Catalytic Hydrogenation Of CO2 Research Articles

NiFe(CoFe)/silica and NiFe(CoFe)/alumina nanocomposites for the catalytic hydrogenation of CO2

The fumed SiO2 and Al2O3 oxides with a specific surface area of about 80 m2 g–1 were used for the synthesis of Ni(80)Fe(20)/SiO2, Co(93)Fe(7)/SiO2, Ni(80)Fe(20)/Al2O3 and Co(93)Fe(7)/Al2O3 nanocomposites, and numbers between brackets indicate the metal content in wt%, being 10 wt% of the mass of catalysts. Catalytically active bimetallic compositions (NiFe and CoFe) that modified the fumed oxides’ surface were prepared using the solvate-stimulated method with subsequent thermal decomposition and reduction of the metal oxides to corresponding metals with hydrogen. The catalysts were characterized using the TGA in dynamic hydrogen, nitrogen physisorption, and PXRD methods. The complete conversion of carbon dioxide is observed in the temperature range of 350–425 °C at the maximum methane yield of 72–84%. The long-time catalytic test demonstrates the high stability of the catalyst during 5 weeks of exposure to the reaction mixture. The yield of methane was decreased by 3–14% after 1–2 months of long-time testing.

Highly efficient and stable photothermal catalytic CO2 hydrogenation to methanol over Ru/In2O3 under atmospheric pressure

Photothermal catalytic CO2 hydrogenation to CH3OH with renewable H2 is a promising method to convert solar energy into chemical energy. However, it is still impeded by limited CO2 conversion efficiency and poor CH3OH selectivity under mild conditions. Herein, we report a Ru/In2O3 catalyst for efficient and stable photothermal CH3OH production from CO2 hydrogenation under atmospheric pressure. The Ru/In2O3 catalyst delivers a remarkable solar CH3OH production of 280.4 μmol g-1 h-1, which is ∼50 times higher than that of pure In2O3 under the same conditions and surpasses by far reported In2O3-based photothermal catalysts. Detailed characterizations demonstrate that the synergy of photothermal heating effect and hot-carriers-induced activation of reactants on Ru together with the interaction between Ru and In2O3 enhances the activation of CO2 and H2. Moreover, Ru modulates the electronic structure of In2O3 and promotes the generation of oxygen vacancies, which is favorable for the hydrogenation process to form CH3OH. This work paves a way for the rational design of efficient catalysts for solar CH3OH production from CO2 hydrogenation under mild conditions.

A review of in situ/operando studies of heterogeneous catalytic hydrogenation of CO2 to methanol

Repurposing CO2 into chemicals, one of the Carbon Dioxide Removal (CDR) strategies, still faces significant challenges in conversion and energy efficiency due to the lack of effective catalysts and processes. Fundamental understanding through in situ/operando investigations of the reaction mechanisms and catalyst structures is pivotal for developing the efficient catalysts. This paper reviews the past and recent in situ/operando studies of methanol synthesis from heterogeneous CO2 hydrogenation over a few typical catalysts including Cu-based, oxide-based, and noble-metal-based catalysts. With the development of high-pressure reactors, in situ/operando IR, X-ray absorption spectroscopy (XAS), X-ray diffraction (XRD), neutron diffraction and imaging have been used to reveal the surface intermediates and structures of working catalysts under CO2 hydrogenation conditions. On the one hand, the combined operando techniques shed light on working mechanisms for some catalytic systems. On the other hand, due to the complexity of selective CO2 hydrogenation reaction and limited sensitivity of current accessible operando techniques to the surface structure of catalysts, it is still murky about the exact nature of the active sites at the surface/interface and how different sites promote different reaction paths. It is concluded that new methodologies for differentiating signals from different sites, and the development of surface-sensitive techniques for high pressure reactions are needed for providing structural descriptors of highly active and selective CO2 conversion catalysts.

Performance of Cu/ZnO Nanosheets on Electrospun Al2O3 Nanofibers in CO2 Catalytic Hydrogenation to Methanol and Dimethyl Ether

