Formic Acid Production Research Articles

Ligand-Dependent Intracluster Interactions in Electrochemical CO2 Reduction Using Cu14 Nanoclusters.

The electrochemical CO2 reduction reaction (CO2RR) has been extensively studied because it can be leveraged to directly convert CO2 into valuable hydrocarbons. Among the various catalysts, copper nanoclusters (Cu NCs) exhibit high selectivity and efficiency for producing CO2RR products owing to their unique geometric/electronic structures. However, the influence of protective ligands on the CO2RR performance of Cu NCs remains unclear. In this study, it is shown that different thiolate ligands, despite having nearly identical geometries, can substantially affect the electrochemical stability of Cu14 NCs in the CO2RR. Notably, Cu14 NCs protected by 2-phenylethanethiolate exhibit greater stability and achieve a relatively higher selectivity (≈40%) for formic acid production compared with the cyclohexanethiolate-protected counterpart. These insights are crucial for designing Cu NCs that are both stable and highly selective, enhancing their efficacy for electrochemical CO2 reduction.

Selective Electrocatalytic Production of Formic Acid from Plastic Waste Using a Ni Metal Organic Framework Constructed from a Biomass‐Derived Ligand

A novel nickel‐based metal organic framework (MOF) [Ni(FDC)(CH3OH)1.5(H2O)0.5](H2O)0.35 (UOW‐6) utilizing biomass‐derived 2,5‐furan dicarboxylate (FDC) as a ligand is reported as an electrocatalyst for anodic ethylene glycol oxidation with cathodic hydrogen evolution. The MOF structure was analyzed using single crystal X‐ray‐diffraction, TGA and thermodiffractometry, to establish its structure and verify phase purity. The material was dropcast on carbon fiber paper as a catalyst, and by using a three‐electrode system, UOW‐6 requires only 1.47 V to attain a current density of 50 mAcm‐2. During oxidation of the ethylene glycol (EG), UOW‐6 shows unprecedented selectivity towards formic acid with a Faradaic efficiency of 94% and remarkable stability over 20 days. The combination of electrochemical measurements and in situ Raman confirmed in situ formed NiOOH at the surface of UOW‐6 as the catalytically active sites for EG oxidation. This work not only presents a pioneering application of FDC‐based MOFs for polyethylene terephthalate (PET) upcycling but also underscores the potential of electrocatalysis in advancing sustainable plastic valorization strategies.

Oxidation of glyoxal with the Mo-oxime complex in a benzalkonium chloride interface: Raghavan and Srinivasan kinetic model

Gaining an understanding of the glucose oxidation product (glyoxal) interaction with the metal–organic complex in a biological environment is pivotal to its usage. Thus, the glyoxal (Gyx) oxidation with Mo-oxime complex (MC) is studied with the spectrophotometric method, following a pseudo-phase approach. The result highlights the inclusion of hydrolysis, ion catalysis, the neutral primary salt effect, and radical generation as the essential factors in Gyx oxidation, with the exclusion of intermediate species formation. The hydrolysis of Gxy is observed to actively engage MC without charge inhibition as charge-neutral reacting species are involved, thus, implicating neutral primary salt effect where the variation of ionic strength of the system keeps the redox rate unchanged. The involvement of charge-neutral specie at the rate controlling step encouraged electrostatic attraction when Mg2+ ion additive is incorporated into the system, leading to ion catalysis. The generation of free radical from Gxy aids the emergence of formic acid. The zero intercept of Michealis-Menten type plot and the non-appreciable shift in the maximum absorption wavelength of the reaction system and MC rule-out the presence of intermediate species. The contribution of thermodynamic enthalpy is instrumental in the redox process, leading to the formic acid product. The inclusion of benzalkonium chloride (BZC) hastens the Gxy oxidation, which is supported by Raghavan and Srinivasan’s model.

Plastic waste valorization for formic acid production: A comparison between the electrolysis and hydrogenation process

Plastic waste valorization for formic acid production: A comparison between the electrolysis and hydrogenation process

Synergistic effect between amino functional group and graphene oxide in selective photocatalytic CO2 reduction to formic acid

Carbon dioxide (CO2) reduction to useful possible chemicals is of great significance to energy supply, while formic acid is one of the most desirable product among the many other chemicals. In this study, a novel reduced graphene oxide (rGO) coupled doped TiO2 with NH2-MIL-125(Ti)(TiM) composite photocatalysts TiO2@rGO@TiM was designed by using a solvent-thermal method to facilitate the photocatalytic CO2 reduction to formic acid under the visible light. Benefiting from the special structure of TiO2@rGO@TiM, up to a rate of 113 µmol•g−1•h−1 of formic acid was produced in a photochemical process, which is four times greater than that of pure TiO2 and TiM without any sacrificial agent. The results of structure and photoelectrochemical characterization demonstrated that the enhanced production of formic acid was attributable to the synergistic effect generated by the incorporation of the amino functional group and reduced graphene oxide, resulting in the effective photo-induced carrier spatial segregation and transfer and improving the catalytic activity.

