Plasma-Assisted Synthesis of Metal Nitrides for an Efficient Platinum-Group-Metal-Free Anion-Exchange-Membrane Fuel Cell.

Abstract

In comparison to the well-developed proton-exchange-membrane fuel cells, anion-exchange-membrane fuel cells (AEMFCs) permit adoption of platinum-group-metal (PGM)-free catalysts due to the alkaline environment, giving a substantial cost reduction. However, previous AEMFCs have generally shown unsatisfactory performances due to the lack of effective PGM-free catalysts that can endure harsh fuel cell conditions. Here we report a plasma-assisted synthesis of high-quality nickel nitride (Ni3N) and zirconium nitride (ZrN) employing dinitrogen as the nitrogen resource, exhibiting exceptional catalytic performances toward hydrogen oxidation and oxygen reduction in an alkaline enviroment, respectively. A PGM-free AEMFC assembled by using Ni3N as the anode and ZrN as the cathode delivers power densities of 256 mW cm-2 under an H2-O2 condition and 151 mW cm-2 under an H2-air condition. Furthermore, the fuel cell shows no evidence of degradation after 25 h of operation. This work creates opportunities for developing high-performance and durable AEMFCs based on metal nitrides.