Catalytic Dehydrogenation Of Formic Acid Research Articles

Synthesis of Cr(OH)3/ZrO2@Co-based metal-organic framework from waste poly(ethylene terephthalate) for hydrogen production via formic acid dehydrogenation at low temperature

Recycling waste polyethylene terephthalate (PET) bottles into value-added ligand materials for synthesizing metal-organic frameworks (MOFs) derived catalysts is an eco-friendly and economically viable process. The waste PET bottles were readily broken down into 1,4-benzenedicarboxylic acid (BDC) ligands in a highly alkaline environment. Herein, we fabricated a Co@Cr(OH)3/ZrO2 catalyst via the carbonization of PET-derived UiO-66 metal-organic frameworks for the catalytic dehydrogenation of formic acid at low temperatures. The as-prepared Co@Cr(OH)3/ZrO2 catalyst provides a turnover frequency of 7685 h−1 for hydrogen generation (120 mL in 1.5 min) at ambient temperature. This is due to the uniform dispersion of the fine metal nanoparticle (NPs) (Co NPs, ∼3.75 nm) and the synergistic effect of the Co NPs and Cr(OH)3/ZrO2 supports. In addition, the characterization results indicate that porous Zr-MOFs may effectively enclose tiny particles, which is favorable for enhanced dehydrogenation performance. In addition, the Co@Cr(OH)3/ZrO2 catalysts demonstrated excellent stability against aggregation and were recyclable over seven cycles without any significant catalytic loss. Thus, this study provides a sustainable methodology for the development of MOF-derived, effective, and stable catalysts for formic acid dehydrogenation towards hydrogen production.

Pd Nanoparticles Supported on Carbon Nanotubes with Carbonyl-Driven Pd0–Pdδ+ Interface Formation for the Catalytic Dehydrogenation of Formic Acid

Pd Nanoparticles Supported on Carbon Nanotubes with Carbonyl-Driven Pd⁰–Pd^δ+ Interface Formation for the Catalytic Dehydrogenation of Formic Acid

Catalytic Dehydrogenation of Formic Acid Promoted by Triphos-Co Complexes: Two Competing Pathways for H2 Production.

In this study, we reported the synthesis and structural characterization of a triphos-CoII complex [(κ3-triphos)CoII(CH3CN)2]2+ (1) and a triphos-CoI-H complex [(κ2-triphos)HCoI(CO)2] (4). The facile synthetic pathways from 1 to [(κ3-triphos)CoII(κ2-O2CH)]+ (1') and [(κ3-triphos)CoI(CH3CN)]+ (2), respectively, as well as the interconversion between [(κ3-triphos)CoI(CO)2]+ (3) and 4 have been established. The activation energy barrier, associated with the dehydrogenation of a coordinated formate fragment in 1' yielding the corresponding 2 accompanied by the formation of H2 and CO2, was experimentally determined as 23.9 kcal/mol. With 0.01 mol % loading of 1, a maximum TON ∼ 1735 within 18 h and TOF ∼ 483 h-1 for the first 3 h could be achieved. Kinetic isotope effect (KIE) values of 2.25 (kHCOOH/kDCOOH) and 1.36 (kHCOOH/kHCOOD) for the dehydrogenation of formic acid and its deuterated derivatives, respectively, implicate that the H-COOH bond cleavage is likely the rate-determining step. The catalytic mechanism proposed by density functional theory (DFT) calculations coupled with experimental 1H NMR and gas chromatography-mass spectrometry (GC-MS) analysis unveils two competing pathways for H2 production; specifically, deprotonating a HCOO-H bond by a proposed Co-H intermediate C and homolytic cleavage of the CoII-H moiety of C, presumably via a dimeric Co intermediate D containing a [Co2(μ-H)2]2+ core, to yield the corresponding 2 and H2.

