Hydrogenation Of Bicarbonate Research Articles

Pd-imidate@SBA-15: a multifunctional heterogeneous catalyst for the aqueous room temperature hydrogenation of CO2 to formic acid.

The incorporation of hydrophilic and basic sites from phosphotriazaadamantane and saccharine in a water-soluble Pd complex and the subsequent confinement into mesoporous silica support increases the activity and stability of the palladium catalytic species for the room-temperature aqueous hydrogenation of either bicarbonate or CO2 into formic acid. The use of low Pd loadings (<0.1mmolPd·g-1) of the well-dispersed complex on SBA-15 mesoporous silica allows performing the reaction under room temperature, and aqueous conditions, exhibiting TON of ca. 40-100, for the CO2 or bicarbonate hydrogenation, respectively, which is one order of magnitude higher than the homogeneous case, allowing the easy isolation and recycling of the solid catalyst.

Antioxidant-driven activity and stability enhancement in multiphase bicarbonate hydrogenation catalysis with a Ru-PNP pincer complex

Herein, we present a practical strategy to enhance the performance of a multiphase system for bicarbonate hydrogenation based on a molecular Ru-PNP pincer catalyst. This study demonstrates that the use of organic antioxidants not only mitigates catalyst degradation but also significantly boosts its intrinsic activity. This enables efficient catalyst recycling at ultra-low concentrations. Systematic screening and optimization of a range of organic antioxidants has identified TDTBP (tris(2,4-di-tert-butylphenyl) phosphite) as being exceptionally efficient in stabilizing and enhancing the performance of the Ru-PNP catalyst. With the optimized system an unprecedented integral turnover frequency (TOF) of 115,000 h−1 and a total turnover number (TTON) of 9.43×106 across four recycling tests were demonstrated, conducted at a reaction temperature of 90 ºC and H2 pressure of 50 bar. These findings represent a substantial advancement in sustainable formate/formic acid production, offering a scalable and highly efficient method suitable for industrial-scale application.

Liquid‐Liquid‐Gas Triphasic Hydrogenation of Bicarbonate to Formate in a Continuous Flow Tubular Reactor

AbstractMultiphasic reaction of bicarbonate hydrogenation to form formate using homogeneous Ru PNP pincer catalyst in a continuous flow tubular reactor is reported. The reaction system consists of three phases. Catalyst is dissolved in toluene while potassium bicarbonate is dissolved in water. The significance of efficient mixing among the organic phase, aqueous phase and gaseous hydrogen to improve hydrogenation reaction by using different inert packing materials is studied by operando visualization and also quantitatively discussed. The bicarbonate conversion of up to 67% is achieved after optimization of important reaction and reactor parameters. The designed reactor setup comprised of effective recycling system that recycles the catalyst with &gt;99% activity.

Molybdenum-catalyzed hydrogenation of carbon dioxide, bicarbonate, and inorganic carbonates to formates.

Herein, we report the hydrogenation of carbon dioxide to sodium formate catalyzed by low-valent molybdenum phosphine complexes. The 1,3-bis(diphenylphosphino)propane (DPPP)-based Mo complex was found to be an efficient catalyst in the presence of NaOH affording formate with a TON of 975 at 130 °C in THF/H2O after 24 h utilizing 40 bar (CO2 : H2 = 10 : 30) pressure. The complex was also active in the hydrogenation of sodium bicarbonate and inorganic carbonates to the corresponding formates. Mechanistic investigation revealed that the reaction proceeded via an intermediate formato complex.

