Catalysts For Conversion Of CO2 Research Articles

Carbene-Co2 Adducts Grafted Hierarchical Porous Silica Microspheres as Heterogeneous Catalyst for Efficient Conversion of Co2 into Cyclic Carbonates

Carbene-Co2 Adducts Grafted Hierarchical Porous Silica Microspheres as Heterogeneous Catalyst for Efficient Conversion of Co2 into Cyclic Carbonates

Multifunctional long-lived catalysts for direct hydrogenative conversion of CO2 to liquid hydrocarbons with upscaling C5+ productivity

Rationally designed K-promoted Fe/CuAl2O4 acts as a tandem catalyst for CO2 conversion to C5+ hydrocarbons via the reverse water–gas shift reaction and Fischer–Tropsch synthesis consecutively, achieving upscaling C5+ productivity and stability.

Rational Design of Zeolite Y Supported Oxalate and Borohydride Ligands Functionalized Cu Catalysts for Co2 Conversion to Specialty Chemicals

Rational Design of Zeolite Y Supported Oxalate and Borohydride Ligands Functionalized Cu Catalysts for Co2 Conversion to Specialty Chemicals

Recent Advances and Emerging Opportunities with Metal Organic Framework Catalysts for Co2 Conversion

Recent Advances and Emerging Opportunities with Metal Organic Framework Catalysts for Co2 Conversion

Novel porous organic polymers functionalized by metalloporphyrin and phosphonium salts for the efficient synergistic catalysis of CO2 conversion under mild conditions

Metalloporphyrin- and phosphonium-functionalized porous organic polymers (POPs) were fabricated successfully via a post-synthesis modification strategy, which were demonstrated to be efficient heterogeneous catalysts for CO2 conversion.

Mesoporous Prussian Blue as the highly effective and selective catalyst for CO2 conversion into cyclic carbonates under mild conditions

Developing low-cost, effective, and environmentally friendly heterogeneous catalysts for CO2 conversion into high-value-added products is a crucial task. In this study, Ferric ferrocyanide (Fe4[Fe(CN)6]3), the typical Prussian Blue (FeFe-PB) nanoparticles functionalized with hydroxide groups, is found to be the superior catalyst for CO2 and epoxide coupling to form cyclic carbonates with 100% selectivity and 99% yield under mild reaction conditions (1.0 MPa, 90 °C). A series of characterizations techniques showed that the FeFe-PB structure possesses excellent thermal and chemical stability and a high mesoporous surface area. The hydroxide group functionalized nanoparticles could preserve 97% of their initial activity after six reaction rounds. Additionally, we investigated the origin of epoxides activation with heterogeneous Lewis acid sites and surface hydroxide groups via hydrogen-bond interaction at the solid/liquid interface. These findings demonstrate a simple, ecologically safe, versatile, and efficient route for CO2 conversion into high-value chemicals by the FeFe-PB catalytic system.

Rational Design of Main Group Metal-Embedded Nitrogen-Doped Carbon Materials as Frustrated Lewis Pair Catalysts for CO2 Hydrogenation to Formic Acid.

Developing efficient and inexpensive main group catalysts for CO2 conversion and utilization has attracted increasing attention, as the conversion process would be both economical and environmentally benign. Here, based on the main group element Al, we designed several heterogeneous frustrated Lewis acid/base pair (FLP) catalysts and performed extensive first-principles calculations for the hydrogenation of CO2. These catalysts, including Al@N-Gr-1, Al@N-Gr-2, and Al@C2N, are composed of a single Al atom and two-dimensional (2D) N-doped carbon-based materials to form frustrated Al/C or Al/N Lewis acid/base pairs, which are all predicted to have high reactivity to absorb and activate hydrogen (H2). Compared with Al@N-Gr-1, both Al@N-Gr-2 and Al@C2N, especially Al@N-Gr-2, containing Al/N Lewis pairs exhibit better catalytic activity for CO2 hydrogenation with lower activation energies. CO2 hydrogenation on the three catalysts prefers to go through a three-step mechanism, i.e., the heterolytic dissociation of H2, followed by the transfer of the hydride near Al to CO2, and finally the activation of a second H2 molecule. Other IIIA group element (B and Ga)-embedded N-Gr-2 materials (B@N-Gr-2 and Ga@N-Gr-2) were also explored and compared. Both Al@N-Gr-2 and Ga@N-Gr-2 show higher catalytic activity for CO2 hydrogenation to HCOOH than B@N-Gr-2. However, the CO2 hydrogenation path on Ga@N-Gr-2 tends to follow a two-step mechanism, including H2 dissociation and subsequent hydrogen transfer. The present study provides a potential solution for CO2 hydrogenation by designing novel and effective FLP catalysts based on main group elements.

