Hydrogen generation from formic acid decomposition on Ni(211), Pd(211) and Pt(211)

Scalable Low-Temperature CO2 Electrolysis: Current Status and Outlook

The electrochemical CO2 reduction (eCO2R) in membrane electrode assemblies (MEAs) has brought e-chemical production one step closer to commercialization because of its advantages of minimized ohmic resistance and stackability. However, the current performance of reported eCO2R in MEAs is still far below the threshold for economic feasibility where low overall cell voltage (<2 V) and extensive stability (>5 years) are required. Furthermore, while the production cost of e-chemicals heavily relies on the carbon capture and product separation processes, these areas have received much less attention compared to CO2 electrolysis, itself. In this perspective, we examine the current status of eCO2R technologies from both academic and industrial points of view. We highlight the gap between current capabilities and commercialization standards and offer future research directions for eCO2R technologies with the hope of achieving industrially viable e-chemical production.

Identification of reaction intermediates in the decomposition of formic acid on Pd

Uncovering the role of reaction intermediates is crucial to developing an understanding of heterogeneous catalysis because catalytic reactions often involve complex networks of elementary steps. Identifying the reaction intermediates is often difficult because their short lifetimes and low concentrations make it difficult to observe them with surface sensitive spectroscopic techniques. In this paper we report a different approach to identify intermediates for the formic acid decomposition reaction on Pd(111) and Pd(332) based on accurate measurements of isotopologue specific thermal reaction rates. At low surface temperatures (∼400 K) CO2 formation is the major reaction pathway. The CO2 kinetic data show this occurs via two temporally resolved reaction processes. Thus, there must be two parallel pathways which we attribute to the participation of two intermediate species in the reaction. Isotopic substitution reveals large and isotopologue specific kinetic isotope effects that allow us to identify the two key intermediates as bidentate formate and carboxyl. The decomposition of the bidentate formate is substantially slower than that of carboxyl. On Pd(332), at high surface temperatures (643 K to 693 K) we observe both CO and CO2 production. The observation of CO formation reinforces the conclusion of calculations that suggest the carboxyl intermediate plays a major role in the water-gas shift reaction, where carboxyl exhibits temperature dependent branching between CO2 and CO.

Protocol to operate a large-scale CO2 hydrogenation process for formic acid production

Formic acid is a viable product of CO2 utilization. Here, we present a protocol for designing and operating a pilot-scale formic acid production plant with a 10 kg/day capacity produced via CO2 hydrogenation. We describe the essential process specifications required for successful operation, including prevention of corrosion and formic acid decomposition. We then detail procedures for steady-state operation of the individual units. This protocol provides the necessary information for further scale-up and commercialization of the CO2 hydrogenation process. For complete details on the use and execution of this protocol, please refer to Kim et al.1.

Highly Dispersed Ni on Nitrogen-Doped Carbon for Stable and Selective Hydrogen Generation from Gaseous Formic Acid

Ni supported on N-doped carbon is rarely studied in traditional catalytic reactions. To fill this gap, we compared the structure of 1 and 6 wt% Ni species on porous N-free and N-doped carbon and their efficiency in hydrogen generation from gaseous formic acid. On the N-free carbon support, Ni formed nanoparticles with a mean size of 3.2 nm. N-doped carbon support contained Ni single-atoms stabilized by four pyridinic N atoms (N₄-site) and sub-nanosized Ni clusters. Density functional theory calculations confirmed the clustering of Ni when the N₄-sites were fully occupied. Kinetic studies revealed the same specific Ni mass-based reaction rate for single-atoms and clusters. The N-doped catalyst with 6 wt% of Ni showed higher selectivity in hydrogen production and did not lose activity as compared to the N-free 6 wt% Ni catalyst. The presented results can be used to develop stable Ni catalysts supported on N-doped carbon for various reactions.

Binding Energy and Diffusion Barrier of Formic Acid on Pd(111)

Velocity-resolved kinetics is used to measure the thermal rate of formic acid desorption from Pd(111) between 228 and 273 K for four isotopologues: HCOOH, HCOOD, DCOOH, DCOOD. Upon molecular adsorption, formic acid undergoes decomposition to CO₂ and H₂ and thermal desorption. To disentangle the contributions of individual processes, we implement a mass-balance-based calibration procedure from which the branching ratio between desorption and decomposition for formic acid is determined. From experimentally derived elementary desorption rate constants, we obtain the binding energy 639 ± 8 meV and the diffusion barrier 370 ± 130 meV using the detailed balance rate model (DBRM). The DBRM explains the observed kinetic isotope effects.

Theoretical insights into the effect of terrace width and step edge coverage on CO adsorption and dissociation over stepped Ni surfaces

We rationalized Ni(211) as a representative model for stepped surfaces and explored the effect of coverage on CO activation.

Palladium-atom catalyzed formic acid decomposition and the switch of reaction mechanism with temperature

We carefully calculated the mechanism of one-atom model and its poisoned species, PdCO, as formic acid decomposition catalysts.

Thermogravimetric investigation on the interaction of formic acid with solder joint materials

Reaction mechanisms of gaseous formic acid with oxidized Cu and Sn–Ag–Cu alloy (SAC305) are investigated in the temperature range of soldering (40–260 °C).

Hydrogen energy future with formic acid: a renewable chemical hydrogen storage system

Formic acid, the simplest carboxylic acid, could serve as one of the better fuels for portable devices, vehicles and other energy-related applications in the future.

Catalytic hydrotreatment of fast pyrolysis liquids in batch and continuous set-ups using a bimetallic Ni–Cu catalyst with a high metal content

In this paper, the effects of process conditions on catalyst performance and product properties are reported in both batch and continuous set-ups.

Comparative theoretical study of formic acid decomposition on PtAg(111) and Pt(111) surfaces

This theoretical study compares the catalytic decomposition pathways of HCOOH on pure Pt surface with the ideal single-atom model catalyst of PtAg nanostructures.

Reexamination of formic acid decomposition on the Pt(111) surface both in the absence and in the presence of water, from periodic DFT calculations

The calculated results in literatures for the decomposition of formic acid on Pt(111) into CO cannot rationalize the well-known easy CO poisoning of Pt-based catalysts.