Catalytic Decomposition Of Formic Acid Research Articles

Free Energy Pathway Exploration of Catalytic Formic Acid Decomposition on Pt-Group Metals in Aqueous Surroundings

Free Energy Pathway Exploration of Catalytic Formic Acid Decomposition on Pt-Group Metals in Aqueous Surroundings

Silica-based covalent organic framework composite for efficient separation and enrichment of palladium and its heterogeneous catalysis application

Considering the necessity and challenge in palladium recovery from high-level liquid waste and hydrogen energy development, the first attempt was made to adsorb Pd(II) from simulated high-level liquid waste firstly, then to achieve in situ reduction by a simple method and followed by using it directly for efficient hydrogen production through the catalytic decomposition of formic acid. In this work, a composite of covalent organic framework and SiO2 (Tp-Azo-COF/SiO2) was prepared by wet impregnation method using SiO2 as a carrier. The characteristics of the composite were examined by SEM, EDS, BET, TG, XRD, etc. The results showed that Tp-Azo-COF/SiO2 exhibited regular silicon-based spherical shapes in microscopic form and good heat resistance. In batch experiments, Tp-Azo-COF/SiO2 was demonstrated excellent adsorption and selectivity for Pd(II) at a wide range of HNO3 acidity (1–5 M), and the separation factor was as high as 2653 at 3 M HNO3. Tp-Azo-COF/SiO2 was able to reach a maximum adsorption capacity of 85.40 mg/g at 120 min at 298 K in 3 M HNO3. FT-IR and XPS analysis show that the adsorption mechanism of Pd(II) by the composite occurs mainly on the C-NH of Tp-Azo-COF, and NO3– is also involved in the coordination. In dynamic column experiments, Tp-Azo-COF/SiO2 was demonstrated a nearly complete separation and recovery of Pd(II) with good reusability, and the enrichment coefficients all maintained at about 30. Finally, an efficient and environmentally friendly process was proposed to achieve the in situ reduction of Pd(II)-loaded Tp-Azo-COF/SiO2. Pd-loaded Tp-Azo-COF/SiO2 was demonstrated better decomposition performance than commercial Pd-based catalysts hydrogen production by the catalytic decomposition formic acid.

Mechanistic insights into hydrogen production from formic acid catalyzed by Pd@N-doped graphene: The role of the nitrogen dopant

The catalytic decomposition of formic acid (HCOOH) is a crucial process for hydrogen production technologies. Herein, periodic density functional theory (DFT) calculations were employed to explore the effect of N-doping on the decomposition of formic acid. We designed a series of single Pd-atoms deposited in the single vacancy of N-doped graphene sheets, namely Pd-DGr, Pd–N1Gr, Pd–N2Gr, and Pd–N3Gr, as the proposed catalysts. Our findings show that H2 production from HCOOH dehydrogenation on these surfaces proceeds via the formate (HCOO) pathway (Path-I) rather than the carboxylate (COOH) pathway (Path-II). Furthermore, the Pd–N3Gr catalyst shows the greatest catalytic reactivity toward HCOOH dehydrogenation via Path-I, requiring an activation energy (Ea) of 0.38 eV.On the other hand, the undesirable dehydration of HCOOH to carbon monoxide (CO) through COOH (Path-IIIA) or formyl (HCO) (Path-IIIB) intermediates is unlikely to occur on Pd–N3Gr due to a large activation energy. We found that the active species on the catalyst surface increased with N-doping concentration. Additionally, microkinetic simulations of the HCOOH decomposition on these surfaces confirmed the high activity and selectivity of the Pd–N3Gr catalyst toward HCOOH dehydrogenation (Path-I). These calculated results highlight that the Pd–N3Gr catalyst is a promising candidate for the formic acid decomposition reaction to yield hydrogen.