The synthesis of methanol and dimethyl ether (DME) from carbon dioxide (CO2) and green hydrogen (H2) offers a sustainable pathway to convert CO2 emissions into value-added products. This heterogeneous catalytic reaction often uses copper (Cu) catalysts due to their low cost compared with their noble metal analogs. Nevertheless, improving the activity and selectivity of these Cu catalysts for these products is highly desirable. In the present study, a new architecture of Cu- and Cu/Zn-based catalysts supported on electrospun alumina nanofibers were synthesized. The catalysts were tested under various reaction conditions using high-throughput equipment to highlight the role of the hierarchical fibrous structure on the reaction activity and selectivity. The Cu or Cu/ZnO formed a unique structure of nanosheets, covering the alumina fiber surface. This exceptional morphology provides a large surface area, up to ~300 m2/g, accessible for reaction. Maximal production of methanol (~1106 gmethanolKgCu-1∙h-1) and DME (760 gDMEKgCu-1∙h-1) were obtained for catalysts containing 7% wt. Cu/Zn with a weight ratio of 2.3 Zn to Cu (at 300 °C, 50 bar). The promising results in CO2 hydrogenation to methanol and DME obtained here point out the significant advantage of nanofiber-based catalysts in heterogeneous catalysis.

Nanostructured Materials for Photothermal Carbon Dioxide Hydrogenation: Regulating Solar Utilization and Catalytic Performance.

Converting carbon dioxide (CO2) into value-added fuels or chemicals through photothermal catalytic CO2 hydrogenation is a promising approach to alleviate the energy shortage and global warming. Understanding the nanostructured material strategies in the photothermal catalytic CO2 hydrogenation process is vital for designing photothermal devices and catalysts and maximizing the photothermal CO2 hydrogenation performance. In this Perspective, we first describe several essential nanomaterial design concepts to enhance sunlight absorption and utilization in photothermal CO2 hydrogenation. Subsequently, we review the latest progress in photothermal CO2 hydrogenation into C1 (e.g., CO, CH4, and CH3OH) and multicarbon hydrocarbon (C2+) products. Finally, the relevant challenges and opportunities in this exciting research realm are discussed. This perspective provides a comprehensive understanding for the light-heat synergy over nanomaterials and instruction for rational photothermal catalyst design for CO2 utilization.

Catalytic Hydrogenation of CO2 to Formate Using Ruthenium Nanoparticles Immobilized on Supported Ionic Liquid Phases.

Ruthenium nanoparticles (NPs) immobilized on imidazolium-based supported ionic liquid phases (Ru@SILP) act as effective heterogeneous catalysts for the hydrogenation of carbon dioxide (CO2 ) to formate in a mixture of water and triethylamine (NEt3 ). The structure of the imidazolium-based molecular modifiers is varied systematically regarding side chain functionality (neutral, basic, and acidic) and anion to assess the influence of the IL-type environment on the NPs synthesis and catalytic properties. The resulting Ru@SILP materials contain well-dispersed Ru NPs with diameters in the range 0.8-2.9nm that are found 2 to 10 times more active for CO2 hydrogenation than a reference Ru@SiO2 catalyst under identical conditions. Introduction of sulfonic acid groups in the IL modifiers results in a greatly increased turnover number (TON) and turnover frequency (TOF) at reduced metal loadings. As a result, excellent productivity with TONs up to 16100 at an initial TOF of 1430 h-1 can be achieved with the Ru@SILP(SO3 H-OAc) catalyst. H/D exchange and other control experiments suggest an accelerated desorption of the formate species from the Ru NPs promoted by the presence of ammonium sulfonate species on Ru@SILP(SO3 H-X) materials, resulting in enhanced catalyst activity and productivity.

Highly Active Catalytic CO2Hydrogenation to LowerOlefins via Spinel ZnGaOxCombined with SAPO-34.

A key primary methodfor creating a carbon cycle and carbon neutrality is the catalytic hydrogenation of CO2into high value-added chemicals or fuels. In this work, ZnGaOxoxides were prepared by parallel co-precipitation and physically mixed with SAPO-34 molecular sieves prepared by hydrothermal synthesis to produce ZnGaOx/SAPO-34 bifunctional catalysts, which were evaluated for the catalytic synthesis of lower olefins (C2=-C4=) from carbon dioxide hydrogenation.It was demonstrated that the reaction process requires oxygen defect activation, synergistic hydrogenation, and CO2alkaline adsorption of ZnGaOx. The spinel structure of ZnGaOxhas more abundant oxygen defectsand alkaline adsorption sitesthan the ZnGaOxsolid solution, which effectively enhances the catalytic performance.The CO2conversion was 28.52%, the selectivity of C2=-C4=in hydrocarbons reached 70.01%, and the single-pass yield of C2=-C4=was 10.95% at 370°C, 3.0 MPa, and 4800 mL/gcat/h.

