Fe-doped Ni0.85Se nanospheres interspersed into carbon nanotubes as efficient and stable electrocatalyst for overall water splitting

Developing and preparation of stable and efficient non-noble metal electrocatalysts is vital for overall wa-ter splitting. Herein, a series of Fe-doped Ni0.85Se (FexNi0.85-xSe, x = 0.02, 0.04, 0.05, 0.06, 0.08, 0.1, 0.15, 0.2, 0.3 and 0.4) catalysts are synthesized successfully by one-step hydrothermal method and studied as high active bifunctional catalyst for oxygen evolution reaction (OER) and hydrogen evolution reac-tion (HER) in electrolysis water splitting. The results indicates that a suitable doping can make different metal ions have a synergistic effect and improve catalytic performance. The optimal Fe0.08Ni0.77Se sam-ple shows excellent OER and HER activities. Subsequently, the introduction of carbon nanotubes (CNTs) forming Fe0.08Ni0.77Se/CNT composite further enhances the electrocatalytic activity due to high electric conductivity of carbon nanotubes network. The resulted Fe0.08Ni0.77Se/CNT3 composite exhibits smaller overpotential of 204 mV and 108 mV at a current density of 10 mA cm(-2) and a low Tafel slope of 58 mV dec(-1) and 59 mV dec(-1) than that of other composites for OER and HER, respectively. The results demon-strate that Fe0.08Ni0.77Se/CNT3 is an excellent bifunctional catalyst, providing a promising candidate for electrocatalytic water splitting. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The study successfully synthesized a series of Fe-doped Ni0.85Se catalysts using hydrothermal method and found that appropriate doping can improve catalytic performance. The optimized Fe0.08Ni0.77Se sample exhibited excellent OER and HER activities. The introduction of carbon nanotubes forming Fe0.08Ni0.77Se/CNT composite further enhanced the electrocatalytic activity.