Conversion Of Carbon Dioxide Research Articles

Enhanced selective photocatalytic CO2 reduction to CO on AuPd decorated Bi2O2.33 nanosheets

Photocatalytic conversion of carbon dioxide (CO2) into valuable fuels addresses pressing needs for renewable energy and carbon neutrality. However, conventional photocatalytic CO2 reduction on semiconductor is usually limited by sluggish electron kinetics, poor efficiency and low product selectivity. Herein, we developed a bimetallic Au/Pd-decorated Bi2O2.33 ultrathin nanosheet photocatalyst for highly selective CO2 reduction to CO under visible light irradiation. Bi2O2.33 nanosheets self-assembled from nanodots serve as ideal supports for Au/Pd anchoring due to abundant grain boundaries. Systematic characterization reveals the formation of alloyed Au/Pd nanoparticles on the Bi2O2.33 surface, which endowed a superior CO production rate of 436.8 μmol g−1 h−1 with a selectivity of 96.68 % from CO2 photoreduction. Quantum chemical calculations uncover that plasmonic Au/Pd alloys facilitates interfacial charge transfer and CO2 activation to form the CO-yielding intermediate. This work demonstrates an effective strategy for designing bimetallic plasmonic cocatalysts to optimize the photoreduction selectivity and efficiency of semiconductor photocatalysts.

Enhanced electrochemical reduction of CO2 to ethylene using boosted hydrophobicity of polyvinyl dichloride‐coated CuO electrodes

Cu-based materials have gathered significant attention as efficient electrocatalysts for converting carbon dioxide (CO2) to ethylene. CuO electrode was coated with Polyvinyl dichloride (PVDC) to finely tune its surface hydrophobicity, thereby effectively suppressing the hydrogen evolution reaction (HER) while promoting CO2 conversion to ethylene. PVDC modification on modulating proton transfer and enhancing the stability of the electrocatalysts was investigated systematically by varying the coating material, coating amount, and coating order. The CuO-PVDC electrode with a 50 μg/cm2 PVDC coating demonstrated an optimal level of hydrophobicity where the water contact angle (WCA) increased from 94.8 ° to 122.0 °) and led to highly efficient production of ethylene (FEethylene increased from 32.2% to 41.4%) at a low potential of −0.89 V vs. RHE, while effectively suppressing hydrogen evolution. Comparative tests and calculations revealed that PVDC modification balances proton transfer and CO2 availability. Hence, PVDC regulates the degree of reduction in CuO, leading to an increased proportion of Cu ions on the surface of the CuO-PVDC electrode, which facilitates the C-C coupling process exhibiting long-lasting hydrophobic properties without sacrificing conductivity, which is a promising strategy for mitigating the environmental impact of CO2 and their efficient conversion to produce valuable chemicals.

Current Research on CO2 Reduction Technology

The technology of carbon dioxide reduction has become a focus of research in the fields of environmental protection and sustainable development. With the exacerbation of global warming and energy crises, the issue of carbon dioxide emissions has become increasingly severe, exerting immense pressure on human society and the natural environment. In this context, carbon dioxide reduction technology has emerged as one of the important approaches to addressing climate change and energy demands. This technology involves the reaction of carbon dioxide with hydrogen or other reducing agents to produce organic compounds or fuels. Its advent not only promises to reduce carbon dioxide emissions but also to convert carbon dioxide into useful organic compounds or fuels, thereby facilitating the recycling of resources. The development of carbon dioxide reduction technology holds significant implications for addressing climate change and energy demands. By employing this technology, discarded carbon dioxide can be transformed into valuable products, reducing reliance on fossil fuels, lowering greenhouse gas emissions, and providing new energy sources for sustainable development. Furthermore, carbon dioxide reduction technology has the potential to integrate with other fields such as photocatalysis and electrochemistry, further expanding its application scope and reducing costs. This paper aims to provide reference and guidance for further research and industrial application of carbon dioxide reduction technology, promoting its sustainable utilization and environmental friendliness in practical production.