Cover Feature: Promoted Photothermal Catalytic CO Hydrogenation by Using TiC‐Supported Co−Fe5C2 Catalysts (Chem. Eur. J. 7/2023)

Driven by renewable solar energy, photocatalytic CO hydrogenation offers a promising way to synthesize valuable hydrocarbon chemicals. In their Research Article (DOI: 10.1002/chem.202202891), M. Zhong and co-workers show that an efficient photochemical and photothermal synergy between the nearby catalytic and plasmonic centers can accelerate the reaction. By using Co−Fe5C2 on a TiC photocatalyst, a 59 % C2+ selectivity and a 30 % CO conversion were obtained at the high GHSV of 12 000 mL g−1 h−1.

Methanation of CO2 over High Surface Nickel/Aluminates Compounds Prepared by a Self-Generated Carbon Template

Catalytic gas-phase hydrogenation of CO2 into CH4 was tested under three different nickel/aluminate catalysts obtained from precursors of hexaaluminate composition (MAl16O19, M = Mg, Ca, Ba). These catalysts were prepared using a carbon template method, where carbon is self-generated from a sol-gel that contains an excess of citric acid and the Al and M salts (Ba2+, Ca2+, Mg2+) by two-step calcination in an inert/oxidizing atmosphere. This procedure yielded Ni particles decorating the surface of a porous high surface area matrix, which presents a typical XRD pattern of aluminate structure. Ni particles are obtained with a homogeneous distribution over the surface and an average diameter of ca 25–30 nm. Obtained materials exhibit a high conversion of CO2 below 500 °C, yielding CH4 as a final product with selectivity >95%. The observed trend with the alkaline earth cation follows the order NiBaAlO-PRx > NiCaAlO-PRx > NiMgAlO-PRx. We propose that the high performance of the NiBaAlO sample is derived from both an appropriate distribution of Ni particle size and the presence of BaCO3, acting as a CO2 buffer in the process.

Promoted Photothermal Catalytic CO Hydrogenation by Using TiC-Supported Co-Fe5 C2 Catalysts.

Photothermal catalytic CO hydrogenation offers the potential to synthesize light hydrocarbons by using solar energy. However, the selectivity and activity of the reaction are still far below those achieved in conventional thermal catalytic processes. Herein, we report that the Co-modified Fe5 C2 on TiC catalyst promotes photothermal catalytic CO hydrogenation with a 59 % C2+ selectivity in the produced hydrocarbons and a 30 % single-pass CO conversion at a high gas hourly space-time velocity of 12 000 mL g-1 h-1 . Using in-situ-irradiated XPS, we show that light-induced hot electron injection from TiC to Fe5 C2 modulates the chemical state of Fe, thereby increasing the CO-to-C2+ conversion. This work suggests that it is possible for plasmon-mediated surface chemistry to enhance the activity and selectivity of photothermal catalytic reactions.

Addressing the CO2 challenge through thermocatalytic hydrogenation to carbon monoxide, methanol and methane

Addressing the CO2 challenge is mandatory for the well-being of Earth's ecosystem and humanity. CO2 catalytic hydrogenation is a suitable solution.

Amine-modified polyionic liquid supports enhance the efficacy of PdNPs for the catalytic hydrogenation of CO2 to formate.

Palladium nanoparticles stabilised by aniline modified polymer immobilised ionic liquid is a remarkably active catalyst for the hydrogenation of CO2 to formate; the initial TOF of 500 h-1 is markedly higher than either unmodified catalyst or its benzylamine and N,N-dimethylaniline modified counterparts and is among the highest to be reported for a PdNP-based catalyst.

Ni–N synergy enhanced the synthesis of formic acid via CO2 hydrogenation under mild conditions

Catalytic hydrogenation of CO2 to formic acid over Ni-based catalyst supported over N-doped TiO2.

A review of the recent progress on direct heterogeneous catalytic CO2 hydrogenation to gasoline-range hydrocarbons

This review presents important progress, main catalytic systems and critical scientific issues on direct heterogeneous catalytic CO2 hydrogenation to gasoline-range hydrocarbons.

Boosting methanol productionviaplasma catalytic CO2hydrogenation over a MnOx/ZrO2catalyst

Boosted methanol production over MnOx/ZrO2catalyst could be achievedviaplasma-assisted catalytic CO2hydrogenation at ambient temperature and pressure.

