Ultra-thin NiFeSe nanosheets as a highly efficient bifunctional electrocatalyst for overall water splitting

Developing a bifunctional electrocatalyst with a facile method, low cost, excellent performance and good stability for overall water splitting is essential for the wide application of hydrogen production. The present work fabricated an efficient bifunctional electrocatalyst based on NiFeSe nanosheets via a simple one-step hydrothermal method. The interaction of iron and selenium during the hydrothermal process leads to the formation of NiFeSe nanosheets with an ultra-thin structure on nickel foam, and the synergistic effect among the multiple elements offers excellent catalytic performance. The influence of NiFeSe composition on the micro-structure and electrocatalytic activity was systematically investigated. The results showed that ultra-thin NiFe10Se10 with a nanosheet structure exhibits the best OER and HER activity with low overpotentials of 199 mV and 154 mV to afford a current density of 10 mA cm−2, respectively. A current density of 10 mA cm−2 will be achieved at a low cell voltage of 1.61 V when NiFe10Se10 is applied as both the anode and cathode during the overall water electrolysis.