Thermo-electrocatalytic reduction of potassium bicarbonate to formate on an indium electrode

Abstract In this work, we developed a thermo-electrochemical bicarbonate reduction (TEBR) process for the production of formate on a simple indium foil electrode. The TEBR process relies on the synergistic effect of thermochemical and electrochemical processes, which ensures the continuous redox of metals on the electrode surface. In the thermochemical environment, indium can interact with water to form InO(OH), which facilitates the absorption and hydrogenation of bicarbonate to form formate. In the electrochemical environment, the reduction of indium oxide to indium supports the maintenance of a dynamic interface of In3+/In. This study revealed that, when an indium electrode is employed in the reaction system, the Faraday efficiency and partial current density of formate can reach 86.2% and 86.5 mA cm−2, respectively, at 100 °C with a KHCO3 concentration of 3.0 mol L−1. Therefore, an indium electrode can be effectively employed for the direct reduction of bicarbonate to produce formate. This study provides an insight into the synergistic effect of thermochemical and electrochemical processes, and suggests a potential application of indium in the production of formate via a TEBR process.

The d band center dependent catalytic activity of n-doped carbon nanospheres with wrinkled cages supported PdPt alloy catalysts in transfer hydrogenation of bicarbonate with glycerol

Catalytic transfer hydrogenation of bicarbonate, a typical product of CO2 captured in an alkaline solution, with glycerol (GLY) as a hydrogen donor to formate (FA) and lactate (LA) is a sustainable and green approach for simultaneous valorization of CO2 and the major byproduct from biodiesel production. Conventional monometallic noble metal catalysts can catalyze this transfer hydrogenation reaction, but generally required a high reaction temperature, leading to a low yield of FA. In this work, N-doped carbon spheres with wrinkled cages (NCSWCs) supported PdPt alloy catalysts were prepared and their electronic structures were determined by Valence Band Spectra (VBS) and Density Functional Theory (DFT). It was found that the relationship between the d band center and catalytic activity exhibits volcano-shaped behaviors, where Pd2Pt1/NCSWCs is on the top of the curve, 85.4% of GLY conversion with 67.3% yield of LA and 56.5% yield of FA can be achieved at 200 °C. DFT calculations also revealed that Pd2Pt1/NCSWCs possessed an intermediate d band center, which tunes the adsorption and dissociation energy of H species on its surface, allowing maximum H transfer during the transfer hydrogenation of bicarbonate, leading to high catalytic activity. Such a d band center catalyst tuning could be efficient way to design new catalysts.

Kinetics, Model Discrimination, and Parameters Estimation of CO2 Methanation on Highly Active Ni/CeO2 Catalyst

The reaction kinetics of CO2 methanation over a highly active 8.5% Ni/CeO2 catalyst was determined in a fixed-bed reactor, in the absence of heat- and mass-transfer limitations. Once the catalyst activity was stabilized, more than 120 kinetic experiments (with varying values of reaction temperature, total pressure, space velocity (GHSV), and partial pressure of products and reactants) were performed. From initial reaction rates, an apparent activation energy of 103.9 kJ mol–1 was determined, as well as the effect of reactants (positive) and water partial pressures (negative) on CO2 methanation rate. Three mechanistic models reported in the literature, in which CO2 is adsorbed dissociatively (carbon and formyl routes) or directly (formate route), were explored for modeling the entire reaction kinetics. For that, the corresponding rate equations were developed through the Langmuir–Hinshelwood–Hougen–Watson (LHHW) approach. In agreement with DRIFTS experiments, formate route, in which the hydrogenation of bicarbonate to formate is considered to be the rate-determining step, reflects the kinetic data accurately, operating from differential conversion to thermodynamic equilibrium. In fact, this mechanism results in a mean deviation (D) of 10.38%. Based on previous own mechanistic studies, the participation of two different active sites has been also considered. Formate route on two active sites maintains a high fitting quality of experimental data, providing kinetics parameters with a higher physical significance. Thus, the LHHW mechanism, in which Ni0 sites as well as oxygen vacant near to Ni-CeO2 interface participate in CO2 methanation, is able to predict the kinetics of Ni/CeO2 catalyst accurately for a wide range of operational conditions.

