Journal of CO2 Utilization最新文献

The use of synthetic natural gas (SNG) as a plug-and-play fuel coming from renewables can help to overcome the limitations given by the intermittency of renewable energy. A way to implement the production of SNG pass through the co-electrolysis of CO₂ to a mixture of hydrogen, carbon monoxide and carbon dioxide, steam and small amounts of methane, followed by CO and CO₂ methanation. The presence of different reactants and processes requires the comprehension and quantification of the kinetics of the reactions involved with the aim of optimizing methanation. In this work a kinetic model that considers both the direct CO₂ methanation and the indirect RWGS + CO methanation pathways has been developed over a Ni(10 %wt)/Ce_0.33Zr_0.63Pr_0.04O₂. The kinetic study made it possible to understand the influence of the reactants and products on the reactions through the calculation of reaction rates. This allowed to test, by linearization, the models found in the literature and their adjustment permitted to calculate sixteen kinetic parameters (activation energies, heats of adsorption and pre-exponential factors) present in the rate laws of methanation of CO₂, CO and the Reverse Water Gas Shift reaction. The models then made it possible to simulate the evolution of partial flow rates in an isothermal plug flow reactor and were compared to experimental data.

This study introduces a three-dimensional, densely packed amide polyphthalocyaninezinc, supported by fibrous phosphosilicate (FPS), for the first time (referred to as Complex@Zn-IL/FPS). The XPS and EDX images confirmed that the Complex@Zn-IL nanosaramic was evenly distributed on the FPS’s surface. The cycloaddition reaction from CO₂ and natural epoxide using Complex@Zn-IL/FPS nanosaramic as catalysts was reported. Furthermore, the catalyst’s structural heterogeneity was examined using various methods, including SEM, FT-IR, XPS, TEM, and TGA. There was no evidence of zinc leaching into the fluid. In addition, hot filtration provided a comprehensive understanding of the catalyst’s heterogeneous nature. The catalyst’s practical and straightforward reusability was noted after the reaction was completed.

Aggregate accounts for 60‐80% volume fraction of concrete, which has a great influence on the CO₂ emission and performance of concrete. Apart from natural coarse aggregate (NCA), recycled coarse aggregate (RCA) and carbonation recycled coarse aggregate (CRCA) are becoming an important component. This study established a database containing 925 experimental samples of compressive strength (CS) and CO₂ emission, which including NCA, RCA, and CRCA concrete respectively. Additionally, the CO₂ intensity index was introduced to evaluate the CS and CO₂ emission. Machine learning (ML) methods were utilized to establish prediction models for CS, CO₂ emissions, and CO₂ intensity. The significance of features was analyzed through SHAP and PDP. For the optimization of coarse aggregate mix proportion, the GA and MOPSO algorithms were employed for single and bi-objective optimization designs, respectively. The results indicated that the optimization of coarse aggregate mix proportion can effectively reduce CO₂ emission and CO₂ intensity of concrete. A CRCA content of 30% is optimal for achieving both enhanced CS and reduced CO₂ emissions. The carbonation treatment of RCA presents a viable approach for mitigating CO₂ footprint and enhancing the mechanical properties of RCA concrete. The proposed optimization frame can facilitate appropriate decision making for low-carbon concrete design.

The main objective of the present study is to synthesize iron oxide catalysts with engineered crystal defects and to clarify their crucial impact on the final catalytic activity in the CO2 hydrogenation process. The method used to engineer the desired crystal defects is based on changing the precipitation reaction conditions, such as the addition rate and the order of the precipitant during the primary phase of the synthesis of iron oxide catalysts. The catalyst synthesis process is based on the formation of iron oxalates in the first step, followed by thermal decomposition into iron oxides in the second step, which were subsequently tested as catalysts in CO₂ hydrogenation. The reversed double-beam photoacoustic spectroscopy used for advanced characterization of the prepared catalysts demonstrated that the observed change in catalytic activity is related to the energy and density of electron traps connected with the defects in the crystal lattice of the catalysts. These defects occur during the precipitation of oxalates, and their formation is significantly affected by changes in the precipitation conditions, i.e., the course of nucleation and growth of iron oxalate crystals. The results of the presented study thus affirmed the cardinal importance of defect engineering in heterogeneous catalysis.