Oxophilic Sn to promote glucose oxidation to formic acid in Ni nanoparticles.

The electrochemical glucose oxidation reaction (GOR) presents an opportunity to produce hydrogen and high-value chemical products. Herein, we investigate the effect of Sn in Ni nanoparticles for the GOR to formic acid (FA). Electrochemical results show that the maximum activity is related to the amount of Ni, as Ni sites are responsible for catalyzing GOR via the NiOOH/Ni(OH)2 pair. However, the GOR kinetics increases with the amount of Sn, associated with an enhancement of the OH- supply to the catalyst surface for Ni(OH)2 reoxidation to NiOOH. NiSn nanoparticles supported on carbon nanotubes (NiSn/CNT) exhibit excellent current densities and direct GOR via C-C cleavage mechanism, obtaining FA with a Faradaic efficiency (FE) of 93% at 1.45 V vs. reversible hydrogen electrode. GOR selectivity is further studied by varying the applied potential, glucose concentration, reaction time, and temperature. FE toward FA production decreases due to formic overoxidation to carbonates at low glucose concentrations and high applied potentials, while acetic and lactic acids are obtained with high selectivity at high glucose concentrations and 55 °C. Density functional theory calculations show that the SnO2 facilitates the adsorption of glucose on the surface of Ni and promotes the formation of the catalytic active Ni3+ species.

Mechanism of glycerol oxidation on bismuth vanadate photoanodes: Influence of tantalum doping

This study investigated the mechanisms underlying the photoelectrochemical oxidation of glycerol to dihydroxyacetone (DHA) and glyceraldehyde (GLAD) on BiVO4 and Bi–O–Ta species using density functional theory calculations. The results revealed that for both products and metal-oxides, the first proton-coupled electron-transfer (PCET) step, which forms a carbon-centered radical, served as the rate-limiting step. The formation of DHA from a secondary-carbon-centered radical encountered lower energy barriers compared to the formation of GLAD from a primary-carbon-centered radical, indicating the favorability of the DHA production pathway. The differences between the energy inputs required for DHA and GLAD production were greater on the Bi–O–Ta species compared to the BiVO4. Furthermore, the production of formic acid (FA) from glycerol via GLAD, involving three H2O molecules and eight PCET steps, encountered greater energy barriers on Bi–O–Ta species than on BiVO4. These computational results confirm that the Bi–O–Ta species enhances DHA generation from glycerol while suppressing the production of unfavorable byproducts such as GLAD and FA. Correspondingly, the Ta-doped BiVO4 photoanode achieves a greater Faradaic efficiency than the BiVO4 photoanode and approximately 100% selectivity for DHA in acidic media owing to the Bi–O–Ta species formed on the surface.

Electrolyte Composition-Dependent Product Selectivity in CO2 Reduction with a Porphyrinic Metal-Organic Framework Catalyst.

A copper porphyrin-derived metal-organic framework electrocatalyst, FICN-8, was synthesized and its catalytic activity for CO2 reduction reaction (CO2RR) was investigated. FICN-8 selectively catalyzed electrochemical reduction of CO2 to CO in anhydrous acetonitrile electrolyte. However, formic acid became the dominant CO2RR product with the addition of a proton source to the system. Mechanistic studies revealed the change of major reduction pathway upon proton source addition, while catalyst-bound hydride (*H) species was proposed as the key intermediate for formic acid production. This work highlights the importance of electrolyte composition on CO2RR product selectivity.

