Palladium cobalt alloy encapsulated in carbon nanofibers as bifunctional electrocatalyst for high-efficiency overall hydrazine splitting

Abstract

Electrolytic water splitting is a promising strategy to generate clean hydrogen energy but still restricted by the sluggish kinetics during the anodic oxygen evolution reaction (OER). A highly efficient route to significantlyreduce the cell voltage of electrolytic water splitting is to replace OER with hydrazine oxidation reaction (HzOR) so as to assist hydrogen generation effectively. Here, we report the fabrication of carbon nanofibers (CNFs) embedded with palladium cobalt (PdCo) alloy nanoparticles, via an electrospinning followed by a carbonization treatment. The as-synthesized PdCo-CNFs catalyst displays a superior electrocatalytic activity toward HzOR with a working potential of 258 mV (vs. RHE) to drive a current density of 50 mA cm−2 in an alkaline solution with 0.2 M hydrazine. Furthermore, the favorable hydrogen evolution reaction (HER) activity of this catalyst enables it highly efficient electrolytic hydrogen production, and the two-electrode system using PdCo-CNFs as both the cathode and anode for overall hydrazine splitting is capable of delivering a cell voltage of 0.440 V to attain 10 mA cm−2, which is 1.496 V less than that for pure water splitting using the same electrodes and even 0.459 V less than the overall hydrazine splitting device using Pt/C//RuO2 as electrocatalysts. This work provides a reliable way for the fabrication of promising bifunctional electrocatalysts to promote energy-saving hydrogen production for practical applications.