Catalysts For Conversion Of CO2 Research Articles

A novel porphyrin MOF catalyst for efficient conversion of CO2 with propargyl amines.

The capture and conversion of carbon dioxide (CO2) into valuable chemical products under mild conditions is an important and challenging approach for contemporary industry. Carboxylic acid ligands are widely used in the development of functionalized metal organic framework materials due to their excellent stability. Herein, a novel mixed-metal organic framework Cu-TCPP(Fe) was assembled from iron-(Fe)-porphyrin ligands, which can efficiently catalyze the reaction of propargylic amines and CO2 to synthesize 2-oxazolidinones.

Designing bifunctional catalysts for the one-pot conversion of CO2 to sustainable marine transportation fuels

A highly selective bifunctional catalyst for the one-pot conversion of CO2 to DME using CuZnO nanoparticles located on SAPO-34 crystals.

Subnanometric Pt clusters dispersed over Cs-doped TiO2 for CO2 upgrading via low-temperature RWGS: operando mechanistic insights to guide an optimal catalyst design

Cs-doped Pt/TiO2 advanced catalysts for CO2 conversion via low-temperature RWGS: from operando and mechanistic study to real-catalyst design to combat global warming.

Design and Investigation of Superatoms for Redox Applications: First-Principles Studies.

A superatom is a cluster of atoms that acts like a single atom. Two main groups of superatoms are superalkalis and superhalogens, which mimic the chemistry of alkali and halogen atoms, respectively. The ionization energies of superalkalis are smaller than those of alkalis (<3.89 eV for cesium atom), and the electron affinities of superhalogens are larger than that of halogens (>3.61 eV for chlorine atom). Exploring new superalkali/superhalogen aims to provide reliable data and predictions of the use of such compounds as redox agents in the reduction/oxidation of counterpart systems, as well as the role they can play more generally in materials science. The low ionization energies of superalkalis make them candidates for catalysts for CO2 conversion into renewable fuels and value-added chemicals. The large electron affinity of superhalogens makes them strong oxidizing agents for bonding and removing toxic molecules from the environment. By using the superatoms as building blocks of cluster-assembled materials, we can achieve the functional features of atom-based materials (like conductivity or catalytic potential) while having more flexibility to achieve higher performance. This feature paper covers the issues of designing such compounds and demonstrates how modifications of the superatoms (superhalogens and superalkalis) allow for the tuning of the electronic structure and might be used to create unique functional materials. The designed superatoms can form stable perovskites for solar cells, electrolytes for Li-ion batteries of electric vehicles, superatomic solids, and semiconducting materials. The designed superatoms and their redox potential evaluation could help experimentalists create new materials for use in fields such as energy storage and climate change.

A mesoporous ionic metal-organic framework decorated by flexible alkyl imidazolium bromide as heterogeneous catalyst for efficient conversion of CO2 to cyclic carbonates

A mesoporous ionic MOF-based catalyst (Br−)C3H7-Imidazolium-MOF-1 for the cycloaddition of CO2 to epoxides (CCE) was synthesized by template-assisted method, and its composite and structure were determined by FT-IR, PXRD, NMR, SEM, TEM, XPS and N2 adsorption. (Br−)C3H7-Imidazolium-MOF-1, is constructed by Zr6O4(OH)4 clusters and linear dicarboxylic acid ligands covalently modified by flexible alkyl imidazolium groups (1-methylene-3-propyl-imidazolium bromide). By the synergistic effect of Zr4+ Lewis acid sites and Br− nucleophiles, (Br−)C3H7-Imidazolium-MOF-1 shown superior catalytic performance for the cycloaddition of CO2 to epichlorohydrin in the absence of any co-catalyst under mild conditions. Small steric hindrance from the flexible imidazolium groups and rapid mass transport of reactants and products in the mesoporous catalyst acted synergistically to promote this process. A firm bond between the imidazolium bromide and the framework of (Br−)C3H7-Imidazolium-MOF-1 made it a recyclable heterogeneous catalyst. Furthermore, several additional coupling reactions were investigated with other epoxides as substrates.

