Spinous α-Fe2O3 hierarchical structures anchored on Ni foam for supercapacitor electrodes and visible light driven photocatalysts

Abstract

Spinous α-Fe₂O₃ hierarchical structures grown on a Ni foam substrate have been successfully obtained by a facile one-step hydrothermal method. The prepared products are functionalized as supercapacitor electrodes without adding any ancillary materials such as carbon black or binders. Their electrochemical properties show a high discharge areal capacitance (681 mF cm⁻² at 1 mA cm⁻²), good rate performance (495 mF cm⁻² at 5 mA cm⁻²) and long-term cycling stability (23.9% loss after 6000 repetitive cycles at 1 mA cm⁻²). Such excellent supercapacitive characteristics could be mainly attributed to their unique spatial structures which provide many active sites and enhance the combination between the electrode and Ni foam to support fast ion and electron transfer. In addition, the prepared α-Fe₂O₃ product is also used as a photocatalyst for the photocatalytic degradation of several harmful organic dyes under visible light illumination. By comparing the photocatalytic performance towards Congo red dye with other photocatalysts, it was observed that the prepared spinous α-Fe₂O₃ hierarchical structure exhibited superior photocatalytic performance. Finally, photocatalytic recycle tests showed the superiority of the prepared α-Fe₂O₃ product. This demonstrates that spinous α-Fe₂O₃ structures could be promising candidate materials for high-capacity, low-cost supercapacitor electrodes and environmentally friendly photocatalysts.