Size‐Dependent Multi‐Electron Donation in Metal‐Complex Quantum Dots Hybrid Catalyst for Photocatalytic Carbon Dioxide Reduction

AbstractThe effective conversion of carbon dioxide (CO2) into valuable chemical fuels relies significantly on the donation of multiple electrons. Its efficiency is closely linked to both the density and lifetime of excited charge carriers. In this study, a hybrid catalyst system comprising covalently bonded InP/ZnS quantum dots (QDs) and Re‐complexes is showcased. The electronic band alignment between the QDs and the Re‐complexes is revealed to dominate the multi‐electron transfer process for photocatalytic conversion to methane (CH4). Notably, the size of the QDs is found to be a determining parameter. Among the three QD sizes investigated, transient absorption spectroscopy studies unveil that rapid multi‐electron transfer from the QDs to the Re‐catalyst occurs in smaller QDs (2.3 nm) due to the substantial driving force. Consequently, the photocatalytic conversion of CO2 to CH4 is significantly enhanced with a turnover number of 6, corresponding to the overall apparent quantum yield of ≈1%. This research underscores the possibilities of engineering multi‐electron transfer by manipulating the electronic band alignment within a catalytic system. This can serve as a guide for optimizing photocatalytic CO2 reduction.

Electron-catalytic conversion of carbon dioxide into formaldehyde and methanol

Since the mid-19th century, there has been a steady increase in the amount of CO2 in the atmosphere, leading to global warming due to the greenhouse effect. CO2 can be utilized to obtain a large number of organic compounds. The formation of these compounds depends on the methods of CO2 processing, which include biological, thermal conversion, photochemical, and plasma methods. Most of these methods involve the use of catalysts. One of the plasma methods is the electron-catalytic method using a barrier discharge. Studies on the catalytic conversion of CO2 into methanol and formaldehyde were carried out on a laboratory setup consisting of two sources of low-temperature plasma – dischargers, one of which contains a heterogeneous catalyst. Water vapor was used as the source of hydrogen. The formation of methanol and formaldehyde was investigated under different operating modes of the setup. The effect of sample aging for a day was determined. As a result, there is an increase in the concentration of methanol in the sample from 5.8% to 49.74% and formaldehyde from 4.1% to 50.01% for different operating modes of the setup. The observed results are explained by a sharp increase in the yield of oxygen-containing radicals and , which are formed by the interaction of ozone, formed from CO2 in the discharge zone, with aqueous solutions.

Recent Advances and Challenges in Electrocatalytic Carboxylation of CO2

AbstractThe electrochemical fixation of carbon dioxide onto organic matter has emerged as a promising approach in recent years. By combining the unique features of electrochemistry with the goal of carbon dioxide fixation, researchers aim to develop new strategies that can contribute to a more sustainable and environmentally friendly synthesis of organic compounds. One advantage of electrochemical methods is their ability to provide both electrons and energy for chemical transformations. This allows for the direct conversion of carbon dioxide into valuable organic products, without the need for transition metal catalysts or harsh reaction conditions. As a result, electrochemical carbon dioxide fixation offers the potential for milder and more efficient processes compared to traditional methods. Scientists have made noteworthy progress in exploring different strategies for the fixation of carbon dioxide under electrochemical conditions. These strategies involve the activation of various types of chemical bonds, including C(sp2)–C(sp2), C(sp2)–H, C–X (X = halogen), and C(sp3)–X (X = S, C, O, N). This review aims to provide an overview of the current state of research on electrochemical carbon dioxide fixation into organic matter. It will discuss the different strategies employed, the key findings, and the challenges that remain to be addressed. By highlighting the recent advancements in this field, this review hopes to inspire further exploration and innovation in the area of electrochemical synthesis for carbon dioxide fixation.1 Introduction2 Electrocatalytic Monocarboxylation of CO2 2.1 Monocarboxylation of C(sp2)–C(sp2)2.2 Monocarboxylation of C(sp2)–H2.3 Monocarboxylation of C–X (X = Cl, Br, I)2.4 Monocarboxylation of C(sp3)–X (X = S, C, O, N)3 Electrocatalytic Dicarboxylation of CO2 4 Electrocatalytic Esterification of CO2 5 Conclusions

Towards Lipid from Microalgae: Products, Biosynthesis, and Genetic Engineering.