Catalytic coupling of CO2 and epoxides by lignin-based catalysts: A combined experimental and theoretical study

A new strategy for the construction of an amine-modified lignin has been developed through the Mannich reaction. The lignin-based catalyst, (PEI(70000)-SL/ZnBr2), acted as a green and reusable heterogeneous catalyst for the catalytic conversion of CO2 and epoxides into cyclic carbonates. This catalyst exhibited excellent conversion and selectivity in the CO2 cycloaddition reaction due to the synergistic effects of the hydroxyls (-OH) and metal (Zn2+) as Lewis acid sites, and organic amines (-NH2) and halogen anions (Br-) as nucleophiles. Some lignin model compounds were used to study the relationship between structure and activity in order to evaluate the synergistic effects during the cycloaddition reaction. Functional groups, such as Zn2+, -OH and -NH2, in adjacent positions of the lignin-based catalyst yielded the cyclic carbonates in high efficiencies and selectivities. Furthermore, DFT calculation and the experimental results revealed that Zn2+ enhanced the ring-opening process via SN1 mechanism, with the energy barrier of the ring-opening process of 18.9 kcal mol-1 due to the cooperation of the Zn2+ with phenolic hydroxyl groups. These findings do not only provide a novel design concept for biomass-based catalysts but also accomplished the transformation of CO2 into valuable products.

Atomic Pd-promoted ZnZrOx solid solution catalyst for CO2 hydrogenation to methanol

The development of efficient CO2 conversion catalysts is a long-lasting desire. Herein, we introduce an atomic Pd-promoted ZnZrOx solid solution catalyst (Pd-ZnZrOx), which shows markedly enhanced rate of methanol production compared to bare ZnZrOx, as well as excellent stability over 100 h on stream. Up to 0.8 at% (i.e. 0.6 wt%), Pd can be atomically dispersed in ZnZrOx, leading to more oxygen vacancies on the mixed oxide that foster methanol production. Kinetic analysis and in situ DRIFTS reveal that hydrogen activation is limited on ZnZrOx, but Pd doping facilitates H2 dissociation as well as the consequent formation of HCOO*, thus boosting CO2 conversion to methanol. DFT analyses suggest that the presence of atomic Pd enables a more exothermic H2 dissociation, which increases the availability of surface H and facilitates CO2 hydrogenation on adjacent Zn sites, providing rationale on the high activity and robustness of Pd-ZnZrOx in CO2 hydrogenation.

Cu nanoparticles-dispersed Mg-Al layered double hydroxides as efficient catalysts for CO2 conversion with propargyl alcohols

