Carbon Monoxide Production Research Articles

Thermodynamic phase control of Cu-Sn alloy electrocatalysts for selective CO2 reduction.

In the electrochemical CO2 reduction reaction (CO2RR), Cu alloy electrocatalysts can control the CO2RR selectivity by modulating the intermediate binding energy. Here, we report the thermodynamic-based Cu-Sn bimetallic phase control in heterogeneous catalysts for selective CO2 conversion. Starting from the thermodynamic understanding about Cu-Sn bimetallic compounds, we established the specific processing window for Cu-Sn bimetallic phase control. To modulate the Cu-Sn bimetallic phases, we controlled the oxygen partial pressure (pO2) during the calcination of electrospun Cu and Sn ions-incorporated nanofibers (NFs). This resulted in the formation of CuO-SnO2 NFs (full oxidation), Cu-SnO2 NFs (selective reduction), Cu3Sn/CNFs, Cu41Sn11/CNFs, and Cu6Sn5/CNFs (full reduction). In the CO2RR, CuO-SnO2 NFs exhibited formate (HCOO-) production and Cu-SnO2 NFs showed carbon monoxide (CO) production with the faradaic efficiency (FE) of 65.3% at -0.99 V (vs. RHE) and 59.1% at -0.89 V (vs. RHE) respectively. Cu-rich Cu41Sn11/CNFs and Cu3Sn/CNFs enhanced the methane (CH4) production with the FE of 39.1% at -1.36 V (vs. RHE) and 34.7% at -1.50 V (vs. RHE). However, Sn-rich Cu6Sn5/CNFs produced HCOO- with the FE of 58.6% at -2.31 V (vs. RHE). This study suggests the methodology for bimetallic catalyst design and steering the CO2RR pathway by controlling the active sites of Cu-Sn alloys.

Carbon monoxide and prognosis in smokers hospitalised with acute cardiac events: a multicentre, prospective cohort study

Smoking cigarettes produces carbon monoxide (CO), which can reduce the oxygen-carrying capacity of the blood. We aimed to determine whether elevated expiratory CO levels would be associated with a worse prognosis in smokers presenting with acute cardiac events. From 7 to 22 April 2021, expiratory CO levels were measured in a prospective registry including all consecutive patients admitted for acute cardiac event in 39 centres throughout France. The primary outcome was 1-year all-cause death. Initial in-hospital major adverse cardiac events (MAE; death, resuscitated cardiac arrest and cardiogenic shock) were also analysed. The study was registered at ClinicalTrials.gov (NCT05063097). Among 1379 patients (63±15 years, 70% men), 368 (27%) were active smokers. Expiratory CO levels were significantly raised in active smokers compared to non-smokers. A CO level >11parts per million (ppm) found in 94 (25.5%) smokers was associated with a significant increase in death (14.9% for CO>11ppm vs. 2.9% for CO≤11ppm; p<0.001). Similar results were found after adjustment for comorbidities (hazard ratio [HR] [95% confidence interval (CI)]): 5.92 [2.43-14.38]) or parameters of in-hospital severity (HR 6.09, 95% CI [2.51-14.80]) and propensity score matching (HR 7.46, 95% CI [1.70-32.8]). CO>11ppm was associated with a significant increase in MAE in smokers during initial hospitalisation after adjustment for comorbidities (odds ratio [OR] 15.75, 95% CI [5.56-44.60]) or parameters of in-hospital severity (OR 10.67, 95% CI [4.06-28.04]). In the overall population, CO>11ppm but not smoking was associated with an increased rate of all-cause death (HR 4.03, 95% CI [2.33-6.98] and 1.66 [0.96-2.85] respectively). Elevated CO level is independently associated with a 6-fold increase in 1-year death and 10-fold in-hospital MAE in smokers hospitalized for acute cardiac events. Grant from Fondation Coeur & Recherche.

Electrochemical CO2-to-CO via enriched oxygen vacancies at gold/ceria interfaces

We report a strategy of catalyst design to modulate oxygen vacancies through the control of Au/ceria interface structures, promoting Au activity for carbon monoxide production in carbon dioxide electroreduction.