Recycling copper wire waste into active Cu-based catalysts for value-added chemicals production via CO2 electrochemical reduction

The CO2 electroreduction reaction (CO2RR) is a method for producing value-added compounds from CO2. This study aimed to use copper from wiring waste to create Cu-based catalysts on Vulcan XC-72R carbon for converting CO2 into valuable chemicals. Copper nanopowder with an average crystallite size of 27 nm derived from the wiring waste solution was utilized as the starting material for mono and bimetallic catalysts preparation. During the bimetallic PdCu/C catalyst synthesis, a galvanic displacement reaction between Pd and Cu occurred, resulting in the formation of PdCu alloy and a reduction in the copper crystallite size. The inclusion of Pd on Cu/C in CO2RR decreased the onset potentials for C1 and C2 chemical production. The yields of methanol, formic acid, and formaldehyde products were generally increased as the Pd:Cu ratio increased. The 1:2-PdCu/C exhibited the smallest crystallite size and an onset potential of less than −1.0 V, resulting in the highest Faradaic efficiency of the products. This catalyst converted CO2 into formic acid (FE = 71.5 %) at a potential of −0.8 V and methanol (FE = 65.4 %) at −0.5 V. The catalyst’s stability was demonstrated for more than 6000 s at current densities of approximately 2 mA /mgcatalyst.

Bi2S3/In(OH)3 heterojunction for enhanced CO2 electroreduction to formic acid

Electroreduction of CO2 for formic acid production has been regarded as an efficient option for CO2 utilization. However, under high current, achieving high selectivity for formic acid is challenging, which cannot meet industrial demands. Herein, we reported a type of Bi/In(OH)3 (BIO) heterojunction reconstructed from Bi2S3/In(OH)3 during electrochemical process, in which In(OH)3 was applied to modulate the electronic structure of Bi. This strategy efficiently enhanced the ∗OCHO intermediates adsorption and lead to a decent selectivity towards formic acid under high current density. BIO displays faraday efficiency of formic acid beyond 95 ​% across a wide range current density of 200–400 ​mA ​cm−2, where the highest value reached 97.7 ​% at 400 ​mA ​cm−2. This work clarified the mechanism of CO2 electroreduction to HCOOH on heterojunction, guiding the design of advanced catalysts.

Effects of carbon support ozonation on the electrochemical reduction of CO2 to formate and syngas in a flow cell on Pd nanostructures

Pd convers electrochemically CO2 into formate at the most positive known potentials but with low activity. Additionally, Pd is CO selective at more negative potentials, but is poisoned by the strongly bound CO∗ intermediate. Improving the activity and stability of Pd-based electrocatalysts holds promise for improving the electrochemical production of formic acid. Herein, we studied the effects of carbon support and its ozonation on the selectivity of electrochemical CO2 reduction on Pd. The ozone treatment is found to improve the activity and formate selectivity at low overpotentials on single-walled carbon nanotube-supported catalysts with partial current densities up to −12 mA cm−2 in 0.5 M KHCO3 at potentials of −0.35 V and −0.45 V (vs. RHE). At more negative potentials, the catalysts become more selective towards CO and an opposite trend for CO-selectivity and ozonation duration is demonstrated. Unfortunately, the materials show deactivation in the form of decreased formate selectivity and increased hydrogen and CO evolution, especially when supports treated with ozone for a longer duration. The results and possible mechanisms are discussed based on previous findings and the physicochemical characterizations of the prepared catalysts. This work shows that a simple ozone treatment of carbons changes the efficiency of CO2 electroreduction.

Innovatively Designed Chalk-Shaped CdS@ACC Nanocomposite Photocatalyst-Enzyme Attached Artificial Photosynthesis Reactor for Production of Formic Acid from CO2

Innovatively Designed Chalk-Shaped CdS@ACC Nanocomposite Photocatalyst-Enzyme Attached Artificial Photosynthesis Reactor for Production of Formic Acid from CO2

An Emerging Solid‐State Electrolyte Reactor to Drive the Future of Electrochemical Synthesis

AbstractElectrochemical reactors, powered by renewable electricity, have garnered widespread attention for chemical synthesis due to their low energy consumption and pollution‐free features. However, the inherent design flaw of traditional electrochemical reactors has persistently hindered the advancement of electrochemical synthesis, as they result in low product concentrations, low purity, and continuous production issues. As a novel electrochemical reactor, the porous solid‐state electrolyte (PSE) reactor is elaborately designed to overcome the limitation by enabling the direct and continuous synthesis of pure products, possessing a modular and scalable structure with high efficiency, safety, and long stability. In this work, first, the distinctive design of the PSE reactor, highlighting its structural features, core components, and variable configurations, is introduced. Furthermore, the configuration‐relevant applications in electrosynthesis, such as formic acid, acetic acid, and hydrogen peroxide (H2O2) production, are summarized. Integrated applications are also discussed, along with potential domains for improvements and optimization. Finally, the future developmental directions of the PSE devices are thoroughly explored. By addressing its unique design attributes, showcasing its capabilities, and envisioning prospective refinements and diverse applications, the aim is to boost the progression of this transformative technology toward widespread commercialization and industrial adoption, thereby revolutionizing sustainable electrochemical synthesis.