Upgrading carbon dioxide (CO2) into valuable products is a highly promising strategy of artificial carbon cycle. In this study, a series of in situ reduced CuMgAl layered double hydroxides (R-CuMgAl-LDHs) composites were synthesized, in which Cu nanoparticles were effectively dispersed and anchored on MgAl-LDHs with formation of Cu+ and Cu0 species. The optimized R-Cu1.5Mg1.5Al1-LDH exhibited excellent catalytic performance for the carboxylative cyclization of 2-methyl-3-butyn-2-ol with CO2 (turnover number of 243) under mild conditions. The layered structure of LDH stabilized the active Cu species with high dispersion, enhancing the catalytic efficiency of this carboxylative cyclization reaction. Simultaneously, the dual-activation of both CO2 and propargylic alcohol by Cu0/Cu+ species generated on the surface of LDH contributed significantly to the catalytic efficiency enhancement. Furthermore, R-Cu1.5Mg1.5Al1-LDH catalyzed the reaction of a wide range of terminal or internal propargyl alcohols with CO2, yielding various functionalized α-alkylene cyclic carbonates. Finally, a reasonable reaction mechanism was put forward according to the comprehensive analysis.

Encapsulated Lewis acidic ionic liquids by halloysite using as efficient catalyst for CO2 conversion

A type of clay-supported catalysts were developed for conversion of CO2 by encapsulating ZnBr2-based Lewis acidic ionic liquids (ZnBr2/IL) in halloysite (Hal) via a one-step strategy. The Lewis acidic ionic liquid was loaded within enlarged lumens of Hal via acid treatment, and the mesoporous structure was found to benefit for CO2 storage/conversion. The composite ZnBr2/IL@P-Hal was found to have an adsorption capacity (6.43 cm3/g) of CO2 via adsorption/desorption isotherm measurements. The composite ZnBr2/IL@P-Hal showed excellent catalytic performance (TOF value was 1747.7 h−1) for coupling of CO2 with epoxides to produce propylene carbonate under the lack of any cocatalyst. Kinetic investigations indicated the reaction followed an order of one, with respect to catalyst ZnBr2/IL@P-Hal. The overall pathway of CO2 cycloaddition was theoretically validated via DFT calculations. These experimental and computational efforts deepen comprehension of the rational design of clay-based catalysts for CO2 cycloaddition, further elucidated halloysite was a promising support.

Zeolite-encapsulated single-atom catalysts for efficient CO2 conversion

Zeolite-supported single-atom catalysts (SACs) have emerged as a novel class of cheap and tuneable catalysts that can exhibit high activity, selectivity and stability. In this work, we conduct an extensive screening by means of density functional theory calculations to determine the usefulness of 3d, 4d and 5d transition metal (TM) SACs-supported in MFI-type Silicalite-1 zeolite for CO2 conversion. Two reaction mechanisms are considered, namely the redox - direct CO2 dissociation - and associative - hydrogen-assisted CO2 dissociation - mechanisms. Early TM SACs exhibit the lowest energy barriers, which follow the redox mechanism. These energy barriers raise when going right in the periodic table up to group 10, where they become prohibitive and the associative mechanism should dominate. By also considering their resistance to aggregation, we support the use of Sc, Y, La, Ru, Rh, Ni, Pd and Pt as potentially active and stable catalysts for CO2 conversion, given their low energy barriers and strong interaction with the zeolite framework.

Porous Organic Polymers for Catalytic Conversion of Carbon Dioxide.

To overcome the challenges of global warming and environmental pollution, it is necessary to reduce the concentration of carbon dioxide (CO2 ) in the atmosphere, which is mainly accumulated in the air through the burning of fossil fuels. Therefore, the development of environmentally friendly strategies to capture carbon dioxide and convert it into value-added products offers a promising way forward for reducing carbon dioxide concentration in the atmosphere. In this context, POPs (porous organic polymers) have shown great potential as CO2 selective adsorbents due to their high specific surface area, chemical stability, nanoscale porosity and structural diversity, as well as POPs based heterogeneous catalysts for CO2 conversion. This review provides a concise account of preparation methods of various POPs, challenges and current development trends of POPs in photocatalytic CO2 reduction, electrocatalytic CO2 reduction and chemical CO2 conversion.