Integrated Capture and Electrochemical Conversion of CO2 into CO

The capture and electrochemical conversion of CO2, powered by renewable electricity, is an attractive method of sustainably producing valuable chemicals and fuels (e.g. carbon monoxide (CO)), reducing atmospheric CO2, and storing intermittent renewable energy. Integrated capture and conversion (reactive capture) of CO2 presents a CO2-to-CO electrolysis pathway that eliminates most of the upstream capital and energy costs by releasing CO2 directly inside the electrolyzer using an internal pH-swing. The reactive capture system readily allows for the collection of produced gas products via phase separation, thus minimizing downstream separation costs.Industrial-scale integration of reactive capture systems with upgrading processes require a pure and consistent product stream. Previous studies using bicarbonate electrolytes have demonstrated high selectivity towards CO. However, the limited CO2 capture capacity of bicarbonate electrolytes dilute the cathode product gas stream with excess CO2. This mandates a secondary CO2 capture unit and increases the cost of downstream separation. Other studies using carbonate or carbamate electrolyte as the inlet feed did not simultaneously achieve high CO selectivity and long-term stability.This study sought to improve the Faradaic efficiency (FE) toward CO in our carbonate electrolysis system by engineering a novel membrane electrode assembly structure. We designed a composite CO2 diffusion layer (CDL) between the cathode and the membrane that attains high CO selectivity by simultaneously achieving high alkalinity and sufficient CO2 availability at the cathode. We determined that the thickness, wettability, and permeability of the CDL affected species transport and were important optimization parameters. Applying this strategy, we produced syngas, a mixture of CO and hydrogen (H2), with an industrial H2/CO ratio of 1.16 at 200 mA cm-2. This corresponded to a CO Faradaic efficiency (FE) of 46% and energy intensity of 52 GJ tsyngas-1. The syngas produced in this system was not diluted by CO2 and contained sufficient CO content to meet industrial standards. We further increased the FE towards CO by exploring different capture solutions and designing selective catalysts for energy efficient CO production. System parameters such as temperature and pressure effects were also investigated to improve the CO2 concentration at the cathode. This study illustrated the potential for the industrial implementation of an energy efficient and capital cost effective CO2-to-CO pathway via reactive capture.

Development of Durable Large-Sized CO2 Electrolysis Cells for Industrial Applications

Utilization of carbon dioxide (CO2) as a feedstock of valuable chemicals is necessary to achieve carbon neutrality. Toshiba is developing the low-temperature zero-gap type CO2 electrolysis cells to produce carbon monoxide (CO) [1,2]. CO can further be converted into various chemicals and fuels by catalytic reactions with hydrogen. To make the CO2 electrolysis technology industrially feasible, it is necessary to establish high-throughput system by expanding the electrode area and stacking the cells. Large-sized cells and stacks often suffer from low Faradaic efficiency for the CO production, which is related to insufficient and nonuniform supply of reactant CO2 gas to the cathode reaction sites. This time we focused on the development of large-sized single cells and fabricated an electrolysis cell with 400 cm2 electrodes. With properly designed gas flow plates and gaskets, the cell voltage and the CO Faradaic efficiency of the fabricated cell at a current density of 400 mA cm-2 were comparable to those of the previously developed smaller cells with 4 cm2 electrodes. The CO concentration in the cathode outlet gas reached ca. 80% by controlling the inlet CO2 flow rate. Stability is another essential property of CO2 electrolysis cells required for the industrial application. Cathode flooding and salt precipitation are major stability issues characteristic of relatively short-term operations, whose detailed mechanism is still in debate [3]. To mitigate those stability issues, we focused on the cathode inlet humidity and the pressure difference between the cathode and the anode. The former is related to the salt concentration in electrolyte solution around the cathode reaction sites, and the latter is related to the convection of electrolyte from the anode side to the cathode side. By controlling those parameters, stable performance over 100 h was achieved.Part of this work was commissioned by Ministry of the Environment, Government of Japan.[1] Y. Kofuji, A. Ono, Y. Sugano, A. Motoshige, Y. Kudo, M. Yamagiwa, J. Tamura, S. Mikoshiba, and R. Kitagawa, Chem. Lett., 50, 482-484 (2021).[2] Y. Kiyota, Y. Kofuji, A. Ono, S. Mikoshiba, and R. Kitagawa, 242nd ECS Meeting, I05-1942 (2022).[3] M. Sassenburg, M. Kelly, S. Subramanian, W. A. Smith, and T. Burdyny, ACS Energy Lett., 8, 321-331 (2023).