Ru/ZrO2 as a Facile and Efficient Heterogeneous Catalyst for the Catalytic Hydrogenation of Bicarbonate Using Biodiesel-Waste Glycerol as a Hydrogen Donor

Ru/ZrO₂ as a Facile and Efficient Heterogeneous Catalyst for the Catalytic Hydrogenation of Bicarbonate Using Biodiesel-Waste Glycerol as a Hydrogen Donor

Simultaneous transformation of sugars and CO2 into sugar derivatives and formate at room temperature: Effect of alcohols and cations

Catalytic hydrogenation of CO2 to formate is an attractive pathway for CO2 utilization. In this system, replacing fossil fuel based H2 with a biomass-derived H2 source and using a recyclable heterogeneous catalyst at mild reaction conditions are advantageous to construct a green and sustainable process. Here, we demonstrate the transfer hydrogenation of biomass-derived sugars to CO2 affording sugar-derivatives and formate using a physical mixture of Pt/C and Pd/C catalysts. In this regard, the effects of various parameters such as the solvent composition, CO2 source, reactant concentrations, and sugar source were systematically investigated. In addition, the glucose dehydrogenation and bicarbonate hydrogenation were separately conducted to understand the effect of the parameters on each reaction. Based on the catalytic results and 13C NMR study, the reaction mechanism was suggested. The results demonstrated that the hydrogen transferring ability, salt solubility, and water structure breaking as well as pH and H2 solubility were crucial factors that could affect the catalytic activity. The high- concentration reaction was carried out to enhance the productivity, and high turnover numbers of 1018 and 99.8 were obtained for Pt/C and Pd/C, respectively. Moreover, the reaction system heterogeneity was confirmed by retained activity after consecutive cycling tests.

Unsupported Nanoporous Palladium Catalyst for Highly Selective Hydrogenation of Carbon Dioxide and Sodium Bicarbonate into Formate

AbstractDeveloping an efficient and simple heterogeneous catalytic system for CO2 conversion into formic acid (FA) is a vibrant research area because FA is recognized as a liquid organic hydrogen carrier. On the basis of our previous work on unsupported nanoporous palladium‐catalyzed hydrogenation proceeding through a Pd‐hydride intermediate, we report herein four types of PdNPore catalysts for the CO2 hydrogenation. The PdNPore‐1 catalyst exhibited high catalytic activity for CO2 hydrogenation into formate and obtained a yield of 86 % at 80 °C under H2 (1.0 MPa) and CO2 (1.5 MPa) with 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) as a base in acetonitrile. Moreover, the catalyst was easily recovered and reused without any loss of catalytic activity. Sodium bicarbonate could also be hydrogenated using the PdNPore‐1 catalyst.

Homogeneous hydrogenation of saturated bicarbonate slurry to formates using multiphase catalysis

A highly efficient bicarbonate hydrogenation catalyst system based on ppm concentrations of a Ru-PNP pincer complex is presented. It allows converting supersaturated bicarbonate slurries to aqueous formate solutions up to 12 M in molarity.

Chiral-at-Metal: Iridium(III) Tetrazole Complexes With Proton-Responsive P-OH Groups for CO2 Hydrogenation.