Recent strategies for enhancing the catalytic activity of CO2 hydrogenation to formate/formic acid over Pd-based catalyst

The “greenhouse effect” caused by presence of the large amounts of carbon dioxide (CO2) is becoming extremely serious for the environment. Therefore, it is crucial to advance the progress of practical technologies to minimize the CO2 emissions. The catalytic CO2 hydrogenation with hydrogen (H2) to form formic acid/formate over Pd-based catalysts has been considered as an effective technology to deal with environment and CO2 emission issues. In the past decades, increasing efforts have been contributed to these fields and significant achievements have been obtained. In this review, the state-of-the-art of Pd-based heterogenous catalysts for catalytic conversion of CO2 to formate/formic acid is systematically summarized. First, the key factors associated with catalytic performance are discussed including Pd metal dispersion, electron density of Pd metal and acidity of supports. Second, major achievements on the design of efficient Pd nanometal supported on various materials, mainly metal-organic frameworks (MOFs), carbon materials, silica, zeolites and other porous material, are summarized. Third, the successful strategies applied to maximize catalytic activity of CO2 conversion by reducing the particle size of Pd, alloying foreign metal with Pd to change the electron density of Pd, as well as anchoring of functional groups were also highlighted. Special attention has been given to the mechanism of the catalytic reaction. Finally, a brief perspective to the challenges and new directions in the development of innovative catalytic materials to achieve high catalytic activity in CO2 conversion is also proposed, which would be of great interest in realizing carbon-neutrality in near future.

Core-shell catalyst with synergistic hydroxyl and nitrogen active sites for CO2 cycloaddition

Developing heterogeneous catalyst with multiple active sites has been a hot-spot for cycloaddition of CO2 with epoxides to value-added chemicals. In this work, a new N- doped carbon/silica core-shell material (M-41/CN) with special hydroxy (Si-OH) and pyridinic N active sites were designed and synthesized. The prepared M-41/CN showed good features: (1) exhibited synergistic effects of Si-OH groups (Acid sites) and pyridinic N species (Lewis basic sites), and (2) held porous structure with specific surface area reaching 308.7 m2/g. The M-41/CN exhibited excellent catalytic activity and stability for cycloaddition of CO2 with epichlorohydrin, with conversion of epichlorohydrin >98% after 4th reuse. Hence, the M-41/CN with acid-base duality offers a new choice for preparing low-cost, environment-friendly and high-efficiency catalysts for CO2 conversion.

Covalent Organic Frameworks for Simultaneous CO2 Capture and Selective Catalytic Transformation

Combination of capture and simultaneous conversion of CO2 into valuable chemicals is a fascinating strategy for reducing CO2 emissions. Therefore, searching for heterogeneous catalysts for efficient catalytic conversion of CO2 is of great importance for carbon capture and utilization. Herein, we report a metalloporphyrin-based covalent organic framework (Co(II)@TA-TF COF) that can capture CO2 and simultaneously convert it into cyclic carbonates under mild conditions. The COF was designed to possess micropores for the adsorption of CO2 and integrated with cobalt(II) porphyrin (Co(II)@TAPP) units as catalytic sites into the vertices of the layered tetragonal networks. The structure of the Co(II)@TA-TF COF is unique where Co(II)@TAPP units are alternately stacked along the z direction with a slipped distance of 1.7 Å, which gives an accessible space to accommodate small molecules, making it possible to expose catalytic sites to substrates within the adjacent stacked layers. As a result, this COF is found to be highly effective for the addition of CO2 and epoxides. Importantly, the Co(II)@TA-TF COF exhibited a dramatic size selectivity for substrates. In conjunction with its reusability, our results highlight the development of a new function of COFs for targeting simultaneous CO2 absorption and utilization upon complementary exploration of the structural features of skeletons and pores. Such promising catalytic performance of the COF makes it possible for its potential practical application.

