Efficient precious-metal free bifunctional electrocatalyst for overall water splitting
The research into developing cost-effective and active catalyst materials that can replace the precious-metal-based benchmarks for electrocatalytic water splitting as well as for large-scale utilisation has been intense. Some reported that encapsulation of transition metals (TMs) inside nitrogen doped graphitic carbon (NC) showe a great potential in improving the electrocatalytic performances of the obtained catalyst materials. Albeit some noticeable achievements with these composites in separate OER or HER, few of them can function well toward both reactions for an ehanced overall water splitting due to associated distinctive reaction stepas as well as intermediates.
Herein, for the first time, we reported the preparation of an ultrathin Fe-N-C nanosheet encapsulated Fe-doped CoNi alloy nanoparticles (FeCoNi@FeNC) composite thorugh a facile and scaleable preparation method. The local electronic structure of the carbon cage is simultaneously tuned by the Fe dopant and the encapsulated FeCoNi nanoparticles, resulting in synergistic effects that are beneficial for catalysing both OER and HER. The two electrode elecrolyzer using the FeCoNi@FeNC composite exhibits a current density of 12 mA/cm2 at a potential of 1.63V. This strategy provided a reasonable way toward the rational design of versatile electrocatalysts with low cost and high catalytic activity.