Hierarchically nanostructured (Ni,Co)phosphides for hydrazine electrooxidation

Transition metal phosphides are intriguing but less well investigated electrocatalytic materials for potential application in the direct hydrazine fuel cell (DHFC). Herein, we present a systematic study of hierarchically nanostructured (Ni,Co)phosphides for hydrazine electrooxidation reaction (HzOR). A series of nickel foam (NF) supported (Ni,Co)phosphides featured with an urchin-like structure were fabricated using a hydrothermal method followed by reductive calcination and phosphatization treatments. Our study revealed the composition dependences of phase structure and catalytic properties of (Ni,Co)phosphides for HzOR. In general, incorporation of Co into NixP catalyst leads to improvement of HzOR activity, but causes an aggravation of non-faradaic hydrazine decomposition. Among the examined series, NiCoP/NF exhibits the highest activity for HzOR via the 4-electron pathway, outperforming the top-notch HzOR electrocatalysts hitherto reported. But its performance in suppressing non-faradaic hydrazine decomposition was inferior to that of NixP catalyst. Our study demonstrated the great potential as well as the challenge in developing (Ni,Co)phosphides as high-performance anode electrocatalysts of DHFC. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The study revealed that nickel-cobalt phosphides have high catalytic activity for hydrazine electrooxidation, outperforming previously reported electrocatalysts, but they also face challenges in suppressing non-faradaic hydrazine decomposition.