Carbon Capture Science & Technology最新文献

Enhancing photosynthesis is a pivotal strategy for achieving sustainable plant production. Blue and red light facilitate plant growth since these wavelengths are readily absorbed by chlorophyll pigments and power crucial photosynthetic processes. In this investigation, double light conversion films were prepared by incorporating biomass-derived carbon dots into a polyvinyl alcohol matrix (CDs@PVAs). The study conclusively demonstrated that CDs@PVAs can convert ultraviolet and green light from sunlight into blue and red light. Using 2-week-old Athaliana plants as the model organism, the Athaliana plants were covered with CDs@PVAs and then exposed to simulated sunlight (0.57 mW cm⁻²) for 1 hour. The Fv/Fm value in the presence of the CDs@PVAs was approximately 12% higher than without the film, indicating a significant boost in photosynthesis. Analysis of gene expression showed that the CDs@PVAs cause significant upregulation of genes associated with photosynthesis. These double light conversion films thus emerge as promising contenders for eco-friendly plant cultivation methods that circumvent reliance on electric power. Their potential applications in agriculture are substantial, underscoring their significance in promoting sustainable practices.

Injecting CO₂ into subsea basalt can provide permanent storage via multiple trapping mechanisms, including mineralization reactions which convert the CO₂ into solid carbonates over time. Injecting CO₂ together with water can accelerate the process of mineralization, but presents additional challenges, such as high energy and water requirements. A techno-economic model of CO₂ transport and injection into ocean basalt was developed to compare injection strategies using pure supercritical CO₂, pure liquid CO₂, and CO₂ dissolved in seawater. The model was applied to a representative injection site off the coast of British Columbia, Canada. Injection of CO₂ dissolved into seawater was found to be more energy and cost intensive than injection of supercritical or liquid CO₂; this is primarily due to the reduced quantities of CO₂ that can be injected into each well, and additional pumping energy required for the accompanying seawater. For the base assumptions, transport and storage costs for supercritical, liquid, and dissolved injection were estimated as $43/t, $38/t, and $250/t respectively. Their energy requirements were estimated as 93 kWh/t, 90 kWh/t, and 213 kWh/t respectively. The current best estimates of geological parameters for ocean basalt suggest good injectivity and very large storage capacities per well. This may help to compensate for the additional project expenses incurred by deep water, allowing cost-effective liquid and supercritical injection. However, this result is sensitive to high uncertainties in both geological parameters and component cost data.

Electrochemical CO₂ reduction to synthetic fuels and commodity chemicals using renewable energy offers a promising approach to mitigate CO₂ emissions and alleviate energy crisis. Copper-based catalysts show potential for electrochemical CO₂ reduction applications, while they face the key challenges of high potential, sluggish kinetics, and poor selectivity. In this work, Cu-Zn, Cu-Co, Cu-Cd, and Cu-In bimetallic catalysts are synthesized via the electrodeposition method for electrochemical CO₂ reduction to syngas with adjustable CO/H₂ ratios. The bimetallic catalysts are characterized using various techniques to reveal their crystalline structures, morphologies, and elemental compositions. The structure-property-activity relationships of these catalysts are investigated to identify optimal candidates for electrochemical CO₂ reduction applications. The findings reveal that the bare Cu mesh catalyst exhibits poor CO₂ reduction activity, and the products are dominated by hydrogen evolution reaction (HER). The bimetallic catalysts exhibit improved CO₂ reduction performance, with the Cu-Zn and Cu-Cd catalysts showing excellent activity, and the CO/H₂ ratio in syngas can be tuned over a wide range by adjusting the applied potential. The Cu-Zn and Cu-Cd catalysts demonstrate outstanding performance with Faradic efficiencies of ∼90 % and ∼80 % towards syngas production with CO/H₂ ratios of ∼2.0 and ∼1.5 at −0.81 and −1.01 V vs. RHE, respectively, making the produced syngas suitable for various industrial applications. Stability tests over 450 min show that the Cu-Zn and Cu-Cd catalysts maintain stable catalytic activity, syngas selectivity and CO/H₂ ratio, making them robust candidates for syngas production. The results will provide valuable insights into the design of robust catalysts for electrochemical CO₂ reduction, offering a promising path toward sustainable syngas production.