A rise in atmospheric CO2 levels, following years of burning fossil fuels, has brought about increase in global temperatures and climate change due to the greenhouse effect. As such, recent efforts in addressing this problem have been directed to the use of CO2 as a non-expensive and non-toxic single carbon, C1, source for making chemical products. Herein, we report on the use of tetrazolyl complexes as catalyst precursors for hydrogenation of CO2. Specifically, tetrazolyl compounds bearing P–S bonds have been synthesized with the view of using these as P∧N bidentate tetrazolyl ligands (1–3) that can coordinate to iridium(III), thereby forming heteroatomic five-member complexes. Interestingly, reacting the P,N′-bidentate tetrazolyl ligands with [Ir(C5Me5)Cl2]2 led to serendipitous isolation of chiral-at-metal iridium(III) half-sandwich complexes (7–9) instead. Complexes 7–9 were obtained via prior formation of non-chiral iridium(III) half-sandwich complexes (4–6). The complexes undergo prior P–S bond heterolysis of the precursor ligands, which then ultimately results in new half-sandwich iridium(III) complexes featuring monodentate phosphine co-ligands with proton-responsive P-OH groups. Conditions necessary to significantly affect the rate of P–S bond heterolysis in the precursor ligand and the subsequent coordination to iridium have been reported. The complexes served as catalyst precursors and exhibited activity in CO2 and bicarbonate hydrogenation in excellent catalytic activity, at low catalyst loadings (1 μmol or 0.07 mol% with respect to base), producing concentrated formate solutions (ca 180 mM) exclusively. Catalyst precursors with proton-responsive P-OH groups were found to influence catalytic activity when present as racemates, while ease of dissociation of the ligand from the iridium center was observed to influence activity in spite of the presence of electron-donating ligands. A test for homogeneity indicated that hydrogenation of CO2 proceeded by homogeneous means. Subsequently, the mechanism of the reaction by the iridium(III) catalyst precursors was studied using 1H NMR techniques. This revealed that a chiral-at-metal iridium hydride species generated in situ served as the active catalyst.

Enhancing the activity, stability and retainability of Ni-ZnO/SiO2 for CO2 utilization by amino-functionalization

The utilization of CO2 is nowadays important for alleviating energy and environmental crisis. Herein, amino-functionalization was used to improve the performance of SiO2-supported Ni-ZnO nanocatalyst for the hydrogenation of sodium bicarbonate to formic acid. The activity, stability and retainability were all improved upon the introduction of amino group. A formic acid yield of 30.4% was obtained from sodium bicarbonate when passing 5 vol% H2/N2 at 70 °C for 4.5 h, which is considered among the best catalytic performances reported under ambient pressure. The simultaneous improvement of the three aspects through a simple operation is attractive in the field of catalysis.

Ultrasmall Ni-ZnO/SiO2 Synergistic Catalyst for Highly Efficient Hydrogenation of NaHCO3 to Formic Acid.

Conversion of CO2 into fuels and chemicals has been considered to be an important strategy to reduce greenhouse gas emissions and alleviate the energy crisis. Bicarbonate as a CO2 source is convenient for experimental operation. Herein, based on the synergistic effect of Ni and ZnO benefitting from the electronic transfer, ultrasmall Ni-ZnO clusters (∼2 nm) stabilized by microporous silica nanoparticles were designed and prepared for catalyzing the hydrogenation of sodium bicarbonate to formic acid. The yield of formic acid reached up to 97.0% at 260 °C/3 MPa for 2 h, which is higher than those reported non-noble metal-based catalysts. The good performance of Ni-ZnO/SiO2 can be attributed to the ultrasmall active component size and the synergy effect based on electron transfer between Ni and ZnO.

Facile hydrogenation of bicarbonate to formate in aqueous medium by highly stable nickel-azatrane complex

Molecular catalyst-based direct hydrogenation of bicarbonate to formate in aqueous medium is a challenging research topic for the H2 storage. Finding a green and effective method for the bicarbonate to formate conversion with non-precious metal-based catalyst is vital to the practical application. We report the direct hydrogenation of bicarbonate to formate using a water soluble nickel-azatrane complex. Catalysts 1–5, designed and synthesized, were screened for the hydrogenation of bicarbonate to formate in aqueous medium; the best TON of 121 was obtained for catalyst 4 at 120 °C (60 bar). Introduction of isopropyl (2) and methyl (3 and 4) groups in the coordination environment of the metal center enhances the production of formate. Further, the hydrogenation of bicarbonate with CO2 promoted the formate production for catalyst 4 with a TON of 92 (3 h). The use of green solvent and non-precious metal catalyst makes this catalytic method environmentally sustainable.

A MOF-assisted phosphine free bifunctional iron complex for the hydrogenation of carbon dioxide, sodium bicarbonate and carbonate to formate.