Synthesis of heterogeneous nanocomposite catalyst ZrO2@SBA-15 for formic acid production from hemicelluloses

Heterogeneous nanocomposite ZrO2@SBA-15 catalysts containing 10 wt. % of zirconium oxide were synthesized by two methods: co-condensation and incipient wetness impregnation. The silica support and catalysts were characterized by X-ray diffraction, gas adsorption, FTIR-spectroscopy and other physicochemical methods. As a result of zirconia introduction into the silica wall, the mesostructured of SBA-15 is preserved, but the specific surface area and pore Volume are reduced. It was established that during one-stage co-condensation synthesis, the particle fibers shorten and stick together. The catalysts were tested in the process of catalytic hydrolysis-oxidation of hemicelluloses of aspen wood. The optimal formic acid synthesis conditions were determined: 150°С, 3 h. The highest formic acid yield obtained over the catalyst obtained by co-condensation under best reaction conditions was 28.4 wt. %.

Catalyst Design and Engineering for CO2-to-Formic Acid Electrosynthesis for a Low-Carbon Economy.

Formic acid (FA) has emerged as a promising candidate for hydrogen energy storage due to its favorable properties such as low toxicity, low flammability, and high volumetric hydrogen storage capacity under ambient conditions. Recent analyses have suggested that FA produced by electrochemical carbon dioxide (CO2) reduction reaction (eCO2RR) using low-carbon electricity exhibits lower fugitive hydrogen (H2) emissions and global warming potential (GWP) during the H2 carrier production, storage and transportation processes compared to those of other alternatives like methanol, methylcyclohexane, and ammonia. eCO2RR to FA can enable industrially relevant current densities without the need for high pressures, high temperatures, or auxiliary hydrogen sources. However, the widespread implementation of eCO2RR to FA is hindered by the requirement for highly stable and selective catalysts. Herein, the aim is to explore and evaluate the potential of catalyst engineering in designing stable and selective nanostructured catalysts that can facilitate economically viable production of FA.

Rational Design of Formate Dehydrogenase for Enhanced Thermal Stability and Catalytic Activity in Bioelectrocatalysis.

Formate dehydrogenase can be utilized as a biocatalyst in the bioelectrocatalysis of converting CO2 into formic acid. However, its industrial application has been hindered by limited thermal stability. This study successfully obtained a mutant (D533S/E684I) with enhanced thermal stability and catalytic activity through the rational design of flexible regions. The mutant exhibited a half-life (t1/2) 1.5 times longer than the wild type (WT) at 35 °C, along with a specific enzyme activity 7.46 times higher than that of the WT. Additionally, the catalytic efficiency (kcat/Km value) of the mutant toward the substrate was 2.72 s-1·mM-1, representing a 19.4-fold increase compared to the WT (0.14 s-1·mM-1). Formic acid production reached 53.4 mM through bioelectrocatalysis after 10 h, utilizing the mutant as the biocatalyst. Molecular dynamics simulations and structural analysis were employed to investigate the molecular mechanisms behind the enhanced thermal stability and activity. The displacement of a highly flexible region in the mutant may counteract the stability-activity trade-off. This study proposed a method for improving both thermal stability and activity in enzyme evolution.

Development of an infant colon simulating in vitro model, I-TIM-2, to study the effects of modulation strategies on the infant gut microbiome composition and function.