The Impact of Fine Particulate Matters (PM10, PM2.5) from Incense Smokes on the Various Organ Systems: A Review of an Invisible Killer

AbstractThe drastic increase in industrialization has led to numerous adverse effects on the environment and human health. Respiratory tract disorders are one of the major emerging global health issues that lead to a high mortality rate every year. The quality of indoor and outdoor air has lowered in the last decade.The quality of indoor air has deteriorated by cooking, smoking, and burning incense sticks or smoke. The smoke released from incense and incense sticks contains gaseous products (carbon monoxide, nitrogen dioxide, and oxide of sulfur), particular matter (PM10, PM2.5), volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons (PAHs). These toxic components released from various incense sources pose a significant risk to human health and the environment. The inhalation and exposure of smoke from various incenses is hazardous to health as it inevitably culminates in deadly organ‐related diseases. With such insights, the present review article focuses on the characteristic attributes of particulate matter released from incense and other sources emphasizing healthcare and environmental concerns.

Molecular dynamics simulation of gasification technology to produce hydrogen from biomass at different initial pressures in the presence of platinum catalyst

Biomass is a renewable source of energy obtained from biological materials. Gasification technology is commonly used to produce hydrogen (H2) from biomass. This method is based on the partial oxidation of the input materials and their conversion into synthetic gas. After gasification, the biomass is converted into a gas consisting of H2, carbon monoxide (CO), carbon dioxide (CO2), and other compounds. This research investigates the number of H2 molecules (n(H2)) and CO molecules (n(CO)) in the basic structure at a temperature and pressure of 1 bar and 1800 K. Additionally, the effect of initial pressure (IP) changes on the n(H2) and n(CO) produced with a 10 % volume fraction of platinum (Pt) catalyst was evaluated using molecular dynamics (MD) simulation. The results demonstrate that the produced n(H2) and n(CO) increase from 559 to 146 to 586 and 165, increasing the Pt nanocatalyst ratio from 1 % to 10 %. Furthermore, the n(H2) and n(CO) increase from 586 to 165 to 598 and 175, respectively, by increasing the IP from 1 to 5 bar. Also, the results reveal that the combustion efficiency (CE) increases from 62 % to 66 % with increasing IP from 1 to 5 bar. The application of this research is to study the production of hydrogen and carbon monoxide from biomass using gasification technology. This information can be useful for improving the efficiency of biomass gasification for hydrogen production.

Air-Blown Biomass Gasification Process Intensification for Green Hydrogen Production: Modeling and Simulation in Aspen Plus

Hydrogen produced sustainably has the potential to be an important energy source in the short term. Biomass gasification is one of the fastest-growing technologies to produce green hydrogen. In this work, an air-blown gasification model was developed in Aspen Plus®, integrating a water–gas shift (WGS) reactor to study green hydrogen production. A sensitivity analysis was performed based on two approaches with the objective of optimizing the WGS reaction. The gasifier is optimized for carbon monoxide production (Case A) or hydrogen production (Case B). A CO2 recycling stream is approached as another intensification process. Results suggested that the Case B approach is more favorable for green hydrogen production, allowing for a 52.5% molar fraction. The introduction of CO2 as an additional gasifying agent showed a negative effect on the H2 molar fraction. A general conclusion can be drawn that the combination of a WGS reactor with an air-blown biomass gasification process allows for attaining 52.5% hydrogen content in syngas with lower steam flow rates than a pure steam gasification process. These results are relevant for the hydrogen economy because they represent reference data for further studies towards the implementation of biomass gasification projects for green hydrogen production.