Hydrogen production by heterogeneous catalytic dehydrogenation of formic acid. A review

Hydrogen production by heterogeneous catalytic dehydrogenation of formic acid. A review

In situ synthesis of C–SiO2 enhanced Pd nanoparticles for catalytic dehydrogenation of formic acid

Formic acid (FA, HCOOH), as a liquid chemical hydrogen storage carrier with low cost, high hydrogen content, and convenient storage and transportation, has attracted extensive attention. Pd-based catalysts for hydrogen production from FA are easy to aggregate and deactivate in the reaction process, which hinders the further development of FA as a hydrogen storage carrier. Therefore, the exploitation of carriers with simple preparation methods and excellent performance can effectively improve the catalytic activity of Pd-based catalysts. Porous carbon and SiO2 have been widely used for their unique structural properties, and the preparation of composite carriers by combining the advantages of both is a current research hotspot. Herein, this work synthesized C–SiO2 for the deposition of Pd nanoparticles by a one-step method, and the obtained Pd/C–SiO2 exhibits a superior FA dehydrogenation activity with a turnover frequency value of 1278 h−1 and a favorable stability with only a slight decrease in activity after five cycles.

A genuine germylene PGeP pincer ligand for formic acid dehydrogenation with iridium.

We report an iridium system constructed around a long-tethered PGeP ligand that facilitates access to the less common germylene form, so far unreported for an 'NHC-type' Ge ligand. Its bonding is substantiated by computational studies and we have demonstrated its use for the catalytic dehydrogenation of formic acid, highlighting the potential of this underdeveloped type of ligand.

Insights into N dopants during dehydrogenation of formic acid over Pd/N-doped carbon catalysts

Catalytic dehydrogenation of formic acid (FA) is one strategy to generate hydrogen from an easily handled chemical and meet the clean-energy demand simultaneously. The Pd/N-doped carbon catalyst is famous for boosting the activity of active metal in FA dehydrogenation. However, the origin of achieving highly catalytic activity remains controversial. Herein, a variety of Pd/N-doped carbon catalysts were systematically prepared by regulating different N doping content and reduction conditions (H2 and NaBH4) for promoting hydrogen production from FA under ambient conditions without additives. The results showed that N dopants have a great impact on the electronic state and particle size of Pd. Moreover, the electronic state of Pd is also sensitive to the reduction methods. The catalyst with the highest pyridinic-N content presented the best catalytic performance after being reduced in H2 flow at 260 °C, and its initial TOF value is 2656 h−1 without additives at 50 °C. The electronic levels investigation of the active metal can provide new ideas for the design of highly efficient catalysts for FA dehydrogenation.

Monitoring of catalytic dehydrogenation of formic acid by a ruthenium (II) complex through manometry

A Ru-based polypyridine complex [Ru(2py-tpy)(DQN)Cl](PF6) ([Ru-(DQN)]) has been synthesised and employed as an active catalyst for the decomposition of formic acid. The activation energy required for the dehydrogenation of formic acid was 31.45 kJ/mol. The dehydrogenation of formic acid at pH 7.0 was also observed along with the CO2 gas. • The [Ru(2py-tpy)(DQN)Cl](PF6) complex has synthesized. • It has been employed as a catalyst for HCOOH decomposition. • H2 and CO2 was detected through GC. • The Ea for the dehydrogenation of formic acid was 31.45 kJ/mol. • The ΔG was estimated to be 81.33 kJ. • The gas pressure analysis was conducted by manometry. The [Ru(2py-tpy)(DQN)Cl](PF 6 ) ( [Ru-(DQN)] ) (Where 2,3-di(pyridin-2-yl) quinoxaline = DQN ) complex has been synthesised and employed for the dehydrogenation of the formic acid in the presence of sodium formate. The catalytic activity of the complex was studied at different temperatures and by varying the concentration of the acid, base, and complex. The catalytic gas evolutions were investigated using the differential manometry technique to avoid the ambiguities in back-pressure and burette methods. The activation energy required for the dehydrogenation of formic acid was 31.45 kJ/mol obtained from the Arrhenius plot, and ΔG was estimated to be 81.33 kJ from the Eyring plot. The catalyst shows the highest TOF at pH 7.0.