Plasma-surface-modified SnO2–CuCl nanocomposite for highly selective electrocatalytic CO2 conversion

Conversion of CO2 into useful chemicals via electrochemical methods is a promising approach for mitigating global CO2 emissions and transiting towards green chemical production. In this work, a tin oxide-copper chloride (SnO2–CuCl) nanocomposite catalyst for efficient CO2 conversion is developed using low-temperature atmospheric-pressure plasmas. The SnO2–CuCl catalyst which acquired a unique structure subjected to the dielectric barrier discharge (DBD) plasma (SnO2–CuCl-DBD), effectively inhibits the hydrogen evolution reaction (HER) in the electrocatalytic process. Compared with the untreated SnO2–CuCl sample, the H2 generation efficiency of the SnO2–CuCl-DBD electrocatalyst decreased from 9.79 to 3.41 %. The demonstrated efficiency of SnO2–CuCl-DBD catalyst for conversion of CO2 to C1 products (formate and CO) is 94.37 % at 1.8 V (vs Ag/AgCl), which is very competitive to the reported state-of-the-art catalyst. The outcomes of this research provide a new practical surface science approach for engineering advanced electrocatalysts for effective conversion of CO2 into value-added chemical products.

Insight into catalytic contribution of non-halogen cation and anion for CO2 conversion into cyclic carbonate

Non-halogen ionic liquids are considered efficient catalyst for CO2 conversion into cyclic carbonates. In this work, six carboxylic acid ionic liquids with different types and sizes of cations are designed and synthesized to systematically investigate the catalytic contribution of the non-halogen cation and anion for CO2 conversion into cyclic carbonate. The result shows that the anion could improve the catalytic activity by improve the basicity of ionic liquids, and the cation that has a weak interaction with anion is more conducive for the reactivity. Further, the reaction mechanism is deeply studied by using the optimized [P4444][IsoNic]: two reaction intermediates are captured by In-situ infrared, combined with DFT calculation, the anion directly inducing ring-opening mechanism is proposed. This work provides an in-depth understanding of catalytic contribution of non-halogen ionic liquids used in cycloaddition reaction.

Water-activation-facilitated photocatalytic CO2 reduction by a heterogeneous synergetic single-atomic Zn sites and Pd nanocrystals

Enhancing the photoreduction of carbon dioxide (CO2) to produce valuable chemicals, such as carbon monoxide (CO), is of significant importance. The bottleneck in developing advanced catalysts lies in the rational design of catalytic centers with efficient CO2 activation and hydrogen proton production. In this work, palladium nanoparticles (Pd NPs) were successfully modified on UiO-66-NH2-Zn SAs (UN-Zn SAs) by a photo-deposition method. The optimized photocatalyst, 4 Pd NPs-UN-0.7Zn SAs, demonstrated exceptional performance in converting CO2 to CO, exhibiting approximately 1.4-fold and 7.8-fold enhancements compared to UN-0.7Zn SAs and UN, respectively. A combination of time-resolved photoluminescence spectroscopy and electron paramagnetic resonance results unveiled that the introduction of Pd NPs effectively promoted the photogenerated charge separation and facilitated water activation to produce more hydrogen protons. The generated hydrogen protons were subsequently coupled with nearby CO2 that was activated by Zn SAs, thus achieving the facile water-activation-induced CO2 reduction process. Theoretical calculations further confirmed that the heterogeneous synergistic effects between Zn SAs and Pd NPs lowered the energy barrier for the rate-limiting step of CO2 conversion to COOH* , thereby achieving efficient photocatalytic CO2 reduction reactions. This work provides a new perspective on the development of efficient catalysts for the effective conversion of CO2.

Schottky Junction and D-A1 -A2 System Dual Regulation of Covalent Triazine Frameworks for Highly Efficient CO2 Photoreduction.

Covalent triazine frameworks (CTFs) are emerging as a promising molecular platform for photocatalysis. Nevertheless, the construction of highly effective charge transfer pathways in CTFs for oriented delivery of photoexcited electrons to enhance photocatalytic performance remains highly challenging. Herein, a molecular engineering strategy is presented to achieve highly efficient charge separation and transport in both the lateral and vertical directions for solar-to-formate conversion. Specifically, a large π-delocalized and π-stacked Schottky junction (Ru-Th-CTF/RGO) that synergistically knits a rebuilt extended π-delocalized network of the D-A1 -A2 system (multiple donor or acceptor units, Ru-Th-CTF) with reduced graphene oxide (RGO) is developed. It is verified that the single-site Ru units in Ru-Th-CTF/RGO act as effective secondary electron acceptors in the lateral direction for multistage charge separation/transport. Simultaneously, the π-stacked and covalently bonded graphene is regarded as a hole extraction layer, accelerating the separation/transport of the photogenerated charges in the vertical direction over the Ru-Th-CTF/RGO Schottky junction with full use of photogenerated electrons for the reduction reaction. Thus, the obtained photocatalyst has an excellent CO2 -to-formate conversion rate (≈11050 µmol g-1 h-1 ) and selectivity (≈99%), producing a state-of-the-art catalyst for the heterogeneous conversion of CO2 to formate without an extra photosensitizer.

