Electrocatalytic Mechanisms in Direct Borohydride Fuel Cells

Direct borohydride fuel cells (DBFCs) represent a class of electrochemical energy converters in which sodium borohydride (NaBH₄) undergoes anodic oxidation to release electrons and hydrogen species, while a suitable oxidant is reduced at the cathode. The anodic reaction ideally proceeds through an eight-electron transfer per BH₄⁻ ion, yielding water and borate by-products. However, partial hydrolysis to hydrogen and lower-electron pathways can occur, affecting utilisation and power density. Electrocatalysts at the anode surface play a pivotal role in directing the reaction pathway, enhancing kinetics and suppressing undesired side reactions such as hydrogen evolution. Transition-metal catalysts, notably palladium- and nickel-based materials, as well as gold and silver nanostructures, have been studied for their ability to modulate adsorption energies, reaction intermediates and local pH. Advances in catalyst supports and membrane architectures seek to optimise mass transport, ionic conductivity and fuel crossover. Together, these developments aim to deliver scalable, high-energy-density systems for portable power, marine and aerospace applications, offering a carbon-free alternative with rapid refuelling and minimal environmental impact.

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Electrocatalytic Mechanisms in Direct Borohydride Fuel Cells publication trend

The graph below shows the total number of articles in electrocatalytic mechanisms in direct borohydride fuel cells across all publications each year (not limited to Nature Index journals).

Technical terms

Direct borohydride fuel cell (DBFC): An electrochemical device in which borohydride ions are oxidised at the anode and an oxidant (often hydrogen peroxide or oxygen) is reduced at the cathode to generate electrical power.

Borohydride oxidation reaction (BOR): The multi-electron electrochemical process by which BH₄⁻ is converted into reaction products (water, borate species) at the anode, ideally involving eight electrons per molecule.

Ionomer: A polymer containing charged functional groups (anion-exchange or cation-exchange) used to bind catalyst particles, facilitate ionic conduction and influence local pH in the electrode layer.

Apparent activation energy: The effective energy barrier for an electrochemical reaction measured under specific conditions, reflecting the sensitivity of the reaction rate to temperature.

References

1. Selective Borohydride Oxidation Reaction on Nickel Catalyst with Anion and Cation Exchange Ionomer for High‐Performance Direct Borohydride Fuel Cells. Advanced Energy Materials (2022).
2. High-performance metal (Au,Cu)–polypyrrole nanocomposites for electrochemical borohydride oxidation in fuel cell applications. International Journal of Hydrogen Energy (2022).
3. Ionic Liquid-Derived Carbon-Supported Metal Electrocatalysts as Anodes in Direct Borohydride-Peroxide Fuel Cells. Catalysts (2021).