Nanotubular g-C3N4 confining AuPd particle for the improved catalytic reactivity in hydrogen production from formic acid

Hydrogen is a promising energy vector that provides an alternative to carbon fuels. Catalytic dehydrogenation of formic acid is an efficient solution to produce hydrogen, as formic acid can store hydrogen economically. In this study, novel AuPd supported by nanotubular T-g-C3N4 was synthesized using a chemical wet impregnation and reduction method. The graphene, bulk B-g-C3N4, and nanosheet-like S-g-C3N4 were also employed as AuPd supports for comparison. It was observed that the AuPd nanoparticles on carbon nitrides have higher dispersion and activity than those on graphene, due to the anchoring and electron donation effects of nitrogen. The reactivity of AuPd nanocatalyst was related to the geometry of g-C3N4 support. The T-g-C3N4 possesses the lowest surface area, which induced the lower dispersion of supported AuPd, as compared to B-g-C3N4 and S-g-C3N4. However, the AuPd/T-g-C3N4 delivered the highest catalytic activity, attributed to the confinement effect of the nanotubular geometry.

Formic acid dehydrogenation over Pd single atom or cluster supported on nitrogen-doped graphene: A DFT study

Formic acid (FA, HCOOH) is one of the most promising hydrogen carriers. Developing cost-effective dehydrogenation catalyst for formic acid is the key to the application of formic acid as hydrogen storage compound. In this study, we systematically studied the catalytic performance of nitrogen-doped graphene supported Pd1 single-atom and Pd4 single-cluster for dehydrogenation of formic acid by density functional theory calculations. Three types of nitrogen-dopants (pyridinic N, pyrrolic N and graphitic N) were introduced into graphene to determine which N dopant plays an important role in catalytic dehydrogenation of formic acid. The results showed that HCOOH decomposition proceeds via the formate (HCOO) intermediate to yield product CO2 and H2, so all catalysts have 100 % H2 selectivity. On graphN3 support, the catalytic activity of Pd4 single-cluster catalyst (SCC) is better than that of Pd1 single-atom catalyst (SAC), while on pyriN3 and pyrroN3, the catalytic activity of Pd1 SAC is better. Compared with traditional Pd(111), the present SACs and SCCs exhibit higher HCOOH dehydrogenation activity, and Pd4@graphN3 has the best catalytic performance with an energetic span of 0.75 eV, much lower than 1.33 eV of Pd(111). Our work provides an insight into the effects of the coordination environment of N-doped graphene support and active center size on FA dehydrogenation performance.

Bimetallic palladium chromium nanoparticles anchored on amine-functionalized titanium carbides for remarkably catalytic dehydrogenation of formic acid at mild conditions

Heterogeneous catalysis of formic acid dehydrogenation is considered as a promising strategy for safe and efficient hydrogen production and transportation. Herein, we reported the immobilization of the bimetallic PdCr nanoparticles on amine-functionalized titanium carbides (PdCr/NH2-MXene). By the amine group, the ultrafine PdCr NPs with the size of 1.8 nm were well dispersed on MXene. The optimized Pd0.7Cr0.3/NH2-MXene system exhibit an excellent activity toward catalyzing FA dehydrogenation, affording the overall turnover frequency (TOF) value of as high as 1906 h−1 at 323 K. Such an excellent catalytic performance is attributed that the introduction of amine group not only benefits the formation of ultrafine and well-dispersed PdCr NPs, but also modulates the electronic structure of metal catalytic sites, resulting in an enhancement for catalyzing FA dehydrogenation. This work may supply a new strategy for development of high-performance bimetallic nanosystem for tremendous catalytic application in the future.