Incorporation of Chromophores into Metal–Organic Frameworks for Boosting CO2 Conversion

The exploitation of highly stable and active catalysts for the conversion of CO2 into valuable fuels is desirable but is a great challenge. Herein, we report that the incorporation of chromophores into metal-organic frameworks (MOFs) could afford robust catalysts for efficient CO2 conversion. Specifically, a porous Nd(III) MOF (Nd-TTCA; TTCA3- = triphenylene-2,6,10-tricarboxylate) was constructed by incorporating one-dimensional Nd(CO2)n chains and TTCA3- ligands, which exhibits a very high stability, retaining its framework not only in the air at 300 °C for 2 h but also in boiling aqueous solutions at pH 1-12 for 7 days. More importantly, Nd-TTCA has achieved a 5-fold improvement in photocatalytic activity for reducing CO2 to HCOOH and a 10-fold improvement in catalytic activity for the cycloaddition of CO2 into cyclic carbonate in comparison to those of H3TTCA itself. This work gives a new strategy to design efficient artificial crystalline catalysts for CO2 conversion.

Recent advances in fibrous catalysts for CO2 conversion: A short review

In recent years, CO2 conversion reactions such as CO2 reforming of CH4 and CO2 methanation have devoted significant attention on account of their advantages in utilizing greenhouse gases (CO2 and CH4). The development of an excellent catalyst with great properties is a crucial strategy in the catalytic reaction, as it could enhance the efficiency of reaction. Additionally, the tunable characteristics of support materials may influence the distribution of active metal sites, strength of metal-supporting interactions, and amount of oxygen vacancies. To improve metal dispersion on a support, the production of support materials with fibrous morphology and dendrimeric structures is becoming an exciting approach. This short review highlighted recent developments in the preparation of fibrous catalysts and their relation with the physical and chemical properties of catalyst. This article also discussed the governing factor of fibrous morphology in CO2 conversions. Owing to the fascinating physicochemical properties of fibrous catalyst, further research is needed to explore its potential in various applications.

Catalyst Design for Electrochemical Reduction of CO2 to Multicarbon Products.

Electrochemical reduction of CO2 (CO2 RR), driven by renewable energy (such as wind and solar energy), is an effective route toward carbon neutralization. The multicarbon (C2+ ) products from CO2 RR are highly desirable, since they are important fuels, chemicals, and industrial raw materials. However, selective reduction of CO2 to C2+ products is especially challenging, due to low selectivity, poor yield, and high overpotential. Since the performance of CO2 RR is closely related to the structure and composition of catalysts, which alter the binding energy of intermediates generated in CO2 RR, it is necessary to study these effects systematically to achieve possible design strategies. Herein, design strategies toward catalysts for CO2 conversion to C2+ products are discussed on the basis of the adjustment of the structure and composition of catalysts, such as morphology control, defect engineering, bimetal, and surface modification. Meanwhile the reaction mechanisms and structure evolution of catalysts during CO2 RR are focused on in particular. Finally, challenges and perspectives are proposed for further improvement of CO2 RR technologies.

Multifunctional Catalyst Combination for the Direct Conversion of CO2 to Propane.

The production of carbon-rich hydrocarbons via CO2 valorization is essential for the transition to renewable, non-fossil-fuel-based energy sources. However, most of the recent works in the state of the art are devoted to the formation of olefins and aromatics, ignoring the rest of the hydrocarbon commodities that, like propane, are essential to our economy. Hence, in this work, we have developed a highly active and selective PdZn/ZrO2+SAPO-34 multifunctional catalyst for the direct conversion of CO2 to propane. Our multifunctional system displays a total selectivity to propane higher than 50% (with 20% CO, 6% C1, 13% C2, 10% C4, and 1% C5) and a CO2 conversion close to 40% at 350 °C, 50 bar, and 1500 mL g–1 h–1. We attribute these results to the synergy between the intimately mixed PdZn/ZrO2 and SAPO-34 components that shifts the overall reaction equilibrium, boosting CO2 conversion and minimizing CO selectivity. Comparison to a PdZn/ZrO2+ZSM-5 system showed that propane selectivity is further boosted by the topology of SAPO-34. The presence of Pd in the catalyst drives paraffin production via hydrogenation, with more than 99.9% of the products being saturated hydrocarbons, offering very important advantages for the purification of the products.