In the quest to mitigate excessive CO₂ emissions, the electrochemical reduction of CO₂ (eCO₂R) into multi-carbon fuels and vital chemical precursors emerges as a compelling strategy. Meticulous control of the C–C coupling on a catalyst surface is a grand challenge in the selective production of desired C₂₊ products. Ethane and propanol are among the most desirable C₂₊ products in the gas and liquid phase, respectively. Herein, we demonstrate facile femtosecond laser-enabled tuning of Cu selectivity towards ethane and propanol. The laser-enabled tailoring of the Cu surface induces a shift from C₁ products to ethane and propanol. This shift in product composition is attributed to the concurrent creation of hierarchical porous structures, the stabilization of {111}, {200}, and {220} Cu₂O facets, and the promotion of the Cu¹⁺ oxidation state. These alterations collectively enhance the adsorption strength, leading to an increased propensity for C-C coupling and, consequently, an elevated selectivity toward C₂₊ products.

Valorisation of fruit processing by-products and waste is an important task for increasing the sustainability of agro-food sector. In this study, pitted sour cherry pomace was mechanically pre-fractionated into the 6 different particle size (>10, 4−10, 3−4, 1−3, 0.8−1, <0.8 mm) fractions (9.71−16.41 % proteins, 5.68−12.16 % fat, 62.55−78.39 % carbohydrates) and subjected to supercritical fluid extraction with CO₂ for the recovery of lipophilic constituents. Extract yield depended on fat content and was from 3.38 % to 8.69 %. Linoleic (38.52−47.11 %) and oleic (21.85−39.03 %) were major fatty acids, while triacylglycerols composed of these acids were major in the extracted oils. The concentrations of tocopherols, carotenoids and phytosterols in the extracts were 116.3−432.0, 1218−2564 and 4294−8449 μg/g. Antioxidant activity values were determined for the extracts and solids of initial dry pomace and its residue after extraction. Folin-Ciocalteu Index (basically similar to total phenolic content, TPC), ABTS^•+-scavenging and oxygen radical absorbance (ORAC) values of extracts were 7.86−8.75 mg of gallic acid equivalents/g, 1.72−6.37 and 35.12−95.49 of mg trolox equivalents/g, respectively. It is the first report on comprehensive characterisation of sour cherry pomace fractions extracted by supercritical CO₂.

A 3D flower-like structure composed of porous bismuth oxychloride (p-BiOCl) nanosheets was synthesized through a hydrothermal process utilizing Bi(NO₃)₃･5 H₂O, cetyltrimethylammonium bromide (CTAB) and LiCl. Powder X-ray diffraction (PXRD) studies confirmed the successful formation of the p-BiOCl. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were exploited to identify the nanosheet structure. The catalyst appeared as reduced Bi⁰ nanosheets at an applied cathodic potential of − 0.92 V (vs. RHE (reversible hydrogen electrode)). The maintenance of Bi nanosheet structures, controlled by the cationic surfactant of CTAB, resulted in enhanced electrochemical activity with a favorable Tafel slope and lower charge resistance. Defects of under-coordinated Bi sites and oxygen vacancy with interconnected 3D structures possess abundant active sites that further assist the activity. In 1.0 and 2.0 M KHCO₃ electrolytes, the catalyst achieved a maximum current density of − 80 and 100 mA/cm², respectively, at − 0.92 V (vs. RHE) with Faradaic efficiency > 99 % for converting CO₂ to formate in H-cell electrolyzers. The substantial H/D kinetic isotope effect revealed from H₂O versus D₂O electrolytes, and the feature of bicarbonate concentration-dependent performance provided the mechanistic insights that bicarbonate intermediates are in equilibrium with CO₂, activated by water, in the aqueous environment, together with the effects of electrode surface modulated by CTAB, are essential for the efficient electrochemical CO₂ reduction reaction to formate.