Invigorating surface frustrated Lewis pairs on bifunctional quasi-disordered Sn-based catalyst for solar photothermocatalytic conversion of CO2 from air

Designing adsorption-enhanced solid catalysts with excellent bifunctional features is feasible for achieving carbon neutrality. In this study, surface-frustrated Lewis pair sites (sFLPs) were fabricated on a quasi-disordered Sn catalyst. Catalysts with different degrees of disorder were synthesized by thermochemical control. The disordered catalyst exhibited randomly distributed lattice disorder, in-plane oxygen vacancies, and mixed-valence Sn. The coexistence of Sn (IV, II) Lewis acidic sites and −OH Lewis basic sites was crucial in the activation of CO2. In addition, sFLPs were further stimulated on the disorder-engineered surface using simultaneous inclusion of PTA (W6+) and hydroxylation. The optimized catalyst exhibited an exceptionally high adsorption capacity and photothermocatalytic activity for 400 ppm CO2 in air compared to pristine SnO2. The enhanced adsorption and photothermocatalytic activity were attributed to distinctive chemistry of the redox-active sFLPs. This study highlights the potential of high-density sFLPs on disordered catalysts for CO2 abatement from the air.

Microkinetic Modeling of CO2 Hydrogenation to Formic Acid on Transition Metal Doped Ni(111) Surface

The direct conversion of carbon dioxide (CO2) into valuable chemicals plays a crucial role in mitigating climate change and fostering a sustainable future. To facilitate this process, identifying an effective catalyst is of utmost importance. This study focuses on investigating the potential of nickel-based surfaces as catalysts for the direct hydrogenation of CO2 into formic acid (HCOOH), a valuable chemical with applications as a fuel and hydrogen storage. Several nickel surface models were considered, including pristine Ni(111) and Ni(111) surfaces doped with Cu, Pd, Pt, and Rh metals. Through a microkinetic investigation, we examined the reaction kinetics and determined the rate-determining steps on the Ni(111) surfaces. By elucidating the reaction pathways and characterizing the reaction intermediates, we gained comprehensive insights into the fundamental processes involved in CO2 hydrogenation to HCOOH. This knowledge is crucial for the rational design and optimization of catalysts, enabling the development of highly active catalysts for CO2 conversion. Our study revealed insights into the effect of transition metal doping on the catalytic activity of Ni(111) surfaces. Among the investigated dopants, we found that the addition of Pt in the first layer of Ni(111) surface yielded the best turnover frequency (TOF) for the CO2 conversion to HCOOH. The Pt dopants induced unique electronic properties in the Ni(111) surface, resulting in a reduced activation barrier for key reaction intermediates. This effect contributed to a more efficient conversion of CO2 to HCOOH.

Design of composite based on UiO-66 and ionic liquid for the CO2 conversion into cyclocarbonate

Exploiting an effective catalyst for CO2 conversion into value-added chemicals under mild circumstances still remains a challenge. Herein, UiO-66 decorated with ionic liquids (ILs) (denoted as UiO-66-ILs) were facilely synthesized by the mixed ligands of 1,4-benzene dicarboxylic acid and pyridyl-containing mono-carboxylic acid isomer (including nicotinic acid (NA), isonicotinic acid (INA), and 2-pyridine carboxylic acid (PCA)), followed by the further modification with different bromoalkanes. Among various UiO-66-ILs, UiO-66 derivative containing the ILs composed of PCA and bromoethane (named as UiO-66-ILs(PCA-EtBr)) displayed superior catalytic performance on CO2-epichlorohydrin cycloaddition into chloropropene carbonate, with a high yield of 90 % under 0.1 MPa CO2 at 110 °C without the addition of any solvent and cocatalyst. Whereas, UiO-66-ILs(NA-EtBr) and UiO-66-ILs(INA-EtBr) as analogues of UiO-66-ILs(PCA-EtBr) presented a low yield of 77 % and 67 %, respectively, unveiling that the orientation of carboxyl at monocarboxyl pyridine ligand played a great influence on the catalytic activity. The excellent activity of UiO-66-ILs(PCA-EtBr) was attributed to the synergetic effect of Lewis acidity from MOF nodes for activating C–O bond of epoxide, CO2 absorption by pyridyl moiety, and nucleophilicity of ILs decoration. In addition, UiO-66-ILs(PCA-EtBr) exhibited a broad scope of epoxide substrate, as well as a great recyclability. Moreover, a possible catalytic mechanism was proposed for CO2 conversion into cyclocarbonate.