Formic Acid Dehydrogenation Using Noble-Metal Nanoheterogeneous Catalysts: Towards Sustainable Hydrogen-Based Energy

The need for sustainable energy sources is now more urgent than ever, and hydrogen is significant in the future of energy. However, several obstacles remain in the way of widespread hydrogen use, most of which are related to transport and storage. Dilute formic acid (FA) is recognized asa a safe fuel for low-temperature fuel cells. This review examines FA as a potential hydrogen storage molecule that can be dehydrogenated to yield highly pure hydrogen (H2) and carbon dioxide (CO2) with very little carbon monoxide (CO) gas produced via nanoheterogeneous catalysts. It also present the use of Au and Pd as nanoheterogeneous catalysts for formic acid liquid phase decomposition, focusing on the influence of noble metals in monometallic, bimetallic, and trimetallic compositions on the catalytic dehydrogenation of FA under mild temperatures (20–50 °C). The review shows that FA production from CO2 without a base by direct catalytic carbon dioxide hydrogenation is far more sustainable than existing techniques. Finally, using FA as an energy carrier to selectively release hydrogen for fuel cell power generation appears to be a potential technique.

Recent Progress in Homogeneous Catalytic Dehydrogenation of Formic Acid.

Recently, there has been a strong demand for technologies that use hydrogen as an energy carrier, instead of fossil fuels. Hence, new and effective hydrogen storage technologies are attracting increasing attention. Formic acid (FA) is considered an effective liquid chemical for hydrogen storage because it is easier to handle than solid or gaseous materials. This review presents recent advances in research into the development of homogeneous catalysts, primarily focusing on hydrogen generation by FA dehydrogenation. Notably, this review will aid in the development of useful catalysts, thereby accelerating the transition to a hydrogen-based society.

Pressurized Formic Acid Dehydrogenation: An Entropic Spring Replaces Hydrogen Compression Cost.

Formic acid is unique among liquid organic hydrogen carriers (LOHCs), because its dehydrogenation is highly entropically driven. This enables the evolution of high-pressure hydrogen at mild temperatures that is difficult to achieve with other LOHCs, conceptually by releasing the "spring" of energy stored entropically in the liquid carrier. Applications calling for hydrogen-on-demand, such as vehicle filling, require pressurized H2. Hydrogen compression dominates the cost for such applications, yet there are very few reports of selective, catalytic dehydrogenation of formic acid at elevated pressure. Herein, we show that homogenous catalysts with various ligand frameworks, including Noyori-type tridentate (PNP, SNS, SNP, SNPO), bidentate chelates (pyridyl)NHC, (pyridyl)phosphine, (pyridyl)sulfonamide, and their metallic precursors, are suitable catalysts for the dehydrogenation of neat formic acid under self-pressurizing conditions. Quite surprisingly, we discovered that their structural differences can be related to performance differences in their respective structural families, with some tolerant or intolerant of pressure and others that are significantly advantaged by pressurized conditions. We further find important roles for H2 and CO in catalyst activation and speciation. In fact, for certain systems, CO behaves as a healing reagent when trapped in a pressurizing reactor system, enabling extended life from systems that would be otherwise deactivated.

Ultrafine Pd nanoparticles on amine-functionalized carbon nanotubes for hydrogen production from formic acid

Formic acid is a promising hydrogen source and liquid organic hydrogen carrier because of its high hydrogen density. To produce hydrogen from formic acid, catalytic dehydrogenation of formic acid over Pd-based catalysts has been investigated. Here, a highly active catalyst is rationally designed. Carbon nanotubes without micropores were adopted as a support to facilitate the mass transport of reactants or products. Pd particles were made as small as possible to provide a large number of active sites and to alleviate the activation barrier for hydrogen desorption. Amine functional groups were introduced into carbon nanotubes to generate formate anions by capturing protons from formic acid. Based on this design, ultrafine Pd nanoparticles (1.76 nm) on amine-functionalized carbon nanotubes were successfully synthesized. This catalyst demonstrated remarkable activity for the formic acid dehydrogenation reaction, with a high turnover frequency value of 2560 h−1 at 30 °C.