Investigation of co-gasification characteristics of coal with wood biomass and rubber seals in a fixed bed gasifier

The thermochemical processing of waste in gasification to hydrogen-rich gas is considered to be a novel, promising technological option, complementing the currently employed hydrogen production methods and an effective and environment friendly way of waste utilization. The paper discusses the results of the experimental study on this novel technological option of co-gasification of coal with automotive rubber seals or wood chips in a fixed bed reactor with the application of oxygen and steam mixture as a gasification agent. The experiments were performed with the use of waste to coal blending ratio of 10:90, 15:85 and 20:80 (%w/w), and at the temperature range of 700–900 °C. The contents of carbon monoxide, carbon dioxide, hydrogen and methane in the gaseous product reported in the study were in the range of 35–36 %vol., 31–33 %vol., 29–31 %vol., and 0.10–0.16 %vol., respectively. The maximum values of the lower heating value and the total gas volume were reported for fuel blends of 10%w/w waste content at 900 °C. Hydrogen and carbon monoxide production increased with process temperature, and declined with waste fraction in a fuel blend. Gasification of fuel blends composed of coal and rubber resulted in higher hydrogen production than the gasification of coal-biomass fuel blends, which may be attributed principally to the higher fixed carbon content and higher alkali index of rubber when compared to the respective values of wood chips.

Relationship between red blood cell lifespan and endogenous carbon monoxide in the common bottlenose dolphin and beluga.

Certain deep-diving marine mammals [i.e., northern elephant seal (Mirounga angustirostris), Weddell seal (Leptonychotes weddellii)] have blood carbon monoxide (CO) levels that are comparable with those of chronic cigarette smokers. Most CO produced in humans is a byproduct of heme degradation, which is released when red blood cells (RBCs) are destroyed. Elevated CO can occur in humans when RBC lifespan decreases. The contribution of RBC turnover to CO concentrations in marine mammals is unknown. Here, we report the first RBC lifespans in two healthy marine mammal species with different diving capacities and heme stores, the shallow-diving bottlenose dolphin (Tursiops truncatus) and deep-diving beluga whale (Delphinapterus leucas), and we relate the lifespans to the levels of CO in blood and breath. The belugas, with high blood heme stores, had the longest mean RBC lifespan compared with humans and bottlenose dolphins. Both cetacean species were found to have three times higher blood CO content compared with humans. The estimated CO production rate from heme degradation indicates some marine mammals may have additional mechanisms for CO production, or delay CO removal from the body, potentially from long-duration breath-holds.NEW & NOTEWORTHY This is the first study to determine the red blood cell lifespan in a marine mammal species. High concentrations of carbon monoxide (CO) were found in the blood of bottlenose dolphins and in the blood and breath of belugas compared with healthy humans. Red blood cell turnover accounted for these high levels in bottlenose dolphins, but there may be alternative mechanisms of endogenous CO production that are contributing to the CO concentrations observed in belugas.

Mechanistic Insight into Acceptorless Dehydrogenation of Methanol to Syngas Catalyzed by MACHO-Type Ruthenium and Manganese Complexes: A DFT Study.

The acceptorless dehydrogenation of methanol to produce carbon monoxide (CO) and dihydrogen (H2) mediated by MACHO-type 1-Ru and 1-Mn complexes was theoretically investigated via density functional theory calculations. The 1-Ru-catalyzed process involves the formation of active species 4-Ru through a methanol-bridged H2 release pathway. Methanol dehydrogenation by 4-Ru yields formaldehyde and 1-Ru, followed by H2 release to regenerate 4-Ru (rate-determining step, ΔG‡ = 32.5 kcal/mol). Formaldehyde further reacts with methanol via nucleophilic attack of the MeO- ligand in the Ru complex (ΔG‡ = 9.6 kcal/mol), which is more favorable than the traditional methanol-to-formaldehyde nucleophilic attack (ΔG‡ = 33.8 kcal/mol) due to the higher nucleophilicity of MeO-. CO is ultimately produced through the methyl formate decarbonylation reaction. Accelerated H2 release in the early reaction stage compared to CO results from the initial methanol dehydrogenation and condensation of formaldehyde with methanol. In contrast, CO generation occurs later via methyl formate decarbonylation. The 1-Mn-catalyzed reaction has reduced efficiency compared to 1-Ru for the higher Gibbs energy barrier (ΔG‡ = 34.1 kcal/mol) of the rate-determining step. Excess NaOtBu promotes the reaction of CO and methanol, forming methyl formate, significantly reducing the CO/H2 ratio as the catalyst amount decreases. These findings deepen our understanding of the methanol-to-syngas transformation and can drive progress in this field.