Atomic-Layer-Deposition Derived Pt subnano Clusters on the (110) Facet of Hexagonal Al2O3 Plates: Efficient for Formic Acid Decomposition and Water Gas Shift

The Pt subnano clusters dispersed on the (110) facet of regularly shaped hexagonal Al2O3 plates were fabricated via an atomic layer deposition approach. The resulting material contains Pt loading as low as 0.07 wt %; the interfacial structure exhibits nearly full CO conversion for water gas shift reaction at 210 °C, and the turnover frequency (TOF) of CO is as high as 2.1 s–1, outperforming most of the systems reported. The same interfacial structure was also found to be highly active for catalytic decomposition of formic acid (FA), with full FA conversion (with little CO product) and the TOF being 1.02 s–1. Further characterizations together with density functional theory simulations elucidate that the superior catalytic performances are attributed to the unique interfacial structure and the synergism between the small Pt clusters and the Al2O3 (110) substrate, leading to lower energy barriers for the *COOH intermediate formation over the ultrafine Pt ensembles and the hydroxylation over the Al2O3 (110) substrate close to the Pt entities. Both are favorable for the evolution of *COOH intermediate and the reaction between *COOH and neighbor OH species. The current study provides insights into the effectiveness in generating high-performance catalytic material for clean energy production and modulation through precise control of the metal entity dimension and the oxide substrate engineering to achieve specific facet exposure.

Catalytic decomposition of formic acid in a fixed bed reactor – an experimental and modelling study

Formic acid is one of the key components in green chemistry being involved in energy storage, production of chemical intermediates and fuel components. Therefore the knowledge of its stability is of crucial importance and a systematic study of its decomposition is needed. The kinetics of formic acid decomposition to hydrogen and carbon dioxide was investigated in a laboratory-scale fixed bed reactor at 150–225 °C and atmospheric pressure. Palladium nanoparticles deposited on porous active carbon Sibunit were used as the heterogeneous catalyst. The catalyst was characterized by nitrogen physisorption and high-resolution transmission electron microscopy. The average palladium nanoparticle size was 5–6 nm. The impacts of mass transfer resistance and formic acid dimerization were negligible under the reaction conditions. Prolonged experiments revealed that the catalyst had a good stability. Hydrogen and carbon dioxide were the absolutely dominant reaction products, whereas the amounts of carbon monoxide and water were negligible. The experimental data were described with three kinetic models: first order kinetics, two-step adsorption-reaction model and multistep adsorption-decomposition model of formic acid. The multistep model gave the best description of the data.

DFT and Microkinetic Comparison of Ru-Doped Porphyrin-like Graphene and Nanotubes toward Catalytic Formic Acid Decomposition and Formation

DFT and Microkinetic Comparison of Ru-Doped Porphyrin-like Graphene and Nanotubes toward Catalytic Formic Acid Decomposition and Formation

A Process for Hydrogen Production from the Catalytic Decomposition of Formic Acid over Iridium-Palladium Nanoparticles.

The present study investigates a process for the selective production of hydrogen from the catalytic decomposition of formic acid in the presence of iridium and iridium–palladium nanoparticles under various conditions. It was found that a loading of 1 wt.% of 2% palladium in the presence of 1% iridium over activated charcoal led to a 43% conversion of formic acid to hydrogen at room temperature after 4 h. Increasing the temperature to 60 °C led to further decomposition and an improvement in conversion yield to 63%. Dilution of formic acid from 0.5 to 0.2 M improved the decomposition, reaching conversion to 81%. The reported process could potentially be used in commercial applications.

Efficient hydrogen production via sunlight-driven thermal formic acid decomposition over a porous film of molybdenum carbide

A porous Mo1.98C1.02 film exhibits efficient sunlight-driven thermal catalytic formic acid decomposition, and the H2 generation rate is about two orders of magnitude faster than that of the reported non-precious photocatalysts.

