One-Pot Synthesis of NiCo2S4 Hollow Spheres via Sequential Ion-Exchange as an Enhanced Oxygen Bifunctional Electrocatalyst in Alkaline Solution

Xueting Feng, Qingze Jiao, Huiru Cui, Mengmeng Yin, Qun Li, Yun Zhao, Hansheng Li, Wei Zhou, Caihong Feng*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

119 Citations (Scopus)

Abstract

The oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are considered to be cornerstones of many energy conversion and storage technologies. It is difficult studying high-performance nonprecious materials as cost-effective bifunctional electrocatalysts for both the OER and ORR in future practical applications. In this study, NiCo2S4 hollow spheres (NiCo2S4 HSs) were fabricated via an effective and facile one-pot "green" approach in an N,N-dimethylformamide-ethylene glycol binary solution. The obtained NiCo2S4 HSs had a high specific surface area as well as numerous active sites and showed a remarkable catalytic performance and durability toward both the OER and ORR in an alkaline electrolyte. For the ORR, NiCo2S4 HSs exhibited a positive half-wave potential of 0.80 V and demonstrated outstanding stability and enhanced methanol tolerance. For the OER, NiCo2S4 HSs presented a low overpotential (400 mV) at a current density of 10 mA cm-2, small Tafel slope, and excellent stability in 0.1 M KOH. Moreover, regarding the overall electrocatalytic activity, the potential difference of NiCo2S4 HSs was 0.83 V, surpassing that of NiCo2S4 nanoparticles, binary counterparts (CoS, NiS), and most highly active bifunctional catalysts described in the literature. The superior catalytic performance of NiCo2S4 HSs is mainly ascribed to its unique hollow structure, which increases molecular diffusion and adsorption, as well as the synergistic effect of Ni and Co, which offers richer redox reaction sites. Importantly, this strategy may facilitate the design and preparation of excellent bifunctional nonprecious metal electrocatalysts in various domains.

Original languageEnglish
Pages (from-to)29521-29531
Number of pages11
JournalACS applied materials & interfaces
Volume10
Issue number35
DOIs
Publication statusPublished - 5 Sept 2018

Keywords

  • NiCoS HSs
  • alkaline electrolyte
  • nonprecious metal electrocatalysts
  • oxygen evolution reaction
  • oxygen reduction reaction

Fingerprint

Dive into the research topics of 'One-Pot Synthesis of NiCo2S4 Hollow Spheres via Sequential Ion-Exchange as an Enhanced Oxygen Bifunctional Electrocatalyst in Alkaline Solution'. Together they form a unique fingerprint.

Cite this