Microalgae can convert carbon dioxide into organic matter through photosynthesis. Thus, they are considered as an environment-friendly and efficient cell chassis for biologically active metabolites. Microalgal lipids are a class of organic compounds that can be used as raw materials for food, feed, cosmetics, healthcare products, bioenergy, etc., with tremendous potential for commercialization. In this review, we summarized the commercial lipid products from eukaryotic microalgae, and updated the mechanisms of lipid synthesis in microalgae. Moreover, we reviewed the enhancement of lipids, triglycerides, polyunsaturated fatty acids, pigments, and terpenes in microalgae via environmental induction and/or metabolic engineering in the past five years. Collectively, we provided a comprehensive overview of the products, biosynthesis, induced strategies and genetic engineering in microalgal lipids. Meanwhile, the outlook has been presented for the development of microalgal lipids industries, emphasizing the significance of the accurate analysis of lipid bioactivity, as well as the high-throughput screening of microalgae with specific lipids.

Introduction of a Conductive Layer into Flood-Resistant Gas Diffusion Electrodes with Polymer Substrate for an Efficient Electrochemical CO2 Reduction with Copper Oxide.

Conversion of atmospheric carbon dioxide (CO2) into valuable feedstocks is a crucial technology, and electrochemical reduction of CO2 is a promising approach that can provide a useful source of ethylene (C2H4). Gas diffusion electrodes (GDEs) placed at the interface of the CO2 gas and electrolyte can achieve high current density through a sufficient supply of dissolved CO2 to the reaction site, making them indispensable in industrial applications. However, conventional GDEs with carbon substrate have suffered from electrolyte flooding and consequent loss of efficiency, posing an obstacle for practical application. While flood-resistant GDEs with hydrophobic polymer substrate have been proposed recently, only conductive materials can be employed as electrocatalysts because of their insulative properties, despite the high activities of oxide materials such as copper oxide. Here, we introduce an aluminum conductive layer in GDE with polymer substrate to enable the use of electrically resistive catalysts. Cuprous oxide (Cu2O) with silver particles was tested as a model material and has shown prolonged stability (>17 h) with high C2H4 Faraday efficiency (>50%) while suppressing flooding. A thorough characterization revealed that the conductive layer makes Cu2O an efficient electrocatalyst, even on the polymer substrate, by providing sufficient electrons through its conduction path. This research significantly expands the scope of electrode design by enabling the incorporation of a wide range of nonelectrically conductive materials on GDEs with polymer substrate.

Synthesis of nanoporous solid polymer electrolyte AuNiCe/NC hydrogenation membrane electrode

In this study, using graphite fiber cloth as the support, gold-based solid polymer electrolyte (SPE) membrane electrodes were synthesized by high-vacuum ion beam sputtering, nitrogen doping of the support, combined electrochemical dealloying, and hot-pressing technology. The application of the SPE membrane electrode to couple hydrogen evolution and liquid organic hydrogen storage is of significant importance for sustainable hydrogen energy and efficient carbon dioxide conversion. Using various characterization techniques, we systematically analyzed the phase structure, surface morphology, porous structure, and electrocatalytic performance of the membrane electrode for the hydrogenation of cyclohexene. The results indicated that doping the carbonaceous support with nitrogen (NC), doping with cerium as catalyst promoter, and combined electrochemical dealloying can all enhance the activity of the catalyst. Cerium doping provides the catalyst with oxygen vacancies for accelerated electron transfer. After combined electrochemical dealloying, AuNiCe/NC formed a three-dimensional bicontinuous porous structure. The electrochemically active surface area increased by 23.94 times, the energy consumption of catalytic cyclohexene hydrogenation decreased by 35.7%, and current efficiency and the formation rate of cyclohexane increased by 54.9% and 29.4%, respectively.