Theoretical insight into the role of nitrogen in the formic acid decomposition over Pt13/N-GNS

Catalytic decomposition of formic acid is regarded as one of the most promising hydrogen source conversion technologies. Nitrogen doped carbon supported metal catalyst emerges in recent years and delivers excellent performance in formic acid hydrogenation. However, there is not a well-recognized explanation about the real role of the nitrogen dopant in carbon support. In this work, density functional theory-based calculations were used to individually study the ligand effect and catalytic effect from the nitrogen dopant. Ligand effect mainly tunes the electronic properties of metal active center by shifting d-band center far away from Fermi level. The result unravels that CH scission path is more favorable compared with OH scission path. Catalytic effect is originated from the lower electrostatic potential of nitrogen active site compared with platinum, making N site an efficient capturer for hydrogen atom. Though activation energy for cleaving OH bond is higher than CH bond, nitrogen site can efficiently cleave the OH bond. Microkinetic simulations are performed to obtain the best nitrogen doping concentration in the carbon support. It implies that the optimal nitrogen concentration is a function of temperature, according to the optimized curve. This work will improve the understanding of mechanism of formic acid decomposition and provide new method in modifying metal/carbon support catalysts.

Homogeneous Molecular Iron Catalysts for Direct Photocatalytic Conversion of Formic Acid to Syngas (CO+H2 ).

The catalytic decomposition of formic acid to generate syngas (a mixture of H2 and CO) is a highly valuable strategy for energy conversion. Syngas can be used directly in internal combustion engines or can be converted to liquid fuels, meeting future energy challenges in a sustainable manner. Herein, we report the use of homogeneous molecular iron catalysts combined with a CdS nanorods (NRs) semiconductor to construct a highly efficient photocatalytic system for direct conversion of formic acid to syngas at room temperature and atmospheric pressure. Under optimal conditions, the photocatalytic system presents an activity of 150 mmol gcatalyst -1 h-1 towards H2 , and an apparent quantum yield (AQY) of 16.8 %, making it among the most active noble-metal-free photocatalytic systems for H2 evolution from formic acid under visible light. Meanwhile, these iron-based molecular catalysts also demonstrate remarkable enhancement in CO evolution with robust stability. The mechanistic role of the molecular catalyst is further investigated by using cyclic voltammetry, which suggests the formation of FeI species as the key step in the catalytic conversion of formic acid to syngas.

Homogeneous Molecular Iron Catalysts for Direct Photocatalytic Conversion of Formic Acid to Syngas (CO+H2)

AbstractThe catalytic decomposition of formic acid to generate syngas (a mixture of H2 and CO) is a highly valuable strategy for energy conversion. Syngas can be used directly in internal combustion engines or can be converted to liquid fuels, meeting future energy challenges in a sustainable manner. Herein, we report the use of homogeneous molecular iron catalysts combined with a CdS nanorods (NRs) semiconductor to construct a highly efficient photocatalytic system for direct conversion of formic acid to syngas at room temperature and atmospheric pressure. Under optimal conditions, the photocatalytic system presents an activity of 150 mmol gcatalyst−1 h−1 towards H2, and an apparent quantum yield (AQY) of 16.8 %, making it among the most active noble‐metal‐free photocatalytic systems for H2 evolution from formic acid under visible light. Meanwhile, these iron‐based molecular catalysts also demonstrate remarkable enhancement in CO evolution with robust stability. The mechanistic role of the molecular catalyst is further investigated by using cyclic voltammetry, which suggests the formation of FeI species as the key step in the catalytic conversion of formic acid to syngas.

Amino-functionalized graphene oxide-supported networked Pd–Ag nanowires as highly efficient catalyst for reducing Cr(VI) in industrial effluent by formic acid

Cr(VI) pollution in wastewater has increasingly become a global environmental problem owing to its acute toxicity. Herein, we present the one-pot procedure for preparing the amino-functionalized (-NH2) graphene oxide (GO-) supported networked Pd–Ag nanowires by co-reduction growth in polyol solution, which show the highly efficient catalytic performance with the excellent cycling stability for the catalytic Cr(VI) reduction by formic acid as an in-situ source of hydrogen at room temperature. The electron transfer from Ag and amino to Pd increases the electron density of Pd, which enhances the catalytic formic acid decomposition and subsequent the catalytic Cr(VI) reduction. The catalytic reduction rate constant of Pd3Ag1/GO-NH2 is determined to be 0.0768 min−1, which is much superior to the monometallic Pd/GO-NH2 and Pd3Ag1/GO. This study provides a novel strategy to develop catalysts for the catalytic reduction of Cr(VI) to Cr(III) in the industrial effluent using formic acid as an in-situ source of hydrogen.