ZnIn2S4/TiO2 photocatalyst for CO2 photoreduction: Advancing sustainable energy conversion to renewable solar fuels

The rapid increase in CO2 concentration in the atmosphere raised global climate challenges, which creates attention for the researcher to mitigate CO2 from the atmosphere so that the environment can be sustained for generations. From the photocatalysis perspective, reducing CO2 into carbon monoxide (CO) and methane (CH4) is a promising pathway for sustainable solar fuel production. Here, we fabricated a heterojunction nanocomposite photocatalyst of ZnIn2S4 and TiO2. The photocatalyst was highly efficient for CO2 reduction with 1754 and 481 μmol/g yields of CO and CH4, respectively. The photocatalyst had excellent photocatalytic activity and was stable for five consecutive experiments without significant activity loss. The potential of ZnIn2S4/TiO2 photocatalyst to revolutionize carbon monoxide production for various applications underscores its significance in advancing sustainable carbon mitigation strategies.

Heme Oxygenase-1 and Its Role in Colorectal Cancer.

Heme oxygenase-1 (HO-1) is an enzyme located at the endoplasmic reticulum, which is responsible for the degradation of cellular heme into ferrous iron, carbon monoxide and biliverdin-IXa. In addition to this main function, the enzyme is involved in many other homeostatic, toxic and cancer-related mechanisms. In this review, we first summarize the importance of HO-1 in physiology and pathophysiology with a focus on the digestive system. We then detail its structure and function, followed by a section on the regulatory mechanisms that control HO-1 expression and activity. Moreover, HO-2 as important further HO isoform is discussed, highlighting the similarities and differences with regard to HO-1. Subsequently, we describe the direct and indirect cytoprotective functions of HO-1 and its breakdown products carbon monoxide and biliverdin-IXa, but also highlight possible pro-inflammatory effects. Finally, we address the role of HO-1 in cancer with a particular focus on colorectal cancer. Here, relevant pathways and mechanisms are presented, through which HO-1 impacts tumor induction and tumor progression. These include oxidative stress and DNA damage, ferroptosis, cell cycle progression and apoptosis as well as migration, proliferation, and epithelial-mesenchymal transition.

Dealuminated Beta stabilized bimetallic PtCo nanoparticles for oxidative dehydrogenation of propane with CO2

Oxidative dehydrogenation of propane in the presence of carbon dioxide (CO2) effectively promotes the utilization of alkanes and CO2 to produce high value-added olefins and carbon monoxide products. In this work, bimetallic PtCo nanoparticles with diameter of 1–2.5 nm loaded on dealuminated nano-Beta zeolite were successfully prepared for propane oxidative dehydrogenation with CO2. The silanol groups formed after dealuminization of nano-Beta zeolite acted as the anchoring sites to enhance the dispersion of PtCo nanoparticles, and the introduction of Co further promoted the uniform distribution of Pt, resulting in smaller bimetallic PtCo nanoparticles. By optimizing the Pt/Co ratio, the conversion of propane and CO2 at 550 °C was as high as 51.8 % and 30.6 %, respectively. The dealuminized Beta supported PtCo nanoparticles exhibited high stability during the reaction, and there was no obvious aggregation of PtCo nanoparticles after 6 h on stream. In this study, the highly efficient catalyst prepared by impregnation method using modified commercial zeolite as the carrier is suitable for large-scale production and shows great practical prospect in the application of propane oxidative dehydrogenation with CO2.

Feasibility of Efficient Pyrolysis of Wood Chips and its Product Yield in Developing Countries