Photocatalytic conversion of CH4 and CO2 to acetic acid over Cu/ZnO catalysts under mild conditions

The conversion of methane (CH4) and carbon dioxide (CO2) into high-value products under mild conditions is crucial for addressing the greenhouse effect and advancing C1 chemistry. In this study, Cu/ZnO catalysts were prepared through a one-step wet reduction process, and the catalytic conversion of CH4 and CO2 into acetic acid molecules (CH3COOH) was achieved via photon activation at ambient temperature. The yield of acetic acid was 411.6 μmol/Lgcat−1h−1 with a selectivity of 89.5 % under optimal conditions (100 mWcm−2 light intensity, 25 ± 2 °C, 2 MPa pressure, and a 1:1 CH4:CO2 volume ratio). Enhanced solubility of CH4 in aqueous under increased pressure and temperature was observed to improve acetic acid production. Additionally, the catalytic mechanism involved surface chemisorption of CH4 and CO2, facilitated by ZnO and Cu in the catalyst, leading to C-C coupling and subsequent acetic acid formation, driven by photogenerated electron-hole migration. This study provides a foundational understanding for the synthesis of value-added chemicals through CH4 and CO2 conversion via C-C coupling in mild environments.

Light-Mediated Sustainable Conversion of Carbon Dioxide to Valuable Methanol by Highly Efficient Covalent Organic Framework g-C3N4 Composites as a Reusable Photocatalyst

Light-Mediated Sustainable Conversion of Carbon Dioxide to Valuable Methanol by Highly Efficient Covalent Organic Framework g-C₃N₄ Composites as a Reusable Photocatalyst

Fast and sustainable CO2 conversion to propylene carbonate using fluoroalcohol-based bifunctional ionic liquids: Insights from experiments and theoretical simulations

We report on the metal-free and rapid catalytic conversion of carbon dioxide into cyclic carbonates under solventless conditions utilizing novel bifunctional fluoroalcohol-based ionic liquids (FBILs) as catalsyts. In the presence of 2.5 mol% 4-(1,1,1,3,3,3-hexafluoro-2-hydroxyisopropyl) phenyl trimethylammonium iodide (FBIL-1), under 0.1 MPa and 90 °C, excellent yield of propylene carbonate(>95%) was achieved in 1 h, which significantly shortens the reaction time, compared with the conventional catalysts. DFT calculations reveal that FBILs with fluorine-substituted hydroxyl groups exhibit stronger hydrogen bonding with epoxides compared to ILs lacking fluorine substitutions. The hydrogen bond length for ILF/PO is 1.658 Å, shorter than that for IL/PO (1.813 Å). This characteristic contributes to reducing the activation energy for the ring-opening reaction of epoxides. In the ILF/PO system, the reaction barrier is 88.72 kJ·mol−1, lower than the 101.46 kJ·mol−1 barrier for IL/PO, allowing the former to more rapidly facilitate the fixation of carbon dioxide into cyclic carbonates. Besides high catalytic efficiency, these FBILs have the characteristics of a facile synthesis route and easy post-reaction recovery.

Ambient electrosynthesis of urea from carbon dioxide and nitrate over Mo2C nanosheet

Electrocatalytic synthesis of urea through CN bond formation, converting carbon dioxide (CO2) and nitrate (NO3–), presents a promising, less energy-intensive alternative to industrial urea production process. In this communication, we report the application of Mo2C nanosheets-decorated carbon sheets (Mo2C/C) as a highly efficient electrocatalyst for facilitating CN coupling in ambient urea electrosynthesis. In CO2-saturated 0.2 mol/L Na2SO4 solution containing 0.05 mol/L NO3–, the Mo2C/C catalyst achieves an impressive urea yield of 579.13 µg h–1 mg–1 with high Faradaic efficiency of 44.80% at –0.5 V versus the reversible hydrogen electrode. Further theoretical calculations reveal that the multiple Mo active sites enhance the formation of *CO and *NH2 intermediates and facilitate their CN coupling. This research propels the use of Mo2C-based electrodes in electrocatalysis and accentuates the capabilities of binary metal-based catalysts in CN coupling reactions.