Estimating surface electric fields using reactive formic acid probes and SEM image brightness analysis

By changing the electrical bias imposed on a Ni catalyst attached to an external circuit, the selectivity of catalytic formic acid decomposition is shown to change—favoring CO2/H2 production under negative bias and CO/H2O production under positive bias. A method for estimating the strength of externally generated surface electric fields by measuring this selectivity change is presented and used to approximate field strengths on the order of 0.20 V/nm. A COMSOL model of the catalyst was created which indicated that the presence of Ni particles increased field strength and uniformity across the catalyst. Comparing this model to SEM imaging of the catalyst verified that the field strengths are highest on the surface of the catalyst particles, pore edges, and microscopic defects. The methods developed herein may be useful to future reaction engineers seeking to incorporate applied electric fields into process designs.

Catalytic decomposition of formic acid on Cu(100): Optimization and dynamic Monte Carlo simulation

Dynamic Monte Carlo simulation and response surface methodology have been used to study optimum conditions for the heterogeneous catalytic formic acid decomposition reaction on Cu(100) for the first time. The mechanism, kinetic parameters, optimum conditions and the effects of temperature, pressure and reaction time on the hydrogen yield were studied. Formate (HCOO) species is the active reaction intermediate and the adsorption of formic acid is considered as the rate-controlling step. The proposed optimum conditions provided a turnover frequency (TOF) of 0.044 s−1 for hydrogen production.

Surface Modification on Pd-TiO2 Hybrid Nanostructures towards Highly Efficient H2 Production from Catalytic Formic Acid Decomposition.

Metal-containing nanocrystals with well-designed surface structures represent a class of model systems for revealing the fundamental physical and chemical processes involved in heterogeneous catalysis. Herein it is shown how surface modification can be utilized as an efficient strategy for controlling the surface electronic state of catalysts and, thus, for tuning their catalytic activity. As model catalysts, the Pd-tetrahedron-TiO2 nanostructures, modified on the surface with different foreign atoms, showed a varied activity in the catalytic decomposition of formic acid towards H2 production. The catalytic activity increases with a reduction in the work function of modified atoms; this reduction can be well explained by a surface polarization mechanism. In this hybrid system, the difference in the work functions of Pd and modified atoms results in surface polarization on the Pd surface and, thus, in the tuning of its charge state. Together with the Schottky junction between TiO2 and metals, the tuned charge state enables the promotion of catalytic efficiency in the catalytic decomposition of formic acid to H2 and CO2 .

Enhanced hydrogen selectivity from catalytic decomposition of formic acid over FeZnIr nanocatalyst at room temperature

Hydrogen is considered a promising energy carrier for the future, especially for clean energy generation via fuel cell technologies. Formic acid is one of the prominent sources of clean and cheap hydrogen. In this work, Fe–Zn–Ir nanocatalysts show exceptional performance for selective hydrogen production via HCOOH decomposition, offering a promising alternative that could solve issues associated with hydrogen storage and distribution. Our results show that Fe atoms on the Fe–Zn–Ir surface are responsible for activating the HCOOH molecules; however, the identity of the surface metal atoms (Ir and Zn) dictate the selectivity of the reaction adjacent to the Fe atoms when there is no CO contamination. The high content of Fe atoms that reside at the Fe–Zn–Ir interface sites favored the dehydrogenation of HCOOH. The greater selectivity towards H2 was measured to be 97.4% at 30 min for the higher Fe content (50 wt%). These observations suggest that by controlling the arrangement of surface Fe, Zn, and Ir atoms, the reactivity and selectivity of HCOOH decomposition over Fe–Zn–Ir catalysts could be tailored, optimizing the surface composition. The findings in this study may prove informative for the rational design of Fe–Zn–Ir catalyst systems for reactions associated with hydrogen production, such as for fuel cell applications.

