Nanomanufacturing of Non-Noble Amorphous Alloys for Electrocatalysis

There is a strong surge in interest for hydrogen and direct alcohol fuel cells as zero-emission energy conversion and storage devices due to their high energy density compared to that for batteries and super-capacitors. However, the critical bottleneck in the widespread adoption of fuel cell technology is the high cost of electrocatalysts used in these devices, which may be lowered by minimizing the noble-metal loading and improving their performance. To that end, alloy catalysts have been developed, which incorporate a broad range of nonprecious transition metals and nonmetals. However, such alloys are limited by their phase stability range and are susceptible to poisoning and performance degradation over time. A potential escape from such limitations is provided by amorphous alloys, which can give access to a much broader composition range of favorable chemistry while exhibiting exceptional chemical stability and durability. This potential of broad chemistry is, however, often limited when the amorphous alloy is fabricated by melt quenching. To overcome this limitation, we introduce a facile pulsed electrodeposition approach to synthesize metallic glass nanowire arrays for two-model alloy systems. This highly practical nanomanufacturing route allows the synthesis of fully amorphous nanowires for alloys with little or no noble-metal content, which exhibit excellent performance in terms of electrocatalytic activity and stability toward electro-oxidation of methanol. Density of states calculated using first-principles show strong d-orbital contributions to the states at the Fermi level and electron localization on the surface of the amorphous alloys accounting for their high catalytic activity.