Carbon Capture and Utilization Technology Development Opportunities Based on Biomethanation

The paper provides an overview of Power-to-Gas (P2G) technology using biomethanation and a proprietary biocatalyst. It addresses the issue of carbon dioxide (CO2) emissions from fossil fuel combustion and proposes the integration of Carbon Capture Utilization and Storage (CCUS) technologies with P2G processes. Currently, the integration of CCUS and P2G is in conceptual stage. The paper emphasizes the sensitivity of biocatalysts to contamination in feed gases, particularly the negative impact of oxygen on methanation processes. Findings from measurements conducted in 2022 using a lab-scale prototype approve that post-combustion technologies can be successfully integrated into P2G technologies through the utilization of biomethanation processes. Various parameters, such as Carbon Dioxide Conversion (CDC), Volumetric Methane Production (VVD), and Higher Heating Value (HHV), were calculated based on the measured datasets. The high CDC value of 96.65%(V/V) and 68.03%(V/V) of methane content indicates successful integration of the two technologies, while increasing the CO2 source and applying higher pressure in the biomethanation reactor can further enhance VVD. In conclusion, the paper highlights the potential of P2G technology based on biomethanation and its integration with CCUS processes. The results obtained from the lab-scale prototype demonstrate promising conversion rates and suggest avenues for improving VVD.

Cu-Metalated Porphyrin-Based MOFs Coupled with Anatase as Photocatalysts for CO2 Reduction: The Effect of Metalation Proportion

Converting carbon dioxide (CO2) into valuable chemicals such as fossil resources via photocatalysis requires the development of advanced materials. Herein, we coupled zirconium-based metal–organic frameworks (MOFs) containing porphyrin and Cu-porphyrin with anatase TiO2. The effect of the porphyrin metalation proportion was also investigated. Notably, while the use of free-base porphyrin as the organic linker resulted in the development of PCN-224, the presence of Cu-porphyrin provided mixed-phase MOF structures containing both PCN-224 and PCN-222. MOF/TiO2 composites bearing partial (50%) metalated porphyrin were proven more active and selective towards the production of CH4, at ambient conditions, in the gas phase and using water vapors without the use of hole scavengers. The optimized composite bearing 15 wt.% of the partial metalated MOF was three times more active than pure TiO2 towards CH4 production. This study provides insights on the effect of precise materials engineering at a molecular level on the development of advanced MOF-based photocatalysts for CO2 reduction.

Advancements on metal oxide semiconductor photocatalysts in photo-electrochemical conversion of carbon dioxide into fuels and other useful products

Advancements on metal oxide semiconductor photocatalysts in photo-electrochemical conversion of carbon dioxide into fuels and other useful products

Application of new tetra-cationic imidazolium ionic liquids for capture and conversion of CO2 to amphiphilic calcium carbonate nanoparticles as a green additive in water based drilling fluids

Conversion and capture of carbon pollutants based on carbon dioxide to valuable green oil-field chemicals are target all over the world for controlling the global warming. The present article used new room temperature amphiphilic imidazolium ionic liquids with superior surface activity in the aqueous solutions to convert carbon dioxide gas to superior amphiphilic calcium carbonate nanoparticles. In this respect, tetra-cationic ionic liquids 2-(4-dodecyldimethylamino) phenyl)-1,3-bis (3-dodecyldimethylammnonio) propyl) bromide-1-H-imidazol-3-ium acetate and 2-(4-hexyldimethylamino) phenyl)-1,3-bis(3-hexcyldimethylammnonio) propyl) bromide-1 H-imidazol-3-ium acetate were prepared. Their chemical structures, thermal as well as their carbon dioxide absorption/ desorption characteristics were evaluated. They were used as solvent and capping agent to synthesize calcium carbonate nanoparticles with controlled crystalline lattice, sizes, thermal properties and spherical surface morphologies. The prepared calcium carbonate nanoparticles were used as additives for the commercial water based drilling mud to improve their filter lose and rheology. The data confirm that the lower concentrations of 2-(4-dodecyldimethylamino) phenyl)-1,3-bis (3-dodecyldimethylammnonio) propyl) bromide-1-H-imidazol-3-ium acetate achieved lower seawater filter lose and improved viscosities.

