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 water splitting. Herein, a series of Fe-doped Ni 0.85 Se (Fe x Ni 0.85-x Se, 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 reaction (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 Fe 0.08 Ni 0.77 Se sample shows excellent OER and HER activities. Subsequently, the introduction of carbon nanotubes (CNTs) forming Fe 0.08 Ni 0.77 Se/CNT composite further enhances the electrocatalytic activity due to high electric conductivity of carbon nanotubes network. The resulted Fe 0.08 Ni 0.77 Se/CNT 3 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 demonstrate that Fe 0.08 Ni 0.77 Se/CNT 3 is an excellent bifunctional catalyst, providing a promising candidate for electrocatalytic water splitting .