While the use of carbonated water in enhanced oil recovery (EOR) within the petroleum sector is well-documented, its applications in other fields remain relatively unexplored. This review aims to shed light on the versatile utility of carbonated water across various sectors, with the objective of stimulating further research to address sustainability challenges. Carbonated water can benefit industrial, agricultural, and domestic contexts by offering a sustainable method for utilizing waste CO₂. This review examines the diverse applications of carbonated water, including its role in enhancing oil recovery, aiding medical and healthcare research, reducing carbon footprint in construction, influencing biofuel production and green chemistry, and contributing to the agricultural sector, household, and cleaning domains. The findings suggest that carbonated water could serve as a viable source for CO₂ utilization, presenting significant advantages across various fields. Despite initial costs and infrastructure requirements, integrating carbonated water into existing practices - especially in agriculture and food production - offers clear benefits for offsetting carbon emissions. Continued research and development are essential to advance these technologies and promote sustainable and environmentally responsible practices. We assert that ongoing research and innovation are crucial to unlocking the full potential of carbonated water in various emerging applications.

Using carbon dioxide (CO₂) as a raw-material to produce value-added chemicals has a strategic role to play in the decarbonization of energy resources and the transition to a climate-neutral economy. E-methanol, Synthetic Natural Gas (SNG) and e-kerosene are one of the most promising pathways to convert CO₂. In this context, the aim of this work is to propose an optimized and integrated CO₂ to methanol process and then to compare it to the CO₂ to SNG process from economic and environmental points of views. An optimized reactor configuration in the CO₂ to methanol conversion unit has been successfully implemented in Aspen Plus® and leads to a thermal energy self-sufficiency of this unit. A heat integration with an advanced capture unit has been performed where 5 % of the heat requirement could be provided from the conversion unit while 95 % come from external steam source. Techno-economic assessment of the optimized process showed that methanol is more profitable when it is used as a raw material to synthetize other chemicals. As an energy carrier, SNG is more interesting. Compared to the reference scenario, a net CO₂ emission reduction of 70 % in the CO₂ to SNG route and of 60 % in the CO₂ to methanol route were obtained. Concerning the fossil depletion impact, in both cases, a reduction of more than 60 % was noticed (ca. 75 % in CO₂ to SNG route and 61 % in CO₂ to methanol case).

The global increase in energy demand requires a continuous search for renewable and clean alternative resources to fossil fuels. Hydrogen is emerging as a promising energy carrier for the future; its production via photocatalysis, driven by sunlight, can directly convert solar energy into a usable or storable energy resource. However, water splitting requires sacrificial agents or electron donors/hole scavengers, such as short-chain organic acids. This research explores the use of lactic acid as a source for photocatalytic hydrogen production, offering valuable alternatives for wastewater management and renewable energy production. This study employed the innovative supercritical antisolvent (SAS) technique to micronize the precursors of both the active phase (CeO₂) and co-catalyst (CuO), ensuring rapid and complete solvent removal and size reduction of photocatalyst precursors. The prepared samples were characterized by field emission scanning electron microscopy (FESEM), Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS) analysis, Brunauer-Emmett-Teller (BET) analysis and thermogravimetric analysis (TGA). This study has shown that the micronization process resulted in a notable improvement in CeO₂ photocatalytic activity, attributed to the reduction of the dimensions of the powders. Hydrogen production was equal to 3989 μmol L⁻¹ for the SAS-produced photocatalyst while using a commercial CeO₂ sample resulted in H₂ production of 2519 μmol L⁻¹. The enhanced photoactivity of CeO₂-CuO composites was found to be related to the presence of CuO. The optimal CuO amount was equal to 0.5 wt%, determining a hydrogen production of 9313 μmol L⁻¹ after 4 h of UV irradiation time. A photocatalytic test carried out with deuterated water (D₂O) instead of distilled H₂O demonstrated that hydrogen was preferentially produced from water splitting reaction, whereas lactic acid acted as a sacrificial agent being oxidized from positive holes photogenerated in the valence band of CuO.