The early life stages are critical for the development of the gut microbiome. Variables such as antibiotics exposure, birth-mode via Cesarean section, and formula feeding are associated with disruptions in microbiome development and are related to adverse health effects later in life. Studying the effects of microbiome-modulating strategies in infants is challenged by appropriate ethical constraints. Therefore, we developed I-TIM-2, an infant in vitro colonic model based on the validated, computer-controlled, dynamic model of the colon, TIM-2. The system, consisting of four separate compartments, was inoculated with feces from four healthy, primarily breastfed infants, displaying distinctive microbiome profiles. For each infant's fecal sample, a 96-h experiment was performed, with two compartments receiving an infant diet adapted medium and two compartments additionally receiving five human milk oligosaccharides (HMOs) in physiological concentrations and proportions. Bacterial composition was determined by shotgun metagenomics and qPCR. Concentrations of short-chain fatty acids (SCFAs) and HMOs were determined by LC-MS. Microbial diversity and high amounts of inoculum-derived species were preserved in the model throughout each experiment. Microbiome composition and SCFA concentrations were consistent with published data from infants. HMOs strongly modulated the microbiome composition by stimulating relative proportions of Bifidobacterium. This affected the metabolic output and resulted in an increased production of acetic and formic acid, characteristic of bifidobacterial HMO metabolism. In conclusion, these data demonstrate the development of a valid model to study the dynamics and modulations of the infant gut microbiome and metabolome.IMPORTANCEThe infant gut microbiome is intricately linked to the health of its host. This is partly mediated through the bacterial production of metabolites that interact with the host cells. Human milk shapes the establishment of the infant gut microbiome as it contains human milk sugars that select for primarily bifidobacteria. The establishment can be disrupted by modern interventions such as formula feeding. This can alter the microbiome composition and metabolite production profile, which can affect the host. In this article, we set up an infant in vitro colonic model to study microbiome interactions and functions. In this model, we investigated the effects of human milk sugars and their promotion of bifidobacteria at the expense of other bacteria. The model is an ideal system to assess the effects of various modulating strategies on the infant gut microbiome and its interactions with its host.

Conversion of Cellobiose to Formic Acid as a Biomass-Derived Renewable Hydrogen Source Using Solid Base Catalysts.

Formic acid is considered a promising hydrogen carrier. Biomass-derived formic acid can be obtained by oxidative decomposition of sugars. This study explored the production of formic acid from cellobiose, a disaccharide consisting of d-glucose linked by β-glycosidic bonds using heterogeneous catalysts under mild reaction conditions. The use of alkaline earth metal oxide solid base catalysts like CaO and MgO in the presence of hydrogen peroxide could afford formic acid from cellobiose at 343 K. While CaO gave 14 % yield of formic acid, the oxide itself was converted to a harmful metal peroxide, CaO2 after the reaction. In contrast, MgO could produce formic acid without the formation of the metal peroxide. The difficulty in selectively synthesizing formic acid from cellobiose using these solid base catalysts was due to the poor conversion of cellobiose to glucose. Using a combination of solid acid and base catalysts, a high formic acid yield of 33 % was obtained under mild reaction conditions due to the quantitative hydrolysis of cellobiose to glucose by a solid acid followed by the selective decomposition of glucose to formic acid by a solid base.

Ultrathin B:NiCoOx-modified BiVO4 photoanode with abundant oxygen vacancies for photoelectrochemical glycerol conversion coupled with hydrogen production

Photoelectrochemical (PEC) conversion of glycerol (GLY) into high value-added chemicals coupled with clean hydrogen production can be achieved over a BiVO4-based PEC cell, but the low photocurrent density and poor photostability of the most BiVO4 photoanodes limit the PEC performance and sustainable application of solar resources. Herein, we construct a high-efficiency stable photoanode by decorating an amorphous ultrathin B-activation NiCoOx (B:NiCoOx) nanolayer with abundant oxygen vacancies (Ov) on the BiVO4 photoanode via a simple immersing process. We demonstrate the optimized B:NiCoOx/BiVO4 photoanode in the PEC GLY oxidation yields a high photocurrent density of 6.05 mA cm−2 at 1.23 VRHE, a formic acid (FA) production rate of 360.3 mmol m−2 h−1, a dihydroxyacetone (DHA) production rate of 228.4 mmol m−2 h−1, with simultaneously hydrogen production at the cathode. An intermittent 60-h PEC GLY oxidation assay results indicates the superb durability of the B:NiCoOx/BiVO4 photoanode. The outstanding PEC performance is predominantly ascribed to the amorphous ultrathin structure of the B:NiCoOx nanolayer (∼ 2 nm) and the abundant Ov, which effectually accelerates the photogenerated holes transport/extraction and offers more catalytic active sites for the PEC GLY oxidation. Moreover, the free state and adsorbed state •OH radicals originated from active oxygen are deduced to be responsible for the oxidation of GLY to FA and GLY to DHA. This study develops a sustainable BiVO4-based catalyst with high activity and photostability for the PEC GLY oxidation and hydrogen production.

Direct Formic Acid Production by CO2 Hydrogenation with Ir Complexes in HFIP under Supercritical Conditions

Direct Formic Acid Production by CO₂ Hydrogenation with Ir Complexes in HFIP under Supercritical Conditions