Investigation of the Catalytic Performance of Pd/CNFs for Hydrogen Evolution from Additive-Free Formic Acid Decomposition

In recent years, research efforts have focused on the development of safe and efficient H2 generation/storage materials toward a fuel-cell-based H2 economy as a long-term solution in the near future. Herein, we report the development of Pd nanoparticles supported on carbon nanofibers (CNFs) via sol-immobilisation and impregnation techniques. Thorough characterisation has been carried out by means of XRD, XPS, SEM-EDX, TEM, and BET. The catalysts have been evaluated for the catalytic decomposition of formic acid (HCOOH), which has been identified as a safe and convenient H2 carrier under mild conditions. The influence of preparation method was investigated and catalysts prepared by the sol-immobilisation method showed higher catalytic performance (PdSI/CNF) than their analogues prepared by the impregnation method (PdIMP/CNF). A high turnover frequency (TOF) of 979 h−1 for PdSI/CNF and high selectivity (>99.99%) was obtained at 30 °C for the additive-free formic acid decomposition. Comparison with a Pd/AC (activated charcoal) catalyst synthesised with sol-immobilisation method using as a support activated charcoal (AC) showed an increase of catalytic activity by a factor of four, demonstrating the improved performance by choosing CNFs as the preferred choice of support for the deposition of preformed colloidal Pd nanoparticles.

Single Pd atom and Pd dimer embedded graphene catalyzed formic acid dehydrogenation: A first-principles study

The catalytic decomposition of formic acid was studied on a series of candidate catalysts using density functional theory calculations. The candidate catalysts were modelled by a single Pd atom embedded in mono- and divacancy in graphene (Pd1m-G vs. Pd1d-G), as well as a Pd dimer embedded in di-, tri-, and quadrivacancy in graphene (Pd2d-G vs. Pd2t-G vs. Pd2q-G). These catalysts can effectively and selectively catalyze formic acid dehydrogenation into hydrogen. Pd2d-G is the most favorable catalyst among the five models with the rate-determining step energy barrier of only 0.68 eV, which is comparable to one of the most active catalysts i.e., Pd(111). Pd1d-G is comparatively less active, with the rate-determining step energy barrier of 0.90 eV. The rest of the three models, i.e., Pd1m-G, Pd2t-G and Pd2q-G, have energy barriers of 1.26, 1.12 and 1.06 eV, respectively. The model catalysts studied in this work are promising for reducing usage of the precious and rare metal Pd compared with Pd bulk catalysts. Additionally, unlike Pd nanoparticle catalysts, the model catalysts in this work clarify the catalytic mechanism.

Non-precious molybdenum-based catalyst derived from biomass: CO-free hydrogen production from formic acid at low temperature

CO-free hydrogen was successfully produced from the dehydrogenation of formic acid at a temperature near its boiling point of 110 °C by using a high-performance non-precious metal molybdenum based catalyst synthesized from soybean and earth-abundant molybdenum. The effect of carbonization temperature, raw material ratio on the catalytic activity for formic acid decomposition were investigated in details. The catalyst Soy-Mo (0.1) prepared at a carbonization temperature of 750 °C, the weight ratio of the soybean powder to Mo precursor of 1:0.1 showed the best catalytic activity among those as-synthesized catalysts. Even at a temperature as low as 110 °C, HCOOH conversion reached above 80% with a 100% H2 selectivity and a long-term stability. It indicated that the catalysts derived from those biomass enriched in protein and alkaline metals have excellent performance for catalytic formic acid decomposition. This approach provided a new path for design and development of catalysts with high performance for CO-free hydrogen generation from formic acid in a large-scale industrial process.

Effect of Carboxylic Acids on Reactive Transfer Printing of Copper Formate Ink

ABSTRACTDuring decomposition of copper formate, a volatile intermediate is formed, that can be utilized to fabricate conductive copper lines for electrical interconnections. By the method called Reactive Transfer Printing (RTP), a pattern of copper (II) formate was printed, and placed adjacent to a second surface; decomposition of the printed pattern led to a transfer of copper to the second substrate. It was found that the yield of the transfer process improved due to presence of several carboxylic acids which are liquid with a high boiling point. Furthermore we found that the transport of copper starts at a lower temperature than previously reported, indicating that the first decomposition step of copper formate is related to the catalytic decomposition of formic acid on a copper surface. The findings enable printing of conductive copper patterns onto the interior surface of a glass vessel.