Anion-rich porous poly(ionic liquid)s for efficient CO2 conversion into cyclic carbonates through hydrogen bonding synergistic effect

Ionic liquids have widely been recognized as highly effective catalysts for the synthesis of cyclic carbonates from CO2 and epoxides. However, the cumbersome separation process hinders the practical application of these catalysts. In this study, a strategy involving free radical polymerization was employed to successfully co-polymerized monomers of ionic liquid and divinylbenzene (DVB), resulting in the fabrication of anion-rich porous poly(ionic liquid)s (PILs) that incorporated a hydrogen bonding site of -NH2-+. The texture properties of the as-prepared PILs were characterized in detail, and they were then utilized as catalysts for the cycloaddition of CO2 and epoxides to form cyclic carbonates. Remarkably, the reaction exhibited a remarkable yield of up to 99 % under solvent- and metal-free conditions. It is noteworthy that PIL-2 demonstrated easy recoverability, with a slight reduction in catalytic activity of about 7 % after five cycles. Additionally, a mechanism based on hydrogen bond synergistic for the conversion of CO2 by anion-rich porous PILs was proposed. This study offers a valuable insight for the development of recyclable poly(ionic liquid)s catalysts for CO2 conversion.

Diamide-linked imidazolyl Poly(dicationic ionic liquid)s for the conversion of CO2 to cyclic carbonates under ambient pressure

The ionic active centers and hydrogen-bond donors (HBDs) in heterogeneous catalytic materials are highly beneficial for enhancing the interaction between solid–liquid-gas three-phase interfaces and promoting effective fixation of carbon dioxide (CO2). Diamide-linked imidazolyl poly(dicationic ionic liquid)s catalysts PIMDILs (PMAIL-x and PBAIL-2) were synthesized through the copolymerization of diamide-linked imidazolyl dicationic ionic liquids (IMDILs) with divinylbenzene (DVB), which successfully enable the simultaneous construction of high-density and uniformly distributed ionic active centers (2.014–4.883 mmol g−1) and hydrogen-bond donors (HBDs). The as-synthesized PIMDILs present excellent catalytic activity in promoting the cycloaddition of CO2 with epoxides. PMAIL-2 could convert epichlorohydrin (ECH) with a quantitative conversion of 99.8 % (selectivity > 99 %) under ambient pressure. Furthermore, only a decrease in activity of 5 % was observed even after six cycles of recycling. The excellent conversions (>97.3 %) were achieved for various terminal substituted epoxides. The experimental and characterization results reveal that the high-density ionic active centers and amide HBDs can effectively activate the reaction substrates, their synergistic effect plays a crucial role at the catalyst interface. This work is expected to provide some useful insights for the rational construction of heterogeneous catalysts for CO2 conversion.

C2-phenyl-substituted benzimidazolium-based covalent organic framework as efficient catalyst for CO2 conversion without solvents, metals, and cocatalysts

C2-phenyl-substituted benzimidazolium-based covalent organic framework as efficient catalyst for CO2 conversion without solvents, metals, and cocatalysts

Single-atom alloys of Cu(211) with earth-abundant metals for enhanced activity towards CO[formula omitted] dissociation

CO2, a byproduct from various industrial reactions, must not be released into the atmosphere and should be managed through capture, conversion, and utilization. The first step in converting CO2 into valuable products is to break the C–O bond. This work focuses on designing Single Atom Catalysts (SACs) by doping Cu(211) surface with 13 different s, p, and d block elements with an aim to minimize the activation barrier for C–O bond cleavage. Our work demonstrates that SACs of Mg/Al/Pt@Cu(211) favor CO2 chemisorption compared to Cu(211) where CO2 physisorbs. The barrier for CO2 dissociation is lowest for Mg@Cu(211) and it increases in the order Mg@Cu(211) < Al@Cu(211) < Pt@Cu(211) < Zn@Cu(211) < Ga@Cu(211) < Cu@Cu(211) < Pd@Cu(211). These findings suggest that doping Cu(211) with earth-abundant metal like Mg can potentially be a viable catalyst for CO2 conversion, providing a promising solution to reduce carbon footprint and mitigate climate change.