The hydrogenation of carbon dioxide into formic acid (FA) with Earth-abundant metals is a vibrant research area because FA is an attractive molecule for hydrogen storage. We report a cyclopentadienyl iron tricarbonyl complex that provides up to 3000 turnover number for carbon dioxide hydrogenation when combined with a catalytic amount of the chromium dicarboxylate MOF MIL-53(Cr). To date, this is the highest turnover number reported in the presence of a phosphine-free iron complex.

Fundamental Mechanisms of Reversible Dehydrogenation of Formate on N-Doped Graphene-Supported Pd Nanoparticles

Reversible formate (HCOO–) dehydrogenation and bicarbonate (HCO3–) hydrogenation would be desirable for the utilization and storage of hydrogen (H2) as an effective energy carrier. Carbon-supported Pd-based nanoparticles demonstrated enormous competitive advantages for these reactions. However, the fundamental mechanisms underlying these reversible reactions have not yet been elucidated. Herein, we report the reaction pathways for reversible reactions on a Pd-based catalyst using density functional theory (DFT) calculations and propose key factors for improving the reaction efficiency. As the first essential step, the difficulty in the conventional DFT modeling, that is simulation of an anion environment caused by HCOO–, was overcome by designing two-sided Pd12 nanoclusters supported on graphene (Pd12NC-G) with extra electrons. Using Pd12NC-G, we demonstrated that the key factor determining the potential limiting steps for the reversible reaction was desorption of hydrogen in HCOO– dehydrogenation (1.24 e...

Generation and Quantification of Formate Ion Produced from Aqueous Sodium Bicarbonate in the Presence of Homogeneous Ruthenium Catalyst.

Formic acid and its salts are an alternative source for hydrogen generation. In this study, we store hydrogen using the formate–bicarbonate cycle. Aqueous sodium bicarbonate is hydrogenated to form sodium formate, which can then be decomposed to release hydrogen and sodium bicarbonate. The hydrogenation step is carried out under mild conditions in the presence of a homogeneous ruthenium catalyst. Hydrogen charge is realized at 70 °C under a hydrogen pressure of 20 bar, achieving yields > 80% and turnover number > 610. The catalyst is stable and robust through numerous cycles of the hydrogenation reaction. The formate ion formed during the bicarbonate hydrogenation is assayed and quantified by ion chromatography.

Towards Hydrogen Storage through an Efficient Ruthenium-Catalyzed Dehydrogenation of Formic Acid.

Hydrogen is of fundamental importance for the construction of modern clean-energy supply systems. In this context, the catalytic dehydrogenation of formic acid (FA) is a convenient method to generate H2 gas from an easily available liquid. One of the issues associated with current catalytic dehydrogenation systems is insufficient stability. Here, we present a robust and recyclable system for FA dehydrogenation by combining a ruthenium 1,1,1-tris(diphenylphosphinomethyl)ethane complex and aluminum trifluoromethanesulfonate (Al(OTf)3 ). This robust system allows steady H2 production under pressure and recycling for an additional 14 runs without any apparent loss of activity (turnover frequencies up to 1920 h-1 , turnover numbers up to 20 000). Notably, the catalyst can also be used for the dehydrogenation of formates and the reverse hydrogenation of bicarbonates and CO2 .

Heterogeneous catalysts for hydrogenation of CO2 and bicarbonates to formic acid and formates

ABSTRACTFormic acid and formates are often produced by hydrogenation of CO2 with hydrogen over homogeneous catalysts. The present review reports recent achievements in utilization of heterogeneous catalysts. It shows that highly dispersed supported metal catalysts are able to carry out this reaction by providing activation of hydrogen on the metal sites and activation of CO2 or bicarbonate on the support sites. Important advances have recently been achieved through utilization of catalysts using CxNy materials as supports. The high activity of these catalysts could be assigned to their ability to stabilize the active metal in a state of single-metal atoms or heterogenized metal complexes, which may demonstrate a higher activity than metal atoms on the surface of metal nanoparticles.