Catalysis

Engineering

Electrochemistry

Metallurgy

Materials science

Cyclic voltammetry

Layer (electronics)

Transition metal

Inorganic chemistry

Chemical engineering

Physical chemistry

Nanotechnology

Organic chemistry

Chronoamperometry

Thin film

Chemistry

Electrode

Nitride

Nickel

Electrolyte

Sputtering

Platinum

ACS Applied Materials & Interfaces

With promising activity and stability for the oxygen reduction reaction (ORR), transition metal nitrides are an interesting class of non-platinum group catalysts for polymer electrolyte membrane fuel cells. Here, we report an active thin-film nickel nitride catalyst synthesized through a reactive sputtering method. In rotating disk electrode testing in a 0.1 M HClO4 electrolyte, the crystalline nickel nitride film achieved high activity and selectivity to four-electron ORR. It also exhibited good stability during 10 and 40 h chronoamperometry measurements in acid and alkaline electrolyte, respectively. A combined experiment-theory approach, with detailed ex situ materials characterization and density functional theory calculations, provides insight into the structure of the catalyst and its surface during catalysis. Design strategies for activity and stability improvement through alloying and nanostructuring are discussed.

Precious Metal-Free Nickel Nitride Catalyst for the Oxygen Reduction Reaction