Self-templated Prussian blue analogue for efficient and robust electrochemical water oxidation

Abstract

The development of high-performance and robust catalysts with low-cost is the major demand for electrochemical water oxidation. Here, a unique and facile method is reported for the synthesis of NiFe alloy derived from templated Prussian blue analogues (PBAs) on carbon cloth, exhibiting excellent water oxidation activity and stability in alkaline solution. The best water oxidation activity is obtained with O-NiFe@C-600, in which overpotential of 250 mV is required for generating water oxidation current density of 10 mA cm−2 and overpotential of 300 mV was needed for affording 100 mA cm−2. In addition, outstanding long-term stability over 25 h in chronoamperometric measurements was achieved for O-NiFe@C-600. The catalysts considerably outperform the activity and stability of the other PBA derived catalysts and even the noble metal catalysts RuO2. The excellent performance is attributable to unique self-supported structures of the PBA-derived NiFe catalysts on carbon cloth as well as the incorporation of reactive oxygen species (ROS) by in-situ O2 plasma activation which further increases the number of active sites for water oxidation. Additionally, well-defined graphitized cells largely enhances stability of the catalyst by acting as chemical protective layers.