Influence of Recycle Operation on the Catalytic Hydrogenation of CO2 to Long-Chain Hydrocarbons

Influence of Recycle Operation on the Catalytic Hydrogenation of CO₂ to Long-Chain Hydrocarbons

Mononuclear Re sites on In2O3 catalyst for highly efficient CO2 hydrogenation to methanol

Catalytic hydrogenation of CO2 to methanol utilizing H2 derived from renewable energy represents one of the most prospective strategies for the sustainable recycle of carbon. Accordingly, the design and preparation of high-performance catalysts for methanol production has received broad attention. Herein, In2O3 supported mononuclear Re is reported to be an efficient catalyst for methanol production which exhibits methanol selectivity of up to 80% at CO2 conversion of 11.5%, providing a methanol STY of 758 mg·h−1·gcat−1 under 5 MPa and 300 °C, more than twice as that for pristine In2O3 (376 mg·h−1·gcat−1). The apparent reaction orders of CO2 and H2 were determined to be around 0 and 0.6 respectively, suggesting the activation of H2 is more crucial compared with CO2. In-depth characterizations reveal that the remarkably improved performance originates from the mononuclear Ren+ sites strongly interacting with In2O3, which significantly enhance the ability of H2 dissociation. Combined experimental and theoretical studies proved the feasibility of formate pathway over In2O3 supported mononuclear Re catalyst. The results of DFT calculations suggest that mononuclear Re site on In2O3(111) model plays a vital role on heterolytic H2 dissociation and intermediates transformation, boosting the formation of HCOO* and lowering the energy barriers of rate-determining step for methanol formation.

Photo-Assisted Catalytic CO2 Hydrogenation to CO with Nearly 100% Selectivity over Rh/TiO2 Catalysts

Photo-assisted catalytic CO2 hydrogenation represents a promising route to convert CO2 into value-added chemicals under mild conditions, but challenges remain in the design and development of highly active and selective catalysts. Herein, we synthesized highly efficient catalysts comprising Rh nanoparticles supported on TiO2 nanosheets for photo-assisted catalytic CO2 hydrogenation, which achieved a high CO production rate of 20.6 mmol gcat–1 h–1 (5.15 mol gRh–1 h–1) with nearly 100 % selectivity and excellent stability at 250 °C under light irradiation, outperforming most reported metal-based catalysts. X-ray photoelectron spectroscopy revealed that the electrons transfer from Rh nanoparticles to TiO2, hinting a strong interaction between Rh and the TiO2 support. Under illumination, the accumulated hot electrons on TiO2 surfaces could effectively promote the activation of CO2 molecules. In situ diffuse reflectance infrared Fourier transform spectroscopy results revealed that formate was the critical intermediate in the reverse water–gas shift reaction process, and light irradiation could effectively facilitate the activation and conversion of reactants and intermediate species, thereby improving CO production. This work provides a new strategy for the integration of solar and thermal energy for an efficient RWGS reaction under mild conditions.

Shvo-Catalyzed Hydrogenation of CO2 in the Presence or Absence of Ionic Liquids for Tandem Reactions.

Ionic liquids (ILs) have been widely used in transition metal-catalyzed processes, but the precise behavior of ILs and catalysts in these reactions is unknown. Herein, the role of ILs and the interaction pattern between Shvo's catalyst and ILs have been revealed with characterization by 1H NMR and crystallography based on the catalytic hydrogenation of CO2. ILs promote the dissociation of Shvo's catalyst and enhance the rate of production of CO. The CO that is produced is subsequently used in the tandem hydroformylation-reduction of alkenes to produce valuable alcohols. In the absence of ILs, formamides can be obtained by N-formylation of most primary or secondary amines.

Machine learning models representing catalytic activity for direct catalytic CO2 hydrogenation to methanol

Direct catalytic hydrogenation of CO2 to methanol is one of the most attractive ways to meet increasing fuel demand and reduce anthropogenic CO2 emission. An efficient catalyst is required for this highly complex structure-based reaction that simultaneously activates the CO2 molecule along with increased selectivity at feasible operating conditions. Application of machine learning models in catalysis research enables researchers to estimate and develop insights on the catalyst performances.This work focuses on development of machine learning (ML) models that include Multi Linear Regression, Least Absolute Shrinkage Selection Operator, Ridge Regression, Support Vector Regression, Gaussian Process Regression (GPR), Random Forest Regression, Gradient Boost Random Forest Regression (GBRT) and Artificial Neural Network (ANN) using published experimental data (698 datapoints) generated in a fixed bed reactor during the years 2010–2020. CO2 conversion and methanol selectivity were considered as catalytic activity performance indicators. Compared to other ML models, GBRT and ANN model predictions outperformed with R2 ∼ 0.95 and R2 ∼ 0.94 for CO2 conversion and with R2 ∼ 0.95 and R2 ∼ 0.95 for methanol selectivity respectively. Further, the input contributions using ANN models reveal that catalyst composition and calcination temperature are the significant inputs for CO2 conversion and methanol selectivity.