Impact of Green Cosolvents on the Catalytic Dehydrogenation of Formic Acid: The Case of Iridium Catalysts Bearing NHC-phosphane Ligands.

The catalysts [Ir(COD)(κ3-P,C,P′-PCNHCP)]BF4 and [Ir(COD)(κ2-P,C-PCNHCO)]BF4 proved to be active in the solventless dehydrogenation of formic acid. The impact of various cosolvents on the activity was evaluated, showing an outstanding improvement of the catalytic performance of [Ir(COD)(κ2-P,C-PCNHCO)]BF4] in “green” organic carbonates: namely, dimethyl carbonate (DMC) and propylene carbonate (PC). The TOF1h value for [Ir(COD)(κ2-P,C-PCNHCO)]BF4 increases from 61 to 988 h–1 upon changing from solventless conditions to a 1/1 (v/v) DMC/HCOOH mixture. However, in the case of [Ir(COD)(PCNHCP)]BF4, only a marginal improvement from 156 to 172 h–1 was observed under analogous conditions. Stoichiometric experiments allowed the identification of various key reaction intermediates, providing valuable information on their reactivity. Experimental data and DFT calculations point to the formation of dinuclear species as the catalyst deactivation pathway, which is prevented in the presence of DMC and PC.

Controllable Synthesis of Supported PdAu Nanoclusters and Their Electronic Structure-Dependent Catalytic Activity in Selective Dehydrogenation of Formic Acid.

We report the design and synthesis of uniform PdAu alloy nanoclusters immobilized on diamine and graphene oxide-functionalized silica nanospheres. The structure-dependent activity for selectively catalytic dehydrogenation of formic acid (FA) has been evaluated and optimized by controlling the Pd/Au mole ratio and the carrier components. The relationship between the catalyst structure and activity has been investigated via both experiments and characterization. High-resolution transmission electron microscopy (TEM) and X-ray diffraction (XRD) proved the formation of PdAu alloy nanoclusters. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), X-ray photoelectron spectroscopy (XPS), and X-ray absorption fine structure (XAFS) analyses verified the electron transfer between Au, Pd, and the support. An outstanding turnover frequency (TOF) value of 16 647 h-1 at 323 K, which is among the highest activity for FA dehydrogenation ever reported, can be achieved at optimized conditions and ascribed to the combination of the bimetallic synergistic effect and the carrier effect.

Bimetallic PdAu Nanoparticles in Amine-Containing Metal–Organic Framework UiO-66 for Catalytic Dehydrogenation of Formic Acid

Ultrafine and well-dispersed PdAu bimetallic nanoparticles (ca. 1.4 nm) are successfully immobilized on amine-containing UiO-66 frameworks (NH2-UiO-66) via a double-solvent impregnation method. By ...

Additive-Free Formic Acid Dehydrogenation Catalyzed by a Cobalt Complex

The reversible storage of hydrogen through the intermediate formation of formic acid (FA) is a promising solution to its safe transport and distribution. However, the common necessity of using bases or additives in the catalytic dehydrogenation of FA is a limitation. In this context, two new cobalt complexes (1 and 2) were synthesized with a pincer PP(NH)P ligand containing a phosphoramine moiety. Their reaction with an excess FA yields a cobalt(I) hydride complex (3). We report here the unprecedented catalytic activity of 3 in the dehydrogenation of FA, with a turnover frequency (TOF) of 67 min–1 measured in the first minute and a turnover number (TON) of 454, without the need for bases or additives. A mechanistic study reveals the existence of ligand–metal cooperativity with intermolecular hydrogen bonding, also influenced by the concentration of formic acid.

Bimetallic AuPd Nanoparticles Loaded on Amine-Functionalized Porous Boron Nitride Nanofibers for Catalytic Dehydrogenation of Formic Acid

Formic acid (FA) has been considered as a promising hydrogen energy carrier due to its nontoxicity, high energy density, easy storage/transport, etc. However, the development of decent FA dehydroge...