Enhancing the Catalytic Activity of Zeolitic Imidazolate Frameworks (ZIFs) via an Etching and Regrowth Method for CO2 Cycloaddition Reaction.

Zeolitic imidazolate frameworks (ZIFs) bearing rich accessible Lewis acidic/basic active sites and hierarchical pores are favorable to catalyze the cycloaddition of CO2 and epoxides with high yields of the target product under mild conditions. In this context, a facile etching and regrowth method is developed here to convert unstable leaf-like zinc-based ZIF-L to one kind of bimetallic ZIF (namely, ZnFe-ZIF) with a rough surface, a porous and accessible three-dimensional structure, and abundant Lewis acidic sites. Owing to the high Fe-doping content functioning as rich Lewis acidic sites and the high CO2 adsorbing capability together with the structural advantages to favor the mass diffusion, the yield of target cyclic carbonate can be up to >99% for the cycloaddition of CO2 and epichlorohydrin by ZnFe-ZIF at 6 h under mild conditions (0.1 MPa and 80 °C) with the selectivity of 100%. More importantly, unlike ZIF-L, which is unstable in the reaction system, the synthesized ZnFe-ZIF displays a satisfactory chemical stability without a loss in catalytic activities after five recycling runs as well as good substrate tolerance, making ZnFe-ZIF a potential high-performance catalyst for CO2 conversion.

Cu-Doped SrTiO3 Nanostructured Catalysts for CO2 Conversion into Solar Fuels Using Localised Surface Plasmon Resonance

Carbon dioxide valorisation is one of the most discussed topics amongst researchers; indeed, finding a way to significantly reduce CO2 concentration in the atmosphere is crucial in order to mitigate climate change effects in the next decades. In this study, SrTiO3-supported Cu nanoparticles are exploited as Localised Surface Plasmon Resonance (LSPR)-mediated catalysts for CO2 reduction. The materials were prepared via sol–gel citrate route methodology, inserting Cu as a dopant in the perovskite structure; reducing treatments at different temperatures were performed to promote copper atom exsolution, thus forming nanostructures upon the surface. The perovskitic structure was confirmed via ex situ and operando XRD analysis, while compositional analysis was carried out through XPS and EDS; SEM and TEM images revealed morphological changes with different reducing treatments, and bulk reducibility was analysed with H2-TPR, revealing different Cu species in the material. Band gap analysis via DRS showed the successful incorporation of copper in the perovskite, affecting the light absorption properties. Finally, catalytic tests showed that copper nanoparticles play a role in CO2 activation with sunlight, proving that LSPR could be exploited for catalytic means.

Two novel types of heterogeneous catalysts apply to synthesize cyclic carbonates through CO2 fixation on epoxides under mild condition

The present work focuses on developing heterogeneous catalysts for conversion of CO2 and mono-/di-epoxides to mono-/bis-cyclic carbonates. To achieve this purpose, two types of recyclable solid catalysts, namely polyurethane (PU-BTP) and polyurethane modified on silica gel-solid support (SG-AU-BPT), are synthesized. On these catalysts, the key promoter CaI2 is pre-absorbed. Both catalysts show high catalytic activity under mild conditions. For example, phenyl glycidyl ether (PGE) can be converted to 4-(phenoxymethyl)− 1,3-dioxolan-2-one at 60 °C within 6 h under 1 atm pressure of CO2. PU-BTP and SG-AU-BPT can be recollected by suction filtration and reused for eight times with conversion larger than 81% and 95% respectively. These results indicate that the degree of CaI2 leaching out from the catalysts in each cycle and loss is low.

A robust low coordinate Co(II) catalyst for efficient conversion of CO2 into methanol under mild conditions

A robust low coordinate Co(II) catalyst for efficient conversion of CO2 into methanol under mild conditions