This paper is about the feasibility of combustibles gases like methane, ethane and carbon monoxide production from wood pyrolysis. This first laboratory experimental stage objective was to see what products can be obtained from wood pyrolysis in absence of oxygen and presence of nitrogen. The effect of temperature on the product yields was investigated. Products were characterized using gas-chromatography. We found that products of wood pyrolysis for temperatures of 700, 800, 900, 1000 and 1100°C were char, CO2 and combustibles gases like CH4, C2H2, CO and tar. NH3 was not found in the produced gases.&#x0D; In our study, condensable gases were not recovered and quantified. A gas condenser would have been necessary inserted for this purpose at the outlet of the pyrolysis reactor before routing the gases to the mass spetrograph. This study show that char production decrease from 17.08% at 700°C on the weight basis to 12.95% at 1100°C. Gases and tar production decrease, going from 82.92% at 700 °C on the weight basis to 87.05% at 1100°C. Carbone dioxide production also increase with temperature. It is the biggest part of produced gases of the wood pyrolysis gases representing an average weight proportion of 6.99% of the initial wood. Carbone monoxide yield is almost constant, around 1.6% at 800, 900 and 1000°C thought its yield at 700°C was found slightly higher accounting for 2.29% weight of the initial wood. Ethylene (C2H4) is only produced in small amount compared to others combustibles gases like methane and carbon monoxide. Its proportion which was observed almost constant, around 0.14% on the weight basis in respect to the initial wood chips weight from 700 to 900°C dropped to 0.02% at 1000°C. Methane (CH4) is produced in weight basis proportions of 2.55% which remain almost constant from 700 to 1000°C.

Thermal Stability, Flame Retardancy and Flame Retardant Mechanisms of Hollow Glass Microspheres/Montmorillonite/Epoxy Sheet Molding Compound Composites

Epoxy sheet molding compound (ESMC) composites have excellent mechanical properties, dimensional stability and electrical insulation, and are widely used in the automotive industry. In our previous work silane coupling agent modified, hollow glass microspheres (SiHGM) and montmorillonite (MMT) were incorporated to enhance the mechanical properties of the ESMC composites. It was found that the ESMC composites containing MMT (EP/SiHGM/MMT-1) exhibited excellent mechanical strength. However, the flammability of the epoxy resin (EP) limits the use of ESMC composites for applications that require good flame retardancy. In this paper we describe our research in which MMT was used to increase the flame retardancy of ESMC composites. The results showed that the addition of MMT made the ESMC composites have excellent flame retardancy. The limiting oxygen index (LOI) of the ESMC composites containing 1 phr MMT (EP/SiHGM/MMT-1) was 26.8%, which was 8.94% higher than that of the ESMC composites without MMT (EP/SiHGM/MMT-0). In addition, the peak heat release rate (PHRR), average heat release rate (AHRR) and total heat release (THR) of the EP/SiHGM/MMT-1 were 322.8 kW/m2, 95.3 kW/m2 and 38.6 MJ/m2, respectively, which were 22.6%, 8.2% and 8.0% lower than those of EP/SiHGM/MMT-0. The carbon monoxide production (COP) and carbon dioxide production (CO2P) of EP/SiHGM/MMT-1 were 0.0092 g/s and 0.2071 g/s, respectively, which were 34.3% and 22.8% lower than those of EP/SiHGM/MMT-0. The fire growth index (FGI) of EP/SiHGM/MMT-1 was 2.4, which was a decrease by 29.4% compared to EP/SiHGM/MMT-0. In addition, the flame retardant mechanisms were revealed. We suggest that MMT promoted dehydration and charring of the epoxy resin and helped construct an intact physical barrier, which had good blocking effects. The prepared composite has great application prospects for those occasions that require high flame retardancy. Thus, this work provides an innovative strategy for preparing low density epoxy composites with excellent flame retardancy and high mechanical properties.

A novel model of a hydrogen production in micro reactor: Conversion reaction of methane with water vapor and catalytic

This study presents a comprehensive investigation of a thermally integrated membrane micro reactor for efficient hydrogen production through the conversion of methane with water vapor. The reactor design incorporates a catalytic Au/ZnO system to enhance performance. The effects of key operational variables, including inlet gas flow rate, pressure, temperature, water-to-methane ratio, and membrane thickness, were examined. Optimal conditions were sought to maximize methane conversion, hydrogen yield, and minimize carbon monoxide production. As feed flow increases, methane conversion decreases due to reduced retention time in the reactor. This decrease is almost six times greater at 240 °C than at 270 °C. Higher water-to-methane ratios improved methane conversion and reduced hydrogen and carbon monoxide production. Shell pressure affected methane conversion, with higher pressures resulting in decreased rates and carbon monoxide levels. As shell airflow velocity increases, methane conversion rises about 0.96 %. Tube pressure influenced hydrogen passage through the membrane, causing decreased hydrogen output from the tube section and increased output from the shell section, while reducing carbon monoxide emissions. These findings contribute to the optimization of a thermally integrated membrane micro reactor for efficient hydrogen production through water vapor-methane conversion.