As atmospheric CO₂ levels continue to rise, contributing to the climate crisis, there is an increasing urgency to separate this gas from others and to expedite related research. Metal-Organic Frameworks (MOFs), known for their porosity and tunability, have already made significant impacts in this field, particularly to be used as part of a membrane material. This study introduces a novel method to enhance the CO₂ separation capabilities of MOFs-based mixed matrix membranes (MMMs). Instead of taking the traditional approach by functionalizing the MOF's ligands or varying the metal or metal-oxo MOF nodes, we harness the properties of metal atoms by integrating them as central elements within porphyrinic MOF linkers through a simple post-metalation method. As a result, by incorporating the post-metalated MOF-525 as fillers into the 6FDA-DAM (6FDA: 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride; DAM: 2,4,6-trimethyl-1,3-diaminobenzene) polymer to fabricate MMMs, we effectively demonstrate improved CO₂/N₂ and CO₂/CH₄ gas separation capabilities of around 20 % without the necessity to use a very high MOF loading (only 2 wt%). Further analysis on the gas transport reveals that such a performance improvement mainly comes from the enhanced CO₂ solubility, which might be attributed to the presence of the metal atoms in the post-metalated MOF 525. Lastly, in order to get a more comprehensive understanding, we also carry out a computational study as a tool to validate and predict the experimental results of our MMMs. This study then opens up the possibility to further investigate the efficacy of introducing various metal atoms in other porphyrinic MOFs when they are used as fillers to significantly boost the CO₂ separation performance of MMMs.

The membrane-cryogenic hybrid process is a promising CO₂ capture process, which combines the advantages of membrane and cryogenic, such as high efficiency (up to 98 % CO₂ captured) and low energy consumption (specific energy consumption around 1.7 MJ/kg CO₂ avoided). Through pretreatment by membranes, CO₂ concentration can be increased, which makes it possible to separate CO₂ via phase change in the cryogenic unit. This work reviews the current status of the development of membrane-cryogenic hybrid processes. The synergy between membrane and cryogenic separation is summarized to identify the bottleneck of such processes and provide insights for process improvement. It was found that cold temperatures would be beneficial to reduce CO₂ activation energy and then improve CO₂ selectivity of membranes. To further improve the CO₂ separation performance, the potential intensification methods of the membrane-cryogenic hybrid process including cold-membrane synthesis, process optimization via heat integration are discussed and envisioned.

Utilizing CO₂ as a carbon source to produce high-value compounds, such as light olefins, is one of the most promising approaches to mitigate CO₂ emissions. Efficient catalysts are critical for optimizing selectivity and yield of light olefins, which is necessary to make the CO₂-to-light olefin process economically viable. Therefore, this review focused on various Fe-based catalysts and multifunctional catalysts containing zeolite used for producing short-chain olefins via CO₂ hydrogenation. There are currently two main strategies to hydrogenate CO₂ into light olefins in a single step: the CO₂−FTS route and the MeOH-mediated route. The primary objective of the CO₂-FT approach is to selectively produce the necessary C₂–C₄ olefins, with a focus on the coordination of active metals, promoters, and supports to adjust the surface H/C ratio, which is crucial for the formation of C₂–C₄ olefins. However, obtaining a high productivity of C₂–C₄ olefins from CO₂ hydrogenation requires a significant improvement in activity with inhibiting secondary reactions. Currently, tandem catalysts containing SAPO-34 are currently favoured for the higher production of short-chain olefins from the hydrogenation of CO₂, owing to their high oxygen vacancies, zeolite topology, and zeolite acidity. Specifically, In₂O₃-based formulations are sufficiently promising to get past the drawbacks of traditional iron catalysts. Tandem catalysts with metal oxide In₂O₃/ZrO₂ and SAPO-34 components demonstrated promising results in reducing CO product poisoning. This article describes the latest progress, challenges, and prospects for research concerning CO₂ hydrogenation into short-chain olefins using iron-based catalysts and alternative catalysts with multifunctional properties.