Mechanistic Insights into Urea‐, Thiourea‐, and Isothiourea‐Based Bifunctional Tetraarylphosphonium Salt Catalysis for Conversion of Carbon Dioxide to Cyclic Carbonates

AbstractA novel bifunctional isothiourea derived from a tetraarylphosphonium salt catalyzes the coupling reaction of monosubstituted epoxides with 1 atm of carbon dioxide to afford five‐membered cyclic carbonates in high yields. Thiourea and urea groups are also effective hydrogen bond donors for the carbon dioxide fixation. Comprehensive mechanistic studies on this catalysis using theoretical calculations disclosed key hydrogen bond interactions between catalysts and intermediates, which relied upon orientation of the binding modes.

Combination of Betulinic Acid Fragments and Carbonic Anhydrase Inhibitors-A New Drug Targeting Approach.

Human carbonic anhydrase IX (hCA IX) is a zinc(II)-dependent metalloenzyme that plays a critical role in the conversion of carbon dioxide and water to protons and bicarbonate. It is a membrane-bound protein with an extracellular catalytic center that is predominantly overexpressed in solid hypoxic tumors. Sulfamates and sulfonamides, for example acetazolamide (AZA), have been used to inhibit hCA IX in order to improve the response to solid hypoxic tumors. In the present study, we propose a new drug targeting approach by attaching the natural cytotoxic substances betulin and betulinic acid (BA) via a linker to sulfonamides. The conjugate was designed with different spacer lengths to accumulate at the target site of hCA IX. Computational and cell biological studies suggest that the length of the linker may influence hCA IX inhibition. Cytotoxicity tests of the newly synthesized bifunctional conjugates 3, 5, and 9 show effective cytotoxicity in the range of 6.4 and 30.1 µM in 2D and 3D tumor models. The hCA IX inhibition constants of this conjugates, measured using an in vitro enzyme assay with p-nitrophenyl acetate, were determined in a low µM-range, and all compounds reveal a significant inhibition of hypoxia-induced CA activity in a cell-based assay using the Wilbur-Anderson method. In addition, the cells respond with G1 increase and apoptosis induction. Overall, the dual strategy to produce cytotoxic tumor therapeutics that inhibit tumor-associated hCA IX was successfully implemented.

Tuning the catalytic active sites of TiO2/CeO2 interactions to improve oxygen vacancy and lattice parameters for CO2 conversion to green fuel additive

In recent years, the conversion of carbon dioxide (CO2) to value-added products has become an area of great interest, both from an industrial and environmental perspective. Here we have successfully synthesized TiO2/CeO2-based catalysts by exo- and endo-template and use for direct conversion of CO2 to dimethyl carbonate (DMC). It was found that the catalytic activity of TiO2/CeO2 catalysts depends on the acidic and basic sites present in the catalyst. The study also investigated the optimization of reaction conditions in a batch reactor. It was found that the catalytic activity of TiO2/CeO2-based catalysts significantly enhances the CO2 conversion and achieves a high DMC yield compared to the performance of pure CeO2 and TiO2. The reusability of the TiO2/CeO2 catalysts was examined as well. Additionally, the heat of the reaction and Gibbs free energy were calculated using chemical equilibrium models. The experimental response data was validated using artificial neural networks (ANN). The R2 values between the expected and experimental results for DMC yield and CO2 conversion were 0.9953 and 0.9969, respectively. The developed ANN model successfully predicts the percentage of CO2 conversion and DMC yield under the given reaction conditions, with prediction accuracy MSE of 0.0013 and 0.0008, respectively.