Inverse-type CoOx-TiO2 catalysts for the Energy-Efficient Thermo-Photo Valorization of CO2

In this research, composite catalysts based on mixtures of titanium and cobalt oxides were synthesized and tested in the thermo-photo reduction of carbon dioxide. The cobalt loading varied between 2% and 8 M %, providing an outstanding activity in the selective production of carbon monoxide through the reverse water gas reaction. The sample doped with 4% Co optimized catalytic performance, with an excess over the photo and thermo alone processes above 27 % and an energy efficiency of 1.1 %. These values indicate that the sample displays the top performance reported so far. A physico-chemical characterization of the catalysts was also carried out showing that nearly amorphous cobalt (II) oxide entities are embedded within nanocrystalline anatase nanoplatelets within an inverse-type configuration. The use of in-situ infrared provides conclusive evidence that the promotion of the catalytic performance under dual excitation is intimately linked with the formation and evolution of formate-type species at the catalyst surface. A novel dual-excitation catalytic process using novel composite CoOx-TiO2 catalysts would open new ways for the energy-efficient elimination and valorization of carbon dioxide.

Thermogravimetric and thermovolumetric study of municipal solid waste (MSW) and wood biomass for hydrogen-rich gas production: a case study of Tashkent region.

Application of municipal solid and wood waste, as dominant sources of biomass, could be a promising alternative for producing energy from renewables via thermochemical gasification technology. In this paper, a study of thermogravimetric analysis (TGA) and excurrent gas composition produced by the municipal solid waste (MSW) and wood biomass gasification is presented. Thermogravimetric and heat flow curves for waste samples were performed at the temperature interval of 20-890 °C with a heating rate of 10 °C min-1 under a nitrogen atmosphere. According to thermal analysis data, differential scanning calorimetry (DSC) curves, the degradation stages of waste samples was determined, which correspond to the mono- or bimodal evolution of volatile compounds and the degradation of the resulting carbon residue. The gasification experiments were conducted in a high-pressure quartz reactor at temperatures of 850, 900, and 950 °C, using steam (0.3 g/min) and argon (2 dm3/min) as the gasifying agents. To ascertain the syngas composition, gas chromatography was employed in conjunction with a thermal conductivity detector. Both types of biomass showed remarkably similar syngas compositions. The highest concentration of hydrogen-rich gases was recorded at 950 °C for wood biomass, with 42.9 vol% and 25.2 vol% for hydrogen (H2) and carbon monoxide (CO), and for MSW, with an average 44.2 vol% and 18 vol% for H2 and CO. Higher temperatures improved the syngas composition by promoting endothermic gasification reactions, increasing hydrogen yield while decreasing tar and solid yields. This research helped to comprehend the evolution of the gasification process and the relationship between increased H2 and CO production as the gasification temperature increased.

Lignin Use in Enhancing the Properties of Willow Pellets

Shrub willow (Salix spp.) is an emerging lignocellulosic biomass utilized in fuel pellets as an energy source. However, improvements are needed to increase the efficacy of pellets in areas such as the energy content, durability, and hazardous carbon monoxide emissions. This study examined the effect of utilizing lignin as an additive on willow pellet properties. Two types of lignin were used in individual treatments: lignin recovered from the hot water extraction of willow (RecL) and commercial softwood kraft lignin (ComL). A statistical analysis of the ash content, energy content, bulk density, durability, pellet length, moisture absorption, and carbon monoxide emissions for the pellets with and without the addition of RecL or ComL lignin was conducted. The observed significant reduction in carbon monoxide emissions from RecL pellets was an important effect of the lignin addition. There were also significant increases in the energy content, bulk density, and durability of lignin-added pellets. While the production of carbon monoxide via pellets continues to be explored, lignin can be utilized as an additive to reduce carbon monoxide emissions and simultaneously improve other pellet properties.