Electrocatalytic Oxidation Mechanisms of Formic Acid

The electrocatalytic oxidation of formic acid has emerged as a pivotal reaction for direct formic acid fuel cells and sustainable energy conversion systems. Mechanistically, the process bifurcates into a direct dehydrogenation pathway—where formic acid is oxidised straight to carbon dioxide with minimal surface‐bound intermediates—and an indirect pathway that generates adsorbed carbon monoxide species, leading to catalyst poisoning and performance loss. Central to enhancing activity and durability is the design of catalysts that promote the direct route, suppress CO adsorption and facilitate rapid charge transfer. Palladium and platinum‐based materials remain the benchmark, yet advances in alloying, shape engineering, support interactions and single‐atom strategies have yielded major improvements. Key factors include the tuning of the metal d-band via electronic effects, the use of oxophilic components to supply oxygen species for intermediate removal and the exploitation of atomic ensembles or bifunctional sites to lower overpotential and accelerate reaction kinetics. Nanostructuring—through porous architectures, high-index facets and hollow morphologies—further optimises mass transport and maximises exposed active surface area. Collectively, these insights are shaping the future of high-performance formic acid electrooxidation.

Research from Nature Portfolio

In a seminal study, polyhedral palladium–silver alloy nanocrystals were synthesised by a controlled hydrothermal route to examine synergistic effects in formic acid oxidation. The introduction of silver atoms modulates the electronic structure of palladium, weakening the binding of poisoning intermediates and steering the reaction towards the direct dehydrogenation pathway. The uniform polyhedral shape affords high-index facets that enhance activity, while alloy stability under cycling demonstrates the durability of tailored bimetallic ensembles. This foundational work established that precise alloy composition and morphology can fundamentally alter oxidation mechanisms to yield both high activity and robust performance.

Electrocatalytic Oxidation Mechanisms of Formic Acid publication trend

The graph below shows the total number of articles in electrocatalytic oxidation mechanisms of formic acid across all publications each year (not limited to Nature Index journals).

Technical terms

Electrocatalytic oxidation: An electrochemical process in which a catalyst lowers the activation energy for substrate oxidation under applied potential.

Direct pathway: A reaction route where formic acid is oxidised directly to CO₂ without forming strongly bound intermediates.

Indirect pathway: A route involving the formation of adsorbed CO intermediates, which can poison the catalyst surface.

Bifunctional mechanism: A catalytic concept in which two distinct sites or components cooperate to activate reactants or remove intermediates.

Single-atom catalyst: A material in which isolated metal atoms are anchored on a support, maximising atomic efficiency and site homogeneity.

References

1. Polyhedral Palladium–Silver Alloy Nanocrystals as Highly Active and Stable Electrocatalysts for the Formic Acid Oxidation Reaction. Scientific Reports (2015).
2. Porous palladium phosphide nanotubes for formic acid electrooxidation. Carbon Energy (2022).
3. Catalyst Electrodes with PtCu Nanowire Arrays In Situ Grown on Gas Diffusion Layers for Direct Formic Acid Fuel Cells. ACS Applied Materials & Interfaces (2022).
4. Hollow Carbon Nanorod Confined Single Atom Rh for Direct Formic Acid Electrooxidation. Advanced Science (2022).