict the concentrations of PM2.5 and CO within households in an informal settlement in Fort Portal City, Uganda.MethodologyA cross-sectional study was conducted in 374 households. Concentrations of PM2.5 and CO were measured using a multi-purpose laser particle detector and a carbon monoxide IAQ meter, respectively. Data on household characteristics were collected using a structured questionnaire and an observational checklist. Data were analysed using STATA version 14.0. Linear regression was used to establish the relationship between PM2.5, CO concentrations and household cooking characteristics.ResultsThe majority (89%, 332/374) of the households used charcoal for cooking. More than half (52%, 194/374) cooked outdoors. Cooking areas had significantly higher PM2.5 and CO concentrations (t = 18.14, p ≤ 0.05) and (t = 5.77 p ≤ 0.05), respectively. Cooking outdoors was associated with a 0.112 increase in the PM2.5 concentrations in the cooking area (0.112 [95% CI: -0.069, 1.614; p = 0.033]). Cooking with moderately polluting fuel was associated with a 0.718 increase in CO concentrations (0.718 [95% CI: 0.084, 1.352; p = 0.027]) in the living area.ConclusionsThe cooking and the living areas had high concentrations of PM2.5 and CO during the cooking time. Cooking with charcoal resulted in higher CO in the living area. Furthermore, cooking outdoors did not have a protective effect against PM2.5, and ambient PM2.5 exceeded the WHO Air quality limits. Interventions to improve the indoor air quality in informal settlements should promote a switch to cleaner cooking energy and improvement in the ambient air quality.

Oxygen deficient Ce doped CO supported on alumina catalyst for low-temperature CO oxidation in presence of H2O and SO2

The carbon monoxide (CO) oxidation has been carried out using Ce doped Co/Al2O3 prepared by coprecipitation followed by deposition precipitation. The 0.1 mol Ce doped Co supported on alumina showed maximum CO oxidation activity compared to the undoped catalyst at a low temperature. The physicochemical characteristics of synthesized catalysts were investigated by FTIR, XRD, Raman, XPS, 27Al solid-state NMR, H2-TPR, HR-TEM, etc. Ce doping promoted a distortion in the cobalt lattice structure. The distortion leads to an increase in reactive oxygen and the number of oxygen vacancies. In addition, Ce modification prevents the generation of the cobalt aluminate phase and stimulates the production of the Co3O4 active phase for CO oxidation. The presence of hexa and penta-coordinated alumina increases the defect and oxygen vacancy formation, which was responsible for a higher CO oxidation rate. The Ce doped Co/Al2O3 catalyst showed maximum water and SO2 tolerance due to the Ce doping. The mechanistic and kinetic details for CO oxidation have been explained by correlating with characterization.

Detailed Analysis of PAH Formation, Toxicity and Regulated Pollutants in a Diesel Engine Running on Diesel Blends with n-Propanol, n-Butanol and n-Pentanol

There are a number of emissions produced by internal combustion engines that are regulated to limit atmospheric pollution. However, it is equally important for both environmental and human health to also monitor and control polycyclic aromatic hydrocarbons (PAHs). Using high-carbon alcohols with straight-chain structures, such as n-propanol (Pro), n-butanol (Bu) and n-pentanol (Pen), together with diesel fuel (D), can be a way to reduce these harmful pollutants. In this study, nine different test fuels were created by mixing each higher alcohol with diesel fuel at 5%, 20% and 30% mixing ratios. In order to compare the effects of these test fuels on regulated pollutants and PAH compounds, fuel blends were evaluated in a diesel engine at partial loads and at a constant speed. Regulated emissions were measured using a standard 5-gas analyzer, and PAHs were detected and quantified using rigorous analytical chemistry methods, such as gas chromatography–mass spectrometry (GC–MS). While higher carbon monoxide (CO) and hydrocarbon (HC) pollutants were emitted by the binary blends due to their high oxygen content and latent heat of evaporation (LHE), a decrease in nitrogen oxides (NOx) emissions between 4.98% and 20.08% was observed depending on the alcohol concentration. With the exception of the 20% n-pentanol mixture, PAH concentrations in the exhaust gas were significantly reduced in other binary blends. The 35% n-butanol mixture stood out in reducing total PAHs by 80.98%. In toxicity reduction, the 20% n-propanol mixture was the most effective with a decrease of 91.23% in toxicity. Overall, higher alcohols have been shown to be effective additives not only in reducing overall PAH emissions and toxicity, but also in reducing high-ring and heavier PAHs, which are more carcinogenic and cause a greater risk to engine lifedue to wet stacking under cold starting or low-load conditions.