Negative emission technologies (NETs) are considered essential to keep global warming below 2 °C. Situating wind-powered carbon dioxide removal (CDR) devices offshore and injecting carbon dioxide (CO2) into deep-water sub-seafloor basalt aquifers has the potential to offer large CO2 removal capacity. It also avoids land and water-use competition and provides additional low-risk protections against post-injection leakage compared to terrestrial CO2 storage. This paper seeks to identify locations where offshore wind and potential basalt storage locations exist within close proximity to one another around the globe. A global mean wind power density map at 150 m height was computed using 30 years (1986–2016) of ERA5 hourly wind speed reanalysis data. Offshore regions with mean wind speed greater than 8 m/s were identified. Offshore regions with basalt aquifers along seismic or aseismic ridges which provide potential CO2 storage sites were identified and selected based on sediment thickness, age, and distance from plate boundaries. Four scenarios were constructed to capture a range of constraints with implications for technical, economic and regulatory difficulties. For each scenario, eligible regions for CO2 injection were filled by regularly spaced grid points and the distance to the nearest eligible wind resource was calculated for each point to identify the most promising configurations. Total available storage capacity within reach of wind resources was estimated to be between 4,300Gt and 196,000Gt depending on both uncertainties in porosity and other imposed constraints; even the most conservative estimates represent enormous capacity compared to global targets for negative emissions technologies. Typically, the best areas were found close to the poles due to the greater prevalence of good wind resources in those areas. Site-specific properties such as water depth and distance from shore are computed for the identified locations in order to characterize the conditions in which such locations are typically found.

Electrochemical CO₂ reduction can convert CO₂ into high-value-added products for special forms of energy storage and efficient carbon utilization for renewable electricity. To investigate the influence of biochar-Cu-based catalysts properties on electrochemical CO₂ reduction performance, Cu is loaded onto rice husk-based biochar by impregnation method combined with pyrolysis and calcination in this study. The three synthesized biochar-Cu-based catalysts are tested for activity and electrochemical CO₂ reduction performance in Flow Cell. The results show that biochar's properties, such as its high specific surface area, rich pore structure, and adjustable pore structure, provide sufficient sites for CO₂ reduction. Urea can relatively increase the copper loading by 44 %, but it will also increase the clustering of copper. In the reduction performance test, the current density of char-Cu-700 is 2.08 times higher than that of char-Cu and 1.45 times higher than char-Cu-N at a reduction potential of -0.45 (V vs. RHE). The current density enhancement of the catalyst loaded on biochar with Cu particle size of 10 nm is about 50 % higher than that of the catalyst with a particle size of 20 nm. It indicates that the smaller the particle size of Cu at the nanoscale, the lower the average coordination of surface atoms and the greater the catalyst's reactivity. This study provides novel ideas for synthesizing biochar-Cu-based catalysts, lays part of the theoretical foundation for using biochar-Cu-based catalysts for electrochemical CO₂ reduction, and provides experimental support for optimizing the catalyst structure.

In recent years, research into biphasic solvents has become an important direction more efficient control of CO₂ emissions. However, most biphasic absorbents still face challenges such as low cyclic capacity and high viscosity of the rich phase. To develop a novel solvent with enhanced cyclic capacity and reduced regeneration energy consumption, a biphasic solvent consisting of DETA/Isobutanol/H₂O was proposed. The results demonstrate excellent absorption and desorption performance of the DETA/Isobutanol/H₂O biphasic solvent, with an absorption capacity ranging from 1.13 to 1.35 mol/mol and a cyclic capacity ranging from 0.61 to 0.84 mol/mol. After conducting 5 times absorption-desorption experiments, the cyclic capacity of DETA/Isobutanol/H₂O biphasic solvent remained at 0.8 mol/mol. The estimated energy consumption for regeneration, under lean phase load, was calculated to be 2.42 GJ/t CO₂, which was 42.24 % lower than that of 30wt% MEA aqueous solution (4.19 GJ/t CO₂). The DETA/Isobutanol/H₂O solution exhibits promising potential in terms of absorption-desorption performance and regenerative energy consumption, making it an exceptional CO₂ absorbent.

This review provides a comprehensive analysis of the latest development of hydrogen (H₂)-selective metallic membranes for pre-combustion carbon dioxide (CO₂) capture. Highlighting the essential role of these membranes in CO₂ capture and storage technologies, we detail the membrane performance through the measurement of H₂ permeability under different operating conditions (i.e., temperature and pressure). Our assessments cover the advancement in alloy compositions, surface treatments, and manufacturing techniques to achieve improved membrane performance. Apart from this, in this review, we discuss the challenges encountered in fabricating metallic membranes, such as embrittlement, sulfur contamination, and high production costs, while suggesting potential solutions to these issues. Last but not least, future research direction for metallic membranes is proposed to emphasize the important strategies in developing these membranes in a scalable and cost-effective manner.